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-rw-r--r--fs/afs/dir.c666
1 files changed, 666 insertions, 0 deletions
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
new file mode 100644
index 000000000000..6682d6d7f294
--- /dev/null
+++ b/fs/afs/dir.c
@@ -0,0 +1,666 @@
+/* dir.c: AFS filesystem directory handling
+ *
+ * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/smp_lock.h>
+#include "vnode.h"
+#include "volume.h"
+#include <rxrpc/call.h>
+#include "super.h"
+#include "internal.h"
+
+static struct dentry *afs_dir_lookup(struct inode *dir, struct dentry *dentry,
+ struct nameidata *nd);
+static int afs_dir_open(struct inode *inode, struct file *file);
+static int afs_dir_readdir(struct file *file, void *dirent, filldir_t filldir);
+static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd);
+static int afs_d_delete(struct dentry *dentry);
+static int afs_dir_lookup_filldir(void *_cookie, const char *name, int nlen,
+ loff_t fpos, ino_t ino, unsigned dtype);
+
+struct file_operations afs_dir_file_operations = {
+ .open = afs_dir_open,
+ .readdir = afs_dir_readdir,
+};
+
+struct inode_operations afs_dir_inode_operations = {
+ .lookup = afs_dir_lookup,
+ .getattr = afs_inode_getattr,
+#if 0 /* TODO */
+ .create = afs_dir_create,
+ .link = afs_dir_link,
+ .unlink = afs_dir_unlink,
+ .symlink = afs_dir_symlink,
+ .mkdir = afs_dir_mkdir,
+ .rmdir = afs_dir_rmdir,
+ .mknod = afs_dir_mknod,
+ .rename = afs_dir_rename,
+#endif
+};
+
+static struct dentry_operations afs_fs_dentry_operations = {
+ .d_revalidate = afs_d_revalidate,
+ .d_delete = afs_d_delete,
+};
+
+#define AFS_DIR_HASHTBL_SIZE 128
+#define AFS_DIR_DIRENT_SIZE 32
+#define AFS_DIRENT_PER_BLOCK 64
+
+union afs_dirent {
+ struct {
+ uint8_t valid;
+ uint8_t unused[1];
+ __be16 hash_next;
+ __be32 vnode;
+ __be32 unique;
+ uint8_t name[16];
+ uint8_t overflow[4]; /* if any char of the name (inc
+ * NUL) reaches here, consume
+ * the next dirent too */
+ } u;
+ uint8_t extended_name[32];
+};
+
+/* AFS directory page header (one at the beginning of every 2048-byte chunk) */
+struct afs_dir_pagehdr {
+ __be16 npages;
+ __be16 magic;
+#define AFS_DIR_MAGIC htons(1234)
+ uint8_t nentries;
+ uint8_t bitmap[8];
+ uint8_t pad[19];
+};
+
+/* directory block layout */
+union afs_dir_block {
+
+ struct afs_dir_pagehdr pagehdr;
+
+ struct {
+ struct afs_dir_pagehdr pagehdr;
+ uint8_t alloc_ctrs[128];
+ /* dir hash table */
+ uint16_t hashtable[AFS_DIR_HASHTBL_SIZE];
+ } hdr;
+
+ union afs_dirent dirents[AFS_DIRENT_PER_BLOCK];
+};
+
+/* layout on a linux VM page */
+struct afs_dir_page {
+ union afs_dir_block blocks[PAGE_SIZE / sizeof(union afs_dir_block)];
+};
+
+struct afs_dir_lookup_cookie {
+ struct afs_fid fid;
+ const char *name;
+ size_t nlen;
+ int found;
+};
+
+/*****************************************************************************/
+/*
+ * check that a directory page is valid
+ */
+static inline void afs_dir_check_page(struct inode *dir, struct page *page)
+{
+ struct afs_dir_page *dbuf;
+ loff_t latter;
+ int tmp, qty;
+
+#if 0
+ /* check the page count */
+ qty = desc.size / sizeof(dbuf->blocks[0]);
+ if (qty == 0)
+ goto error;
+
+ if (page->index==0 && qty!=ntohs(dbuf->blocks[0].pagehdr.npages)) {
+ printk("kAFS: %s(%lu): wrong number of dir blocks %d!=%hu\n",
+ __FUNCTION__,dir->i_ino,qty,ntohs(dbuf->blocks[0].pagehdr.npages));
+ goto error;
+ }
+#endif
+
+ /* determine how many magic numbers there should be in this page */
+ latter = dir->i_size - (page->index << PAGE_CACHE_SHIFT);
+ if (latter >= PAGE_SIZE)
+ qty = PAGE_SIZE;
+ else
+ qty = latter;
+ qty /= sizeof(union afs_dir_block);
+
+ /* check them */
+ dbuf = page_address(page);
+ for (tmp = 0; tmp < qty; tmp++) {
+ if (dbuf->blocks[tmp].pagehdr.magic != AFS_DIR_MAGIC) {
+ printk("kAFS: %s(%lu): bad magic %d/%d is %04hx\n",
+ __FUNCTION__, dir->i_ino, tmp, qty,
+ ntohs(dbuf->blocks[tmp].pagehdr.magic));
+ goto error;
+ }
+ }
+
+ SetPageChecked(page);
+ return;
+
+ error:
+ SetPageChecked(page);
+ SetPageError(page);
+
+} /* end afs_dir_check_page() */
+
+/*****************************************************************************/
+/*
+ * discard a page cached in the pagecache
+ */
+static inline void afs_dir_put_page(struct page *page)
+{
+ kunmap(page);
+ page_cache_release(page);
+
+} /* end afs_dir_put_page() */
+
+/*****************************************************************************/
+/*
+ * get a page into the pagecache
+ */
+static struct page *afs_dir_get_page(struct inode *dir, unsigned long index)
+{
+ struct page *page;
+
+ _enter("{%lu},%lu", dir->i_ino, index);
+
+ page = read_cache_page(dir->i_mapping,index,
+ (filler_t *) dir->i_mapping->a_ops->readpage,
+ NULL);
+ if (!IS_ERR(page)) {
+ wait_on_page_locked(page);
+ kmap(page);
+ if (!PageUptodate(page))
+ goto fail;
+ if (!PageChecked(page))
+ afs_dir_check_page(dir, page);
+ if (PageError(page))
+ goto fail;
+ }
+ return page;
+
+ fail:
+ afs_dir_put_page(page);
+ return ERR_PTR(-EIO);
+} /* end afs_dir_get_page() */
+
+/*****************************************************************************/
+/*
+ * open an AFS directory file
+ */
+static int afs_dir_open(struct inode *inode, struct file *file)
+{
+ _enter("{%lu}", inode->i_ino);
+
+ BUG_ON(sizeof(union afs_dir_block) != 2048);
+ BUG_ON(sizeof(union afs_dirent) != 32);
+
+ if (AFS_FS_I(inode)->flags & AFS_VNODE_DELETED)
+ return -ENOENT;
+
+ _leave(" = 0");
+ return 0;
+
+} /* end afs_dir_open() */
+
+/*****************************************************************************/
+/*
+ * deal with one block in an AFS directory
+ */
+static int afs_dir_iterate_block(unsigned *fpos,
+ union afs_dir_block *block,
+ unsigned blkoff,
+ void *cookie,
+ filldir_t filldir)
+{
+ union afs_dirent *dire;
+ unsigned offset, next, curr;
+ size_t nlen;
+ int tmp, ret;
+
+ _enter("%u,%x,%p,,",*fpos,blkoff,block);
+
+ curr = (*fpos - blkoff) / sizeof(union afs_dirent);
+
+ /* walk through the block, an entry at a time */
+ for (offset = AFS_DIRENT_PER_BLOCK - block->pagehdr.nentries;
+ offset < AFS_DIRENT_PER_BLOCK;
+ offset = next
+ ) {
+ next = offset + 1;
+
+ /* skip entries marked unused in the bitmap */
+ if (!(block->pagehdr.bitmap[offset / 8] &
+ (1 << (offset % 8)))) {
+ _debug("ENT[%Zu.%u]: unused\n",
+ blkoff / sizeof(union afs_dir_block), offset);
+ if (offset >= curr)
+ *fpos = blkoff +
+ next * sizeof(union afs_dirent);
+ continue;
+ }
+
+ /* got a valid entry */
+ dire = &block->dirents[offset];
+ nlen = strnlen(dire->u.name,
+ sizeof(*block) -
+ offset * sizeof(union afs_dirent));
+
+ _debug("ENT[%Zu.%u]: %s %Zu \"%s\"\n",
+ blkoff / sizeof(union afs_dir_block), offset,
+ (offset < curr ? "skip" : "fill"),
+ nlen, dire->u.name);
+
+ /* work out where the next possible entry is */
+ for (tmp = nlen; tmp > 15; tmp -= sizeof(union afs_dirent)) {
+ if (next >= AFS_DIRENT_PER_BLOCK) {
+ _debug("ENT[%Zu.%u]:"
+ " %u travelled beyond end dir block"
+ " (len %u/%Zu)\n",
+ blkoff / sizeof(union afs_dir_block),
+ offset, next, tmp, nlen);
+ return -EIO;
+ }
+ if (!(block->pagehdr.bitmap[next / 8] &
+ (1 << (next % 8)))) {
+ _debug("ENT[%Zu.%u]:"
+ " %u unmarked extension (len %u/%Zu)\n",
+ blkoff / sizeof(union afs_dir_block),
+ offset, next, tmp, nlen);
+ return -EIO;
+ }
+
+ _debug("ENT[%Zu.%u]: ext %u/%Zu\n",
+ blkoff / sizeof(union afs_dir_block),
+ next, tmp, nlen);
+ next++;
+ }
+
+ /* skip if starts before the current position */
+ if (offset < curr)
+ continue;
+
+ /* found the next entry */
+ ret = filldir(cookie,
+ dire->u.name,
+ nlen,
+ blkoff + offset * sizeof(union afs_dirent),
+ ntohl(dire->u.vnode),
+ filldir == afs_dir_lookup_filldir ?
+ ntohl(dire->u.unique) : DT_UNKNOWN);
+ if (ret < 0) {
+ _leave(" = 0 [full]");
+ return 0;
+ }
+
+ *fpos = blkoff + next * sizeof(union afs_dirent);
+ }
+
+ _leave(" = 1 [more]");
+ return 1;
+} /* end afs_dir_iterate_block() */
+
+/*****************************************************************************/
+/*
+ * read an AFS directory
+ */
+static int afs_dir_iterate(struct inode *dir, unsigned *fpos, void *cookie,
+ filldir_t filldir)
+{
+ union afs_dir_block *dblock;
+ struct afs_dir_page *dbuf;
+ struct page *page;
+ unsigned blkoff, limit;
+ int ret;
+
+ _enter("{%lu},%u,,", dir->i_ino, *fpos);
+
+ if (AFS_FS_I(dir)->flags & AFS_VNODE_DELETED) {
+ _leave(" = -ESTALE");
+ return -ESTALE;
+ }
+
+ /* round the file position up to the next entry boundary */
+ *fpos += sizeof(union afs_dirent) - 1;
+ *fpos &= ~(sizeof(union afs_dirent) - 1);
+
+ /* walk through the blocks in sequence */
+ ret = 0;
+ while (*fpos < dir->i_size) {
+ blkoff = *fpos & ~(sizeof(union afs_dir_block) - 1);
+
+ /* fetch the appropriate page from the directory */
+ page = afs_dir_get_page(dir, blkoff / PAGE_SIZE);
+ if (IS_ERR(page)) {
+ ret = PTR_ERR(page);
+ break;
+ }
+
+ limit = blkoff & ~(PAGE_SIZE - 1);
+
+ dbuf = page_address(page);
+
+ /* deal with the individual blocks stashed on this page */
+ do {
+ dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /
+ sizeof(union afs_dir_block)];
+ ret = afs_dir_iterate_block(fpos, dblock, blkoff,
+ cookie, filldir);
+ if (ret != 1) {
+ afs_dir_put_page(page);
+ goto out;
+ }
+
+ blkoff += sizeof(union afs_dir_block);
+
+ } while (*fpos < dir->i_size && blkoff < limit);
+
+ afs_dir_put_page(page);
+ ret = 0;
+ }
+
+ out:
+ _leave(" = %d", ret);
+ return ret;
+} /* end afs_dir_iterate() */
+
+/*****************************************************************************/
+/*
+ * read an AFS directory
+ */
+static int afs_dir_readdir(struct file *file, void *cookie, filldir_t filldir)
+{
+ unsigned fpos;
+ int ret;
+
+ _enter("{%Ld,{%lu}}", file->f_pos, file->f_dentry->d_inode->i_ino);
+
+ fpos = file->f_pos;
+ ret = afs_dir_iterate(file->f_dentry->d_inode, &fpos, cookie, filldir);
+ file->f_pos = fpos;
+
+ _leave(" = %d", ret);
+ return ret;
+} /* end afs_dir_readdir() */
+
+/*****************************************************************************/
+/*
+ * search the directory for a name
+ * - if afs_dir_iterate_block() spots this function, it'll pass the FID
+ * uniquifier through dtype
+ */
+static int afs_dir_lookup_filldir(void *_cookie, const char *name, int nlen,
+ loff_t fpos, ino_t ino, unsigned dtype)
+{
+ struct afs_dir_lookup_cookie *cookie = _cookie;
+
+ _enter("{%s,%Zu},%s,%u,,%lu,%u",
+ cookie->name, cookie->nlen, name, nlen, ino, dtype);
+
+ if (cookie->nlen != nlen || memcmp(cookie->name, name, nlen) != 0) {
+ _leave(" = 0 [no]");
+ return 0;
+ }
+
+ cookie->fid.vnode = ino;
+ cookie->fid.unique = dtype;
+ cookie->found = 1;
+
+ _leave(" = -1 [found]");
+ return -1;
+} /* end afs_dir_lookup_filldir() */
+
+/*****************************************************************************/
+/*
+ * look up an entry in a directory
+ */
+static struct dentry *afs_dir_lookup(struct inode *dir, struct dentry *dentry,
+ struct nameidata *nd)
+{
+ struct afs_dir_lookup_cookie cookie;
+ struct afs_super_info *as;
+ struct afs_vnode *vnode;
+ struct inode *inode;
+ unsigned fpos;
+ int ret;
+
+ _enter("{%lu},%p{%s}", dir->i_ino, dentry, dentry->d_name.name);
+
+ /* insanity checks first */
+ BUG_ON(sizeof(union afs_dir_block) != 2048);
+ BUG_ON(sizeof(union afs_dirent) != 32);
+
+ if (dentry->d_name.len > 255) {
+ _leave(" = -ENAMETOOLONG");
+ return ERR_PTR(-ENAMETOOLONG);
+ }
+
+ vnode = AFS_FS_I(dir);
+ if (vnode->flags & AFS_VNODE_DELETED) {
+ _leave(" = -ESTALE");
+ return ERR_PTR(-ESTALE);
+ }
+
+ as = dir->i_sb->s_fs_info;
+
+ /* search the directory */
+ cookie.name = dentry->d_name.name;
+ cookie.nlen = dentry->d_name.len;
+ cookie.fid.vid = as->volume->vid;
+ cookie.found = 0;
+
+ fpos = 0;
+ ret = afs_dir_iterate(dir, &fpos, &cookie, afs_dir_lookup_filldir);
+ if (ret < 0) {
+ _leave(" = %d", ret);
+ return ERR_PTR(ret);
+ }
+
+ ret = -ENOENT;
+ if (!cookie.found) {
+ _leave(" = %d", ret);
+ return ERR_PTR(ret);
+ }
+
+ /* instantiate the dentry */
+ ret = afs_iget(dir->i_sb, &cookie.fid, &inode);
+ if (ret < 0) {
+ _leave(" = %d", ret);
+ return ERR_PTR(ret);
+ }
+
+ dentry->d_op = &afs_fs_dentry_operations;
+ dentry->d_fsdata = (void *) (unsigned long) vnode->status.version;
+
+ d_add(dentry, inode);
+ _leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%lu }",
+ cookie.fid.vnode,
+ cookie.fid.unique,
+ dentry->d_inode->i_ino,
+ dentry->d_inode->i_version);
+
+ return NULL;
+} /* end afs_dir_lookup() */
+
+/*****************************************************************************/
+/*
+ * check that a dentry lookup hit has found a valid entry
+ * - NOTE! the hit can be a negative hit too, so we can't assume we have an
+ * inode
+ * (derived from nfs_lookup_revalidate)
+ */
+static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+ struct afs_dir_lookup_cookie cookie;
+ struct dentry *parent;
+ struct inode *inode, *dir;
+ unsigned fpos;
+ int ret;
+
+ _enter("{sb=%p n=%s},", dentry->d_sb, dentry->d_name.name);
+
+ /* lock down the parent dentry so we can peer at it */
+ parent = dget_parent(dentry->d_parent);
+
+ dir = parent->d_inode;
+ inode = dentry->d_inode;
+
+ /* handle a negative dentry */
+ if (!inode)
+ goto out_bad;
+
+ /* handle a bad inode */
+ if (is_bad_inode(inode)) {
+ printk("kAFS: afs_d_revalidate: %s/%s has bad inode\n",
+ dentry->d_parent->d_name.name, dentry->d_name.name);
+ goto out_bad;
+ }
+
+ /* force a full look up if the parent directory changed since last the
+ * server was consulted
+ * - otherwise this inode must still exist, even if the inode details
+ * themselves have changed
+ */
+ if (AFS_FS_I(dir)->flags & AFS_VNODE_CHANGED)
+ afs_vnode_fetch_status(AFS_FS_I(dir));
+
+ if (AFS_FS_I(dir)->flags & AFS_VNODE_DELETED) {
+ _debug("%s: parent dir deleted", dentry->d_name.name);
+ goto out_bad;
+ }
+
+ if (AFS_FS_I(inode)->flags & AFS_VNODE_DELETED) {
+ _debug("%s: file already deleted", dentry->d_name.name);
+ goto out_bad;
+ }
+
+ if ((unsigned long) dentry->d_fsdata !=
+ (unsigned long) AFS_FS_I(dir)->status.version) {
+ _debug("%s: parent changed %lu -> %u",
+ dentry->d_name.name,
+ (unsigned long) dentry->d_fsdata,
+ (unsigned) AFS_FS_I(dir)->status.version);
+
+ /* search the directory for this vnode */
+ cookie.name = dentry->d_name.name;
+ cookie.nlen = dentry->d_name.len;
+ cookie.fid.vid = AFS_FS_I(inode)->volume->vid;
+ cookie.found = 0;
+
+ fpos = 0;
+ ret = afs_dir_iterate(dir, &fpos, &cookie,
+ afs_dir_lookup_filldir);
+ if (ret < 0) {
+ _debug("failed to iterate dir %s: %d",
+ parent->d_name.name, ret);
+ goto out_bad;
+ }
+
+ if (!cookie.found) {
+ _debug("%s: dirent not found", dentry->d_name.name);
+ goto not_found;
+ }
+
+ /* if the vnode ID has changed, then the dirent points to a
+ * different file */
+ if (cookie.fid.vnode != AFS_FS_I(inode)->fid.vnode) {
+ _debug("%s: dirent changed", dentry->d_name.name);
+ goto not_found;
+ }
+
+ /* if the vnode ID uniqifier has changed, then the file has
+ * been deleted */
+ if (cookie.fid.unique != AFS_FS_I(inode)->fid.unique) {
+ _debug("%s: file deleted (uq %u -> %u I:%lu)",
+ dentry->d_name.name,
+ cookie.fid.unique,
+ AFS_FS_I(inode)->fid.unique,
+ inode->i_version);
+ spin_lock(&AFS_FS_I(inode)->lock);
+ AFS_FS_I(inode)->flags |= AFS_VNODE_DELETED;
+ spin_unlock(&AFS_FS_I(inode)->lock);
+ invalidate_remote_inode(inode);
+ goto out_bad;
+ }
+
+ dentry->d_fsdata =
+ (void *) (unsigned long) AFS_FS_I(dir)->status.version;
+ }
+
+ out_valid:
+ dput(parent);
+ _leave(" = 1 [valid]");
+ return 1;
+
+ /* the dirent, if it exists, now points to a different vnode */
+ not_found:
+ spin_lock(&dentry->d_lock);
+ dentry->d_flags |= DCACHE_NFSFS_RENAMED;
+ spin_unlock(&dentry->d_lock);
+
+ out_bad:
+ if (inode) {
+ /* don't unhash if we have submounts */
+ if (have_submounts(dentry))
+ goto out_valid;
+ }
+
+ shrink_dcache_parent(dentry);
+
+ _debug("dropping dentry %s/%s",
+ dentry->d_parent->d_name.name, dentry->d_name.name);
+ d_drop(dentry);
+
+ dput(parent);
+
+ _leave(" = 0 [bad]");
+ return 0;
+} /* end afs_d_revalidate() */
+
+/*****************************************************************************/
+/*
+ * allow the VFS to enquire as to whether a dentry should be unhashed (mustn't
+ * sleep)
+ * - called from dput() when d_count is going to 0.
+ * - return 1 to request dentry be unhashed, 0 otherwise
+ */
+static int afs_d_delete(struct dentry *dentry)
+{
+ _enter("%s", dentry->d_name.name);
+
+ if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
+ goto zap;
+
+ if (dentry->d_inode) {
+ if (AFS_FS_I(dentry->d_inode)->flags & AFS_VNODE_DELETED)
+ goto zap;
+ }
+
+ _leave(" = 0 [keep]");
+ return 0;
+
+ zap:
+ _leave(" = 1 [zap]");
+ return 1;
+} /* end afs_d_delete() */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-11 23:47:31 +0000