// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2012 Alexander Block. All rights reserved. */ #include <linux/bsearch.h> #include <linux/fs.h> #include <linux/file.h> #include <linux/sort.h> #include <linux/mount.h> #include <linux/xattr.h> #include <linux/posix_acl_xattr.h> #include <linux/radix-tree.h> #include <linux/vmalloc.h> #include <linux/string.h> #include <linux/compat.h> #include <linux/crc32c.h> #include "send.h" #include "backref.h" #include "locking.h" #include "disk-io.h" #include "btrfs_inode.h" #include "transaction.h" #include "compression.h" #include "xattr.h" /* * Maximum number of references an extent can have in order for us to attempt to * issue clone operations instead of write operations. This currently exists to * avoid hitting limitations of the backreference walking code (taking a lot of * time and using too much memory for extents with large number of references). */ #define SEND_MAX_EXTENT_REFS 64 /* * A fs_path is a helper to dynamically build path names with unknown size. * It reallocates the internal buffer on demand. * It allows fast adding of path elements on the right side (normal path) and * fast adding to the left side (reversed path). A reversed path can also be * unreversed if needed. */ struct fs_path { union { struct { char *start; char *end; char *buf; unsigned short buf_len:15; unsigned short reversed:1; char inline_buf[]; }; /* * Average path length does not exceed 200 bytes, we'll have * better packing in the slab and higher chance to satisfy * a allocation later during send. */ char pad[256]; }; }; #define FS_PATH_INLINE_SIZE \ (sizeof(struct fs_path) - offsetof(struct fs_path, inline_buf)) /* reused for each extent */ struct clone_root { struct btrfs_root *root; u64 ino; u64 offset; u64 found_refs; }; #define SEND_CTX_MAX_NAME_CACHE_SIZE 128 #define SEND_CTX_NAME_CACHE_CLEAN_SIZE (SEND_CTX_MAX_NAME_CACHE_SIZE * 2) struct send_ctx { struct file *send_filp; loff_t send_off; char *send_buf; u32 send_size; u32 send_max_size; u64 total_send_size; u64 cmd_send_size[BTRFS_SEND_C_MAX + 1]; u64 flags; /* 'flags' member of btrfs_ioctl_send_args is u64 */ struct btrfs_root *send_root; struct btrfs_root *parent_root; struct clone_root *clone_roots; int clone_roots_cnt; /* current state of the compare_tree call */ struct btrfs_path *left_path; struct btrfs_path *right_path; struct btrfs_key *cmp_key; /* * infos of the currently processed inode. In case of deleted inodes, * these are the values from the deleted inode. */ u64 cur_ino; u64 cur_inode_gen; int cur_inode_new; int cur_inode_new_gen; int cur_inode_deleted; u64 cur_inode_size; u64 cur_inode_mode; u64 cur_inode_rdev; u64 cur_inode_last_extent; u64 cur_inode_next_write_offset; bool ignore_cur_inode; u64 send_progress; struct list_head new_refs; struct list_head deleted_refs; struct radix_tree_root name_cache; struct list_head name_cache_list; int name_cache_size; struct file_ra_state ra; /* * We process inodes by their increasing order, so if before an * incremental send we reverse the parent/child relationship of * directories such that a directory with a lower inode number was * the parent of a directory with a higher inode number, and the one * becoming the new parent got renamed too, we can't rename/move the * directory with lower inode number when we finish processing it - we * must process the directory with higher inode number first, then * rename/move it and then rename/move the directory with lower inode * number. Example follows. * * Tree state when the first send was performed: * * . * |-- a (ino 257) * |-- b (ino 258) * | * | * |-- c (ino 259) * | |-- d (ino 260) * | * |-- c2 (ino 261) * * Tree state when the second (incremental) send is performed: * * . * |-- a (ino 257) * |-- b (ino 258) * |-- c2 (ino 261) * |-- d2 (ino 260) * |-- cc (ino 259) * * The sequence of steps that lead to the second state was: * * mv /a/b/c/d /a/b/c2/d2 * mv /a/b/c /a/b/c2/d2/cc * * "c" has lower inode number, but we can't move it (2nd mv operation) * before we move "d", which has higher inode number. * * So we just memorize which move/rename operations must be performed * later when their respective parent is processed and moved/renamed. */ /* Indexed by parent directory inode number. */ struct rb_root pending_dir_moves; /* * Reverse index, indexed by the inode number of a directory that * is waiting for the move/rename of its immediate parent before its * own move/rename can be performed. */ struct rb_root waiting_dir_moves; /* * A directory that is going to be rm'ed might have a child directory * which is in the pending directory moves index above. In this case, * the directory can only be removed after the move/rename of its child * is performed. Example: * * Parent snapshot: * * . (ino 256) * |-- a/ (ino 257) * |-- b/ (ino 258) * |-- c/ (ino 259) * | |-- x/ (ino 260) * | * |-- y/ (ino 261) * * Send snapshot: * * . (ino 256) * |-- a/ (ino 257) * |-- b/ (ino 258) * |-- YY/ (ino 261) * |-- x/ (ino 260) * * Sequence of steps that lead to the send snapshot: * rm -f /a/b/c/foo.txt * mv /a/b/y /a/b/YY * mv /a/b/c/x /a/b/YY * rmdir /a/b/c * * When the child is processed, its move/rename is delayed until its * parent is processed (as explained above), but all other operations * like update utimes, chown, chgrp, etc, are performed and the paths * that it uses for those operations must use the orphanized name of * its parent (the directory we're going to rm later), so we need to * memorize that name. * * Indexed by the inode number of the directory to be deleted. */ struct rb_root orphan_dirs; }; struct pending_dir_move { struct rb_node node; struct list_head list; u64 parent_ino; u64 ino; u64 gen; struct list_head update_refs; }; struct waiting_dir_move { struct rb_node node; u64 ino; /* * There might be some directory that could not be removed because it * was waiting for this directory inode to be moved first. Therefore * after this directory is moved, we can try to rmdir the ino rmdir_ino. */ u64 rmdir_ino; u64 rmdir_gen; bool orphanized; }; struct orphan_dir_info { struct rb_node node; u64 ino; u64 gen; u64 last_dir_index_offset; }; struct name_cache_entry { struct list_head list; /* * radix_tree has only 32bit entries but we need to handle 64bit inums. * We use the lower 32bit of the 64bit inum to store it in the tree. If * more then one inum would fall into the same entry, we use radix_list * to store the additional entries. radix_list is also used to store * entries where two entries have the same inum but different * generations. */ struct list_head radix_list; u64 ino; u64 gen; u64 parent_ino; u64 parent_gen; int ret; int need_later_update; int name_len; char name[]; }; #define ADVANCE 1 #define ADVANCE_ONLY_NEXT -1 enum btrfs_compare_tree_result { BTRFS_COMPARE_TREE_NEW, BTRFS_COMPARE_TREE_DELETED, BTRFS_COMPARE_TREE_CHANGED, BTRFS_COMPARE_TREE_SAME, }; __cold static void inconsistent_snapshot_error(struct send_ctx *sctx, enum btrfs_compare_tree_result result, const char *what) { const char *result_string; switch (result) { case BTRFS_COMPARE_TREE_NEW: result_string = "new"; break; case BTRFS_COMPARE_TREE_DELETED: result_string = "deleted"; break; case BTRFS_COMPARE_TREE_CHANGED: result_string = "updated"; break; case BTRFS_COMPARE_TREE_SAME: ASSERT(0); result_string = "unchanged"; break; default: ASSERT(0); result_string = "unexpected"; } btrfs_err(sctx->send_root->fs_info, "Send: inconsistent snapshot, found %s %s for inode %llu without updated inode item, send root is %llu, parent root is %llu", result_string, what, sctx->cmp_key->objectid, sctx->send_root->root_key.objectid, (sctx->parent_root ? sctx->parent_root->root_key.objectid : 0)); } static int is_waiting_for_move(struct send_ctx *sctx, u64 ino); static struct waiting_dir_move * get_waiting_dir_move(struct send_ctx *sctx, u64 ino); static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino, u64 gen); static int need_send_hole(struct send_ctx *sctx) { return (sctx->parent_root && !sctx->cur_inode_new && !sctx->cur_inode_new_gen && !sctx->cur_inode_deleted && S_ISREG(sctx->cur_inode_mode)); } static void fs_path_reset(struct fs_path *p) { if (p->reversed) { p->start = p->buf + p->buf_len - 1; p->end = p->start; *p->start = 0; } else { p->start = p->buf; p->end = p->start; *p->start = 0; } } static struct fs_path *fs_path_alloc(void) { struct fs_path *p; p = kmalloc(sizeof(*p), GFP_KERNEL); if (!p) return NULL; p->reversed = 0; p->buf = p->inline_buf; p->buf_len = FS_PATH_INLINE_SIZE; fs_path_reset(p); return p; } static struct fs_path *fs_path_alloc_reversed(void) { struct fs_path *p; p = fs_path_alloc(); if (!p) return NULL; p->reversed = 1; fs_path_reset(p); return p; } static void fs_path_free(struct fs_path *p) { if (!p) return; if (p->buf != p->inline_buf) kfree(p->buf); kfree(p); } static int fs_path_len(struct fs_path *p) { return p->end - p->start; } static int fs_path_ensure_buf(struct fs_path *p, int len) { char *tmp_buf; int path_len; int old_buf_len; len++; if (p->buf_len >= len) return 0; if (len > PATH_MAX) { WARN_ON(1); return -ENOMEM; } path_len = p->end - p->start; old_buf_len = p->buf_len; /* * First time the inline_buf does not suffice */ if (p->buf == p->inline_buf) { tmp_buf = kmalloc(len, GFP_KERNEL); if (tmp_buf) memcpy(tmp_buf, p->buf, old_buf_len); } else { tmp_buf = krealloc(p->buf, len, GFP_KERNEL); } if (!tmp_buf) return -ENOMEM; p->buf = tmp_buf; /* * The real size of the buffer is bigger, this will let the fast path * happen most of the time */ p->buf_len = ksize(p->buf); if (p->reversed) { tmp_buf = p->buf + old_buf_len - path_len - 1; p->end = p->buf + p->buf_len - 1; p->start = p->end - path_len; memmove(p->start, tmp_buf, path_len + 1); } else { p->start = p->buf; p->end = p->start + path_len; } return 0; } static int fs_path_prepare_for_add(struct fs_path *p, int name_len, char **prepared) { int ret; int new_len; new_len = p->end - p->start + name_len; if (p->start != p->end) new_len++; ret = fs_path_ensure_buf(p, new_len); if (ret < 0) goto out; if (p->reversed) { if (p->start != p->end) *--p->start = '/'; p->start -= name_len; *prepared = p->start; } else { if (p->start != p->end) *p->end++ = '/'; *prepared = p->end; p->end += name_len; *p->end = 0; } out: return ret; } static int fs_path_add(struct fs_path *p, const char *name, int name_len) { int ret; char *prepared; ret = fs_path_prepare_for_add(p, name_len, &prepared); if (ret < 0) goto out; memcpy(prepared, name, name_len); out: return ret; } static int fs_path_add_path(struct fs_path *p, struct fs_path *p2) { int ret; char *prepared; ret = fs_path_prepare_for_add(p, p2->end - p2->start, &prepared); if (ret < 0) goto out; memcpy(prepared, p2->start, p2->end - p2->start); out: return ret; } static int fs_path_add_from_extent_buffer(struct fs_path *p, struct extent_buffer *eb, unsigned long off, int len) { int ret; char *prepared; ret = fs_path_prepare_for_add(p, len, &prepared); if (ret < 0) goto out; read_extent_buffer(eb, prepared, off, len); out: return ret; } static int fs_path_copy(struct fs_path *p, struct fs_path *from) { int ret; p->reversed = from->reversed; fs_path_reset(p); ret = fs_path_add_path(p, from); return ret; } static void fs_path_unreverse(struct fs_path *p) { char *tmp; int len; if (!p->reversed) return; tmp = p->start; len = p->end - p->start; p->start = p->buf; p->end = p->start + len; memmove(p->start, tmp, len + 1); p->reversed = 0; } static struct btrfs_path *alloc_path_for_send(void) { struct btrfs_path *path; path = btrfs_alloc_path(); if (!path) return NULL; path->search_commit_root = 1; path->skip_locking = 1; path->need_commit_sem = 1; return path; } static int write_buf(struct file *filp, const void *buf, u32 len, loff_t *off) { int ret; u32 pos = 0; while (pos < len) { ret = kernel_write(filp, buf + pos, len - pos, off); /* TODO handle that correctly */ /*if (ret == -ERESTARTSYS) { continue; }*/ if (ret < 0) return ret; if (ret == 0) { return -EIO; } pos += ret; } return 0; } static int tlv_put(struct send_ctx *sctx, u16 attr, const void *data, int len) { struct btrfs_tlv_header *hdr; int total_len = sizeof(*hdr) + len; int left = sctx->send_max_size - sctx->send_size; if (unlikely(left < total_len)) return -EOVERFLOW; hdr = (struct btrfs_tlv_header *) (sctx->send_buf + sctx->send_size); put_unaligned_le16(attr, &hdr->tlv_type); put_unaligned_le16(len, &hdr->tlv_len); memcpy(hdr + 1, data, len); sctx->send_size += total_len; return 0; } #define TLV_PUT_DEFINE_INT(bits) \ static int tlv_put_u##bits(struct send_ctx *sctx, \ u##bits attr, u##bits value) \ { \ __le##bits __tmp = cpu_to_le##bits(value); \ return tlv_put(sctx, attr, &__tmp, sizeof(__tmp)); \ } TLV_PUT_DEFINE_INT(64) static int tlv_put_string(struct send_ctx *sctx, u16 attr, const char *str, int len) { if (len == -1) len = strlen(str); return tlv_put(sctx, attr, str, len); } static int tlv_put_uuid(struct send_ctx *sctx, u16 attr, const u8 *uuid) { return tlv_put(sctx, attr, uuid, BTRFS_UUID_SIZE); } static int tlv_put_btrfs_timespec(struct send_ctx *sctx, u16 attr, struct extent_buffer *eb, struct btrfs_timespec *ts) { struct btrfs_timespec bts; read_extent_buffer(eb, &bts, (unsigned long)ts, sizeof(bts)); return tlv_put(sctx, attr, &bts, sizeof(bts)); } #define TLV_PUT(sctx, attrtype, data, attrlen) \ do { \ ret = tlv_put(sctx, attrtype, data, attrlen); \ if (ret < 0) \ goto tlv_put_failure; \ } while (0) #define TLV_PUT_INT(sctx, attrtype, bits, value) \ do { \ ret = tlv_put_u##bits(sctx, attrtype, value); \ if (ret < 0) \ goto tlv_put_failure; \ } while (0) #define TLV_PUT_U8(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 8, data) #define TLV_PUT_U16(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 16, data) #define TLV_PUT_U32(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 32, data) #define TLV_PUT_U64(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 64, data) #define TLV_PUT_STRING(sctx, attrtype, str, len) \ do { \ ret = tlv_put_string(sctx, attrtype, str, len); \ if (ret < 0) \ goto tlv_put_failure; \ } while (0) #define TLV_PUT_PATH(sctx, attrtype, p) \ do { \ ret = tlv_put_string(sctx, attrtype, p->start, \ p->end - p->start); \ if (ret < 0) \ goto tlv_put_failure; \ } while(0) #define TLV_PUT_UUID(sctx, attrtype, uuid) \ do { \ ret = tlv_put_uuid(sctx, attrtype, uuid); \ if (ret < 0) \ goto tlv_put_failure; \ } while (0) #define TLV_PUT_BTRFS_TIMESPEC(sctx, attrtype, eb, ts) \ do { \ ret = tlv_put_btrfs_timespec(sctx, attrtype, eb, ts); \ if (ret < 0) \ goto tlv_put_failure; \ } while (0) static int send_header(struct send_ctx *sctx) { struct btrfs_stream_header hdr; strcpy(hdr.magic, BTRFS_SEND_STREAM_MAGIC); hdr.version = cpu_to_le32(BTRFS_SEND_STREAM_VERSION); return write_buf(sctx->send_filp, &hdr, sizeof(hdr), &sctx->send_off); } /* * For each command/item we want to send to userspace, we call this function. */ static int begin_cmd(struct send_ctx *sctx, int cmd) { struct btrfs_cmd_header *hdr; if (WARN_ON(!sctx->send_buf)) return -EINVAL; BUG_ON(sctx->send_size); sctx->send_size += sizeof(*hdr); hdr = (struct btrfs_cmd_header *)sctx->send_buf; put_unaligned_le16(cmd, &hdr->cmd); return 0; } static int send_cmd(struct send_ctx *sctx) { int ret; struct btrfs_cmd_header *hdr; u32 crc; hdr = (struct btrfs_cmd_header *)sctx->send_buf; put_unaligned_le32(sctx->send_size - sizeof(*hdr), &hdr->len); put_unaligned_le32(0, &hdr->crc); crc = btrfs_crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size); put_unaligned_le32(crc, &hdr->crc); ret = write_buf(sctx->send_filp, sctx->send_buf, sctx->send_size, &sctx->send_off); sctx->total_send_size += sctx->send_size; sctx->cmd_send_size[get_unaligned_le16(&hdr->cmd)] += sctx->send_size; sctx->send_size = 0; return ret; } /* * Sends a move instruction to user space */ static int send_rename(struct send_ctx *sctx, struct fs_path *from, struct fs_path *to) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret; btrfs_debug(fs_info, "send_rename %s -> %s", from->start, to->start); ret = begin_cmd(sctx, BTRFS_SEND_C_RENAME); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, from); TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_TO, to); ret = send_cmd(sctx); tlv_put_failure: out: return ret; } /* * Sends a link instruction to user space */ static int send_link(struct send_ctx *sctx, struct fs_path *path, struct fs_path *lnk) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret; btrfs_debug(fs_info, "send_link %s -> %s", path->start, lnk->start); ret = begin_cmd(sctx, BTRFS_SEND_C_LINK); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, lnk); ret = send_cmd(sctx); tlv_put_failure: out: return ret; } /* * Sends an unlink instruction to user space */ static int send_unlink(struct send_ctx *sctx, struct fs_path *path) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret; btrfs_debug(fs_info, "send_unlink %s", path->start); ret = begin_cmd(sctx, BTRFS_SEND_C_UNLINK); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); ret = send_cmd(sctx); tlv_put_failure: out: return ret; } /* * Sends a rmdir instruction to user space */ static int send_rmdir(struct send_ctx *sctx, struct fs_path *path) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret; btrfs_debug(fs_info, "send_rmdir %s", path->start); ret = begin_cmd(sctx, BTRFS_SEND_C_RMDIR); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); ret = send_cmd(sctx); tlv_put_failure: out: return ret; } /* * Helper function to retrieve some fields from an inode item. */ static int __get_inode_info(struct btrfs_root *root, struct btrfs_path *path, u64 ino, u64 *size, u64 *gen, u64 *mode, u64 *uid, u64 *gid, u64 *rdev) { int ret; struct btrfs_inode_item *ii; struct btrfs_key key; key.objectid = ino; key.type = BTRFS_INODE_ITEM_KEY; key.offset = 0; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret) { if (ret > 0) ret = -ENOENT; return ret; } ii = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_inode_item); if (size) *size = btrfs_inode_size(path->nodes[0], ii); if (gen) *gen = btrfs_inode_generation(path->nodes[0], ii); if (mode) *mode = btrfs_inode_mode(path->nodes[0], ii); if (uid) *uid = btrfs_inode_uid(path->nodes[0], ii); if (gid) *gid = btrfs_inode_gid(path->nodes[0], ii); if (rdev) *rdev = btrfs_inode_rdev(path->nodes[0], ii); return ret; } static int get_inode_info(struct btrfs_root *root, u64 ino, u64 *size, u64 *gen, u64 *mode, u64 *uid, u64 *gid, u64 *rdev) { struct btrfs_path *path; int ret; path = alloc_path_for_send(); if (!path) return -ENOMEM; ret = __get_inode_info(root, path, ino, size, gen, mode, uid, gid, rdev); btrfs_free_path(path); return ret; } typedef int (*iterate_inode_ref_t)(int num, u64 dir, int index, struct fs_path *p, void *ctx); /* * Helper function to iterate the entries in ONE btrfs_inode_ref or * btrfs_inode_extref. * The iterate callback may return a non zero value to stop iteration. This can * be a negative value for error codes or 1 to simply stop it. * * path must point to the INODE_REF or INODE_EXTREF when called. */ static int iterate_inode_ref(struct btrfs_root *root, struct btrfs_path *path, struct btrfs_key *found_key, int resolve, iterate_inode_ref_t iterate, void *ctx) { struct extent_buffer *eb = path->nodes[0]; struct btrfs_item *item; struct btrfs_inode_ref *iref; struct btrfs_inode_extref *extref; struct btrfs_path *tmp_path; struct fs_path *p; u32 cur = 0; u32 total; int slot = path->slots[0]; u32 name_len; char *start; int ret = 0; int num = 0; int index; u64 dir; unsigned long name_off; unsigned long elem_size; unsigned long ptr; p = fs_path_alloc_reversed(); if (!p) return -ENOMEM; tmp_path = alloc_path_for_send(); if (!tmp_path) { fs_path_free(p); return -ENOMEM; } if (found_key->type == BTRFS_INODE_REF_KEY) { ptr = (unsigned long)btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); item = btrfs_item_nr(slot); total = btrfs_item_size(eb, item); elem_size = sizeof(*iref); } else { ptr = btrfs_item_ptr_offset(eb, slot); total = btrfs_item_size_nr(eb, slot); elem_size = sizeof(*extref); } while (cur < total) { fs_path_reset(p); if (found_key->type == BTRFS_INODE_REF_KEY) { iref = (struct btrfs_inode_ref *)(ptr + cur); name_len = btrfs_inode_ref_name_len(eb, iref); name_off = (unsigned long)(iref + 1); index = btrfs_inode_ref_index(eb, iref); dir = found_key->offset; } else { extref = (struct btrfs_inode_extref *)(ptr + cur); name_len = btrfs_inode_extref_name_len(eb, extref); name_off = (unsigned long)&extref->name; index = btrfs_inode_extref_index(eb, extref); dir = btrfs_inode_extref_parent(eb, extref); } if (resolve) { start = btrfs_ref_to_path(root, tmp_path, name_len, name_off, eb, dir, p->buf, p->buf_len); if (IS_ERR(start)) { ret = PTR_ERR(start); goto out; } if (start < p->buf) { /* overflow , try again with larger buffer */ ret = fs_path_ensure_buf(p, p->buf_len + p->buf - start); if (ret < 0) goto out; start = btrfs_ref_to_path(root, tmp_path, name_len, name_off, eb, dir, p->buf, p->buf_len); if (IS_ERR(start)) { ret = PTR_ERR(start); goto out; } BUG_ON(start < p->buf); } p->start = start; } else { ret = fs_path_add_from_extent_buffer(p, eb, name_off, name_len); if (ret < 0) goto out; } cur += elem_size + name_len; ret = iterate(num, dir, index, p, ctx); if (ret) goto out; num++; } out: btrfs_free_path(tmp_path); fs_path_free(p); return ret; } typedef int (*iterate_dir_item_t)(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, u8 type, void *ctx); /* * Helper function to iterate the entries in ONE btrfs_dir_item. * The iterate callback may return a non zero value to stop iteration. This can * be a negative value for error codes or 1 to simply stop it. * * path must point to the dir item when called. */ static int iterate_dir_item(struct btrfs_root *root, struct btrfs_path *path, iterate_dir_item_t iterate, void *ctx) { int ret = 0; struct extent_buffer *eb; struct btrfs_item *item; struct btrfs_dir_item *di; struct btrfs_key di_key; char *buf = NULL; int buf_len; u32 name_len; u32 data_len; u32 cur; u32 len; u32 total; int slot; int num; u8 type; /* * Start with a small buffer (1 page). If later we end up needing more * space, which can happen for xattrs on a fs with a leaf size greater * then the page size, attempt to increase the buffer. Typically xattr * values are small. */ buf_len = PATH_MAX; buf = kmalloc(buf_len, GFP_KERNEL); if (!buf) { ret = -ENOMEM; goto out; } eb = path->nodes[0]; slot = path->slots[0]; item = btrfs_item_nr(slot); di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item); cur = 0; len = 0; total = btrfs_item_size(eb, item); num = 0; while (cur < total) { name_len = btrfs_dir_name_len(eb, di); data_len = btrfs_dir_data_len(eb, di); type = btrfs_dir_type(eb, di); btrfs_dir_item_key_to_cpu(eb, di, &di_key); if (type == BTRFS_FT_XATTR) { if (name_len > XATTR_NAME_MAX) { ret = -ENAMETOOLONG; goto out; } if (name_len + data_len > BTRFS_MAX_XATTR_SIZE(root->fs_info)) { ret = -E2BIG; goto out; } } else { /* * Path too long */ if (name_len + data_len > PATH_MAX) { ret = -ENAMETOOLONG; goto out; } } if (name_len + data_len > buf_len) { buf_len = name_len + data_len; if (is_vmalloc_addr(buf)) { vfree(buf); buf = NULL; } else { char *tmp = krealloc(buf, buf_len, GFP_KERNEL | __GFP_NOWARN); if (!tmp) kfree(buf); buf = tmp; } if (!buf) { buf = kvmalloc(buf_len, GFP_KERNEL); if (!buf) { ret = -ENOMEM; goto out; } } } read_extent_buffer(eb, buf, (unsigned long)(di + 1), name_len + data_len); len = sizeof(*di) + name_len + data_len; di = (struct btrfs_dir_item *)((char *)di + len); cur += len; ret = iterate(num, &di_key, buf, name_len, buf + name_len, data_len, type, ctx); if (ret < 0) goto out; if (ret) { ret = 0; goto out; } num++; } out: kvfree(buf); return ret; } static int __copy_first_ref(int num, u64 dir, int index, struct fs_path *p, void *ctx) { int ret; struct fs_path *pt = ctx; ret = fs_path_copy(pt, p); if (ret < 0) return ret; /* we want the first only */ return 1; } /* * Retrieve the first path of an inode. If an inode has more then one * ref/hardlink, this is ignored. */ static int get_inode_path(struct btrfs_root *root, u64 ino, struct fs_path *path) { int ret; struct btrfs_key key, found_key; struct btrfs_path *p; p = alloc_path_for_send(); if (!p) return -ENOMEM; fs_path_reset(path); key.objectid = ino; key.type = BTRFS_INODE_REF_KEY; key.offset = 0; ret = btrfs_search_slot_for_read(root, &key, p, 1, 0); if (ret < 0) goto out; if (ret) { ret = 1; goto out; } btrfs_item_key_to_cpu(p->nodes[0], &found_key, p->slots[0]); if (found_key.objectid != ino || (found_key.type != BTRFS_INODE_REF_KEY && found_key.type != BTRFS_INODE_EXTREF_KEY)) { ret = -ENOENT; goto out; } ret = iterate_inode_ref(root, p, &found_key, 1, __copy_first_ref, path); if (ret < 0) goto out; ret = 0; out: btrfs_free_path(p); return ret; } struct backref_ctx { struct send_ctx *sctx; /* number of total found references */ u64 found; /* * used for clones found in send_root. clones found behind cur_objectid * and cur_offset are not considered as allowed clones. */ u64 cur_objectid; u64 cur_offset; /* may be truncated in case it's the last extent in a file */ u64 extent_len; /* data offset in the file extent item */ u64 data_offset; /* Just to check for bugs in backref resolving */ int found_itself; }; static int __clone_root_cmp_bsearch(const void *key, const void *elt) { u64 root = (u64)(uintptr_t)key; struct clone_root *cr = (struct clone_root *)elt; if (root < cr->root->root_key.objectid) return -1; if (root > cr->root->root_key.objectid) return 1; return 0; } static int __clone_root_cmp_sort(const void *e1, const void *e2) { struct clone_root *cr1 = (struct clone_root *)e1; struct clone_root *cr2 = (struct clone_root *)e2; if (cr1->root->root_key.objectid < cr2->root->root_key.objectid) return -1; if (cr1->root->root_key.objectid > cr2->root->root_key.objectid) return 1; return 0; } /* * Called for every backref that is found for the current extent. * Results are collected in sctx->clone_roots->ino/offset/found_refs */ static int __iterate_backrefs(u64 ino, u64 offset, u64 root, void *ctx_) { struct backref_ctx *bctx = ctx_; struct clone_root *found; /* First check if the root is in the list of accepted clone sources */ found = bsearch((void *)(uintptr_t)root, bctx->sctx->clone_roots, bctx->sctx->clone_roots_cnt, sizeof(struct clone_root), __clone_root_cmp_bsearch); if (!found) return 0; if (found->root == bctx->sctx->send_root && ino == bctx->cur_objectid && offset == bctx->cur_offset) { bctx->found_itself = 1; } /* * Make sure we don't consider clones from send_root that are * behind the current inode/offset. */ if (found->root == bctx->sctx->send_root) { /* * If the source inode was not yet processed we can't issue a * clone operation, as the source extent does not exist yet at * the destination of the stream. */ if (ino > bctx->cur_objectid) return 0; /* * We clone from the inode currently being sent as long as the * source extent is already processed, otherwise we could try * to clone from an extent that does not exist yet at the * destination of the stream. */ if (ino == bctx->cur_objectid && offset + bctx->extent_len > bctx->sctx->cur_inode_next_write_offset) return 0; } bctx->found++; found->found_refs++; if (ino < found->ino) { found->ino = ino; found->offset = offset; } else if (found->ino == ino) { /* * same extent found more then once in the same file. */ if (found->offset > offset + bctx->extent_len) found->offset = offset; } return 0; } /* * Given an inode, offset and extent item, it finds a good clone for a clone * instruction. Returns -ENOENT when none could be found. The function makes * sure that the returned clone is usable at the point where sending is at the * moment. This means, that no clones are accepted which lie behind the current * inode+offset. * * path must point to the extent item when called. */ static int find_extent_clone(struct send_ctx *sctx, struct btrfs_path *path, u64 ino, u64 data_offset, u64 ino_size, struct clone_root **found) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret; int extent_type; u64 logical; u64 disk_byte; u64 num_bytes; u64 extent_item_pos; u64 flags = 0; struct btrfs_file_extent_item *fi; struct extent_buffer *eb = path->nodes[0]; struct backref_ctx *backref_ctx = NULL; struct clone_root *cur_clone_root; struct btrfs_key found_key; struct btrfs_path *tmp_path; struct btrfs_extent_item *ei; int compressed; u32 i; tmp_path = alloc_path_for_send(); if (!tmp_path) return -ENOMEM; /* We only use this path under the commit sem */ tmp_path->need_commit_sem = 0; backref_ctx = kmalloc(sizeof(*backref_ctx), GFP_KERNEL); if (!backref_ctx) { ret = -ENOMEM; goto out; } if (data_offset >= ino_size) { /* * There may be extents that lie behind the file's size. * I at least had this in combination with snapshotting while * writing large files. */ ret = 0; goto out; } fi = btrfs_item_ptr(eb, path->slots[0], struct btrfs_file_extent_item); extent_type = btrfs_file_extent_type(eb, fi); if (extent_type == BTRFS_FILE_EXTENT_INLINE) { ret = -ENOENT; goto out; } compressed = btrfs_file_extent_compression(eb, fi); num_bytes = btrfs_file_extent_num_bytes(eb, fi); disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); if (disk_byte == 0) { ret = -ENOENT; goto out; } logical = disk_byte + btrfs_file_extent_offset(eb, fi); down_read(&fs_info->commit_root_sem); ret = extent_from_logical(fs_info, disk_byte, tmp_path, &found_key, &flags); up_read(&fs_info->commit_root_sem); if (ret < 0) goto out; if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { ret = -EIO; goto out; } ei = btrfs_item_ptr(tmp_path->nodes[0], tmp_path->slots[0], struct btrfs_extent_item); /* * Backreference walking (iterate_extent_inodes() below) is currently * too expensive when an extent has a large number of references, both * in time spent and used memory. So for now just fallback to write * operations instead of clone operations when an extent has more than * a certain amount of references. */ if (btrfs_extent_refs(tmp_path->nodes[0], ei) > SEND_MAX_EXTENT_REFS) { ret = -ENOENT; goto out; } btrfs_release_path(tmp_path); /* * Setup the clone roots. */ for (i = 0; i < sctx->clone_roots_cnt; i++) { cur_clone_root = sctx->clone_roots + i; cur_clone_root->ino = (u64)-1; cur_clone_root->offset = 0; cur_clone_root->found_refs = 0; } backref_ctx->sctx = sctx; backref_ctx->found = 0; backref_ctx->cur_objectid = ino; backref_ctx->cur_offset = data_offset; backref_ctx->found_itself = 0; backref_ctx->extent_len = num_bytes; /* * For non-compressed extents iterate_extent_inodes() gives us extent * offsets that already take into account the data offset, but not for * compressed extents, since the offset is logical and not relative to * the physical extent locations. We must take this into account to * avoid sending clone offsets that go beyond the source file's size, * which would result in the clone ioctl failing with -EINVAL on the * receiving end. */ if (compressed == BTRFS_COMPRESS_NONE) backref_ctx->data_offset = 0; else backref_ctx->data_offset = btrfs_file_extent_offset(eb, fi); /* * The last extent of a file may be too large due to page alignment. * We need to adjust extent_len in this case so that the checks in * __iterate_backrefs work. */ if (data_offset + num_bytes >= ino_size) backref_ctx->extent_len = ino_size - data_offset; /* * Now collect all backrefs. */ if (compressed == BTRFS_COMPRESS_NONE) extent_item_pos = logical - found_key.objectid; else extent_item_pos = 0; ret = iterate_extent_inodes(fs_info, found_key.objectid, extent_item_pos, 1, __iterate_backrefs, backref_ctx, false); if (ret < 0) goto out; if (!backref_ctx->found_itself) { /* found a bug in backref code? */ ret = -EIO; btrfs_err(fs_info, "did not find backref in send_root. inode=%llu, offset=%llu, disk_byte=%llu found extent=%llu", ino, data_offset, disk_byte, found_key.objectid); goto out; } btrfs_debug(fs_info, "find_extent_clone: data_offset=%llu, ino=%llu, num_bytes=%llu, logical=%llu", data_offset, ino, num_bytes, logical); if (!backref_ctx->found) btrfs_debug(fs_info, "no clones found"); cur_clone_root = NULL; for (i = 0; i < sctx->clone_roots_cnt; i++) { if (sctx->clone_roots[i].found_refs) { if (!cur_clone_root) cur_clone_root = sctx->clone_roots + i; else if (sctx->clone_roots[i].root == sctx->send_root) /* prefer clones from send_root over others */ cur_clone_root = sctx->clone_roots + i; } } if (cur_clone_root) { *found = cur_clone_root; ret = 0; } else { ret = -ENOENT; } out: btrfs_free_path(tmp_path); kfree(backref_ctx); return ret; } static int read_symlink(struct btrfs_root *root, u64 ino, struct fs_path *dest) { int ret; struct btrfs_path *path; struct btrfs_key key; struct btrfs_file_extent_item *ei; u8 type; u8 compression; unsigned long off; int len; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = ino; key.type = BTRFS_EXTENT_DATA_KEY; key.offset = 0; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; if (ret) { /* * An empty symlink inode. Can happen in rare error paths when * creating a symlink (transaction committed before the inode * eviction handler removed the symlink inode items and a crash * happened in between or the subvol was snapshoted in between). * Print an informative message to dmesg/syslog so that the user * can delete the symlink. */ btrfs_err(root->fs_info, "Found empty symlink inode %llu at root %llu", ino, root->root_key.objectid); ret = -EIO; goto out; } ei = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_file_extent_item); type = btrfs_file_extent_type(path->nodes[0], ei); compression = btrfs_file_extent_compression(path->nodes[0], ei); BUG_ON(type != BTRFS_FILE_EXTENT_INLINE); BUG_ON(compression); off = btrfs_file_extent_inline_start(ei); len = btrfs_file_extent_ram_bytes(path->nodes[0], ei); ret = fs_path_add_from_extent_buffer(dest, path->nodes[0], off, len); out: btrfs_free_path(path); return ret; } /* * Helper function to generate a file name that is unique in the root of * send_root and parent_root. This is used to generate names for orphan inodes. */ static int gen_unique_name(struct send_ctx *sctx, u64 ino, u64 gen, struct fs_path *dest) { int ret = 0; struct btrfs_path *path; struct btrfs_dir_item *di; char tmp[64]; int len; u64 idx = 0; path = alloc_path_for_send(); if (!path) return -ENOMEM; while (1) { len = snprintf(tmp, sizeof(tmp), "o%llu-%llu-%llu", ino, gen, idx); ASSERT(len < sizeof(tmp)); di = btrfs_lookup_dir_item(NULL, sctx->send_root, path, BTRFS_FIRST_FREE_OBJECTID, tmp, strlen(tmp), 0); btrfs_release_path(path); if (IS_ERR(di)) { ret = PTR_ERR(di); goto out; } if (di) { /* not unique, try again */ idx++; continue; } if (!sctx->parent_root) { /* unique */ ret = 0; break; } di = btrfs_lookup_dir_item(NULL, sctx->parent_root, path, BTRFS_FIRST_FREE_OBJECTID, tmp, strlen(tmp), 0); btrfs_release_path(path); if (IS_ERR(di)) { ret = PTR_ERR(di); goto out; } if (di) { /* not unique, try again */ idx++; continue; } /* unique */ break; } ret = fs_path_add(dest, tmp, strlen(tmp)); out: btrfs_free_path(path); return ret; } enum inode_state { inode_state_no_change, inode_state_will_create, inode_state_did_create, inode_state_will_delete, inode_state_did_delete, }; static int get_cur_inode_state(struct send_ctx *sctx, u64 ino, u64 gen) { int ret; int left_ret; int right_ret; u64 left_gen; u64 right_gen; ret = get_inode_info(sctx->send_root, ino, NULL, &left_gen, NULL, NULL, NULL, NULL); if (ret < 0 && ret != -ENOENT) goto out; left_ret = ret; if (!sctx->parent_root) { right_ret = -ENOENT; } else { ret = get_inode_info(sctx->parent_root, ino, NULL, &right_gen, NULL, NULL, NULL, NULL); if (ret < 0 && ret != -ENOENT) goto out; right_ret = ret; } if (!left_ret && !right_ret) { if (left_gen == gen && right_gen == gen) { ret = inode_state_no_change; } else if (left_gen == gen) { if (ino < sctx->send_progress) ret = inode_state_did_create; else ret = inode_state_will_create; } else if (right_gen == gen) { if (ino < sctx->send_progress) ret = inode_state_did_delete; else ret = inode_state_will_delete; } else { ret = -ENOENT; } } else if (!left_ret) { if (left_gen == gen) { if (ino < sctx->send_progress) ret = inode_state_did_create; else ret = inode_state_will_create; } else { ret = -ENOENT; } } else if (!right_ret) { if (right_gen == gen) { if (ino < sctx->send_progress) ret = inode_state_did_delete; else ret = inode_state_will_delete; } else { ret = -ENOENT; } } else { ret = -ENOENT; } out: return ret; } static int is_inode_existent(struct send_ctx *sctx, u64 ino, u64 gen) { int ret; if (ino == BTRFS_FIRST_FREE_OBJECTID) return 1; ret = get_cur_inode_state(sctx, ino, gen); if (ret < 0) goto out; if (ret == inode_state_no_change || ret == inode_state_did_create || ret == inode_state_will_delete) ret = 1; else ret = 0; out: return ret; } /* * Helper function to lookup a dir item in a dir. */ static int lookup_dir_item_inode(struct btrfs_root *root, u64 dir, const char *name, int name_len, u64 *found_inode, u8 *found_type) { int ret = 0; struct btrfs_dir_item *di; struct btrfs_key key; struct btrfs_path *path; path = alloc_path_for_send(); if (!path) return -ENOMEM; di = btrfs_lookup_dir_item(NULL, root, path, dir, name, name_len, 0); if (IS_ERR_OR_NULL(di)) { ret = di ? PTR_ERR(di) : -ENOENT; goto out; } btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key); if (key.type == BTRFS_ROOT_ITEM_KEY) { ret = -ENOENT; goto out; } *found_inode = key.objectid; *found_type = btrfs_dir_type(path->nodes[0], di); out: btrfs_free_path(path); return ret; } /* * Looks up the first btrfs_inode_ref of a given ino. It returns the parent dir, * generation of the parent dir and the name of the dir entry. */ static int get_first_ref(struct btrfs_root *root, u64 ino, u64 *dir, u64 *dir_gen, struct fs_path *name) { int ret; struct btrfs_key key; struct btrfs_key found_key; struct btrfs_path *path; int len; u64 parent_dir; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = ino; key.type = BTRFS_INODE_REF_KEY; key.offset = 0; ret = btrfs_search_slot_for_read(root, &key, path, 1, 0); if (ret < 0) goto out; if (!ret) btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]); if (ret || found_key.objectid != ino || (found_key.type != BTRFS_INODE_REF_KEY && found_key.type != BTRFS_INODE_EXTREF_KEY)) { ret = -ENOENT; goto out; } if (found_key.type == BTRFS_INODE_REF_KEY) { struct btrfs_inode_ref *iref; iref = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_inode_ref); len = btrfs_inode_ref_name_len(path->nodes[0], iref); ret = fs_path_add_from_extent_buffer(name, path->nodes[0], (unsigned long)(iref + 1), len); parent_dir = found_key.offset; } else { struct btrfs_inode_extref *extref; extref = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_inode_extref); len = btrfs_inode_extref_name_len(path->nodes[0], extref); ret = fs_path_add_from_extent_buffer(name, path->nodes[0], (unsigned long)&extref->name, len); parent_dir = btrfs_inode_extref_parent(path->nodes[0], extref); } if (ret < 0) goto out; btrfs_release_path(path); if (dir_gen) { ret = get_inode_info(root, parent_dir, NULL, dir_gen, NULL, NULL, NULL, NULL); if (ret < 0) goto out; } *dir = parent_dir; out: btrfs_free_path(path); return ret; } static int is_first_ref(struct btrfs_root *root, u64 ino, u64 dir, const char *name, int name_len) { int ret; struct fs_path *tmp_name; u64 tmp_dir; tmp_name = fs_path_alloc(); if (!tmp_name) return -ENOMEM; ret = get_first_ref(root, ino, &tmp_dir, NULL, tmp_name); if (ret < 0) goto out; if (dir != tmp_dir || name_len != fs_path_len(tmp_name)) { ret = 0; goto out; } ret = !memcmp(tmp_name->start, name, name_len); out: fs_path_free(tmp_name); return ret; } /* * Used by process_recorded_refs to determine if a new ref would overwrite an * already existing ref. In case it detects an overwrite, it returns the * inode/gen in who_ino/who_gen. * When an overwrite is detected, process_recorded_refs does proper orphanizing * to make sure later references to the overwritten inode are possible. * Orphanizing is however only required for the first ref of an inode. * process_recorded_refs does an additional is_first_ref check to see if * orphanizing is really required. */ static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen, const char *name, int name_len, u64 *who_ino, u64 *who_gen, u64 *who_mode) { int ret = 0; u64 gen; u64 other_inode = 0; u8 other_type = 0; if (!sctx->parent_root) goto out; ret = is_inode_existent(sctx, dir, dir_gen); if (ret <= 0) goto out; /* * If we have a parent root we need to verify that the parent dir was * not deleted and then re-created, if it was then we have no overwrite * and we can just unlink this entry. */ if (sctx->parent_root && dir != BTRFS_FIRST_FREE_OBJECTID) { ret = get_inode_info(sctx->parent_root, dir, NULL, &gen, NULL, NULL, NULL, NULL); if (ret < 0 && ret != -ENOENT) goto out; if (ret) { ret = 0; goto out; } if (gen != dir_gen) goto out; } ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len, &other_inode, &other_type); if (ret < 0 && ret != -ENOENT) goto out; if (ret) { ret = 0; goto out; } /* * Check if the overwritten ref was already processed. If yes, the ref * was already unlinked/moved, so we can safely assume that we will not * overwrite anything at this point in time. */ if (other_inode > sctx->send_progress || is_waiting_for_move(sctx, other_inode)) { ret = get_inode_info(sctx->parent_root, other_inode, NULL, who_gen, who_mode, NULL, NULL, NULL); if (ret < 0) goto out; ret = 1; *who_ino = other_inode; } else { ret = 0; } out: return ret; } /* * Checks if the ref was overwritten by an already processed inode. This is * used by __get_cur_name_and_parent to find out if the ref was orphanized and * thus the orphan name needs be used. * process_recorded_refs also uses it to avoid unlinking of refs that were * overwritten. */ static int did_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen, u64 ino, u64 ino_gen, const char *name, int name_len) { int ret = 0; u64 gen; u64 ow_inode; u8 other_type; if (!sctx->parent_root) goto out; ret = is_inode_existent(sctx, dir, dir_gen); if (ret <= 0) goto out; if (dir != BTRFS_FIRST_FREE_OBJECTID) { ret = get_inode_info(sctx->send_root, dir, NULL, &gen, NULL, NULL, NULL, NULL); if (ret < 0 && ret != -ENOENT) goto out; if (ret) { ret = 0; goto out; } if (gen != dir_gen) goto out; } /* check if the ref was overwritten by another ref */ ret = lookup_dir_item_inode(sctx->send_root, dir, name, name_len, &ow_inode, &other_type); if (ret < 0 && ret != -ENOENT) goto out; if (ret) { /* was never and will never be overwritten */ ret = 0; goto out; } ret = get_inode_info(sctx->send_root, ow_inode, NULL, &gen, NULL, NULL, NULL, NULL); if (ret < 0) goto out; if (ow_inode == ino && gen == ino_gen) { ret = 0; goto out; } /* * We know that it is or will be overwritten. Check this now. * The current inode being processed might have been the one that caused * inode 'ino' to be orphanized, therefore check if ow_inode matches * the current inode being processed. */ if ((ow_inode < sctx->send_progress) || (ino != sctx->cur_ino && ow_inode == sctx->cur_ino && gen == sctx->cur_inode_gen)) ret = 1; else ret = 0; out: return ret; } /* * Same as did_overwrite_ref, but also checks if it is the first ref of an inode * that got overwritten. This is used by process_recorded_refs to determine * if it has to use the path as returned by get_cur_path or the orphan name. */ static int did_overwrite_first_ref(struct send_ctx *sctx, u64 ino, u64 gen) { int ret = 0; struct fs_path *name = NULL; u64 dir; u64 dir_gen; if (!sctx->parent_root) goto out; name = fs_path_alloc(); if (!name) return -ENOMEM; ret = get_first_ref(sctx->parent_root, ino, &dir, &dir_gen, name); if (ret < 0) goto out; ret = did_overwrite_ref(sctx, dir, dir_gen, ino, gen, name->start, fs_path_len(name)); out: fs_path_free(name); return ret; } /* * Insert a name cache entry. On 32bit kernels the radix tree index is 32bit, * so we need to do some special handling in case we have clashes. This function * takes care of this with the help of name_cache_entry::radix_list. * In case of error, nce is kfreed. */ static int name_cache_insert(struct send_ctx *sctx, struct name_cache_entry *nce) { int ret = 0; struct list_head *nce_head; nce_head = radix_tree_lookup(&sctx->name_cache, (unsigned long)nce->ino); if (!nce_head) { nce_head = kmalloc(sizeof(*nce_head), GFP_KERNEL); if (!nce_head) { kfree(nce); return -ENOMEM; } INIT_LIST_HEAD(nce_head); ret = radix_tree_insert(&sctx->name_cache, nce->ino, nce_head); if (ret < 0) { kfree(nce_head); kfree(nce); return ret; } } list_add_tail(&nce->radix_list, nce_head); list_add_tail(&nce->list, &sctx->name_cache_list); sctx->name_cache_size++; return ret; } static void name_cache_delete(struct send_ctx *sctx, struct name_cache_entry *nce) { struct list_head *nce_head; nce_head = radix_tree_lookup(&sctx->name_cache, (unsigned long)nce->ino); if (!nce_head) { btrfs_err(sctx->send_root->fs_info, "name_cache_delete lookup failed ino %llu cache size %d, leaking memory", nce->ino, sctx->name_cache_size); } list_del(&nce->radix_list); list_del(&nce->list); sctx->name_cache_size--; /* * We may not get to the final release of nce_head if the lookup fails */ if (nce_head && list_empty(nce_head)) { radix_tree_delete(&sctx->name_cache, (unsigned long)nce->ino); kfree(nce_head); } } static struct name_cache_entry *name_cache_search(struct send_ctx *sctx, u64 ino, u64 gen) { struct list_head *nce_head; struct name_cache_entry *cur; nce_head = radix_tree_lookup(&sctx->name_cache, (unsigned long)ino); if (!nce_head) return NULL; list_for_each_entry(cur, nce_head, radix_list) { if (cur->ino == ino && cur->gen == gen) return cur; } return NULL; } /* * Removes the entry from the list and adds it back to the end. This marks the * entry as recently used so that name_cache_clean_unused does not remove it. */ static void name_cache_used(struct send_ctx *sctx, struct name_cache_entry *nce) { list_del(&nce->list); list_add_tail(&nce->list, &sctx->name_cache_list); } /* * Remove some entries from the beginning of name_cache_list. */ static void name_cache_clean_unused(struct send_ctx *sctx) { struct name_cache_entry *nce; if (sctx->name_cache_size < SEND_CTX_NAME_CACHE_CLEAN_SIZE) return; while (sctx->name_cache_size > SEND_CTX_MAX_NAME_CACHE_SIZE) { nce = list_entry(sctx->name_cache_list.next, struct name_cache_entry, list); name_cache_delete(sctx, nce); kfree(nce); } } static void name_cache_free(struct send_ctx *sctx) { struct name_cache_entry *nce; while (!list_empty(&sctx->name_cache_list)) { nce = list_entry(sctx->name_cache_list.next, struct name_cache_entry, list); name_cache_delete(sctx, nce); kfree(nce); } } /* * Used by get_cur_path for each ref up to the root. * Returns 0 if it succeeded. * Returns 1 if the inode is not existent or got overwritten. In that case, the * name is an orphan name. This instructs get_cur_path to stop iterating. If 1 * is returned, parent_ino/parent_gen are not guaranteed to be valid. * Returns <0 in case of error. */ static int __get_cur_name_and_parent(struct send_ctx *sctx, u64 ino, u64 gen, u64 *parent_ino, u64 *parent_gen, struct fs_path *dest) { int ret; int nce_ret; struct name_cache_entry *nce = NULL; /* * First check if we already did a call to this function with the same * ino/gen. If yes, check if the cache entry is still up-to-date. If yes * return the cached result. */ nce = name_cache_search(sctx, ino, gen); if (nce) { if (ino < sctx->send_progress && nce->need_later_update) { name_cache_delete(sctx, nce); kfree(nce); nce = NULL; } else { name_cache_used(sctx, nce); *parent_ino = nce->parent_ino; *parent_gen = nce->parent_gen; ret = fs_path_add(dest, nce->name, nce->name_len); if (ret < 0) goto out; ret = nce->ret; goto out; } } /* * If the inode is not existent yet, add the orphan name and return 1. * This should only happen for the parent dir that we determine in * __record_new_ref */ ret = is_inode_existent(sctx, ino, gen); if (ret < 0) goto out; if (!ret) { ret = gen_unique_name(sctx, ino, gen, dest); if (ret < 0) goto out; ret = 1; goto out_cache; } /* * Depending on whether the inode was already processed or not, use * send_root or parent_root for ref lookup. */ if (ino < sctx->send_progress) ret = get_first_ref(sctx->send_root, ino, parent_ino, parent_gen, dest); else ret = get_first_ref(sctx->parent_root, ino, parent_ino, parent_gen, dest); if (ret < 0) goto out; /* * Check if the ref was overwritten by an inode's ref that was processed * earlier. If yes, treat as orphan and return 1. */ ret = did_overwrite_ref(sctx, *parent_ino, *parent_gen, ino, gen, dest->start, dest->end - dest->start); if (ret < 0) goto out; if (ret) { fs_path_reset(dest); ret = gen_unique_name(sctx, ino, gen, dest); if (ret < 0) goto out; ret = 1; } out_cache: /* * Store the result of the lookup in the name cache. */ nce = kmalloc(sizeof(*nce) + fs_path_len(dest) + 1, GFP_KERNEL); if (!nce) { ret = -ENOMEM; goto out; } nce->ino = ino; nce->gen = gen; nce->parent_ino = *parent_ino; nce->parent_gen = *parent_gen; nce->name_len = fs_path_len(dest); nce->ret = ret; strcpy(nce->name, dest->start); if (ino < sctx->send_progress) nce->need_later_update = 0; else nce->need_later_update = 1; nce_ret = name_cache_insert(sctx, nce); if (nce_ret < 0) ret = nce_ret; name_cache_clean_unused(sctx); out: return ret; } /* * Magic happens here. This function returns the first ref to an inode as it * would look like while receiving the stream at this point in time. * We walk the path up to the root. For every inode in between, we check if it * was already processed/sent. If yes, we continue with the parent as found * in send_root. If not, we continue with the parent as found in parent_root. * If we encounter an inode that was deleted at this point in time, we use the * inodes "orphan" name instead of the real name and stop. Same with new inodes * that were not created yet and overwritten inodes/refs. * * When do we have orphan inodes: * 1. When an inode is freshly created and thus no valid refs are available yet * 2. When a directory lost all it's refs (deleted) but still has dir items * inside which were not processed yet (pending for move/delete). If anyone * tried to get the path to the dir items, it would get a path inside that * orphan directory. * 3. When an inode is moved around or gets new links, it may overwrite the ref * of an unprocessed inode. If in that case the first ref would be * overwritten, the overwritten inode gets "orphanized". Later when we * process this overwritten inode, it is restored at a new place by moving * the orphan inode. * * sctx->send_progress tells this function at which point in time receiving * would be. */ static int get_cur_path(struct send_ctx *sctx, u64 ino, u64 gen, struct fs_path *dest) { int ret = 0; struct fs_path *name = NULL; u64 parent_inode = 0; u64 parent_gen = 0; int stop = 0; name = fs_path_alloc(); if (!name) { ret = -ENOMEM; goto out; } dest->reversed = 1; fs_path_reset(dest); while (!stop && ino != BTRFS_FIRST_FREE_OBJECTID) { struct waiting_dir_move *wdm; fs_path_reset(name); if (is_waiting_for_rm(sctx, ino, gen)) { ret = gen_unique_name(sctx, ino, gen, name); if (ret < 0) goto out; ret = fs_path_add_path(dest, name); break; } wdm = get_waiting_dir_move(sctx, ino); if (wdm && wdm->orphanized) { ret = gen_unique_name(sctx, ino, gen, name); stop = 1; } else if (wdm) { ret = get_first_ref(sctx->parent_root, ino, &parent_inode, &parent_gen, name); } else { ret = __get_cur_name_and_parent(sctx, ino, gen, &parent_inode, &parent_gen, name); if (ret) stop = 1; } if (ret < 0) goto out; ret = fs_path_add_path(dest, name); if (ret < 0) goto out; ino = parent_inode; gen = parent_gen; } out: fs_path_free(name); if (!ret) fs_path_unreverse(dest); return ret; } /* * Sends a BTRFS_SEND_C_SUBVOL command/item to userspace */ static int send_subvol_begin(struct send_ctx *sctx) { int ret; struct btrfs_root *send_root = sctx->send_root; struct btrfs_root *parent_root = sctx->parent_root; struct btrfs_path *path; struct btrfs_key key; struct btrfs_root_ref *ref; struct extent_buffer *leaf; char *name = NULL; int namelen; path = btrfs_alloc_path(); if (!path) return -ENOMEM; name = kmalloc(BTRFS_PATH_NAME_MAX, GFP_KERNEL); if (!name) { btrfs_free_path(path); return -ENOMEM; } key.objectid = send_root->root_key.objectid; key.type = BTRFS_ROOT_BACKREF_KEY; key.offset = 0; ret = btrfs_search_slot_for_read(send_root->fs_info->tree_root, &key, path, 1, 0); if (ret < 0) goto out; if (ret) { ret = -ENOENT; goto out; } leaf = path->nodes[0]; btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); if (key.type != BTRFS_ROOT_BACKREF_KEY || key.objectid != send_root->root_key.objectid) { ret = -ENOENT; goto out; } ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref); namelen = btrfs_root_ref_name_len(leaf, ref); read_extent_buffer(leaf, name, (unsigned long)(ref + 1), namelen); btrfs_release_path(path); if (parent_root) { ret = begin_cmd(sctx, BTRFS_SEND_C_SNAPSHOT); if (ret < 0) goto out; } else { ret = begin_cmd(sctx, BTRFS_SEND_C_SUBVOL); if (ret < 0) goto out; } TLV_PUT_STRING(sctx, BTRFS_SEND_A_PATH, name, namelen); if (!btrfs_is_empty_uuid(sctx->send_root->root_item.received_uuid)) TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID, sctx->send_root->root_item.received_uuid); else TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID, sctx->send_root->root_item.uuid); TLV_PUT_U64(sctx, BTRFS_SEND_A_CTRANSID, btrfs_root_ctransid(&sctx->send_root->root_item)); if (parent_root) { if (!btrfs_is_empty_uuid(parent_root->root_item.received_uuid)) TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID, parent_root->root_item.received_uuid); else TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID, parent_root->root_item.uuid); TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID, btrfs_root_ctransid(&sctx->parent_root->root_item)); } ret = send_cmd(sctx); tlv_put_failure: out: btrfs_free_path(path); kfree(name); return ret; } static int send_truncate(struct send_ctx *sctx, u64 ino, u64 gen, u64 size) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct fs_path *p; btrfs_debug(fs_info, "send_truncate %llu size=%llu", ino, size); p = fs_path_alloc(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_TRUNCATE); if (ret < 0) goto out; ret = get_cur_path(sctx, ino, gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, size); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } static int send_chmod(struct send_ctx *sctx, u64 ino, u64 gen, u64 mode) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct fs_path *p; btrfs_debug(fs_info, "send_chmod %llu mode=%llu", ino, mode); p = fs_path_alloc(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_CHMOD); if (ret < 0) goto out; ret = get_cur_path(sctx, ino, gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode & 07777); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } static int send_chown(struct send_ctx *sctx, u64 ino, u64 gen, u64 uid, u64 gid) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct fs_path *p; btrfs_debug(fs_info, "send_chown %llu uid=%llu, gid=%llu", ino, uid, gid); p = fs_path_alloc(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_CHOWN); if (ret < 0) goto out; ret = get_cur_path(sctx, ino, gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_UID, uid); TLV_PUT_U64(sctx, BTRFS_SEND_A_GID, gid); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } static int send_utimes(struct send_ctx *sctx, u64 ino, u64 gen) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct fs_path *p = NULL; struct btrfs_inode_item *ii; struct btrfs_path *path = NULL; struct extent_buffer *eb; struct btrfs_key key; int slot; btrfs_debug(fs_info, "send_utimes %llu", ino); p = fs_path_alloc(); if (!p) return -ENOMEM; path = alloc_path_for_send(); if (!path) { ret = -ENOMEM; goto out; } key.objectid = ino; key.type = BTRFS_INODE_ITEM_KEY; key.offset = 0; ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0); if (ret > 0) ret = -ENOENT; if (ret < 0) goto out; eb = path->nodes[0]; slot = path->slots[0]; ii = btrfs_item_ptr(eb, slot, struct btrfs_inode_item); ret = begin_cmd(sctx, BTRFS_SEND_C_UTIMES); if (ret < 0) goto out; ret = get_cur_path(sctx, ino, gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_ATIME, eb, &ii->atime); TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_MTIME, eb, &ii->mtime); TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_CTIME, eb, &ii->ctime); /* TODO Add otime support when the otime patches get into upstream */ ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); btrfs_free_path(path); return ret; } /* * Sends a BTRFS_SEND_C_MKXXX or SYMLINK command to user space. We don't have * a valid path yet because we did not process the refs yet. So, the inode * is created as orphan. */ static int send_create_inode(struct send_ctx *sctx, u64 ino) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct fs_path *p; int cmd; u64 gen; u64 mode; u64 rdev; btrfs_debug(fs_info, "send_create_inode %llu", ino); p = fs_path_alloc(); if (!p) return -ENOMEM; if (ino != sctx->cur_ino) { ret = get_inode_info(sctx->send_root, ino, NULL, &gen, &mode, NULL, NULL, &rdev); if (ret < 0) goto out; } else { gen = sctx->cur_inode_gen; mode = sctx->cur_inode_mode; rdev = sctx->cur_inode_rdev; } if (S_ISREG(mode)) { cmd = BTRFS_SEND_C_MKFILE; } else if (S_ISDIR(mode)) { cmd = BTRFS_SEND_C_MKDIR; } else if (S_ISLNK(mode)) { cmd = BTRFS_SEND_C_SYMLINK; } else if (S_ISCHR(mode) || S_ISBLK(mode)) { cmd = BTRFS_SEND_C_MKNOD; } else if (S_ISFIFO(mode)) { cmd = BTRFS_SEND_C_MKFIFO; } else if (S_ISSOCK(mode)) { cmd = BTRFS_SEND_C_MKSOCK; } else { btrfs_warn(sctx->send_root->fs_info, "unexpected inode type %o", (int)(mode & S_IFMT)); ret = -EOPNOTSUPP; goto out; } ret = begin_cmd(sctx, cmd); if (ret < 0) goto out; ret = gen_unique_name(sctx, ino, gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_INO, ino); if (S_ISLNK(mode)) { fs_path_reset(p); ret = read_symlink(sctx->send_root, ino, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, p); } else if (S_ISCHR(mode) || S_ISBLK(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { TLV_PUT_U64(sctx, BTRFS_SEND_A_RDEV, new_encode_dev(rdev)); TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode); } ret = send_cmd(sctx); if (ret < 0) goto out; tlv_put_failure: out: fs_path_free(p); return ret; } /* * We need some special handling for inodes that get processed before the parent * directory got created. See process_recorded_refs for details. * This function does the check if we already created the dir out of order. */ static int did_create_dir(struct send_ctx *sctx, u64 dir) { int ret = 0; struct btrfs_path *path = NULL; struct btrfs_key key; struct btrfs_key found_key; struct btrfs_key di_key; struct extent_buffer *eb; struct btrfs_dir_item *di; int slot; path = alloc_path_for_send(); if (!path) { ret = -ENOMEM; goto out; } key.objectid = dir; key.type = BTRFS_DIR_INDEX_KEY; key.offset = 0; ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0); if (ret < 0) goto out; while (1) { eb = path->nodes[0]; slot = path->slots[0]; if (slot >= btrfs_header_nritems(eb)) { ret = btrfs_next_leaf(sctx->send_root, path); if (ret < 0) { goto out; } else if (ret > 0) { ret = 0; break; } continue; } btrfs_item_key_to_cpu(eb, &found_key, slot); if (found_key.objectid != key.objectid || found_key.type != key.type) { ret = 0; goto out; } di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item); btrfs_dir_item_key_to_cpu(eb, di, &di_key); if (di_key.type != BTRFS_ROOT_ITEM_KEY && di_key.objectid < sctx->send_progress) { ret = 1; goto out; } path->slots[0]++; } out: btrfs_free_path(path); return ret; } /* * Only creates the inode if it is: * 1. Not a directory * 2. Or a directory which was not created already due to out of order * directories. See did_create_dir and process_recorded_refs for details. */ static int send_create_inode_if_needed(struct send_ctx *sctx) { int ret; if (S_ISDIR(sctx->cur_inode_mode)) { ret = did_create_dir(sctx, sctx->cur_ino); if (ret < 0) goto out; if (ret) { ret = 0; goto out; } } ret = send_create_inode(sctx, sctx->cur_ino); if (ret < 0) goto out; out: return ret; } struct recorded_ref { struct list_head list; char *name; struct fs_path *full_path; u64 dir; u64 dir_gen; int name_len; }; static void set_ref_path(struct recorded_ref *ref, struct fs_path *path) { ref->full_path = path; ref->name = (char *)kbasename(ref->full_path->start); ref->name_len = ref->full_path->end - ref->name; } /* * We need to process new refs before deleted refs, but compare_tree gives us * everything mixed. So we first record all refs and later process them. * This function is a helper to record one ref. */ static int __record_ref(struct list_head *head, u64 dir, u64 dir_gen, struct fs_path *path) { struct recorded_ref *ref; ref = kmalloc(sizeof(*ref), GFP_KERNEL); if (!ref) return -ENOMEM; ref->dir = dir; ref->dir_gen = dir_gen; set_ref_path(ref, path); list_add_tail(&ref->list, head); return 0; } static int dup_ref(struct recorded_ref *ref, struct list_head *list) { struct recorded_ref *new; new = kmalloc(sizeof(*ref), GFP_KERNEL); if (!new) return -ENOMEM; new->dir = ref->dir; new->dir_gen = ref->dir_gen; new->full_path = NULL; INIT_LIST_HEAD(&new->list); list_add_tail(&new->list, list); return 0; } static void __free_recorded_refs(struct list_head *head) { struct recorded_ref *cur; while (!list_empty(head)) { cur = list_entry(head->next, struct recorded_ref, list); fs_path_free(cur->full_path); list_del(&cur->list); kfree(cur); } } static void free_recorded_refs(struct send_ctx *sctx) { __free_recorded_refs(&sctx->new_refs); __free_recorded_refs(&sctx->deleted_refs); } /* * Renames/moves a file/dir to its orphan name. Used when the first * ref of an unprocessed inode gets overwritten and for all non empty * directories. */ static int orphanize_inode(struct send_ctx *sctx, u64 ino, u64 gen, struct fs_path *path) { int ret; struct fs_path *orphan; orphan = fs_path_alloc(); if (!orphan) return -ENOMEM; ret = gen_unique_name(sctx, ino, gen, orphan); if (ret < 0) goto out; ret = send_rename(sctx, path, orphan); out: fs_path_free(orphan); return ret; } static struct orphan_dir_info *add_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino, u64 dir_gen) { struct rb_node **p = &sctx->orphan_dirs.rb_node; struct rb_node *parent = NULL; struct orphan_dir_info *entry, *odi; while (*p) { parent = *p; entry = rb_entry(parent, struct orphan_dir_info, node); if (dir_ino < entry->ino) p = &(*p)->rb_left; else if (dir_ino > entry->ino) p = &(*p)->rb_right; else if (dir_gen < entry->gen) p = &(*p)->rb_left; else if (dir_gen > entry->gen) p = &(*p)->rb_right; else return entry; } odi = kmalloc(sizeof(*odi), GFP_KERNEL); if (!odi) return ERR_PTR(-ENOMEM); odi->ino = dir_ino; odi->gen = dir_gen; odi->last_dir_index_offset = 0; rb_link_node(&odi->node, parent, p); rb_insert_color(&odi->node, &sctx->orphan_dirs); return odi; } static struct orphan_dir_info *get_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino, u64 gen) { struct rb_node *n = sctx->orphan_dirs.rb_node; struct orphan_dir_info *entry; while (n) { entry = rb_entry(n, struct orphan_dir_info, node); if (dir_ino < entry->ino) n = n->rb_left; else if (dir_ino > entry->ino) n = n->rb_right; else if (gen < entry->gen) n = n->rb_left; else if (gen > entry->gen) n = n->rb_right; else return entry; } return NULL; } static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino, u64 gen) { struct orphan_dir_info *odi = get_orphan_dir_info(sctx, dir_ino, gen); return odi != NULL; } static void free_orphan_dir_info(struct send_ctx *sctx, struct orphan_dir_info *odi) { if (!odi) return; rb_erase(&odi->node, &sctx->orphan_dirs); kfree(odi); } /* * Returns 1 if a directory can be removed at this point in time. * We check this by iterating all dir items and checking if the inode behind * the dir item was already processed. */ static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen, u64 send_progress) { int ret = 0; struct btrfs_root *root = sctx->parent_root; struct btrfs_path *path; struct btrfs_key key; struct btrfs_key found_key; struct btrfs_key loc; struct btrfs_dir_item *di; struct orphan_dir_info *odi = NULL; /* * Don't try to rmdir the top/root subvolume dir. */ if (dir == BTRFS_FIRST_FREE_OBJECTID) return 0; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = dir; key.type = BTRFS_DIR_INDEX_KEY; key.offset = 0; odi = get_orphan_dir_info(sctx, dir, dir_gen); if (odi) key.offset = odi->last_dir_index_offset; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; while (1) { struct waiting_dir_move *dm; if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { ret = btrfs_next_leaf(root, path); if (ret < 0) goto out; else if (ret > 0) break; continue; } btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]); if (found_key.objectid != key.objectid || found_key.type != key.type) break; di = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_dir_item); btrfs_dir_item_key_to_cpu(path->nodes[0], di, &loc); dm = get_waiting_dir_move(sctx, loc.objectid); if (dm) { odi = add_orphan_dir_info(sctx, dir, dir_gen); if (IS_ERR(odi)) { ret = PTR_ERR(odi); goto out; } odi->gen = dir_gen; odi->last_dir_index_offset = found_key.offset; dm->rmdir_ino = dir; dm->rmdir_gen = dir_gen; ret = 0; goto out; } if (loc.objectid > send_progress) { odi = add_orphan_dir_info(sctx, dir, dir_gen); if (IS_ERR(odi)) { ret = PTR_ERR(odi); goto out; } odi->gen = dir_gen; odi->last_dir_index_offset = found_key.offset; ret = 0; goto out; } path->slots[0]++; } free_orphan_dir_info(sctx, odi); ret = 1; out: btrfs_free_path(path); return ret; } static int is_waiting_for_move(struct send_ctx *sctx, u64 ino) { struct waiting_dir_move *entry = get_waiting_dir_move(sctx, ino); return entry != NULL; } static int add_waiting_dir_move(struct send_ctx *sctx, u64 ino, bool orphanized) { struct rb_node **p = &sctx->waiting_dir_moves.rb_node; struct rb_node *parent = NULL; struct waiting_dir_move *entry, *dm; dm = kmalloc(sizeof(*dm), GFP_KERNEL); if (!dm) return -ENOMEM; dm->ino = ino; dm->rmdir_ino = 0; dm->rmdir_gen = 0; dm->orphanized = orphanized; while (*p) { parent = *p; entry = rb_entry(parent, struct waiting_dir_move, node); if (ino < entry->ino) { p = &(*p)->rb_left; } else if (ino > entry->ino) { p = &(*p)->rb_right; } else { kfree(dm); return -EEXIST; } } rb_link_node(&dm->node, parent, p); rb_insert_color(&dm->node, &sctx->waiting_dir_moves); return 0; } static struct waiting_dir_move * get_waiting_dir_move(struct send_ctx *sctx, u64 ino) { struct rb_node *n = sctx->waiting_dir_moves.rb_node; struct waiting_dir_move *entry; while (n) { entry = rb_entry(n, struct waiting_dir_move, node); if (ino < entry->ino) n = n->rb_left; else if (ino > entry->ino) n = n->rb_right; else return entry; } return NULL; } static void free_waiting_dir_move(struct send_ctx *sctx, struct waiting_dir_move *dm) { if (!dm) return; rb_erase(&dm->node, &sctx->waiting_dir_moves); kfree(dm); } static int add_pending_dir_move(struct send_ctx *sctx, u64 ino, u64 ino_gen, u64 parent_ino, struct list_head *new_refs, struct list_head *deleted_refs, const bool is_orphan) { struct rb_node **p = &sctx->pending_dir_moves.rb_node; struct rb_node *parent = NULL; struct pending_dir_move *entry = NULL, *pm; struct recorded_ref *cur; int exists = 0; int ret; pm = kmalloc(sizeof(*pm), GFP_KERNEL); if (!pm) return -ENOMEM; pm->parent_ino = parent_ino; pm->ino = ino; pm->gen = ino_gen; INIT_LIST_HEAD(&pm->list); INIT_LIST_HEAD(&pm->update_refs); RB_CLEAR_NODE(&pm->node); while (*p) { parent = *p; entry = rb_entry(parent, struct pending_dir_move, node); if (parent_ino < entry->parent_ino) { p = &(*p)->rb_left; } else if (parent_ino > entry->parent_ino) { p = &(*p)->rb_right; } else { exists = 1; break; } } list_for_each_entry(cur, deleted_refs, list) { ret = dup_ref(cur, &pm->update_refs); if (ret < 0) goto out; } list_for_each_entry(cur, new_refs, list) { ret = dup_ref(cur, &pm->update_refs); if (ret < 0) goto out; } ret = add_waiting_dir_move(sctx, pm->ino, is_orphan); if (ret) goto out; if (exists) { list_add_tail(&pm->list, &entry->list); } else { rb_link_node(&pm->node, parent, p); rb_insert_color(&pm->node, &sctx->pending_dir_moves); } ret = 0; out: if (ret) { __free_recorded_refs(&pm->update_refs); kfree(pm); } return ret; } static struct pending_dir_move *get_pending_dir_moves(struct send_ctx *sctx, u64 parent_ino) { struct rb_node *n = sctx->pending_dir_moves.rb_node; struct pending_dir_move *entry; while (n) { entry = rb_entry(n, struct pending_dir_move, node); if (parent_ino < entry->parent_ino) n = n->rb_left; else if (parent_ino > entry->parent_ino) n = n->rb_right; else return entry; } return NULL; } static int path_loop(struct send_ctx *sctx, struct fs_path *name, u64 ino, u64 gen, u64 *ancestor_ino) { int ret = 0; u64 parent_inode = 0; u64 parent_gen = 0; u64 start_ino = ino; *ancestor_ino = 0; while (ino != BTRFS_FIRST_FREE_OBJECTID) { fs_path_reset(name); if (is_waiting_for_rm(sctx, ino, gen)) break; if (is_waiting_for_move(sctx, ino)) { if (*ancestor_ino == 0) *ancestor_ino = ino; ret = get_first_ref(sctx->parent_root, ino, &parent_inode, &parent_gen, name); } else { ret = __get_cur_name_and_parent(sctx, ino, gen, &parent_inode, &parent_gen, name); if (ret > 0) { ret = 0; break; } } if (ret < 0) break; if (parent_inode == start_ino) { ret = 1; if (*ancestor_ino == 0) *ancestor_ino = ino; break; } ino = parent_inode; gen = parent_gen; } return ret; } static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm) { struct fs_path *from_path = NULL; struct fs_path *to_path = NULL; struct fs_path *name = NULL; u64 orig_progress = sctx->send_progress; struct recorded_ref *cur; u64 parent_ino, parent_gen; struct waiting_dir_move *dm = NULL; u64 rmdir_ino = 0; u64 rmdir_gen; u64 ancestor; bool is_orphan; int ret; name = fs_path_alloc(); from_path = fs_path_alloc(); if (!name || !from_path) { ret = -ENOMEM; goto out; } dm = get_waiting_dir_move(sctx, pm->ino); ASSERT(dm); rmdir_ino = dm->rmdir_ino; rmdir_gen = dm->rmdir_gen; is_orphan = dm->orphanized; free_waiting_dir_move(sctx, dm); if (is_orphan) { ret = gen_unique_name(sctx, pm->ino, pm->gen, from_path); } else { ret = get_first_ref(sctx->parent_root, pm->ino, &parent_ino, &parent_gen, name); if (ret < 0) goto out; ret = get_cur_path(sctx, parent_ino, parent_gen, from_path); if (ret < 0) goto out; ret = fs_path_add_path(from_path, name); } if (ret < 0) goto out; sctx->send_progress = sctx->cur_ino + 1; ret = path_loop(sctx, name, pm->ino, pm->gen, &ancestor); if (ret < 0) goto out; if (ret) { LIST_HEAD(deleted_refs); ASSERT(ancestor > BTRFS_FIRST_FREE_OBJECTID); ret = add_pending_dir_move(sctx, pm->ino, pm->gen, ancestor, &pm->update_refs, &deleted_refs, is_orphan); if (ret < 0) goto out; if (rmdir_ino) { dm = get_waiting_dir_move(sctx, pm->ino); ASSERT(dm); dm->rmdir_ino = rmdir_ino; dm->rmdir_gen = rmdir_gen; } goto out; } fs_path_reset(name); to_path = name; name = NULL; ret = get_cur_path(sctx, pm->ino, pm->gen, to_path); if (ret < 0) goto out; ret = send_rename(sctx, from_path, to_path); if (ret < 0) goto out; if (rmdir_ino) { struct orphan_dir_info *odi; u64 gen; odi = get_orphan_dir_info(sctx, rmdir_ino, rmdir_gen); if (!odi) { /* already deleted */ goto finish; } gen = odi->gen; ret = can_rmdir(sctx, rmdir_ino, gen, sctx->cur_ino); if (ret < 0) goto out; if (!ret) goto finish; name = fs_path_alloc(); if (!name) { ret = -ENOMEM; goto out; } ret = get_cur_path(sctx, rmdir_ino, gen, name); if (ret < 0) goto out; ret = send_rmdir(sctx, name); if (ret < 0) goto out; } finish: ret = send_utimes(sctx, pm->ino, pm->gen); if (ret < 0) goto out; /* * After rename/move, need to update the utimes of both new parent(s) * and old parent(s). */ list_for_each_entry(cur, &pm->update_refs, list) { /* * The parent inode might have been deleted in the send snapshot */ ret = get_inode_info(sctx->send_root, cur->dir, NULL, NULL, NULL, NULL, NULL, NULL); if (ret == -ENOENT) { ret = 0; continue; } if (ret < 0) goto out; ret = send_utimes(sctx, cur->dir, cur->dir_gen); if (ret < 0) goto out; } out: fs_path_free(name); fs_path_free(from_path); fs_path_free(to_path); sctx->send_progress = orig_progress; return ret; } static void free_pending_move(struct send_ctx *sctx, struct pending_dir_move *m) { if (!list_empty(&m->list)) list_del(&m->list); if (!RB_EMPTY_NODE(&m->node)) rb_erase(&m->node, &sctx->pending_dir_moves); __free_recorded_refs(&m->update_refs); kfree(m); } static void tail_append_pending_moves(struct send_ctx *sctx, struct pending_dir_move *moves, struct list_head *stack) { if (list_empty(&moves->list)) { list_add_tail(&moves->list, stack); } else { LIST_HEAD(list); list_splice_init(&moves->list, &list); list_add_tail(&moves->list, stack); list_splice_tail(&list, stack); } if (!RB_EMPTY_NODE(&moves->node)) { rb_erase(&moves->node, &sctx->pending_dir_moves); RB_CLEAR_NODE(&moves->node); } } static int apply_children_dir_moves(struct send_ctx *sctx) { struct pending_dir_move *pm; struct list_head stack; u64 parent_ino = sctx->cur_ino; int ret = 0; pm = get_pending_dir_moves(sctx, parent_ino); if (!pm) return 0; INIT_LIST_HEAD(&stack); tail_append_pending_moves(sctx, pm, &stack); while (!list_empty(&stack)) { pm = list_first_entry(&stack, struct pending_dir_move, list); parent_ino = pm->ino; ret = apply_dir_move(sctx, pm); free_pending_move(sctx, pm); if (ret) goto out; pm = get_pending_dir_moves(sctx, parent_ino); if (pm) tail_append_pending_moves(sctx, pm, &stack); } return 0; out: while (!list_empty(&stack)) { pm = list_first_entry(&stack, struct pending_dir_move, list); free_pending_move(sctx, pm); } return ret; } /* * We might need to delay a directory rename even when no ancestor directory * (in the send root) with a higher inode number than ours (sctx->cur_ino) was * renamed. This happens when we rename a directory to the old name (the name * in the parent root) of some other unrelated directory that got its rename * delayed due to some ancestor with higher number that got renamed. * * Example: * * Parent snapshot: * . (ino 256) * |---- a/ (ino 257) * | |---- file (ino 260) * | * |---- b/ (ino 258) * |---- c/ (ino 259) * * Send snapshot: * . (ino 256) * |---- a/ (ino 258) * |---- x/ (ino 259) * |---- y/ (ino 257) * |----- file (ino 260) * * Here we can not rename 258 from 'b' to 'a' without the rename of inode 257 * from 'a' to 'x/y' happening first, which in turn depends on the rename of * inode 259 from 'c' to 'x'. So the order of rename commands the send stream * must issue is: * * 1 - rename 259 from 'c' to 'x' * 2 - rename 257 from 'a' to 'x/y' * 3 - rename 258 from 'b' to 'a' * * Returns 1 if the rename of sctx->cur_ino needs to be delayed, 0 if it can * be done right away and < 0 on error. */ static int wait_for_dest_dir_move(struct send_ctx *sctx, struct recorded_ref *parent_ref, const bool is_orphan) { struct btrfs_fs_info *fs_info = sctx->parent_root->fs_info; struct btrfs_path *path; struct btrfs_key key; struct btrfs_key di_key; struct btrfs_dir_item *di; u64 left_gen; u64 right_gen; int ret = 0; struct waiting_dir_move *wdm; if (RB_EMPTY_ROOT(&sctx->waiting_dir_moves)) return 0; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = parent_ref->dir; key.type = BTRFS_DIR_ITEM_KEY; key.offset = btrfs_name_hash(parent_ref->name, parent_ref->name_len); ret = btrfs_search_slot(NULL, sctx->parent_root, &key, path, 0, 0); if (ret < 0) { goto out; } else if (ret > 0) { ret = 0; goto out; } di = btrfs_match_dir_item_name(fs_info, path, parent_ref->name, parent_ref->name_len); if (!di) { ret = 0; goto out; } /* * di_key.objectid has the number of the inode that has a dentry in the * parent directory with the same name that sctx->cur_ino is being * renamed to. We need to check if that inode is in the send root as * well and if it is currently marked as an inode with a pending rename, * if it is, we need to delay the rename of sctx->cur_ino as well, so * that it happens after that other inode is renamed. */ btrfs_dir_item_key_to_cpu(path->nodes[0], di, &di_key); if (di_key.type != BTRFS_INODE_ITEM_KEY) { ret = 0; goto out; } ret = get_inode_info(sctx->parent_root, di_key.objectid, NULL, &left_gen, NULL, NULL, NULL, NULL); if (ret < 0) goto out; ret = get_inode_info(sctx->send_root, di_key.objectid, NULL, &right_gen, NULL, NULL, NULL, NULL); if (ret < 0) { if (ret == -ENOENT) ret = 0; goto out; } /* Different inode, no need to delay the rename of sctx->cur_ino */ if (right_gen != left_gen) { ret = 0; goto out; } wdm = get_waiting_dir_move(sctx, di_key.objectid); if (wdm && !wdm->orphanized) { ret = add_pending_dir_move(sctx, sctx->cur_ino, sctx->cur_inode_gen, di_key.objectid, &sctx->new_refs, &sctx->deleted_refs, is_orphan); if (!ret) ret = 1; } out: btrfs_free_path(path); return ret; } /* * Check if inode ino2, or any of its ancestors, is inode ino1. * Return 1 if true, 0 if false and < 0 on error. */ static int check_ino_in_path(struct btrfs_root *root, const u64 ino1, const u64 ino1_gen, const u64 ino2, const u64 ino2_gen, struct fs_path *fs_path) { u64 ino = ino2; if (ino1 == ino2) return ino1_gen == ino2_gen; while (ino > BTRFS_FIRST_FREE_OBJECTID) { u64 parent; u64 parent_gen; int ret; fs_path_reset(fs_path); ret = get_first_ref(root, ino, &parent, &parent_gen, fs_path); if (ret < 0) return ret; if (parent == ino1) return parent_gen == ino1_gen; ino = parent; } return 0; } /* * Check if ino ino1 is an ancestor of inode ino2 in the given root for any * possible path (in case ino2 is not a directory and has multiple hard links). * Return 1 if true, 0 if false and < 0 on error. */ static int is_ancestor(struct btrfs_root *root, const u64 ino1, const u64 ino1_gen, const u64 ino2, struct fs_path *fs_path) { bool free_fs_path = false; int ret = 0; struct btrfs_path *path = NULL; struct btrfs_key key; if (!fs_path) { fs_path = fs_path_alloc(); if (!fs_path) return -ENOMEM; free_fs_path = true; } path = alloc_path_for_send(); if (!path) { ret = -ENOMEM; goto out; } key.objectid = ino2; key.type = BTRFS_INODE_REF_KEY; key.offset = 0; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; while (true) { struct extent_buffer *leaf = path->nodes[0]; int slot = path->slots[0]; u32 cur_offset = 0; u32 item_size; if (slot >= btrfs_header_nritems(leaf)) { ret = btrfs_next_leaf(root, path); if (ret < 0) goto out; if (ret > 0) break; continue; } btrfs_item_key_to_cpu(leaf, &key, slot); if (key.objectid != ino2) break; if (key.type != BTRFS_INODE_REF_KEY && key.type != BTRFS_INODE_EXTREF_KEY) break; item_size = btrfs_item_size_nr(leaf, slot); while (cur_offset < item_size) { u64 parent; u64 parent_gen; if (key.type == BTRFS_INODE_EXTREF_KEY) { unsigned long ptr; struct btrfs_inode_extref *extref; ptr = btrfs_item_ptr_offset(leaf, slot); extref = (struct btrfs_inode_extref *) (ptr + cur_offset); parent = btrfs_inode_extref_parent(leaf, extref); cur_offset += sizeof(*extref); cur_offset += btrfs_inode_extref_name_len(leaf, extref); } else { parent = key.offset; cur_offset = item_size; } ret = get_inode_info(root, parent, NULL, &parent_gen, NULL, NULL, NULL, NULL); if (ret < 0) goto out; ret = check_ino_in_path(root, ino1, ino1_gen, parent, parent_gen, fs_path); if (ret) goto out; } path->slots[0]++; } ret = 0; out: btrfs_free_path(path); if (free_fs_path) fs_path_free(fs_path); return ret; } static int wait_for_parent_move(struct send_ctx *sctx, struct recorded_ref *parent_ref, const bool is_orphan) { int ret = 0; u64 ino = parent_ref->dir; u64 ino_gen = parent_ref->dir_gen; u64 parent_ino_before, parent_ino_after; struct fs_path *path_before = NULL; struct fs_path *path_after = NULL; int len1, len2; path_after = fs_path_alloc(); path_before = fs_path_alloc(); if (!path_after || !path_before) { ret = -ENOMEM; goto out; } /* * Our current directory inode may not yet be renamed/moved because some * ancestor (immediate or not) has to be renamed/moved first. So find if * such ancestor exists and make sure our own rename/move happens after * that ancestor is processed to avoid path build infinite loops (done * at get_cur_path()). */ while (ino > BTRFS_FIRST_FREE_OBJECTID) { u64 parent_ino_after_gen; if (is_waiting_for_move(sctx, ino)) { /* * If the current inode is an ancestor of ino in the * parent root, we need to delay the rename of the * current inode, otherwise don't delayed the rename * because we can end up with a circular dependency * of renames, resulting in some directories never * getting the respective rename operations issued in * the send stream or getting into infinite path build * loops. */ ret = is_ancestor(sctx->parent_root, sctx->cur_ino, sctx->cur_inode_gen, ino, path_before); if (ret) break; } fs_path_reset(path_before); fs_path_reset(path_after); ret = get_first_ref(sctx->send_root, ino, &parent_ino_after, &parent_ino_after_gen, path_after); if (ret < 0) goto out; ret = get_first_ref(sctx->parent_root, ino, &parent_ino_before, NULL, path_before); if (ret < 0 && ret != -ENOENT) { goto out; } else if (ret == -ENOENT) { ret = 0; break; } len1 = fs_path_len(path_before); len2 = fs_path_len(path_after); if (ino > sctx->cur_ino && (parent_ino_before != parent_ino_after || len1 != len2 || memcmp(path_before->start, path_after->start, len1))) { u64 parent_ino_gen; ret = get_inode_info(sctx->parent_root, ino, NULL, &parent_ino_gen, NULL, NULL, NULL, NULL); if (ret < 0) goto out; if (ino_gen == parent_ino_gen) { ret = 1; break; } } ino = parent_ino_after; ino_gen = parent_ino_after_gen; } out: fs_path_free(path_before); fs_path_free(path_after); if (ret == 1) { ret = add_pending_dir_move(sctx, sctx->cur_ino, sctx->cur_inode_gen, ino, &sctx->new_refs, &sctx->deleted_refs, is_orphan); if (!ret) ret = 1; } return ret; } static int update_ref_path(struct send_ctx *sctx, struct recorded_ref *ref) { int ret; struct fs_path *new_path; /* * Our reference's name member points to its full_path member string, so * we use here a new path. */ new_path = fs_path_alloc(); if (!new_path) return -ENOMEM; ret = get_cur_path(sctx, ref->dir, ref->dir_gen, new_path); if (ret < 0) { fs_path_free(new_path); return ret; } ret = fs_path_add(new_path, ref->name, ref->name_len); if (ret < 0) { fs_path_free(new_path); return ret; } fs_path_free(ref->full_path); set_ref_path(ref, new_path); return 0; } /* * When processing the new references for an inode we may orphanize an existing * directory inode because its old name conflicts with one of the new references * of the current inode. Later, when processing another new reference of our * inode, we might need to orphanize another inode, but the path we have in the * reference reflects the pre-orphanization name of the directory we previously * orphanized. For example: * * parent snapshot looks like: * * . (ino 256) * |----- f1 (ino 257) * |----- f2 (ino 258) * |----- d1/ (ino 259) * |----- d2/ (ino 260) * * send snapshot looks like: * * . (ino 256) * |----- d1 (ino 258) * |----- f2/ (ino 259) * |----- f2_link/ (ino 260) * | |----- f1 (ino 257) * | * |----- d2 (ino 258) * * When processing inode 257 we compute the name for inode 259 as "d1", and we * cache it in the name cache. Later when we start processing inode 258, when * collecting all its new references we set a full path of "d1/d2" for its new * reference with name "d2". When we start processing the new references we * start by processing the new reference with name "d1", and this results in * orphanizing inode 259, since its old reference causes a conflict. Then we * move on the next new reference, with name "d2", and we find out we must * orphanize inode 260, as its old reference conflicts with ours - but for the * orphanization we use a source path corresponding to the path we stored in the * new reference, which is "d1/d2" and not "o259-6-0/d2" - this makes the * receiver fail since the path component "d1/" no longer exists, it was renamed * to "o259-6-0/" when processing the previous new reference. So in this case we * must recompute the path in the new reference and use it for the new * orphanization operation. */ static int refresh_ref_path(struct send_ctx *sctx, struct recorded_ref *ref) { char *name; int ret; name = kmemdup(ref->name, ref->name_len, GFP_KERNEL); if (!name) return -ENOMEM; fs_path_reset(ref->full_path); ret = get_cur_path(sctx, ref->dir, ref->dir_gen, ref->full_path); if (ret < 0) goto out; ret = fs_path_add(ref->full_path, name, ref->name_len); if (ret < 0) goto out; /* Update the reference's base name pointer. */ set_ref_path(ref, ref->full_path); out: kfree(name); return ret; } /* * This does all the move/link/unlink/rmdir magic. */ static int process_recorded_refs(struct send_ctx *sctx, int *pending_move) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct recorded_ref *cur; struct recorded_ref *cur2; struct list_head check_dirs; struct fs_path *valid_path = NULL; u64 ow_inode = 0; u64 ow_gen; u64 ow_mode; int did_overwrite = 0; int is_orphan = 0; u64 last_dir_ino_rm = 0; bool can_rename = true; bool orphanized_dir = false; bool orphanized_ancestor = false; btrfs_debug(fs_info, "process_recorded_refs %llu", sctx->cur_ino); /* * This should never happen as the root dir always has the same ref * which is always '..' */ BUG_ON(sctx->cur_ino <= BTRFS_FIRST_FREE_OBJECTID); INIT_LIST_HEAD(&check_dirs); valid_path = fs_path_alloc(); if (!valid_path) { ret = -ENOMEM; goto out; } /* * First, check if the first ref of the current inode was overwritten * before. If yes, we know that the current inode was already orphanized * and thus use the orphan name. If not, we can use get_cur_path to * get the path of the first ref as it would like while receiving at * this point in time. * New inodes are always orphan at the beginning, so force to use the * orphan name in this case. * The first ref is stored in valid_path and will be updated if it * gets moved around. */ if (!sctx->cur_inode_new) { ret = did_overwrite_first_ref(sctx, sctx->cur_ino, sctx->cur_inode_gen); if (ret < 0) goto out; if (ret) did_overwrite = 1; } if (sctx->cur_inode_new || did_overwrite) { ret = gen_unique_name(sctx, sctx->cur_ino, sctx->cur_inode_gen, valid_path); if (ret < 0) goto out; is_orphan = 1; } else { ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, valid_path); if (ret < 0) goto out; } /* * Before doing any rename and link operations, do a first pass on the * new references to orphanize any unprocessed inodes that may have a * reference that conflicts with one of the new references of the current * inode. This needs to happen first because a new reference may conflict * with the old reference of a parent directory, so we must make sure * that the path used for link and rename commands don't use an * orphanized name when an ancestor was not yet orphanized. * * Example: * * Parent snapshot: * * . (ino 256) * |----- testdir/ (ino 259) * | |----- a (ino 257) * | * |----- b (ino 258) * * Send snapshot: * * . (ino 256) * |----- testdir_2/ (ino 259) * | |----- a (ino 260) * | * |----- testdir (ino 257) * |----- b (ino 257) * |----- b2 (ino 258) * * Processing the new reference for inode 257 with name "b" may happen * before processing the new reference with name "testdir". If so, we * must make sure that by the time we send a link command to create the * hard link "b", inode 259 was already orphanized, since the generated * path in "valid_path" already contains the orphanized name for 259. * We are processing inode 257, so only later when processing 259 we do * the rename operation to change its temporary (orphanized) name to * "testdir_2". */ list_for_each_entry(cur, &sctx->new_refs, list) { ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen); if (ret < 0) goto out; if (ret == inode_state_will_create) continue; /* * Check if this new ref would overwrite the first ref of another * unprocessed inode. If yes, orphanize the overwritten inode. * If we find an overwritten ref that is not the first ref, * simply unlink it. */ ret = will_overwrite_ref(sctx, cur->dir, cur->dir_gen, cur->name, cur->name_len, &ow_inode, &ow_gen, &ow_mode); if (ret < 0) goto out; if (ret) { ret = is_first_ref(sctx->parent_root, ow_inode, cur->dir, cur->name, cur->name_len); if (ret < 0) goto out; if (ret) { struct name_cache_entry *nce; struct waiting_dir_move *wdm; if (orphanized_dir) { ret = refresh_ref_path(sctx, cur); if (ret < 0) goto out; } ret = orphanize_inode(sctx, ow_inode, ow_gen, cur->full_path); if (ret < 0) goto out; if (S_ISDIR(ow_mode)) orphanized_dir = true; /* * If ow_inode has its rename operation delayed * make sure that its orphanized name is used in * the source path when performing its rename * operation. */ if (is_waiting_for_move(sctx, ow_inode)) { wdm = get_waiting_dir_move(sctx, ow_inode); ASSERT(wdm); wdm->orphanized = true; } /* * Make sure we clear our orphanized inode's * name from the name cache. This is because the * inode ow_inode might be an ancestor of some * other inode that will be orphanized as well * later and has an inode number greater than * sctx->send_progress. We need to prevent * future name lookups from using the old name * and get instead the orphan name. */ nce = name_cache_search(sctx, ow_inode, ow_gen); if (nce) { name_cache_delete(sctx, nce); kfree(nce); } /* * ow_inode might currently be an ancestor of * cur_ino, therefore compute valid_path (the * current path of cur_ino) again because it * might contain the pre-orphanization name of * ow_inode, which is no longer valid. */ ret = is_ancestor(sctx->parent_root, ow_inode, ow_gen, sctx->cur_ino, NULL); if (ret > 0) { orphanized_ancestor = true; fs_path_reset(valid_path); ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, valid_path); } if (ret < 0) goto out; } else { ret = send_unlink(sctx, cur->full_path); if (ret < 0) goto out; } } } list_for_each_entry(cur, &sctx->new_refs, list) { /* * We may have refs where the parent directory does not exist * yet. This happens if the parent directories inum is higher * than the current inum. To handle this case, we create the * parent directory out of order. But we need to check if this * did already happen before due to other refs in the same dir. */ ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen); if (ret < 0) goto out; if (ret == inode_state_will_create) { ret = 0; /* * First check if any of the current inodes refs did * already create the dir. */ list_for_each_entry(cur2, &sctx->new_refs, list) { if (cur == cur2) break; if (cur2->dir == cur->dir) { ret = 1; break; } } /* * If that did not happen, check if a previous inode * did already create the dir. */ if (!ret) ret = did_create_dir(sctx, cur->dir); if (ret < 0) goto out; if (!ret) { ret = send_create_inode(sctx, cur->dir); if (ret < 0) goto out; } } if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root) { ret = wait_for_dest_dir_move(sctx, cur, is_orphan); if (ret < 0) goto out; if (ret == 1) { can_rename = false; *pending_move = 1; } } if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root && can_rename) { ret = wait_for_parent_move(sctx, cur, is_orphan); if (ret < 0) goto out; if (ret == 1) { can_rename = false; *pending_move = 1; } } /* * link/move the ref to the new place. If we have an orphan * inode, move it and update valid_path. If not, link or move * it depending on the inode mode. */ if (is_orphan && can_rename) { ret = send_rename(sctx, valid_path, cur->full_path); if (ret < 0) goto out; is_orphan = 0; ret = fs_path_copy(valid_path, cur->full_path); if (ret < 0) goto out; } else if (can_rename) { if (S_ISDIR(sctx->cur_inode_mode)) { /* * Dirs can't be linked, so move it. For moved * dirs, we always have one new and one deleted * ref. The deleted ref is ignored later. */ ret = send_rename(sctx, valid_path, cur->full_path); if (!ret) ret = fs_path_copy(valid_path, cur->full_path); if (ret < 0) goto out; } else { /* * We might have previously orphanized an inode * which is an ancestor of our current inode, * so our reference's full path, which was * computed before any such orphanizations, must * be updated. */ if (orphanized_dir) { ret = update_ref_path(sctx, cur); if (ret < 0) goto out; } ret = send_link(sctx, cur->full_path, valid_path); if (ret < 0) goto out; } } ret = dup_ref(cur, &check_dirs); if (ret < 0) goto out; } if (S_ISDIR(sctx->cur_inode_mode) && sctx->cur_inode_deleted) { /* * Check if we can already rmdir the directory. If not, * orphanize it. For every dir item inside that gets deleted * later, we do this check again and rmdir it then if possible. * See the use of check_dirs for more details. */ ret = can_rmdir(sctx, sctx->cur_ino, sctx->cur_inode_gen, sctx->cur_ino); if (ret < 0) goto out; if (ret) { ret = send_rmdir(sctx, valid_path); if (ret < 0) goto out; } else if (!is_orphan) { ret = orphanize_inode(sctx, sctx->cur_ino, sctx->cur_inode_gen, valid_path); if (ret < 0) goto out; is_orphan = 1; } list_for_each_entry(cur, &sctx->deleted_refs, list) { ret = dup_ref(cur, &check_dirs); if (ret < 0) goto out; } } else if (S_ISDIR(sctx->cur_inode_mode) && !list_empty(&sctx->deleted_refs)) { /* * We have a moved dir. Add the old parent to check_dirs */ cur = list_entry(sctx->deleted_refs.next, struct recorded_ref, list); ret = dup_ref(cur, &check_dirs); if (ret < 0) goto out; } else if (!S_ISDIR(sctx->cur_inode_mode)) { /* * We have a non dir inode. Go through all deleted refs and * unlink them if they were not already overwritten by other * inodes. */ list_for_each_entry(cur, &sctx->deleted_refs, list) { ret = did_overwrite_ref(sctx, cur->dir, cur->dir_gen, sctx->cur_ino, sctx->cur_inode_gen, cur->name, cur->name_len); if (ret < 0) goto out; if (!ret) { /* * If we orphanized any ancestor before, we need * to recompute the full path for deleted names, * since any such path was computed before we * processed any references and orphanized any * ancestor inode. */ if (orphanized_ancestor) { ret = update_ref_path(sctx, cur); if (ret < 0) goto out; } ret = send_unlink(sctx, cur->full_path); if (ret < 0) goto out; } ret = dup_ref(cur, &check_dirs); if (ret < 0) goto out; } /* * If the inode is still orphan, unlink the orphan. This may * happen when a previous inode did overwrite the first ref * of this inode and no new refs were added for the current * inode. Unlinking does not mean that the inode is deleted in * all cases. There may still be links to this inode in other * places. */ if (is_orphan) { ret = send_unlink(sctx, valid_path); if (ret < 0) goto out; } } /* * We did collect all parent dirs where cur_inode was once located. We * now go through all these dirs and check if they are pending for * deletion and if it's finally possible to perform the rmdir now. * We also update the inode stats of the parent dirs here. */ list_for_each_entry(cur, &check_dirs, list) { /* * In case we had refs into dirs that were not processed yet, * we don't need to do the utime and rmdir logic for these dirs. * The dir will be processed later. */ if (cur->dir > sctx->cur_ino) continue; ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen); if (ret < 0) goto out; if (ret == inode_state_did_create || ret == inode_state_no_change) { /* TODO delayed utimes */ ret = send_utimes(sctx, cur->dir, cur->dir_gen); if (ret < 0) goto out; } else if (ret == inode_state_did_delete && cur->dir != last_dir_ino_rm) { ret = can_rmdir(sctx, cur->dir, cur->dir_gen, sctx->cur_ino); if (ret < 0) goto out; if (ret) { ret = get_cur_path(sctx, cur->dir, cur->dir_gen, valid_path); if (ret < 0) goto out; ret = send_rmdir(sctx, valid_path); if (ret < 0) goto out; last_dir_ino_rm = cur->dir; } } } ret = 0; out: __free_recorded_refs(&check_dirs); free_recorded_refs(sctx); fs_path_free(valid_path); return ret; } static int record_ref(struct btrfs_root *root, u64 dir, struct fs_path *name, void *ctx, struct list_head *refs) { int ret = 0; struct send_ctx *sctx = ctx; struct fs_path *p; u64 gen; p = fs_path_alloc(); if (!p) return -ENOMEM; ret = get_inode_info(root, dir, NULL, &gen, NULL, NULL, NULL, NULL); if (ret < 0) goto out; ret = get_cur_path(sctx, dir, gen, p); if (ret < 0) goto out; ret = fs_path_add_path(p, name); if (ret < 0) goto out; ret = __record_ref(refs, dir, gen, p); out: if (ret) fs_path_free(p); return ret; } static int __record_new_ref(int num, u64 dir, int index, struct fs_path *name, void *ctx) { struct send_ctx *sctx = ctx; return record_ref(sctx->send_root, dir, name, ctx, &sctx->new_refs); } static int __record_deleted_ref(int num, u64 dir, int index, struct fs_path *name, void *ctx) { struct send_ctx *sctx = ctx; return record_ref(sctx->parent_root, dir, name, ctx, &sctx->deleted_refs); } static int record_new_ref(struct send_ctx *sctx) { int ret; ret = iterate_inode_ref(sctx->send_root, sctx->left_path, sctx->cmp_key, 0, __record_new_ref, sctx); if (ret < 0) goto out; ret = 0; out: return ret; } static int record_deleted_ref(struct send_ctx *sctx) { int ret; ret = iterate_inode_ref(sctx->parent_root, sctx->right_path, sctx->cmp_key, 0, __record_deleted_ref, sctx); if (ret < 0) goto out; ret = 0; out: return ret; } struct find_ref_ctx { u64 dir; u64 dir_gen; struct btrfs_root *root; struct fs_path *name; int found_idx; }; static int __find_iref(int num, u64 dir, int index, struct fs_path *name, void *ctx_) { struct find_ref_ctx *ctx = ctx_; u64 dir_gen; int ret; if (dir == ctx->dir && fs_path_len(name) == fs_path_len(ctx->name) && strncmp(name->start, ctx->name->start, fs_path_len(name)) == 0) { /* * To avoid doing extra lookups we'll only do this if everything * else matches. */ ret = get_inode_info(ctx->root, dir, NULL, &dir_gen, NULL, NULL, NULL, NULL); if (ret) return ret; if (dir_gen != ctx->dir_gen) return 0; ctx->found_idx = num; return 1; } return 0; } static int find_iref(struct btrfs_root *root, struct btrfs_path *path, struct btrfs_key *key, u64 dir, u64 dir_gen, struct fs_path *name) { int ret; struct find_ref_ctx ctx; ctx.dir = dir; ctx.name = name; ctx.dir_gen = dir_gen; ctx.found_idx = -1; ctx.root = root; ret = iterate_inode_ref(root, path, key, 0, __find_iref, &ctx); if (ret < 0) return ret; if (ctx.found_idx == -1) return -ENOENT; return ctx.found_idx; } static int __record_changed_new_ref(int num, u64 dir, int index, struct fs_path *name, void *ctx) { u64 dir_gen; int ret; struct send_ctx *sctx = ctx; ret = get_inode_info(sctx->send_root, dir, NULL, &dir_gen, NULL, NULL, NULL, NULL); if (ret) return ret; ret = find_iref(sctx->parent_root, sctx->right_path, sctx->cmp_key, dir, dir_gen, name); if (ret == -ENOENT) ret = __record_new_ref(num, dir, index, name, sctx); else if (ret > 0) ret = 0; return ret; } static int __record_changed_deleted_ref(int num, u64 dir, int index, struct fs_path *name, void *ctx) { u64 dir_gen; int ret; struct send_ctx *sctx = ctx; ret = get_inode_info(sctx->parent_root, dir, NULL, &dir_gen, NULL, NULL, NULL, NULL); if (ret) return ret; ret = find_iref(sctx->send_root, sctx->left_path, sctx->cmp_key, dir, dir_gen, name); if (ret == -ENOENT) ret = __record_deleted_ref(num, dir, index, name, sctx); else if (ret > 0) ret = 0; return ret; } static int record_changed_ref(struct send_ctx *sctx) { int ret = 0; ret = iterate_inode_ref(sctx->send_root, sctx->left_path, sctx->cmp_key, 0, __record_changed_new_ref, sctx); if (ret < 0) goto out; ret = iterate_inode_ref(sctx->parent_root, sctx->right_path, sctx->cmp_key, 0, __record_changed_deleted_ref, sctx); if (ret < 0) goto out; ret = 0; out: return ret; } /* * Record and process all refs at once. Needed when an inode changes the * generation number, which means that it was deleted and recreated. */ static int process_all_refs(struct send_ctx *sctx, enum btrfs_compare_tree_result cmd) { int ret; struct btrfs_root *root; struct btrfs_path *path; struct btrfs_key key; struct btrfs_key found_key; struct extent_buffer *eb; int slot; iterate_inode_ref_t cb; int pending_move = 0; path = alloc_path_for_send(); if (!path) return -ENOMEM; if (cmd == BTRFS_COMPARE_TREE_NEW) { root = sctx->send_root; cb = __record_new_ref; } else if (cmd == BTRFS_COMPARE_TREE_DELETED) { root = sctx->parent_root; cb = __record_deleted_ref; } else { btrfs_err(sctx->send_root->fs_info, "Wrong command %d in process_all_refs", cmd); ret = -EINVAL; goto out; } key.objectid = sctx->cmp_key->objectid; key.type = BTRFS_INODE_REF_KEY; key.offset = 0; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; while (1) { eb = path->nodes[0]; slot = path->slots[0]; if (slot >= btrfs_header_nritems(eb)) { ret = btrfs_next_leaf(root, path); if (ret < 0) goto out; else if (ret > 0) break; continue; } btrfs_item_key_to_cpu(eb, &found_key, slot); if (found_key.objectid != key.objectid || (found_key.type != BTRFS_INODE_REF_KEY && found_key.type != BTRFS_INODE_EXTREF_KEY)) break; ret = iterate_inode_ref(root, path, &found_key, 0, cb, sctx); if (ret < 0) goto out; path->slots[0]++; } btrfs_release_path(path); /* * We don't actually care about pending_move as we are simply * re-creating this inode and will be rename'ing it into place once we * rename the parent directory. */ ret = process_recorded_refs(sctx, &pending_move); out: btrfs_free_path(path); return ret; } static int send_set_xattr(struct send_ctx *sctx, struct fs_path *path, const char *name, int name_len, const char *data, int data_len) { int ret = 0; ret = begin_cmd(sctx, BTRFS_SEND_C_SET_XATTR); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len); TLV_PUT(sctx, BTRFS_SEND_A_XATTR_DATA, data, data_len); ret = send_cmd(sctx); tlv_put_failure: out: return ret; } static int send_remove_xattr(struct send_ctx *sctx, struct fs_path *path, const char *name, int name_len) { int ret = 0; ret = begin_cmd(sctx, BTRFS_SEND_C_REMOVE_XATTR); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len); ret = send_cmd(sctx); tlv_put_failure: out: return ret; } static int __process_new_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, u8 type, void *ctx) { int ret; struct send_ctx *sctx = ctx; struct fs_path *p; struct posix_acl_xattr_header dummy_acl; /* Capabilities are emitted by finish_inode_if_needed */ if (!strncmp(name, XATTR_NAME_CAPS, name_len)) return 0; p = fs_path_alloc(); if (!p) return -ENOMEM; /* * This hack is needed because empty acls are stored as zero byte * data in xattrs. Problem with that is, that receiving these zero byte * acls will fail later. To fix this, we send a dummy acl list that * only contains the version number and no entries. */ if (!strncmp(name, XATTR_NAME_POSIX_ACL_ACCESS, name_len) || !strncmp(name, XATTR_NAME_POSIX_ACL_DEFAULT, name_len)) { if (data_len == 0) { dummy_acl.a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); data = (char *)&dummy_acl; data_len = sizeof(dummy_acl); } } ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto out; ret = send_set_xattr(sctx, p, name, name_len, data, data_len); out: fs_path_free(p); return ret; } static int __process_deleted_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, u8 type, void *ctx) { int ret; struct send_ctx *sctx = ctx; struct fs_path *p; p = fs_path_alloc(); if (!p) return -ENOMEM; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto out; ret = send_remove_xattr(sctx, p, name, name_len); out: fs_path_free(p); return ret; } static int process_new_xattr(struct send_ctx *sctx) { int ret = 0; ret = iterate_dir_item(sctx->send_root, sctx->left_path, __process_new_xattr, sctx); return ret; } static int process_deleted_xattr(struct send_ctx *sctx) { return iterate_dir_item(sctx->parent_root, sctx->right_path, __process_deleted_xattr, sctx); } struct find_xattr_ctx { const char *name; int name_len; int found_idx; char *found_data; int found_data_len; }; static int __find_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, u8 type, void *vctx) { struct find_xattr_ctx *ctx = vctx; if (name_len == ctx->name_len && strncmp(name, ctx->name, name_len) == 0) { ctx->found_idx = num; ctx->found_data_len = data_len; ctx->found_data = kmemdup(data, data_len, GFP_KERNEL); if (!ctx->found_data) return -ENOMEM; return 1; } return 0; } static int find_xattr(struct btrfs_root *root, struct btrfs_path *path, struct btrfs_key *key, const char *name, int name_len, char **data, int *data_len) { int ret; struct find_xattr_ctx ctx; ctx.name = name; ctx.name_len = name_len; ctx.found_idx = -1; ctx.found_data = NULL; ctx.found_data_len = 0; ret = iterate_dir_item(root, path, __find_xattr, &ctx); if (ret < 0) return ret; if (ctx.found_idx == -1) return -ENOENT; if (data) { *data = ctx.found_data; *data_len = ctx.found_data_len; } else { kfree(ctx.found_data); } return ctx.found_idx; } static int __process_changed_new_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, u8 type, void *ctx) { int ret; struct send_ctx *sctx = ctx; char *found_data = NULL; int found_data_len = 0; ret = find_xattr(sctx->parent_root, sctx->right_path, sctx->cmp_key, name, name_len, &found_data, &found_data_len); if (ret == -ENOENT) { ret = __process_new_xattr(num, di_key, name, name_len, data, data_len, type, ctx); } else if (ret >= 0) { if (data_len != found_data_len || memcmp(data, found_data, data_len)) { ret = __process_new_xattr(num, di_key, name, name_len, data, data_len, type, ctx); } else { ret = 0; } } kfree(found_data); return ret; } static int __process_changed_deleted_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, u8 type, void *ctx) { int ret; struct send_ctx *sctx = ctx; ret = find_xattr(sctx->send_root, sctx->left_path, sctx->cmp_key, name, name_len, NULL, NULL); if (ret == -ENOENT) ret = __process_deleted_xattr(num, di_key, name, name_len, data, data_len, type, ctx); else if (ret >= 0) ret = 0; return ret; } static int process_changed_xattr(struct send_ctx *sctx) { int ret = 0; ret = iterate_dir_item(sctx->send_root, sctx->left_path, __process_changed_new_xattr, sctx); if (ret < 0) goto out; ret = iterate_dir_item(sctx->parent_root, sctx->right_path, __process_changed_deleted_xattr, sctx); out: return ret; } static int process_all_new_xattrs(struct send_ctx *sctx) { int ret; struct btrfs_root *root; struct btrfs_path *path; struct btrfs_key key; struct btrfs_key found_key; struct extent_buffer *eb; int slot; path = alloc_path_for_send(); if (!path) return -ENOMEM; root = sctx->send_root; key.objectid = sctx->cmp_key->objectid; key.type = BTRFS_XATTR_ITEM_KEY; key.offset = 0; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; while (1) { eb = path->nodes[0]; slot = path->slots[0]; if (slot >= btrfs_header_nritems(eb)) { ret = btrfs_next_leaf(root, path); if (ret < 0) { goto out; } else if (ret > 0) { ret = 0; break; } continue; } btrfs_item_key_to_cpu(eb, &found_key, slot); if (found_key.objectid != key.objectid || found_key.type != key.type) { ret = 0; goto out; } ret = iterate_dir_item(root, path, __process_new_xattr, sctx); if (ret < 0) goto out; path->slots[0]++; } out: btrfs_free_path(path); return ret; } static inline u64 max_send_read_size(const struct send_ctx *sctx) { return sctx->send_max_size - SZ_16K; } static int put_data_header(struct send_ctx *sctx, u32 len) { struct btrfs_tlv_header *hdr; if (sctx->send_max_size - sctx->send_size < sizeof(*hdr) + len) return -EOVERFLOW; hdr = (struct btrfs_tlv_header *)(sctx->send_buf + sctx->send_size); put_unaligned_le16(BTRFS_SEND_A_DATA, &hdr->tlv_type); put_unaligned_le16(len, &hdr->tlv_len); sctx->send_size += sizeof(*hdr); return 0; } static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len) { struct btrfs_root *root = sctx->send_root; struct btrfs_fs_info *fs_info = root->fs_info; struct inode *inode; struct page *page; char *addr; pgoff_t index = offset >> PAGE_SHIFT; pgoff_t last_index; unsigned pg_offset = offset_in_page(offset); int ret; ret = put_data_header(sctx, len); if (ret) return ret; inode = btrfs_iget(fs_info->sb, sctx->cur_ino, root); if (IS_ERR(inode)) return PTR_ERR(inode); last_index = (offset + len - 1) >> PAGE_SHIFT; /* initial readahead */ memset(&sctx->ra, 0, sizeof(struct file_ra_state)); file_ra_state_init(&sctx->ra, inode->i_mapping); while (index <= last_index) { unsigned cur_len = min_t(unsigned, len, PAGE_SIZE - pg_offset); page = find_lock_page(inode->i_mapping, index); if (!page) { page_cache_sync_readahead(inode->i_mapping, &sctx->ra, NULL, index, last_index + 1 - index); page = find_or_create_page(inode->i_mapping, index, GFP_KERNEL); if (!page) { ret = -ENOMEM; break; } } if (PageReadahead(page)) { page_cache_async_readahead(inode->i_mapping, &sctx->ra, NULL, page, index, last_index + 1 - index); } if (!PageUptodate(page)) { btrfs_readpage(NULL, page); lock_page(page); if (!PageUptodate(page)) { unlock_page(page); put_page(page); ret = -EIO; break; } } addr = kmap(page); memcpy(sctx->send_buf + sctx->send_size, addr + pg_offset, cur_len); kunmap(page); unlock_page(page); put_page(page); index++; pg_offset = 0; len -= cur_len; sctx->send_size += cur_len; } iput(inode); return ret; } /* * Read some bytes from the current inode/file and send a write command to * user space. */ static int send_write(struct send_ctx *sctx, u64 offset, u32 len) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct fs_path *p; p = fs_path_alloc(); if (!p) return -ENOMEM; btrfs_debug(fs_info, "send_write offset=%llu, len=%d", offset, len); ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE); if (ret < 0) goto out; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); ret = put_file_data(sctx, offset, len); if (ret < 0) goto out; ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } /* * Send a clone command to user space. */ static int send_clone(struct send_ctx *sctx, u64 offset, u32 len, struct clone_root *clone_root) { int ret = 0; struct fs_path *p; u64 gen; btrfs_debug(sctx->send_root->fs_info, "send_clone offset=%llu, len=%d, clone_root=%llu, clone_inode=%llu, clone_offset=%llu", offset, len, clone_root->root->root_key.objectid, clone_root->ino, clone_root->offset); p = fs_path_alloc(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_CLONE); if (ret < 0) goto out; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto out; TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_LEN, len); TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); if (clone_root->root == sctx->send_root) { ret = get_inode_info(sctx->send_root, clone_root->ino, NULL, &gen, NULL, NULL, NULL, NULL); if (ret < 0) goto out; ret = get_cur_path(sctx, clone_root->ino, gen, p); } else { ret = get_inode_path(clone_root->root, clone_root->ino, p); } if (ret < 0) goto out; /* * If the parent we're using has a received_uuid set then use that as * our clone source as that is what we will look for when doing a * receive. * * This covers the case that we create a snapshot off of a received * subvolume and then use that as the parent and try to receive on a * different host. */ if (!btrfs_is_empty_uuid(clone_root->root->root_item.received_uuid)) TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID, clone_root->root->root_item.received_uuid); else TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID, clone_root->root->root_item.uuid); TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID, btrfs_root_ctransid(&clone_root->root->root_item)); TLV_PUT_PATH(sctx, BTRFS_SEND_A_CLONE_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_OFFSET, clone_root->offset); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } /* * Send an update extent command to user space. */ static int send_update_extent(struct send_ctx *sctx, u64 offset, u32 len) { int ret = 0; struct fs_path *p; p = fs_path_alloc(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_UPDATE_EXTENT); if (ret < 0) goto out; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, len); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } static int send_hole(struct send_ctx *sctx, u64 end) { struct fs_path *p = NULL; u64 read_size = max_send_read_size(sctx); u64 offset = sctx->cur_inode_last_extent; int ret = 0; /* * A hole that starts at EOF or beyond it. Since we do not yet support * fallocate (for extent preallocation and hole punching), sending a * write of zeroes starting at EOF or beyond would later require issuing * a truncate operation which would undo the write and achieve nothing. */ if (offset >= sctx->cur_inode_size) return 0; /* * Don't go beyond the inode's i_size due to prealloc extents that start * after the i_size. */ end = min_t(u64, end, sctx->cur_inode_size); if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA) return send_update_extent(sctx, offset, end - offset); p = fs_path_alloc(); if (!p) return -ENOMEM; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto tlv_put_failure; while (offset < end) { u64 len = min(end - offset, read_size); ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE); if (ret < 0) break; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); ret = put_data_header(sctx, len); if (ret < 0) break; memset(sctx->send_buf + sctx->send_size, 0, len); sctx->send_size += len; ret = send_cmd(sctx); if (ret < 0) break; offset += len; } sctx->cur_inode_next_write_offset = offset; tlv_put_failure: fs_path_free(p); return ret; } static int send_extent_data(struct send_ctx *sctx, const u64 offset, const u64 len) { u64 read_size = max_send_read_size(sctx); u64 sent = 0; if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA) return send_update_extent(sctx, offset, len); while (sent < len) { u64 size = min(len - sent, read_size); int ret; ret = send_write(sctx, offset + sent, size); if (ret < 0) return ret; sent += size; } return 0; } /* * Search for a capability xattr related to sctx->cur_ino. If the capability is * found, call send_set_xattr function to emit it. * * Return 0 if there isn't a capability, or when the capability was emitted * successfully, or < 0 if an error occurred. */ static int send_capabilities(struct send_ctx *sctx) { struct fs_path *fspath = NULL; struct btrfs_path *path; struct btrfs_dir_item *di; struct extent_buffer *leaf; unsigned long data_ptr; char *buf = NULL; int buf_len; int ret = 0; path = alloc_path_for_send(); if (!path) return -ENOMEM; di = btrfs_lookup_xattr(NULL, sctx->send_root, path, sctx->cur_ino, XATTR_NAME_CAPS, strlen(XATTR_NAME_CAPS), 0); if (!di) { /* There is no xattr for this inode */ goto out; } else if (IS_ERR(di)) { ret = PTR_ERR(di); goto out; } leaf = path->nodes[0]; buf_len = btrfs_dir_data_len(leaf, di); fspath = fs_path_alloc(); buf = kmalloc(buf_len, GFP_KERNEL); if (!fspath || !buf) { ret = -ENOMEM; goto out; } ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, fspath); if (ret < 0) goto out; data_ptr = (unsigned long)(di + 1) + btrfs_dir_name_len(leaf, di); read_extent_buffer(leaf, buf, data_ptr, buf_len); ret = send_set_xattr(sctx, fspath, XATTR_NAME_CAPS, strlen(XATTR_NAME_CAPS), buf, buf_len); out: kfree(buf); fs_path_free(fspath); btrfs_free_path(path); return ret; } static int clone_range(struct send_ctx *sctx, struct clone_root *clone_root, const u64 disk_byte, u64 data_offset, u64 offset, u64 len) { struct btrfs_path *path; struct btrfs_key key; int ret; u64 clone_src_i_size = 0; /* * Prevent cloning from a zero offset with a length matching the sector * size because in some scenarios this will make the receiver fail. * * For example, if in the source filesystem the extent at offset 0 * has a length of sectorsize and it was written using direct IO, then * it can never be an inline extent (even if compression is enabled). * Then this extent can be cloned in the original filesystem to a non * zero file offset, but it may not be possible to clone in the * destination filesystem because it can be inlined due to compression * on the destination filesystem (as the receiver's write operations are * always done using buffered IO). The same happens when the original * filesystem does not have compression enabled but the destination * filesystem has. */ if (clone_root->offset == 0 && len == sctx->send_root->fs_info->sectorsize) return send_extent_data(sctx, offset, len); path = alloc_path_for_send(); if (!path) return -ENOMEM; /* * There are inodes that have extents that lie behind its i_size. Don't * accept clones from these extents. */ ret = __get_inode_info(clone_root->root, path, clone_root->ino, &clone_src_i_size, NULL, NULL, NULL, NULL, NULL); btrfs_release_path(path); if (ret < 0) goto out; /* * We can't send a clone operation for the entire range if we find * extent items in the respective range in the source file that * refer to different extents or if we find holes. * So check for that and do a mix of clone and regular write/copy * operations if needed. * * Example: * * mkfs.btrfs -f /dev/sda * mount /dev/sda /mnt * xfs_io -f -c "pwrite -S 0xaa 0K 100K" /mnt/foo * cp --reflink=always /mnt/foo /mnt/bar * xfs_io -c "pwrite -S 0xbb 50K 50K" /mnt/foo * btrfs subvolume snapshot -r /mnt /mnt/snap * * If when we send the snapshot and we are processing file bar (which * has a higher inode number than foo) we blindly send a clone operation * for the [0, 100K[ range from foo to bar, the receiver ends up getting * a file bar that matches the content of file foo - iow, doesn't match * the content from bar in the original filesystem. */ key.objectid = clone_root->ino; key.type = BTRFS_EXTENT_DATA_KEY; key.offset = clone_root->offset; ret = btrfs_search_slot(NULL, clone_root->root, &key, path, 0, 0); if (ret < 0) goto out; if (ret > 0 && path->slots[0] > 0) { btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1); if (key.objectid == clone_root->ino && key.type == BTRFS_EXTENT_DATA_KEY) path->slots[0]--; } while (true) { struct extent_buffer *leaf = path->nodes[0]; int slot = path->slots[0]; struct btrfs_file_extent_item *ei; u8 type; u64 ext_len; u64 clone_len; u64 clone_data_offset; if (slot >= btrfs_header_nritems(leaf)) { ret = btrfs_next_leaf(clone_root->root, path); if (ret < 0) goto out; else if (ret > 0) break; continue; } btrfs_item_key_to_cpu(leaf, &key, slot); /* * We might have an implicit trailing hole (NO_HOLES feature * enabled). We deal with it after leaving this loop. */ if (key.objectid != clone_root->ino || key.type != BTRFS_EXTENT_DATA_KEY) break; ei = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); type = btrfs_file_extent_type(leaf, ei); if (type == BTRFS_FILE_EXTENT_INLINE) { ext_len = btrfs_file_extent_ram_bytes(leaf, ei); ext_len = PAGE_ALIGN(ext_len); } else { ext_len = btrfs_file_extent_num_bytes(leaf, ei); } if (key.offset + ext_len <= clone_root->offset) goto next; if (key.offset > clone_root->offset) { /* Implicit hole, NO_HOLES feature enabled. */ u64 hole_len = key.offset - clone_root->offset; if (hole_len > len) hole_len = len; ret = send_extent_data(sctx, offset, hole_len); if (ret < 0) goto out; len -= hole_len; if (len == 0) break; offset += hole_len; clone_root->offset += hole_len; data_offset += hole_len; } if (key.offset >= clone_root->offset + len) break; if (key.offset >= clone_src_i_size) break; if (key.offset + ext_len > clone_src_i_size) ext_len = clone_src_i_size - key.offset; clone_data_offset = btrfs_file_extent_offset(leaf, ei); if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte) { clone_root->offset = key.offset; if (clone_data_offset < data_offset && clone_data_offset + ext_len > data_offset) { u64 extent_offset; extent_offset = data_offset - clone_data_offset; ext_len -= extent_offset; clone_data_offset += extent_offset; clone_root->offset += extent_offset; } } clone_len = min_t(u64, ext_len, len); if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte && clone_data_offset == data_offset) { const u64 src_end = clone_root->offset + clone_len; const u64 sectorsize = SZ_64K; /* * We can't clone the last block, when its size is not * sector size aligned, into the middle of a file. If we * do so, the receiver will get a failure (-EINVAL) when * trying to clone or will silently corrupt the data in * the destination file if it's on a kernel without the * fix introduced by commit ac765f83f1397646 * ("Btrfs: fix data corruption due to cloning of eof * block). * * So issue a clone of the aligned down range plus a * regular write for the eof block, if we hit that case. * * Also, we use the maximum possible sector size, 64K, * because we don't know what's the sector size of the * filesystem that receives the stream, so we have to * assume the largest possible sector size. */ if (src_end == clone_src_i_size && !IS_ALIGNED(src_end, sectorsize) && offset + clone_len < sctx->cur_inode_size) { u64 slen; slen = ALIGN_DOWN(src_end - clone_root->offset, sectorsize); if (slen > 0) { ret = send_clone(sctx, offset, slen, clone_root); if (ret < 0) goto out; } ret = send_extent_data(sctx, offset + slen, clone_len - slen); } else { ret = send_clone(sctx, offset, clone_len, clone_root); } } else { ret = send_extent_data(sctx, offset, clone_len); } if (ret < 0) goto out; len -= clone_len; if (len == 0) break; offset += clone_len; clone_root->offset += clone_len; data_offset += clone_len; next: path->slots[0]++; } if (len > 0) ret = send_extent_data(sctx, offset, len); else ret = 0; out: btrfs_free_path(path); return ret; } static int send_write_or_clone(struct send_ctx *sctx, struct btrfs_path *path, struct btrfs_key *key, struct clone_root *clone_root) { int ret = 0; u64 offset = key->offset; u64 end; u64 bs = sctx->send_root->fs_info->sb->s_blocksize; end = min_t(u64, btrfs_file_extent_end(path), sctx->cur_inode_size); if (offset >= end) return 0; if (clone_root && IS_ALIGNED(end, bs)) { struct btrfs_file_extent_item *ei; u64 disk_byte; u64 data_offset; ei = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_file_extent_item); disk_byte = btrfs_file_extent_disk_bytenr(path->nodes[0], ei); data_offset = btrfs_file_extent_offset(path->nodes[0], ei); ret = clone_range(sctx, clone_root, disk_byte, data_offset, offset, end - offset); } else { ret = send_extent_data(sctx, offset, end - offset); } sctx->cur_inode_next_write_offset = end; return ret; } static int is_extent_unchanged(struct send_ctx *sctx, struct btrfs_path *left_path, struct btrfs_key *ekey) { int ret = 0; struct btrfs_key key; struct btrfs_path *path = NULL; struct extent_buffer *eb; int slot; struct btrfs_key found_key; struct btrfs_file_extent_item *ei; u64 left_disknr; u64 right_disknr; u64 left_offset; u64 right_offset; u64 left_offset_fixed; u64 left_len; u64 right_len; u64 left_gen; u64 right_gen; u8 left_type; u8 right_type; path = alloc_path_for_send(); if (!path) return -ENOMEM; eb = left_path->nodes[0]; slot = left_path->slots[0]; ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); left_type = btrfs_file_extent_type(eb, ei); if (left_type != BTRFS_FILE_EXTENT_REG) { ret = 0; goto out; } left_disknr = btrfs_file_extent_disk_bytenr(eb, ei); left_len = btrfs_file_extent_num_bytes(eb, ei); left_offset = btrfs_file_extent_offset(eb, ei); left_gen = btrfs_file_extent_generation(eb, ei); /* * Following comments will refer to these graphics. L is the left * extents which we are checking at the moment. 1-8 are the right * extents that we iterate. * * |-----L-----| * |-1-|-2a-|-3-|-4-|-5-|-6-| * * |-----L-----| * |--1--|-2b-|...(same as above) * * Alternative situation. Happens on files where extents got split. * |-----L-----| * |-----------7-----------|-6-| * * Alternative situation. Happens on files which got larger. * |-----L-----| * |-8-| * Nothing follows after 8. */ key.objectid = ekey->objectid; key.type = BTRFS_EXTENT_DATA_KEY; key.offset = ekey->offset; ret = btrfs_search_slot_for_read(sctx->parent_root, &key, path, 0, 0); if (ret < 0) goto out; if (ret) { ret = 0; goto out; } /* * Handle special case where the right side has no extents at all. */ eb = path->nodes[0]; slot = path->slots[0]; btrfs_item_key_to_cpu(eb, &found_key, slot); if (found_key.objectid != key.objectid || found_key.type != key.type) { /* If we're a hole then just pretend nothing changed */ ret = (left_disknr) ? 0 : 1; goto out; } /* * We're now on 2a, 2b or 7. */ key = found_key; while (key.offset < ekey->offset + left_len) { ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); right_type = btrfs_file_extent_type(eb, ei); if (right_type != BTRFS_FILE_EXTENT_REG && right_type != BTRFS_FILE_EXTENT_INLINE) { ret = 0; goto out; } if (right_type == BTRFS_FILE_EXTENT_INLINE) { right_len = btrfs_file_extent_ram_bytes(eb, ei); right_len = PAGE_ALIGN(right_len); } else { right_len = btrfs_file_extent_num_bytes(eb, ei); } /* * Are we at extent 8? If yes, we know the extent is changed. * This may only happen on the first iteration. */ if (found_key.offset + right_len <= ekey->offset) { /* If we're a hole just pretend nothing changed */ ret = (left_disknr) ? 0 : 1; goto out; } /* * We just wanted to see if when we have an inline extent, what * follows it is a regular extent (wanted to check the above * condition for inline extents too). This should normally not * happen but it's possible for example when we have an inline * compressed extent representing data with a size matching * the page size (currently the same as sector size). */ if (right_type == BTRFS_FILE_EXTENT_INLINE) { ret = 0; goto out; } right_disknr = btrfs_file_extent_disk_bytenr(eb, ei); right_offset = btrfs_file_extent_offset(eb, ei); right_gen = btrfs_file_extent_generation(eb, ei); left_offset_fixed = left_offset; if (key.offset < ekey->offset) { /* Fix the right offset for 2a and 7. */ right_offset += ekey->offset - key.offset; } else { /* Fix the left offset for all behind 2a and 2b */ left_offset_fixed += key.offset - ekey->offset; } /* * Check if we have the same extent. */ if (left_disknr != right_disknr || left_offset_fixed != right_offset || left_gen != right_gen) { ret = 0; goto out; } /* * Go to the next extent. */ ret = btrfs_next_item(sctx->parent_root, path); if (ret < 0) goto out; if (!ret) { eb = path->nodes[0]; slot = path->slots[0]; btrfs_item_key_to_cpu(eb, &found_key, slot); } if (ret || found_key.objectid != key.objectid || found_key.type != key.type) { key.offset += right_len; break; } if (found_key.offset != key.offset + right_len) { ret = 0; goto out; } key = found_key; } /* * We're now behind the left extent (treat as unchanged) or at the end * of the right side (treat as changed). */ if (key.offset >= ekey->offset + left_len) ret = 1; else ret = 0; out: btrfs_free_path(path); return ret; } static int get_last_extent(struct send_ctx *sctx, u64 offset) { struct btrfs_path *path; struct btrfs_root *root = sctx->send_root; struct btrfs_key key; int ret; path = alloc_path_for_send(); if (!path) return -ENOMEM; sctx->cur_inode_last_extent = 0; key.objectid = sctx->cur_ino; key.type = BTRFS_EXTENT_DATA_KEY; key.offset = offset; ret = btrfs_search_slot_for_read(root, &key, path, 0, 1); if (ret < 0) goto out; ret = 0; btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (key.objectid != sctx->cur_ino || key.type != BTRFS_EXTENT_DATA_KEY) goto out; sctx->cur_inode_last_extent = btrfs_file_extent_end(path); out: btrfs_free_path(path); return ret; } static int range_is_hole_in_parent(struct send_ctx *sctx, const u64 start, const u64 end) { struct btrfs_path *path; struct btrfs_key key; struct btrfs_root *root = sctx->parent_root; u64 search_start = start; int ret; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = sctx->cur_ino; key.type = BTRFS_EXTENT_DATA_KEY; key.offset = search_start; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; if (ret > 0 && path->slots[0] > 0) path->slots[0]--; while (search_start < end) { struct extent_buffer *leaf = path->nodes[0]; int slot = path->slots[0]; struct btrfs_file_extent_item *fi; u64 extent_end; if (slot >= btrfs_header_nritems(leaf)) { ret = btrfs_next_leaf(root, path); if (ret < 0) goto out; else if (ret > 0) break; continue; } btrfs_item_key_to_cpu(leaf, &key, slot); if (key.objectid < sctx->cur_ino || key.type < BTRFS_EXTENT_DATA_KEY) goto next; if (key.objectid > sctx->cur_ino || key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end) break; fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); extent_end = btrfs_file_extent_end(path); if (extent_end <= start) goto next; if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0) { search_start = extent_end; goto next; } ret = 0; goto out; next: path->slots[0]++; } ret = 1; out: btrfs_free_path(path); return ret; } static int maybe_send_hole(struct send_ctx *sctx, struct btrfs_path *path, struct btrfs_key *key) { int ret = 0; if (sctx->cur_ino != key->objectid || !need_send_hole(sctx)) return 0; if (sctx->cur_inode_last_extent == (u64)-1) { ret = get_last_extent(sctx, key->offset - 1); if (ret) return ret; } if (path->slots[0] == 0 && sctx->cur_inode_last_extent < key->offset) { /* * We might have skipped entire leafs that contained only * file extent items for our current inode. These leafs have * a generation number smaller (older) than the one in the * current leaf and the leaf our last extent came from, and * are located between these 2 leafs. */ ret = get_last_extent(sctx, key->offset - 1); if (ret) return ret; } if (sctx->cur_inode_last_extent < key->offset) { ret = range_is_hole_in_parent(sctx, sctx->cur_inode_last_extent, key->offset); if (ret < 0) return ret; else if (ret == 0) ret = send_hole(sctx, key->offset); else ret = 0; } sctx->cur_inode_last_extent = btrfs_file_extent_end(path); return ret; } static int process_extent(struct send_ctx *sctx, struct btrfs_path *path, struct btrfs_key *key) { struct clone_root *found_clone = NULL; int ret = 0; if (S_ISLNK(sctx->cur_inode_mode)) return 0; if (sctx->parent_root && !sctx->cur_inode_new) { ret = is_extent_unchanged(sctx, path, key); if (ret < 0) goto out; if (ret) { ret = 0; goto out_hole; } } else { struct btrfs_file_extent_item *ei; u8 type; ei = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_file_extent_item); type = btrfs_file_extent_type(path->nodes[0], ei); if (type == BTRFS_FILE_EXTENT_PREALLOC || type == BTRFS_FILE_EXTENT_REG) { /* * The send spec does not have a prealloc command yet, * so just leave a hole for prealloc'ed extents until * we have enough commands queued up to justify rev'ing * the send spec. */ if (type == BTRFS_FILE_EXTENT_PREALLOC) { ret = 0; goto out; } /* Have a hole, just skip it. */ if (btrfs_file_extent_disk_bytenr(path->nodes[0], ei) == 0) { ret = 0; goto out; } } } ret = find_extent_clone(sctx, path, key->objectid, key->offset, sctx->cur_inode_size, &found_clone); if (ret != -ENOENT && ret < 0) goto out; ret = send_write_or_clone(sctx, path, key, found_clone); if (ret) goto out; out_hole: ret = maybe_send_hole(sctx, path, key); out: return ret; } static int process_all_extents(struct send_ctx *sctx) { int ret; struct btrfs_root *root; struct btrfs_path *path; struct btrfs_key key; struct btrfs_key found_key; struct extent_buffer *eb; int slot; root = sctx->send_root; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = sctx->cmp_key->objectid; key.type = BTRFS_EXTENT_DATA_KEY; key.offset = 0; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; while (1) { eb = path->nodes[0]; slot = path->slots[0]; if (slot >= btrfs_header_nritems(eb)) { ret = btrfs_next_leaf(root, path); if (ret < 0) { goto out; } else if (ret > 0) { ret = 0; break; } continue; } btrfs_item_key_to_cpu(eb, &found_key, slot); if (found_key.objectid != key.objectid || found_key.type != key.type) { ret = 0; goto out; } ret = process_extent(sctx, path, &found_key); if (ret < 0) goto out; path->slots[0]++; } out: btrfs_free_path(path); return ret; } static int process_recorded_refs_if_needed(struct send_ctx *sctx, int at_end, int *pending_move, int *refs_processed) { int ret = 0; if (sctx->cur_ino == 0) goto out; if (!at_end && sctx->cur_ino == sctx->cmp_key->objectid && sctx->cmp_key->type <= BTRFS_INODE_EXTREF_KEY) goto out; if (list_empty(&sctx->new_refs) && list_empty(&sctx->deleted_refs)) goto out; ret = process_recorded_refs(sctx, pending_move); if (ret < 0) goto out; *refs_processed = 1; out: return ret; } static int finish_inode_if_needed(struct send_ctx *sctx, int at_end) { int ret = 0; u64 left_mode; u64 left_uid; u64 left_gid; u64 right_mode; u64 right_uid; u64 right_gid; int need_chmod = 0; int need_chown = 0; int need_truncate = 1; int pending_move = 0; int refs_processed = 0; if (sctx->ignore_cur_inode) return 0; ret = process_recorded_refs_if_needed(sctx, at_end, &pending_move, &refs_processed); if (ret < 0) goto out; /* * We have processed the refs and thus need to advance send_progress. * Now, calls to get_cur_xxx will take the updated refs of the current * inode into account. * * On the other hand, if our current inode is a directory and couldn't * be moved/renamed because its parent was renamed/moved too and it has * a higher inode number, we can only move/rename our current inode * after we moved/renamed its parent. Therefore in this case operate on * the old path (pre move/rename) of our current inode, and the * move/rename will be performed later. */ if (refs_processed && !pending_move) sctx->send_progress = sctx->cur_ino + 1; if (sctx->cur_ino == 0 || sctx->cur_inode_deleted) goto out; if (!at_end && sctx->cmp_key->objectid == sctx->cur_ino) goto out; ret = get_inode_info(sctx->send_root, sctx->cur_ino, NULL, NULL, &left_mode, &left_uid, &left_gid, NULL); if (ret < 0) goto out; if (!sctx->parent_root || sctx->cur_inode_new) { need_chown = 1; if (!S_ISLNK(sctx->cur_inode_mode)) need_chmod = 1; if (sctx->cur_inode_next_write_offset == sctx->cur_inode_size) need_truncate = 0; } else { u64 old_size; ret = get_inode_info(sctx->parent_root, sctx->cur_ino, &old_size, NULL, &right_mode, &right_uid, &right_gid, NULL); if (ret < 0) goto out; if (left_uid != right_uid || left_gid != right_gid) need_chown = 1; if (!S_ISLNK(sctx->cur_inode_mode) && left_mode != right_mode) need_chmod = 1; if ((old_size == sctx->cur_inode_size) || (sctx->cur_inode_size > old_size && sctx->cur_inode_next_write_offset == sctx->cur_inode_size)) need_truncate = 0; } if (S_ISREG(sctx->cur_inode_mode)) { if (need_send_hole(sctx)) { if (sctx->cur_inode_last_extent == (u64)-1 || sctx->cur_inode_last_extent < sctx->cur_inode_size) { ret = get_last_extent(sctx, (u64)-1); if (ret) goto out; } if (sctx->cur_inode_last_extent < sctx->cur_inode_size) { ret = send_hole(sctx, sctx->cur_inode_size); if (ret) goto out; } } if (need_truncate) { ret = send_truncate(sctx, sctx->cur_ino, sctx->cur_inode_gen, sctx->cur_inode_size); if (ret < 0) goto out; } } if (need_chown) { ret = send_chown(sctx, sctx->cur_ino, sctx->cur_inode_gen, left_uid, left_gid); if (ret < 0) goto out; } if (need_chmod) { ret = send_chmod(sctx, sctx->cur_ino, sctx->cur_inode_gen, left_mode); if (ret < 0) goto out; } ret = send_capabilities(sctx); if (ret < 0) goto out; /* * If other directory inodes depended on our current directory * inode's move/rename, now do their move/rename operations. */ if (!is_waiting_for_move(sctx, sctx->cur_ino)) { ret = apply_children_dir_moves(sctx); if (ret) goto out; /* * Need to send that every time, no matter if it actually * changed between the two trees as we have done changes to * the inode before. If our inode is a directory and it's * waiting to be moved/renamed, we will send its utimes when * it's moved/renamed, therefore we don't need to do it here. */ sctx->send_progress = sctx->cur_ino + 1; ret = send_utimes(sctx, sctx->cur_ino, sctx->cur_inode_gen); if (ret < 0) goto out; } out: return ret; } struct parent_paths_ctx { struct list_head *refs; struct send_ctx *sctx; }; static int record_parent_ref(int num, u64 dir, int index, struct fs_path *name, void *ctx) { struct parent_paths_ctx *ppctx = ctx; return record_ref(ppctx->sctx->parent_root, dir, name, ppctx->sctx, ppctx->refs); } /* * Issue unlink operations for all paths of the current inode found in the * parent snapshot. */ static int btrfs_unlink_all_paths(struct send_ctx *sctx) { LIST_HEAD(deleted_refs); struct btrfs_path *path; struct btrfs_key key; struct parent_paths_ctx ctx; int ret; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = sctx->cur_ino; key.type = BTRFS_INODE_REF_KEY; key.offset = 0; ret = btrfs_search_slot(NULL, sctx->parent_root, &key, path, 0, 0); if (ret < 0) goto out; ctx.refs = &deleted_refs; ctx.sctx = sctx; while (true) { struct extent_buffer *eb = path->nodes[0]; int slot = path->slots[0]; if (slot >= btrfs_header_nritems(eb)) { ret = btrfs_next_leaf(sctx->parent_root, path); if (ret < 0) goto out; else if (ret > 0) break; continue; } btrfs_item_key_to_cpu(eb, &key, slot); if (key.objectid != sctx->cur_ino) break; if (key.type != BTRFS_INODE_REF_KEY && key.type != BTRFS_INODE_EXTREF_KEY) break; ret = iterate_inode_ref(sctx->parent_root, path, &key, 1, record_parent_ref, &ctx); if (ret < 0) goto out; path->slots[0]++; } while (!list_empty(&deleted_refs)) { struct recorded_ref *ref; ref = list_first_entry(&deleted_refs, struct recorded_ref, list); ret = send_unlink(sctx, ref->full_path); if (ret < 0) goto out; fs_path_free(ref->full_path); list_del(&ref->list); kfree(ref); } ret = 0; out: btrfs_free_path(path); if (ret) __free_recorded_refs(&deleted_refs); return ret; } static int changed_inode(struct send_ctx *sctx, enum btrfs_compare_tree_result result) { int ret = 0; struct btrfs_key *key = sctx->cmp_key; struct btrfs_inode_item *left_ii = NULL; struct btrfs_inode_item *right_ii = NULL; u64 left_gen = 0; u64 right_gen = 0; sctx->cur_ino = key->objectid; sctx->cur_inode_new_gen = 0; sctx->cur_inode_last_extent = (u64)-1; sctx->cur_inode_next_write_offset = 0; sctx->ignore_cur_inode = false; /* * Set send_progress to current inode. This will tell all get_cur_xxx * functions that the current inode's refs are not updated yet. Later, * when process_recorded_refs is finished, it is set to cur_ino + 1. */ sctx->send_progress = sctx->cur_ino; if (result == BTRFS_COMPARE_TREE_NEW || result == BTRFS_COMPARE_TREE_CHANGED) { left_ii = btrfs_item_ptr(sctx->left_path->nodes[0], sctx->left_path->slots[0], struct btrfs_inode_item); left_gen = btrfs_inode_generation(sctx->left_path->nodes[0], left_ii); } else { right_ii = btrfs_item_ptr(sctx->right_path->nodes[0], sctx->right_path->slots[0], struct btrfs_inode_item); right_gen = btrfs_inode_generation(sctx->right_path->nodes[0], right_ii); } if (result == BTRFS_COMPARE_TREE_CHANGED) { right_ii = btrfs_item_ptr(sctx->right_path->nodes[0], sctx->right_path->slots[0], struct btrfs_inode_item); right_gen = btrfs_inode_generation(sctx->right_path->nodes[0], right_ii); /* * The cur_ino = root dir case is special here. We can't treat * the inode as deleted+reused because it would generate a * stream that tries to delete/mkdir the root dir. */ if (left_gen != right_gen && sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) sctx->cur_inode_new_gen = 1; } /* * Normally we do not find inodes with a link count of zero (orphans) * because the most common case is to create a snapshot and use it * for a send operation. However other less common use cases involve * using a subvolume and send it after turning it to RO mode just * after deleting all hard links of a file while holding an open * file descriptor against it or turning a RO snapshot into RW mode, * keep an open file descriptor against a file, delete it and then * turn the snapshot back to RO mode before using it for a send * operation. So if we find such cases, ignore the inode and all its * items completely if it's a new inode, or if it's a changed inode * make sure all its previous paths (from the parent snapshot) are all * unlinked and all other the inode items are ignored. */ if (result == BTRFS_COMPARE_TREE_NEW || result == BTRFS_COMPARE_TREE_CHANGED) { u32 nlinks; nlinks = btrfs_inode_nlink(sctx->left_path->nodes[0], left_ii); if (nlinks == 0) { sctx->ignore_cur_inode = true; if (result == BTRFS_COMPARE_TREE_CHANGED) ret = btrfs_unlink_all_paths(sctx); goto out; } } if (result == BTRFS_COMPARE_TREE_NEW) { sctx->cur_inode_gen = left_gen; sctx->cur_inode_new = 1; sctx->cur_inode_deleted = 0; sctx->cur_inode_size = btrfs_inode_size( sctx->left_path->nodes[0], left_ii); sctx->cur_inode_mode = btrfs_inode_mode( sctx->left_path->nodes[0], left_ii); sctx->cur_inode_rdev = btrfs_inode_rdev( sctx->left_path->nodes[0], left_ii); if (sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) ret = send_create_inode_if_needed(sctx); } else if (result == BTRFS_COMPARE_TREE_DELETED) { sctx->cur_inode_gen = right_gen; sctx->cur_inode_new = 0; sctx->cur_inode_deleted = 1; sctx->cur_inode_size = btrfs_inode_size( sctx->right_path->nodes[0], right_ii); sctx->cur_inode_mode = btrfs_inode_mode( sctx->right_path->nodes[0], right_ii); } else if (result == BTRFS_COMPARE_TREE_CHANGED) { /* * We need to do some special handling in case the inode was * reported as changed with a changed generation number. This * means that the original inode was deleted and new inode * reused the same inum. So we have to treat the old inode as * deleted and the new one as new. */ if (sctx->cur_inode_new_gen) { /* * First, process the inode as if it was deleted. */ sctx->cur_inode_gen = right_gen; sctx->cur_inode_new = 0; sctx->cur_inode_deleted = 1; sctx->cur_inode_size = btrfs_inode_size( sctx->right_path->nodes[0], right_ii); sctx->cur_inode_mode = btrfs_inode_mode( sctx->right_path->nodes[0], right_ii); ret = process_all_refs(sctx, BTRFS_COMPARE_TREE_DELETED); if (ret < 0) goto out; /* * Now process the inode as if it was new. */ sctx->cur_inode_gen = left_gen; sctx->cur_inode_new = 1; sctx->cur_inode_deleted = 0; sctx->cur_inode_size = btrfs_inode_size( sctx->left_path->nodes[0], left_ii); sctx->cur_inode_mode = btrfs_inode_mode( sctx->left_path->nodes[0], left_ii); sctx->cur_inode_rdev = btrfs_inode_rdev( sctx->left_path->nodes[0], left_ii); ret = send_create_inode_if_needed(sctx); if (ret < 0) goto out; ret = process_all_refs(sctx, BTRFS_COMPARE_TREE_NEW); if (ret < 0) goto out; /* * Advance send_progress now as we did not get into * process_recorded_refs_if_needed in the new_gen case. */ sctx->send_progress = sctx->cur_ino + 1; /* * Now process all extents and xattrs of the inode as if * they were all new. */ ret = process_all_extents(sctx); if (ret < 0) goto out; ret = process_all_new_xattrs(sctx); if (ret < 0) goto out; } else { sctx->cur_inode_gen = left_gen; sctx->cur_inode_new = 0; sctx->cur_inode_new_gen = 0; sctx->cur_inode_deleted = 0; sctx->cur_inode_size = btrfs_inode_size( sctx->left_path->nodes[0], left_ii); sctx->cur_inode_mode = btrfs_inode_mode( sctx->left_path->nodes[0], left_ii); } } out: return ret; } /* * We have to process new refs before deleted refs, but compare_trees gives us * the new and deleted refs mixed. To fix this, we record the new/deleted refs * first and later process them in process_recorded_refs. * For the cur_inode_new_gen case, we skip recording completely because * changed_inode did already initiate processing of refs. The reason for this is * that in this case, compare_tree actually compares the refs of 2 different * inodes. To fix this, process_all_refs is used in changed_inode to handle all * refs of the right tree as deleted and all refs of the left tree as new. */ static int changed_ref(struct send_ctx *sctx, enum btrfs_compare_tree_result result) { int ret = 0; if (sctx->cur_ino != sctx->cmp_key->objectid) { inconsistent_snapshot_error(sctx, result, "reference"); return -EIO; } if (!sctx->cur_inode_new_gen && sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) { if (result == BTRFS_COMPARE_TREE_NEW) ret = record_new_ref(sctx); else if (result == BTRFS_COMPARE_TREE_DELETED) ret = record_deleted_ref(sctx); else if (result == BTRFS_COMPARE_TREE_CHANGED) ret = record_changed_ref(sctx); } return ret; } /* * Process new/deleted/changed xattrs. We skip processing in the * cur_inode_new_gen case because changed_inode did already initiate processing * of xattrs. The reason is the same as in changed_ref */ static int changed_xattr(struct send_ctx *sctx, enum btrfs_compare_tree_result result) { int ret = 0; if (sctx->cur_ino != sctx->cmp_key->objectid) { inconsistent_snapshot_error(sctx, result, "xattr"); return -EIO; } if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) { if (result == BTRFS_COMPARE_TREE_NEW) ret = process_new_xattr(sctx); else if (result == BTRFS_COMPARE_TREE_DELETED) ret = process_deleted_xattr(sctx); else if (result == BTRFS_COMPARE_TREE_CHANGED) ret = process_changed_xattr(sctx); } return ret; } /* * Process new/deleted/changed extents. We skip processing in the * cur_inode_new_gen case because changed_inode did already initiate processing * of extents. The reason is the same as in changed_ref */ static int changed_extent(struct send_ctx *sctx, enum btrfs_compare_tree_result result) { int ret = 0; /* * We have found an extent item that changed without the inode item * having changed. This can happen either after relocation (where the * disk_bytenr of an extent item is replaced at * relocation.c:replace_file_extents()) or after deduplication into a * file in both the parent and send snapshots (where an extent item can * get modified or replaced with a new one). Note that deduplication * updates the inode item, but it only changes the iversion (sequence * field in the inode item) of the inode, so if a file is deduplicated * the same amount of times in both the parent and send snapshots, its * iversion becames the same in both snapshots, whence the inode item is * the same on both snapshots. */ if (sctx->cur_ino != sctx->cmp_key->objectid) return 0; if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) { if (result != BTRFS_COMPARE_TREE_DELETED) ret = process_extent(sctx, sctx->left_path, sctx->cmp_key); } return ret; } static int dir_changed(struct send_ctx *sctx, u64 dir) { u64 orig_gen, new_gen; int ret; ret = get_inode_info(sctx->send_root, dir, NULL, &new_gen, NULL, NULL, NULL, NULL); if (ret) return ret; ret = get_inode_info(sctx->parent_root, dir, NULL, &orig_gen, NULL, NULL, NULL, NULL); if (ret) return ret; return (orig_gen != new_gen) ? 1 : 0; } static int compare_refs(struct send_ctx *sctx, struct btrfs_path *path, struct btrfs_key *key) { struct btrfs_inode_extref *extref; struct extent_buffer *leaf; u64 dirid = 0, last_dirid = 0; unsigned long ptr; u32 item_size; u32 cur_offset = 0; int ref_name_len; int ret = 0; /* Easy case, just check this one dirid */ if (key->type == BTRFS_INODE_REF_KEY) { dirid = key->offset; ret = dir_changed(sctx, dirid); goto out; } leaf = path->nodes[0]; item_size = btrfs_item_size_nr(leaf, path->slots[0]); ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); while (cur_offset < item_size) { extref = (struct btrfs_inode_extref *)(ptr + cur_offset); dirid = btrfs_inode_extref_parent(leaf, extref); ref_name_len = btrfs_inode_extref_name_len(leaf, extref); cur_offset += ref_name_len + sizeof(*extref); if (dirid == last_dirid) continue; ret = dir_changed(sctx, dirid); if (ret) break; last_dirid = dirid; } out: return ret; } /* * Updates compare related fields in sctx and simply forwards to the actual * changed_xxx functions. */ static int changed_cb(struct btrfs_path *left_path, struct btrfs_path *right_path, struct btrfs_key *key, enum btrfs_compare_tree_result result, void *ctx) { int ret = 0; struct send_ctx *sctx = ctx; if (result == BTRFS_COMPARE_TREE_SAME) { if (key->type == BTRFS_INODE_REF_KEY || key->type == BTRFS_INODE_EXTREF_KEY) { ret = compare_refs(sctx, left_path, key); if (!ret) return 0; if (ret < 0) return ret; } else if (key->type == BTRFS_EXTENT_DATA_KEY) { return maybe_send_hole(sctx, left_path, key); } else { return 0; } result = BTRFS_COMPARE_TREE_CHANGED; ret = 0; } sctx->left_path = left_path; sctx->right_path = right_path; sctx->cmp_key = key; ret = finish_inode_if_needed(sctx, 0); if (ret < 0) goto out; /* Ignore non-FS objects */ if (key->objectid == BTRFS_FREE_INO_OBJECTID || key->objectid == BTRFS_FREE_SPACE_OBJECTID) goto out; if (key->type == BTRFS_INODE_ITEM_KEY) { ret = changed_inode(sctx, result); } else if (!sctx->ignore_cur_inode) { if (key->type == BTRFS_INODE_REF_KEY || key->type == BTRFS_INODE_EXTREF_KEY) ret = changed_ref(sctx, result); else if (key->type == BTRFS_XATTR_ITEM_KEY) ret = changed_xattr(sctx, result); else if (key->type == BTRFS_EXTENT_DATA_KEY) ret = changed_extent(sctx, result); } out: return ret; } static int full_send_tree(struct send_ctx *sctx) { int ret; struct btrfs_root *send_root = sctx->send_root; struct btrfs_key key; struct btrfs_path *path; struct extent_buffer *eb; int slot; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = BTRFS_FIRST_FREE_OBJECTID; key.type = BTRFS_INODE_ITEM_KEY; key.offset = 0; ret = btrfs_search_slot_for_read(send_root, &key, path, 1, 0); if (ret < 0) goto out; if (ret) goto out_finish; while (1) { eb = path->nodes[0]; slot = path->slots[0]; btrfs_item_key_to_cpu(eb, &key, slot); ret = changed_cb(path, NULL, &key, BTRFS_COMPARE_TREE_NEW, sctx); if (ret < 0) goto out; ret = btrfs_next_item(send_root, path); if (ret < 0) goto out; if (ret) { ret = 0; break; } } out_finish: ret = finish_inode_if_needed(sctx, 1); out: btrfs_free_path(path); return ret; } static int tree_move_down(struct btrfs_path *path, int *level) { struct extent_buffer *eb; BUG_ON(*level == 0); eb = btrfs_read_node_slot(path->nodes[*level], path->slots[*level]); if (IS_ERR(eb)) return PTR_ERR(eb); path->nodes[*level - 1] = eb; path->slots[*level - 1] = 0; (*level)--; return 0; } static int tree_move_next_or_upnext(struct btrfs_path *path, int *level, int root_level) { int ret = 0; int nritems; nritems = btrfs_header_nritems(path->nodes[*level]); path->slots[*level]++; while (path->slots[*level] >= nritems) { if (*level == root_level) return -1; /* move upnext */ path->slots[*level] = 0; free_extent_buffer(path->nodes[*level]); path->nodes[*level] = NULL; (*level)++; path->slots[*level]++; nritems = btrfs_header_nritems(path->nodes[*level]); ret = 1; } return ret; } /* * Returns 1 if it had to move up and next. 0 is returned if it moved only next * or down. */ static int tree_advance(struct btrfs_path *path, int *level, int root_level, int allow_down, struct btrfs_key *key) { int ret; if (*level == 0 || !allow_down) { ret = tree_move_next_or_upnext(path, level, root_level); } else { ret = tree_move_down(path, level); } if (ret >= 0) { if (*level == 0) btrfs_item_key_to_cpu(path->nodes[*level], key, path->slots[*level]); else btrfs_node_key_to_cpu(path->nodes[*level], key, path->slots[*level]); } return ret; } static int tree_compare_item(struct btrfs_path *left_path, struct btrfs_path *right_path, char *tmp_buf) { int cmp; int len1, len2; unsigned long off1, off2; len1 = btrfs_item_size_nr(left_path->nodes[0], left_path->slots[0]); len2 = btrfs_item_size_nr(right_path->nodes[0], right_path->slots[0]); if (len1 != len2) return 1; off1 = btrfs_item_ptr_offset(left_path->nodes[0], left_path->slots[0]); off2 = btrfs_item_ptr_offset(right_path->nodes[0], right_path->slots[0]); read_extent_buffer(left_path->nodes[0], tmp_buf, off1, len1); cmp = memcmp_extent_buffer(right_path->nodes[0], tmp_buf, off2, len1); if (cmp) return 1; return 0; } /* * This function compares two trees and calls the provided callback for * every changed/new/deleted item it finds. * If shared tree blocks are encountered, whole subtrees are skipped, making * the compare pretty fast on snapshotted subvolumes. * * This currently works on commit roots only. As commit roots are read only, * we don't do any locking. The commit roots are protected with transactions. * Transactions are ended and rejoined when a commit is tried in between. * * This function checks for modifications done to the trees while comparing. * If it detects a change, it aborts immediately. */ static int btrfs_compare_trees(struct btrfs_root *left_root, struct btrfs_root *right_root, void *ctx) { struct btrfs_fs_info *fs_info = left_root->fs_info; int ret; int cmp; struct btrfs_path *left_path = NULL; struct btrfs_path *right_path = NULL; struct btrfs_key left_key; struct btrfs_key right_key; char *tmp_buf = NULL; int left_root_level; int right_root_level; int left_level; int right_level; int left_end_reached; int right_end_reached; int advance_left; int advance_right; u64 left_blockptr; u64 right_blockptr; u64 left_gen; u64 right_gen; left_path = btrfs_alloc_path(); if (!left_path) { ret = -ENOMEM; goto out; } right_path = btrfs_alloc_path(); if (!right_path) { ret = -ENOMEM; goto out; } tmp_buf = kvmalloc(fs_info->nodesize, GFP_KERNEL); if (!tmp_buf) { ret = -ENOMEM; goto out; } left_path->search_commit_root = 1; left_path->skip_locking = 1; right_path->search_commit_root = 1; right_path->skip_locking = 1; /* * Strategy: Go to the first items of both trees. Then do * * If both trees are at level 0 * Compare keys of current items * If left < right treat left item as new, advance left tree * and repeat * If left > right treat right item as deleted, advance right tree * and repeat * If left == right do deep compare of items, treat as changed if * needed, advance both trees and repeat * If both trees are at the same level but not at level 0 * Compare keys of current nodes/leafs * If left < right advance left tree and repeat * If left > right advance right tree and repeat * If left == right compare blockptrs of the next nodes/leafs * If they match advance both trees but stay at the same level * and repeat * If they don't match advance both trees while allowing to go * deeper and repeat * If tree levels are different * Advance the tree that needs it and repeat * * Advancing a tree means: * If we are at level 0, try to go to the next slot. If that's not * possible, go one level up and repeat. Stop when we found a level * where we could go to the next slot. We may at this point be on a * node or a leaf. * * If we are not at level 0 and not on shared tree blocks, go one * level deeper. * * If we are not at level 0 and on shared tree blocks, go one slot to * the right if possible or go up and right. */ down_read(&fs_info->commit_root_sem); left_level = btrfs_header_level(left_root->commit_root); left_root_level = left_level; left_path->nodes[left_level] = btrfs_clone_extent_buffer(left_root->commit_root); if (!left_path->nodes[left_level]) { up_read(&fs_info->commit_root_sem); ret = -ENOMEM; goto out; } right_level = btrfs_header_level(right_root->commit_root); right_root_level = right_level; right_path->nodes[right_level] = btrfs_clone_extent_buffer(right_root->commit_root); if (!right_path->nodes[right_level]) { up_read(&fs_info->commit_root_sem); ret = -ENOMEM; goto out; } up_read(&fs_info->commit_root_sem); if (left_level == 0) btrfs_item_key_to_cpu(left_path->nodes[left_level], &left_key, left_path->slots[left_level]); else btrfs_node_key_to_cpu(left_path->nodes[left_level], &left_key, left_path->slots[left_level]); if (right_level == 0) btrfs_item_key_to_cpu(right_path->nodes[right_level], &right_key, right_path->slots[right_level]); else btrfs_node_key_to_cpu(right_path->nodes[right_level], &right_key, right_path->slots[right_level]); left_end_reached = right_end_reached = 0; advance_left = advance_right = 0; while (1) { cond_resched(); if (advance_left && !left_end_reached) { ret = tree_advance(left_path, &left_level, left_root_level, advance_left != ADVANCE_ONLY_NEXT, &left_key); if (ret == -1) left_end_reached = ADVANCE; else if (ret < 0) goto out; advance_left = 0; } if (advance_right && !right_end_reached) { ret = tree_advance(right_path, &right_level, right_root_level, advance_right != ADVANCE_ONLY_NEXT, &right_key); if (ret == -1) right_end_reached = ADVANCE; else if (ret < 0) goto out; advance_right = 0; } if (left_end_reached && right_end_reached) { ret = 0; goto out; } else if (left_end_reached) { if (right_level == 0) { ret = changed_cb(left_path, right_path, &right_key, BTRFS_COMPARE_TREE_DELETED, ctx); if (ret < 0) goto out; } advance_right = ADVANCE; continue; } else if (right_end_reached) { if (left_level == 0) { ret = changed_cb(left_path, right_path, &left_key, BTRFS_COMPARE_TREE_NEW, ctx); if (ret < 0) goto out; } advance_left = ADVANCE; continue; } if (left_level == 0 && right_level == 0) { cmp = btrfs_comp_cpu_keys(&left_key, &right_key); if (cmp < 0) { ret = changed_cb(left_path, right_path, &left_key, BTRFS_COMPARE_TREE_NEW, ctx); if (ret < 0) goto out; advance_left = ADVANCE; } else if (cmp > 0) { ret = changed_cb(left_path, right_path, &right_key, BTRFS_COMPARE_TREE_DELETED, ctx); if (ret < 0) goto out; advance_right = ADVANCE; } else { enum btrfs_compare_tree_result result; WARN_ON(!extent_buffer_uptodate(left_path->nodes[0])); ret = tree_compare_item(left_path, right_path, tmp_buf); if (ret) result = BTRFS_COMPARE_TREE_CHANGED; else result = BTRFS_COMPARE_TREE_SAME; ret = changed_cb(left_path, right_path, &left_key, result, ctx); if (ret < 0) goto out; advance_left = ADVANCE; advance_right = ADVANCE; } } else if (left_level == right_level) { cmp = btrfs_comp_cpu_keys(&left_key, &right_key); if (cmp < 0) { advance_left = ADVANCE; } else if (cmp > 0) { advance_right = ADVANCE; } else { left_blockptr = btrfs_node_blockptr( left_path->nodes[left_level], left_path->slots[left_level]); right_blockptr = btrfs_node_blockptr( right_path->nodes[right_level], right_path->slots[right_level]); left_gen = btrfs_node_ptr_generation( left_path->nodes[left_level], left_path->slots[left_level]); right_gen = btrfs_node_ptr_generation( right_path->nodes[right_level], right_path->slots[right_level]); if (left_blockptr == right_blockptr && left_gen == right_gen) { /* * As we're on a shared block, don't * allow to go deeper. */ advance_left = ADVANCE_ONLY_NEXT; advance_right = ADVANCE_ONLY_NEXT; } else { advance_left = ADVANCE; advance_right = ADVANCE; } } } else if (left_level < right_level) { advance_right = ADVANCE; } else { advance_left = ADVANCE; } } out: btrfs_free_path(left_path); btrfs_free_path(right_path); kvfree(tmp_buf); return ret; } static int send_subvol(struct send_ctx *sctx) { int ret; if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_STREAM_HEADER)) { ret = send_header(sctx); if (ret < 0) goto out; } ret = send_subvol_begin(sctx); if (ret < 0) goto out; if (sctx->parent_root) { ret = btrfs_compare_trees(sctx->send_root, sctx->parent_root, sctx); if (ret < 0) goto out; ret = finish_inode_if_needed(sctx, 1); if (ret < 0) goto out; } else { ret = full_send_tree(sctx); if (ret < 0) goto out; } out: free_recorded_refs(sctx); return ret; } /* * If orphan cleanup did remove any orphans from a root, it means the tree * was modified and therefore the commit root is not the same as the current * root anymore. This is a problem, because send uses the commit root and * therefore can see inode items that don't exist in the current root anymore, * and for example make calls to btrfs_iget, which will do tree lookups based * on the current root and not on the commit root. Those lookups will fail, * returning a -ESTALE error, and making send fail with that error. So make * sure a send does not see any orphans we have just removed, and that it will * see the same inodes regardless of whether a transaction commit happened * before it started (meaning that the commit root will be the same as the * current root) or not. */ static int ensure_commit_roots_uptodate(struct send_ctx *sctx) { int i; struct btrfs_trans_handle *trans = NULL; again: if (sctx->parent_root && sctx->parent_root->node != sctx->parent_root->commit_root) goto commit_trans; for (i = 0; i < sctx->clone_roots_cnt; i++) if (sctx->clone_roots[i].root->node != sctx->clone_roots[i].root->commit_root) goto commit_trans; if (trans) return btrfs_end_transaction(trans); return 0; commit_trans: /* Use any root, all fs roots will get their commit roots updated. */ if (!trans) { trans = btrfs_join_transaction(sctx->send_root); if (IS_ERR(trans)) return PTR_ERR(trans); goto again; } return btrfs_commit_transaction(trans); } /* * Make sure any existing dellaloc is flushed for any root used by a send * operation so that we do not miss any data and we do not race with writeback * finishing and changing a tree while send is using the tree. This could * happen if a subvolume is in RW mode, has delalloc, is turned to RO mode and * a send operation then uses the subvolume. * After flushing delalloc ensure_commit_roots_uptodate() must be called. */ static int flush_delalloc_roots(struct send_ctx *sctx) { struct btrfs_root *root = sctx->parent_root; int ret; int i; if (root) { ret = btrfs_start_delalloc_snapshot(root); if (ret) return ret; btrfs_wait_ordered_extents(root, U64_MAX, 0, U64_MAX); } for (i = 0; i < sctx->clone_roots_cnt; i++) { root = sctx->clone_roots[i].root; ret = btrfs_start_delalloc_snapshot(root); if (ret) return ret; btrfs_wait_ordered_extents(root, U64_MAX, 0, U64_MAX); } return 0; } static void btrfs_root_dec_send_in_progress(struct btrfs_root* root) { spin_lock(&root->root_item_lock); root->send_in_progress--; /* * Not much left to do, we don't know why it's unbalanced and * can't blindly reset it to 0. */ if (root->send_in_progress < 0) btrfs_err(root->fs_info, "send_in_progress unbalanced %d root %llu", root->send_in_progress, root->root_key.objectid); spin_unlock(&root->root_item_lock); } static void dedupe_in_progress_warn(const struct btrfs_root *root) { btrfs_warn_rl(root->fs_info, "cannot use root %llu for send while deduplications on it are in progress (%d in progress)", root->root_key.objectid, root->dedupe_in_progress); } long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg) { int ret = 0; struct btrfs_root *send_root = BTRFS_I(file_inode(mnt_file))->root; struct btrfs_fs_info *fs_info = send_root->fs_info; struct btrfs_root *clone_root; struct send_ctx *sctx = NULL; u32 i; u64 *clone_sources_tmp = NULL; int clone_sources_to_rollback = 0; size_t alloc_size; int sort_clone_roots = 0; if (!capable(CAP_SYS_ADMIN)) return -EPERM; /* * The subvolume must remain read-only during send, protect against * making it RW. This also protects against deletion. */ spin_lock(&send_root->root_item_lock); if (btrfs_root_readonly(send_root) && send_root->dedupe_in_progress) { dedupe_in_progress_warn(send_root); spin_unlock(&send_root->root_item_lock); return -EAGAIN; } send_root->send_in_progress++; spin_unlock(&send_root->root_item_lock); /* * Userspace tools do the checks and warn the user if it's * not RO. */ if (!btrfs_root_readonly(send_root)) { ret = -EPERM; goto out; } /* * Check that we don't overflow at later allocations, we request * clone_sources_count + 1 items, and compare to unsigned long inside * access_ok. */ if (arg->clone_sources_count > ULONG_MAX / sizeof(struct clone_root) - 1) { ret = -EINVAL; goto out; } if (arg->flags & ~BTRFS_SEND_FLAG_MASK) { ret = -EINVAL; goto out; } sctx = kzalloc(sizeof(struct send_ctx), GFP_KERNEL); if (!sctx) { ret = -ENOMEM; goto out; } INIT_LIST_HEAD(&sctx->new_refs); INIT_LIST_HEAD(&sctx->deleted_refs); INIT_RADIX_TREE(&sctx->name_cache, GFP_KERNEL); INIT_LIST_HEAD(&sctx->name_cache_list); sctx->flags = arg->flags; sctx->send_filp = fget(arg->send_fd); if (!sctx->send_filp) { ret = -EBADF; goto out; } sctx->send_root = send_root; /* * Unlikely but possible, if the subvolume is marked for deletion but * is slow to remove the directory entry, send can still be started */ if (btrfs_root_dead(sctx->send_root)) { ret = -EPERM; goto out; } sctx->clone_roots_cnt = arg->clone_sources_count; sctx->send_max_size = BTRFS_SEND_BUF_SIZE; sctx->send_buf = kvmalloc(sctx->send_max_size, GFP_KERNEL); if (!sctx->send_buf) { ret = -ENOMEM; goto out; } sctx->pending_dir_moves = RB_ROOT; sctx->waiting_dir_moves = RB_ROOT; sctx->orphan_dirs = RB_ROOT; sctx->clone_roots = kvcalloc(sizeof(*sctx->clone_roots), arg->clone_sources_count + 1, GFP_KERNEL); if (!sctx->clone_roots) { ret = -ENOMEM; goto out; } alloc_size = array_size(sizeof(*arg->clone_sources), arg->clone_sources_count); if (arg->clone_sources_count) { clone_sources_tmp = kvmalloc(alloc_size, GFP_KERNEL); if (!clone_sources_tmp) { ret = -ENOMEM; goto out; } ret = copy_from_user(clone_sources_tmp, arg->clone_sources, alloc_size); if (ret) { ret = -EFAULT; goto out; } for (i = 0; i < arg->clone_sources_count; i++) { clone_root = btrfs_get_fs_root(fs_info, clone_sources_tmp[i], true); if (IS_ERR(clone_root)) { ret = PTR_ERR(clone_root); goto out; } spin_lock(&clone_root->root_item_lock); if (!btrfs_root_readonly(clone_root) || btrfs_root_dead(clone_root)) { spin_unlock(&clone_root->root_item_lock); btrfs_put_root(clone_root); ret = -EPERM; goto out; } if (clone_root->dedupe_in_progress) { dedupe_in_progress_warn(clone_root); spin_unlock(&clone_root->root_item_lock); btrfs_put_root(clone_root); ret = -EAGAIN; goto out; } clone_root->send_in_progress++; spin_unlock(&clone_root->root_item_lock); sctx->clone_roots[i].root = clone_root; clone_sources_to_rollback = i + 1; } kvfree(clone_sources_tmp); clone_sources_tmp = NULL; } if (arg->parent_root) { sctx->parent_root = btrfs_get_fs_root(fs_info, arg->parent_root, true); if (IS_ERR(sctx->parent_root)) { ret = PTR_ERR(sctx->parent_root); goto out; } spin_lock(&sctx->parent_root->root_item_lock); sctx->parent_root->send_in_progress++; if (!btrfs_root_readonly(sctx->parent_root) || btrfs_root_dead(sctx->parent_root)) { spin_unlock(&sctx->parent_root->root_item_lock); ret = -EPERM; goto out; } if (sctx->parent_root->dedupe_in_progress) { dedupe_in_progress_warn(sctx->parent_root); spin_unlock(&sctx->parent_root->root_item_lock); ret = -EAGAIN; goto out; } spin_unlock(&sctx->parent_root->root_item_lock); } /* * Clones from send_root are allowed, but only if the clone source * is behind the current send position. This is checked while searching * for possible clone sources. */ sctx->clone_roots[sctx->clone_roots_cnt++].root = btrfs_grab_root(sctx->send_root); /* We do a bsearch later */ sort(sctx->clone_roots, sctx->clone_roots_cnt, sizeof(*sctx->clone_roots), __clone_root_cmp_sort, NULL); sort_clone_roots = 1; ret = flush_delalloc_roots(sctx); if (ret) goto out; ret = ensure_commit_roots_uptodate(sctx); if (ret) goto out; mutex_lock(&fs_info->balance_mutex); if (test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)) { mutex_unlock(&fs_info->balance_mutex); btrfs_warn_rl(fs_info, "cannot run send because a balance operation is in progress"); ret = -EAGAIN; goto out; } fs_info->send_in_progress++; mutex_unlock(&fs_info->balance_mutex); current->journal_info = BTRFS_SEND_TRANS_STUB; ret = send_subvol(sctx); current->journal_info = NULL; mutex_lock(&fs_info->balance_mutex); fs_info->send_in_progress--; mutex_unlock(&fs_info->balance_mutex); if (ret < 0) goto out; if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_END_CMD)) { ret = begin_cmd(sctx, BTRFS_SEND_C_END); if (ret < 0) goto out; ret = send_cmd(sctx); if (ret < 0) goto out; } out: WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->pending_dir_moves)); while (sctx && !RB_EMPTY_ROOT(&sctx->pending_dir_moves)) { struct rb_node *n; struct pending_dir_move *pm; n = rb_first(&sctx->pending_dir_moves); pm = rb_entry(n, struct pending_dir_move, node); while (!list_empty(&pm->list)) { struct pending_dir_move *pm2; pm2 = list_first_entry(&pm->list, struct pending_dir_move, list); free_pending_move(sctx, pm2); } free_pending_move(sctx, pm); } WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->waiting_dir_moves)); while (sctx && !RB_EMPTY_ROOT(&sctx->waiting_dir_moves)) { struct rb_node *n; struct waiting_dir_move *dm; n = rb_first(&sctx->waiting_dir_moves); dm = rb_entry(n, struct waiting_dir_move, node); rb_erase(&dm->node, &sctx->waiting_dir_moves); kfree(dm); } WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->orphan_dirs)); while (sctx && !RB_EMPTY_ROOT(&sctx->orphan_dirs)) { struct rb_node *n; struct orphan_dir_info *odi; n = rb_first(&sctx->orphan_dirs); odi = rb_entry(n, struct orphan_dir_info, node); free_orphan_dir_info(sctx, odi); } if (sort_clone_roots) { for (i = 0; i < sctx->clone_roots_cnt; i++) { btrfs_root_dec_send_in_progress( sctx->clone_roots[i].root); btrfs_put_root(sctx->clone_roots[i].root); } } else { for (i = 0; sctx && i < clone_sources_to_rollback; i++) { btrfs_root_dec_send_in_progress( sctx->clone_roots[i].root); btrfs_put_root(sctx->clone_roots[i].root); } btrfs_root_dec_send_in_progress(send_root); } if (sctx && !IS_ERR_OR_NULL(sctx->parent_root)) { btrfs_root_dec_send_in_progress(sctx->parent_root); btrfs_put_root(sctx->parent_root); } kvfree(clone_sources_tmp); if (sctx) { if (sctx->send_filp) fput(sctx->send_filp); kvfree(sctx->clone_roots); kvfree(sctx->send_buf); name_cache_free(sctx); kfree(sctx); } return ret; }