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-rw-r--r--fs/btrfs/file.c1288
1 files changed, 1288 insertions, 0 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
new file mode 100644
index 000000000000..90268334145e
--- /dev/null
+++ b/fs/btrfs/file.c
@@ -0,0 +1,1288 @@
+/*
+ * Copyright (C) 2007 Oracle. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/smp_lock.h>
+#include <linux/backing-dev.h>
+#include <linux/mpage.h>
+#include <linux/swap.h>
+#include <linux/writeback.h>
+#include <linux/statfs.h>
+#include <linux/compat.h>
+#include <linux/version.h>
+#include "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+#include "btrfs_inode.h"
+#include "ioctl.h"
+#include "print-tree.h"
+#include "tree-log.h"
+#include "locking.h"
+#include "compat.h"
+
+
+/* simple helper to fault in pages and copy. This should go away
+ * and be replaced with calls into generic code.
+ */
+static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
+ int write_bytes,
+ struct page **prepared_pages,
+ const char __user *buf)
+{
+ long page_fault = 0;
+ int i;
+ int offset = pos & (PAGE_CACHE_SIZE - 1);
+
+ for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
+ size_t count = min_t(size_t,
+ PAGE_CACHE_SIZE - offset, write_bytes);
+ struct page *page = prepared_pages[i];
+ fault_in_pages_readable(buf, count);
+
+ /* Copy data from userspace to the current page */
+ kmap(page);
+ page_fault = __copy_from_user(page_address(page) + offset,
+ buf, count);
+ /* Flush processor's dcache for this page */
+ flush_dcache_page(page);
+ kunmap(page);
+ buf += count;
+ write_bytes -= count;
+
+ if (page_fault)
+ break;
+ }
+ return page_fault ? -EFAULT : 0;
+}
+
+/*
+ * unlocks pages after btrfs_file_write is done with them
+ */
+static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
+{
+ size_t i;
+ for (i = 0; i < num_pages; i++) {
+ if (!pages[i])
+ break;
+ /* page checked is some magic around finding pages that
+ * have been modified without going through btrfs_set_page_dirty
+ * clear it here
+ */
+ ClearPageChecked(pages[i]);
+ unlock_page(pages[i]);
+ mark_page_accessed(pages[i]);
+ page_cache_release(pages[i]);
+ }
+}
+
+/*
+ * after copy_from_user, pages need to be dirtied and we need to make
+ * sure holes are created between the current EOF and the start of
+ * any next extents (if required).
+ *
+ * this also makes the decision about creating an inline extent vs
+ * doing real data extents, marking pages dirty and delalloc as required.
+ */
+static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct file *file,
+ struct page **pages,
+ size_t num_pages,
+ loff_t pos,
+ size_t write_bytes)
+{
+ int err = 0;
+ int i;
+ struct inode *inode = fdentry(file)->d_inode;
+ struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+ u64 hint_byte;
+ u64 num_bytes;
+ u64 start_pos;
+ u64 end_of_last_block;
+ u64 end_pos = pos + write_bytes;
+ loff_t isize = i_size_read(inode);
+
+ start_pos = pos & ~((u64)root->sectorsize - 1);
+ num_bytes = (write_bytes + pos - start_pos +
+ root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
+
+ end_of_last_block = start_pos + num_bytes - 1;
+
+ lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
+ trans = btrfs_join_transaction(root, 1);
+ if (!trans) {
+ err = -ENOMEM;
+ goto out_unlock;
+ }
+ btrfs_set_trans_block_group(trans, inode);
+ hint_byte = 0;
+
+ set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
+
+ /* check for reserved extents on each page, we don't want
+ * to reset the delalloc bit on things that already have
+ * extents reserved.
+ */
+ btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
+ for (i = 0; i < num_pages; i++) {
+ struct page *p = pages[i];
+ SetPageUptodate(p);
+ ClearPageChecked(p);
+ set_page_dirty(p);
+ }
+ if (end_pos > isize) {
+ i_size_write(inode, end_pos);
+ btrfs_update_inode(trans, root, inode);
+ }
+ err = btrfs_end_transaction(trans, root);
+out_unlock:
+ unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
+ return err;
+}
+
+/*
+ * this drops all the extents in the cache that intersect the range
+ * [start, end]. Existing extents are split as required.
+ */
+int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
+ int skip_pinned)
+{
+ struct extent_map *em;
+ struct extent_map *split = NULL;
+ struct extent_map *split2 = NULL;
+ struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+ u64 len = end - start + 1;
+ int ret;
+ int testend = 1;
+ unsigned long flags;
+ int compressed = 0;
+
+ WARN_ON(end < start);
+ if (end == (u64)-1) {
+ len = (u64)-1;
+ testend = 0;
+ }
+ while (1) {
+ if (!split)
+ split = alloc_extent_map(GFP_NOFS);
+ if (!split2)
+ split2 = alloc_extent_map(GFP_NOFS);
+
+ spin_lock(&em_tree->lock);
+ em = lookup_extent_mapping(em_tree, start, len);
+ if (!em) {
+ spin_unlock(&em_tree->lock);
+ break;
+ }
+ flags = em->flags;
+ if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
+ spin_unlock(&em_tree->lock);
+ if (em->start <= start &&
+ (!testend || em->start + em->len >= start + len)) {
+ free_extent_map(em);
+ break;
+ }
+ if (start < em->start) {
+ len = em->start - start;
+ } else {
+ len = start + len - (em->start + em->len);
+ start = em->start + em->len;
+ }
+ free_extent_map(em);
+ continue;
+ }
+ compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
+ clear_bit(EXTENT_FLAG_PINNED, &em->flags);
+ remove_extent_mapping(em_tree, em);
+
+ if (em->block_start < EXTENT_MAP_LAST_BYTE &&
+ em->start < start) {
+ split->start = em->start;
+ split->len = start - em->start;
+ split->orig_start = em->orig_start;
+ split->block_start = em->block_start;
+
+ if (compressed)
+ split->block_len = em->block_len;
+ else
+ split->block_len = split->len;
+
+ split->bdev = em->bdev;
+ split->flags = flags;
+ ret = add_extent_mapping(em_tree, split);
+ BUG_ON(ret);
+ free_extent_map(split);
+ split = split2;
+ split2 = NULL;
+ }
+ if (em->block_start < EXTENT_MAP_LAST_BYTE &&
+ testend && em->start + em->len > start + len) {
+ u64 diff = start + len - em->start;
+
+ split->start = start + len;
+ split->len = em->start + em->len - (start + len);
+ split->bdev = em->bdev;
+ split->flags = flags;
+
+ if (compressed) {
+ split->block_len = em->block_len;
+ split->block_start = em->block_start;
+ split->orig_start = em->orig_start;
+ } else {
+ split->block_len = split->len;
+ split->block_start = em->block_start + diff;
+ split->orig_start = split->start;
+ }
+
+ ret = add_extent_mapping(em_tree, split);
+ BUG_ON(ret);
+ free_extent_map(split);
+ split = NULL;
+ }
+ spin_unlock(&em_tree->lock);
+
+ /* once for us */
+ free_extent_map(em);
+ /* once for the tree*/
+ free_extent_map(em);
+ }
+ if (split)
+ free_extent_map(split);
+ if (split2)
+ free_extent_map(split2);
+ return 0;
+}
+
+int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
+{
+ return 0;
+#if 0
+ struct btrfs_path *path;
+ struct btrfs_key found_key;
+ struct extent_buffer *leaf;
+ struct btrfs_file_extent_item *extent;
+ u64 last_offset = 0;
+ int nritems;
+ int slot;
+ int found_type;
+ int ret;
+ int err = 0;
+ u64 extent_end = 0;
+
+ path = btrfs_alloc_path();
+ ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
+ last_offset, 0);
+ while (1) {
+ nritems = btrfs_header_nritems(path->nodes[0]);
+ if (path->slots[0] >= nritems) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret)
+ goto out;
+ nritems = btrfs_header_nritems(path->nodes[0]);
+ }
+ slot = path->slots[0];
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &found_key, slot);
+ if (found_key.objectid != inode->i_ino)
+ break;
+ if (found_key.type != BTRFS_EXTENT_DATA_KEY)
+ goto out;
+
+ if (found_key.offset < last_offset) {
+ WARN_ON(1);
+ btrfs_print_leaf(root, leaf);
+ printk(KERN_ERR "inode %lu found offset %llu "
+ "expected %llu\n", inode->i_ino,
+ (unsigned long long)found_key.offset,
+ (unsigned long long)last_offset);
+ err = 1;
+ goto out;
+ }
+ extent = btrfs_item_ptr(leaf, slot,
+ struct btrfs_file_extent_item);
+ found_type = btrfs_file_extent_type(leaf, extent);
+ if (found_type == BTRFS_FILE_EXTENT_REG) {
+ extent_end = found_key.offset +
+ btrfs_file_extent_num_bytes(leaf, extent);
+ } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+ struct btrfs_item *item;
+ item = btrfs_item_nr(leaf, slot);
+ extent_end = found_key.offset +
+ btrfs_file_extent_inline_len(leaf, extent);
+ extent_end = (extent_end + root->sectorsize - 1) &
+ ~((u64)root->sectorsize - 1);
+ }
+ last_offset = extent_end;
+ path->slots[0]++;
+ }
+ if (0 && last_offset < inode->i_size) {
+ WARN_ON(1);
+ btrfs_print_leaf(root, leaf);
+ printk(KERN_ERR "inode %lu found offset %llu size %llu\n",
+ inode->i_ino, (unsigned long long)last_offset,
+ (unsigned long long)inode->i_size);
+ err = 1;
+
+ }
+out:
+ btrfs_free_path(path);
+ return err;
+#endif
+}
+
+/*
+ * this is very complex, but the basic idea is to drop all extents
+ * in the range start - end. hint_block is filled in with a block number
+ * that would be a good hint to the block allocator for this file.
+ *
+ * If an extent intersects the range but is not entirely inside the range
+ * it is either truncated or split. Anything entirely inside the range
+ * is deleted from the tree.
+ *
+ * inline_limit is used to tell this code which offsets in the file to keep
+ * if they contain inline extents.
+ */
+noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct inode *inode,
+ u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
+{
+ u64 extent_end = 0;
+ u64 locked_end = end;
+ u64 search_start = start;
+ u64 leaf_start;
+ u64 ram_bytes = 0;
+ u64 orig_parent = 0;
+ u64 disk_bytenr = 0;
+ u8 compression;
+ u8 encryption;
+ u16 other_encoding = 0;
+ u64 root_gen;
+ u64 root_owner;
+ struct extent_buffer *leaf;
+ struct btrfs_file_extent_item *extent;
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_file_extent_item old;
+ int keep;
+ int slot;
+ int bookend;
+ int found_type = 0;
+ int found_extent;
+ int found_inline;
+ int recow;
+ int ret;
+
+ inline_limit = 0;
+ btrfs_drop_extent_cache(inode, start, end - 1, 0);
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ while (1) {
+ recow = 0;
+ btrfs_release_path(root, path);
+ ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
+ search_start, -1);
+ if (ret < 0)
+ goto out;
+ if (ret > 0) {
+ if (path->slots[0] == 0) {
+ ret = 0;
+ goto out;
+ }
+ path->slots[0]--;
+ }
+next_slot:
+ keep = 0;
+ bookend = 0;
+ found_extent = 0;
+ found_inline = 0;
+ leaf_start = 0;
+ root_gen = 0;
+ root_owner = 0;
+ compression = 0;
+ encryption = 0;
+ extent = NULL;
+ leaf = path->nodes[0];
+ slot = path->slots[0];
+ ret = 0;
+ btrfs_item_key_to_cpu(leaf, &key, slot);
+ if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
+ key.offset >= end) {
+ goto out;
+ }
+ if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
+ key.objectid != inode->i_ino) {
+ goto out;
+ }
+ if (recow) {
+ search_start = max(key.offset, start);
+ continue;
+ }
+ if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
+ extent = btrfs_item_ptr(leaf, slot,
+ struct btrfs_file_extent_item);
+ found_type = btrfs_file_extent_type(leaf, extent);
+ compression = btrfs_file_extent_compression(leaf,
+ extent);
+ encryption = btrfs_file_extent_encryption(leaf,
+ extent);
+ other_encoding = btrfs_file_extent_other_encoding(leaf,
+ extent);
+ if (found_type == BTRFS_FILE_EXTENT_REG ||
+ found_type == BTRFS_FILE_EXTENT_PREALLOC) {
+ extent_end =
+ btrfs_file_extent_disk_bytenr(leaf,
+ extent);
+ if (extent_end)
+ *hint_byte = extent_end;
+
+ extent_end = key.offset +
+ btrfs_file_extent_num_bytes(leaf, extent);
+ ram_bytes = btrfs_file_extent_ram_bytes(leaf,
+ extent);
+ found_extent = 1;
+ } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+ found_inline = 1;
+ extent_end = key.offset +
+ btrfs_file_extent_inline_len(leaf, extent);
+ }
+ } else {
+ extent_end = search_start;
+ }
+
+ /* we found nothing we can drop */
+ if ((!found_extent && !found_inline) ||
+ search_start >= extent_end) {
+ int nextret;
+ u32 nritems;
+ nritems = btrfs_header_nritems(leaf);
+ if (slot >= nritems - 1) {
+ nextret = btrfs_next_leaf(root, path);
+ if (nextret)
+ goto out;
+ recow = 1;
+ } else {
+ path->slots[0]++;
+ }
+ goto next_slot;
+ }
+
+ if (end <= extent_end && start >= key.offset && found_inline)
+ *hint_byte = EXTENT_MAP_INLINE;
+
+ if (found_extent) {
+ read_extent_buffer(leaf, &old, (unsigned long)extent,
+ sizeof(old));
+ root_gen = btrfs_header_generation(leaf);
+ root_owner = btrfs_header_owner(leaf);
+ leaf_start = leaf->start;
+ }
+
+ if (end < extent_end && end >= key.offset) {
+ bookend = 1;
+ if (found_inline && start <= key.offset)
+ keep = 1;
+ }
+
+ if (bookend && found_extent) {
+ if (locked_end < extent_end) {
+ ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
+ locked_end, extent_end - 1,
+ GFP_NOFS);
+ if (!ret) {
+ btrfs_release_path(root, path);
+ lock_extent(&BTRFS_I(inode)->io_tree,
+ locked_end, extent_end - 1,
+ GFP_NOFS);
+ locked_end = extent_end;
+ continue;
+ }
+ locked_end = extent_end;
+ }
+ orig_parent = path->nodes[0]->start;
+ disk_bytenr = le64_to_cpu(old.disk_bytenr);
+ if (disk_bytenr != 0) {
+ ret = btrfs_inc_extent_ref(trans, root,
+ disk_bytenr,
+ le64_to_cpu(old.disk_num_bytes),
+ orig_parent, root->root_key.objectid,
+ trans->transid, inode->i_ino);
+ BUG_ON(ret);
+ }
+ }
+
+ if (found_inline) {
+ u64 mask = root->sectorsize - 1;
+ search_start = (extent_end + mask) & ~mask;
+ } else
+ search_start = extent_end;
+
+ /* truncate existing extent */
+ if (start > key.offset) {
+ u64 new_num;
+ u64 old_num;
+ keep = 1;
+ WARN_ON(start & (root->sectorsize - 1));
+ if (found_extent) {
+ new_num = start - key.offset;
+ old_num = btrfs_file_extent_num_bytes(leaf,
+ extent);
+ *hint_byte =
+ btrfs_file_extent_disk_bytenr(leaf,
+ extent);
+ if (btrfs_file_extent_disk_bytenr(leaf,
+ extent)) {
+ inode_sub_bytes(inode, old_num -
+ new_num);
+ }
+ btrfs_set_file_extent_num_bytes(leaf,
+ extent, new_num);
+ btrfs_mark_buffer_dirty(leaf);
+ } else if (key.offset < inline_limit &&
+ (end > extent_end) &&
+ (inline_limit < extent_end)) {
+ u32 new_size;
+ new_size = btrfs_file_extent_calc_inline_size(
+ inline_limit - key.offset);
+ inode_sub_bytes(inode, extent_end -
+ inline_limit);
+ btrfs_set_file_extent_ram_bytes(leaf, extent,
+ new_size);
+ if (!compression && !encryption) {
+ btrfs_truncate_item(trans, root, path,
+ new_size, 1);
+ }
+ }
+ }
+ /* delete the entire extent */
+ if (!keep) {
+ if (found_inline)
+ inode_sub_bytes(inode, extent_end -
+ key.offset);
+ ret = btrfs_del_item(trans, root, path);
+ /* TODO update progress marker and return */
+ BUG_ON(ret);
+ extent = NULL;
+ btrfs_release_path(root, path);
+ /* the extent will be freed later */
+ }
+ if (bookend && found_inline && start <= key.offset) {
+ u32 new_size;
+ new_size = btrfs_file_extent_calc_inline_size(
+ extent_end - end);
+ inode_sub_bytes(inode, end - key.offset);
+ btrfs_set_file_extent_ram_bytes(leaf, extent,
+ new_size);
+ if (!compression && !encryption)
+ ret = btrfs_truncate_item(trans, root, path,
+ new_size, 0);
+ BUG_ON(ret);
+ }
+ /* create bookend, splitting the extent in two */
+ if (bookend && found_extent) {
+ struct btrfs_key ins;
+ ins.objectid = inode->i_ino;
+ ins.offset = end;
+ btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
+
+ btrfs_release_path(root, path);
+ ret = btrfs_insert_empty_item(trans, root, path, &ins,
+ sizeof(*extent));
+ BUG_ON(ret);
+
+ leaf = path->nodes[0];
+ extent = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ write_extent_buffer(leaf, &old,
+ (unsigned long)extent, sizeof(old));
+
+ btrfs_set_file_extent_compression(leaf, extent,
+ compression);
+ btrfs_set_file_extent_encryption(leaf, extent,
+ encryption);
+ btrfs_set_file_extent_other_encoding(leaf, extent,
+ other_encoding);
+ btrfs_set_file_extent_offset(leaf, extent,
+ le64_to_cpu(old.offset) + end - key.offset);
+ WARN_ON(le64_to_cpu(old.num_bytes) <
+ (extent_end - end));
+ btrfs_set_file_extent_num_bytes(leaf, extent,
+ extent_end - end);
+
+ /*
+ * set the ram bytes to the size of the full extent
+ * before splitting. This is a worst case flag,
+ * but its the best we can do because we don't know
+ * how splitting affects compression
+ */
+ btrfs_set_file_extent_ram_bytes(leaf, extent,
+ ram_bytes);
+ btrfs_set_file_extent_type(leaf, extent, found_type);
+
+ btrfs_mark_buffer_dirty(path->nodes[0]);
+
+ if (disk_bytenr != 0) {
+ ret = btrfs_update_extent_ref(trans, root,
+ disk_bytenr, orig_parent,
+ leaf->start,
+ root->root_key.objectid,
+ trans->transid, ins.objectid);
+
+ BUG_ON(ret);
+ }
+ btrfs_release_path(root, path);
+ if (disk_bytenr != 0)
+ inode_add_bytes(inode, extent_end - end);
+ }
+
+ if (found_extent && !keep) {
+ u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr);
+
+ if (old_disk_bytenr != 0) {
+ inode_sub_bytes(inode,
+ le64_to_cpu(old.num_bytes));
+ ret = btrfs_free_extent(trans, root,
+ old_disk_bytenr,
+ le64_to_cpu(old.disk_num_bytes),
+ leaf_start, root_owner,
+ root_gen, key.objectid, 0);
+ BUG_ON(ret);
+ *hint_byte = old_disk_bytenr;
+ }
+ }
+
+ if (search_start >= end) {
+ ret = 0;
+ goto out;
+ }
+ }
+out:
+ btrfs_free_path(path);
+ if (locked_end > end) {
+ unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
+ GFP_NOFS);
+ }
+ btrfs_check_file(root, inode);
+ return ret;
+}
+
+static int extent_mergeable(struct extent_buffer *leaf, int slot,
+ u64 objectid, u64 bytenr, u64 *start, u64 *end)
+{
+ struct btrfs_file_extent_item *fi;
+ struct btrfs_key key;
+ u64 extent_end;
+
+ if (slot < 0 || slot >= btrfs_header_nritems(leaf))
+ return 0;
+
+ btrfs_item_key_to_cpu(leaf, &key, slot);
+ if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
+ return 0;
+
+ fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
+ if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
+ btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
+ btrfs_file_extent_compression(leaf, fi) ||
+ btrfs_file_extent_encryption(leaf, fi) ||
+ btrfs_file_extent_other_encoding(leaf, fi))
+ return 0;
+
+ extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
+ if ((*start && *start != key.offset) || (*end && *end != extent_end))
+ return 0;
+
+ *start = key.offset;
+ *end = extent_end;
+ return 1;
+}
+
+/*
+ * Mark extent in the range start - end as written.
+ *
+ * This changes extent type from 'pre-allocated' to 'regular'. If only
+ * part of extent is marked as written, the extent will be split into
+ * two or three.
+ */
+int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct inode *inode, u64 start, u64 end)
+{
+ struct extent_buffer *leaf;
+ struct btrfs_path *path;
+ struct btrfs_file_extent_item *fi;
+ struct btrfs_key key;
+ u64 bytenr;
+ u64 num_bytes;
+ u64 extent_end;
+ u64 extent_offset;
+ u64 other_start;
+ u64 other_end;
+ u64 split = start;
+ u64 locked_end = end;
+ u64 orig_parent;
+ int extent_type;
+ int split_end = 1;
+ int ret;
+
+ btrfs_drop_extent_cache(inode, start, end - 1, 0);
+
+ path = btrfs_alloc_path();
+ BUG_ON(!path);
+again:
+ key.objectid = inode->i_ino;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ if (split == start)
+ key.offset = split;
+ else
+ key.offset = split - 1;
+
+ ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+ if (ret > 0 && path->slots[0] > 0)
+ path->slots[0]--;
+
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ BUG_ON(key.objectid != inode->i_ino ||
+ key.type != BTRFS_EXTENT_DATA_KEY);
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ extent_type = btrfs_file_extent_type(leaf, fi);
+ BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
+ extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
+ BUG_ON(key.offset > start || extent_end < end);
+
+ bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+ num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
+ extent_offset = btrfs_file_extent_offset(leaf, fi);
+
+ if (key.offset == start)
+ split = end;
+
+ if (key.offset == start && extent_end == end) {
+ int del_nr = 0;
+ int del_slot = 0;
+ u64 leaf_owner = btrfs_header_owner(leaf);
+ u64 leaf_gen = btrfs_header_generation(leaf);
+ other_start = end;
+ other_end = 0;
+ if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
+ bytenr, &other_start, &other_end)) {
+ extent_end = other_end;
+ del_slot = path->slots[0] + 1;
+ del_nr++;
+ ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
+ leaf->start, leaf_owner,
+ leaf_gen, inode->i_ino, 0);
+ BUG_ON(ret);
+ }
+ other_start = 0;
+ other_end = start;
+ if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
+ bytenr, &other_start, &other_end)) {
+ key.offset = other_start;
+ del_slot = path->slots[0];
+ del_nr++;
+ ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
+ leaf->start, leaf_owner,
+ leaf_gen, inode->i_ino, 0);
+ BUG_ON(ret);
+ }
+ split_end = 0;
+ if (del_nr == 0) {
+ btrfs_set_file_extent_type(leaf, fi,
+ BTRFS_FILE_EXTENT_REG);
+ goto done;
+ }
+
+ fi = btrfs_item_ptr(leaf, del_slot - 1,
+ struct btrfs_file_extent_item);
+ btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
+ btrfs_set_file_extent_num_bytes(leaf, fi,
+ extent_end - key.offset);
+ btrfs_mark_buffer_dirty(leaf);
+
+ ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
+ BUG_ON(ret);
+ goto done;
+ } else if (split == start) {
+ if (locked_end < extent_end) {
+ ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
+ locked_end, extent_end - 1, GFP_NOFS);
+ if (!ret) {
+ btrfs_release_path(root, path);
+ lock_extent(&BTRFS_I(inode)->io_tree,
+ locked_end, extent_end - 1, GFP_NOFS);
+ locked_end = extent_end;
+ goto again;
+ }
+ locked_end = extent_end;
+ }
+ btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
+ extent_offset += split - key.offset;
+ } else {
+ BUG_ON(key.offset != start);
+ btrfs_set_file_extent_offset(leaf, fi, extent_offset +
+ split - key.offset);
+ btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
+ key.offset = split;
+ btrfs_set_item_key_safe(trans, root, path, &key);
+ extent_end = split;
+ }
+
+ if (extent_end == end) {
+ split_end = 0;
+ extent_type = BTRFS_FILE_EXTENT_REG;
+ }
+ if (extent_end == end && split == start) {
+ other_start = end;
+ other_end = 0;
+ if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
+ bytenr, &other_start, &other_end)) {
+ path->slots[0]++;
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ key.offset = split;
+ btrfs_set_item_key_safe(trans, root, path, &key);
+ btrfs_set_file_extent_offset(leaf, fi, extent_offset);
+ btrfs_set_file_extent_num_bytes(leaf, fi,
+ other_end - split);
+ goto done;
+ }
+ }
+ if (extent_end == end && split == end) {
+ other_start = 0;
+ other_end = start;
+ if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
+ bytenr, &other_start, &other_end)) {
+ path->slots[0]--;
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
+ other_start);
+ goto done;
+ }
+ }
+
+ btrfs_mark_buffer_dirty(leaf);
+
+ orig_parent = leaf->start;
+ ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
+ orig_parent, root->root_key.objectid,
+ trans->transid, inode->i_ino);
+ BUG_ON(ret);
+ btrfs_release_path(root, path);
+
+ key.offset = start;
+ ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
+ BUG_ON(ret);
+
+ leaf = path->nodes[0];
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ btrfs_set_file_extent_generation(leaf, fi, trans->transid);
+ btrfs_set_file_extent_type(leaf, fi, extent_type);
+ btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
+ btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
+ btrfs_set_file_extent_offset(leaf, fi, extent_offset);
+ btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
+ btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
+ btrfs_set_file_extent_compression(leaf, fi, 0);
+ btrfs_set_file_extent_encryption(leaf, fi, 0);
+ btrfs_set_file_extent_other_encoding(leaf, fi, 0);
+
+ if (orig_parent != leaf->start) {
+ ret = btrfs_update_extent_ref(trans, root, bytenr,
+ orig_parent, leaf->start,
+ root->root_key.objectid,
+ trans->transid, inode->i_ino);
+ BUG_ON(ret);
+ }
+done:
+ btrfs_mark_buffer_dirty(leaf);
+ btrfs_release_path(root, path);
+ if (split_end && split == start) {
+ split = end;
+ goto again;
+ }
+ if (locked_end > end) {
+ unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
+ GFP_NOFS);
+ }
+ btrfs_free_path(path);
+ return 0;
+}
+
+/*
+ * this gets pages into the page cache and locks them down, it also properly
+ * waits for data=ordered extents to finish before allowing the pages to be
+ * modified.
+ */
+static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
+ struct page **pages, size_t num_pages,
+ loff_t pos, unsigned long first_index,
+ unsigned long last_index, size_t write_bytes)
+{
+ int i;
+ unsigned long index = pos >> PAGE_CACHE_SHIFT;
+ struct inode *inode = fdentry(file)->d_inode;
+ int err = 0;
+ u64 start_pos;
+ u64 last_pos;
+
+ start_pos = pos & ~((u64)root->sectorsize - 1);
+ last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
+
+ if (start_pos > inode->i_size) {
+ err = btrfs_cont_expand(inode, start_pos);
+ if (err)
+ return err;
+ }
+
+ memset(pages, 0, num_pages * sizeof(struct page *));
+again:
+ for (i = 0; i < num_pages; i++) {
+ pages[i] = grab_cache_page(inode->i_mapping, index + i);
+ if (!pages[i]) {
+ err = -ENOMEM;
+ BUG_ON(1);
+ }
+ wait_on_page_writeback(pages[i]);
+ }
+ if (start_pos < inode->i_size) {
+ struct btrfs_ordered_extent *ordered;
+ lock_extent(&BTRFS_I(inode)->io_tree,
+ start_pos, last_pos - 1, GFP_NOFS);
+ ordered = btrfs_lookup_first_ordered_extent(inode,
+ last_pos - 1);
+ if (ordered &&
+ ordered->file_offset + ordered->len > start_pos &&
+ ordered->file_offset < last_pos) {
+ btrfs_put_ordered_extent(ordered);
+ unlock_extent(&BTRFS_I(inode)->io_tree,
+ start_pos, last_pos - 1, GFP_NOFS);
+ for (i = 0; i < num_pages; i++) {
+ unlock_page(pages[i]);
+ page_cache_release(pages[i]);
+ }
+ btrfs_wait_ordered_range(inode, start_pos,
+ last_pos - start_pos);
+ goto again;
+ }
+ if (ordered)
+ btrfs_put_ordered_extent(ordered);
+
+ clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
+ last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
+ GFP_NOFS);
+ unlock_extent(&BTRFS_I(inode)->io_tree,
+ start_pos, last_pos - 1, GFP_NOFS);
+ }
+ for (i = 0; i < num_pages; i++) {
+ clear_page_dirty_for_io(pages[i]);
+ set_page_extent_mapped(pages[i]);
+ WARN_ON(!PageLocked(pages[i]));
+ }
+ return 0;
+}
+
+static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ loff_t pos;
+ loff_t start_pos;
+ ssize_t num_written = 0;
+ ssize_t err = 0;
+ int ret = 0;
+ struct inode *inode = fdentry(file)->d_inode;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct page **pages = NULL;
+ int nrptrs;
+ struct page *pinned[2];
+ unsigned long first_index;
+ unsigned long last_index;
+ int will_write;
+
+ will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
+ (file->f_flags & O_DIRECT));
+
+ nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
+ PAGE_CACHE_SIZE / (sizeof(struct page *)));
+ pinned[0] = NULL;
+ pinned[1] = NULL;
+
+ pos = *ppos;
+ start_pos = pos;
+
+ vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+ current->backing_dev_info = inode->i_mapping->backing_dev_info;
+ err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
+ if (err)
+ goto out_nolock;
+ if (count == 0)
+ goto out_nolock;
+
+ err = file_remove_suid(file);
+ if (err)
+ goto out_nolock;
+ file_update_time(file);
+
+ pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
+
+ mutex_lock(&inode->i_mutex);
+ BTRFS_I(inode)->sequence++;
+ first_index = pos >> PAGE_CACHE_SHIFT;
+ last_index = (pos + count) >> PAGE_CACHE_SHIFT;
+
+ /*
+ * there are lots of better ways to do this, but this code
+ * makes sure the first and last page in the file range are
+ * up to date and ready for cow
+ */
+ if ((pos & (PAGE_CACHE_SIZE - 1))) {
+ pinned[0] = grab_cache_page(inode->i_mapping, first_index);
+ if (!PageUptodate(pinned[0])) {
+ ret = btrfs_readpage(NULL, pinned[0]);
+ BUG_ON(ret);
+ wait_on_page_locked(pinned[0]);
+ } else {
+ unlock_page(pinned[0]);
+ }
+ }
+ if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
+ pinned[1] = grab_cache_page(inode->i_mapping, last_index);
+ if (!PageUptodate(pinned[1])) {
+ ret = btrfs_readpage(NULL, pinned[1]);
+ BUG_ON(ret);
+ wait_on_page_locked(pinned[1]);
+ } else {
+ unlock_page(pinned[1]);
+ }
+ }
+
+ while (count > 0) {
+ size_t offset = pos & (PAGE_CACHE_SIZE - 1);
+ size_t write_bytes = min(count, nrptrs *
+ (size_t)PAGE_CACHE_SIZE -
+ offset);
+ size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
+ PAGE_CACHE_SHIFT;
+
+ WARN_ON(num_pages > nrptrs);
+ memset(pages, 0, sizeof(struct page *) * nrptrs);
+
+ ret = btrfs_check_free_space(root, write_bytes, 0);
+ if (ret)
+ goto out;
+
+ ret = prepare_pages(root, file, pages, num_pages,
+ pos, first_index, last_index,
+ write_bytes);
+ if (ret)
+ goto out;
+
+ ret = btrfs_copy_from_user(pos, num_pages,
+ write_bytes, pages, buf);
+ if (ret) {
+ btrfs_drop_pages(pages, num_pages);
+ goto out;
+ }
+
+ ret = dirty_and_release_pages(NULL, root, file, pages,
+ num_pages, pos, write_bytes);
+ btrfs_drop_pages(pages, num_pages);
+ if (ret)
+ goto out;
+
+ if (will_write) {
+ btrfs_fdatawrite_range(inode->i_mapping, pos,
+ pos + write_bytes - 1,
+ WB_SYNC_NONE);
+ } else {
+ balance_dirty_pages_ratelimited_nr(inode->i_mapping,
+ num_pages);
+ if (num_pages <
+ (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
+ btrfs_btree_balance_dirty(root, 1);
+ btrfs_throttle(root);
+ }
+
+ buf += write_bytes;
+ count -= write_bytes;
+ pos += write_bytes;
+ num_written += write_bytes;
+
+ cond_resched();
+ }
+out:
+ mutex_unlock(&inode->i_mutex);
+
+out_nolock:
+ kfree(pages);
+ if (pinned[0])
+ page_cache_release(pinned[0]);
+ if (pinned[1])
+ page_cache_release(pinned[1]);
+ *ppos = pos;
+
+ if (num_written > 0 && will_write) {
+ struct btrfs_trans_handle *trans;
+
+ err = btrfs_wait_ordered_range(inode, start_pos, num_written);
+ if (err)
+ num_written = err;
+
+ if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
+ trans = btrfs_start_transaction(root, 1);
+ ret = btrfs_log_dentry_safe(trans, root,
+ file->f_dentry);
+ if (ret == 0) {
+ btrfs_sync_log(trans, root);
+ btrfs_end_transaction(trans, root);
+ } else {
+ btrfs_commit_transaction(trans, root);
+ }
+ }
+ if (file->f_flags & O_DIRECT) {
+ invalidate_mapping_pages(inode->i_mapping,
+ start_pos >> PAGE_CACHE_SHIFT,
+ (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
+ }
+ }
+ current->backing_dev_info = NULL;
+ return num_written ? num_written : err;
+}
+
+int btrfs_release_file(struct inode *inode, struct file *filp)
+{
+ if (filp->private_data)
+ btrfs_ioctl_trans_end(filp);
+ return 0;
+}
+
+/*
+ * fsync call for both files and directories. This logs the inode into
+ * the tree log instead of forcing full commits whenever possible.
+ *
+ * It needs to call filemap_fdatawait so that all ordered extent updates are
+ * in the metadata btree are up to date for copying to the log.
+ *
+ * It drops the inode mutex before doing the tree log commit. This is an
+ * important optimization for directories because holding the mutex prevents
+ * new operations on the dir while we write to disk.
+ */
+int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
+{
+ struct inode *inode = dentry->d_inode;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ int ret = 0;
+ struct btrfs_trans_handle *trans;
+
+ /*
+ * check the transaction that last modified this inode
+ * and see if its already been committed
+ */
+ if (!BTRFS_I(inode)->last_trans)
+ goto out;
+
+ mutex_lock(&root->fs_info->trans_mutex);
+ if (BTRFS_I(inode)->last_trans <=
+ root->fs_info->last_trans_committed) {
+ BTRFS_I(inode)->last_trans = 0;
+ mutex_unlock(&root->fs_info->trans_mutex);
+ goto out;
+ }
+ mutex_unlock(&root->fs_info->trans_mutex);
+
+ root->fs_info->tree_log_batch++;
+ filemap_fdatawrite(inode->i_mapping);
+ btrfs_wait_ordered_range(inode, 0, (u64)-1);
+ root->fs_info->tree_log_batch++;
+
+ /*
+ * ok we haven't committed the transaction yet, lets do a commit
+ */
+ if (file->private_data)
+ btrfs_ioctl_trans_end(file);
+
+ trans = btrfs_start_transaction(root, 1);
+ if (!trans) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ret = btrfs_log_dentry_safe(trans, root, file->f_dentry);
+ if (ret < 0)
+ goto out;
+
+ /* we've logged all the items and now have a consistent
+ * version of the file in the log. It is possible that
+ * someone will come in and modify the file, but that's
+ * fine because the log is consistent on disk, and we
+ * have references to all of the file's extents
+ *
+ * It is possible that someone will come in and log the
+ * file again, but that will end up using the synchronization
+ * inside btrfs_sync_log to keep things safe.
+ */
+ mutex_unlock(&file->f_dentry->d_inode->i_mutex);
+
+ if (ret > 0) {
+ ret = btrfs_commit_transaction(trans, root);
+ } else {
+ btrfs_sync_log(trans, root);
+ ret = btrfs_end_transaction(trans, root);
+ }
+ mutex_lock(&file->f_dentry->d_inode->i_mutex);
+out:
+ return ret > 0 ? EIO : ret;
+}
+
+static struct vm_operations_struct btrfs_file_vm_ops = {
+ .fault = filemap_fault,
+ .page_mkwrite = btrfs_page_mkwrite,
+};
+
+static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+ vma->vm_ops = &btrfs_file_vm_ops;
+ file_accessed(filp);
+ return 0;
+}
+
+struct file_operations btrfs_file_operations = {
+ .llseek = generic_file_llseek,
+ .read = do_sync_read,
+ .aio_read = generic_file_aio_read,
+ .splice_read = generic_file_splice_read,
+ .write = btrfs_file_write,
+ .mmap = btrfs_file_mmap,
+ .open = generic_file_open,
+ .release = btrfs_release_file,
+ .fsync = btrfs_sync_file,
+ .unlocked_ioctl = btrfs_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = btrfs_ioctl,
+#endif
+};