/* 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, u64 ino, unsigned dtype);
const struct file_operations afs_dir_file_operations = {
.open = afs_dir_open,
.readdir = afs_dir_readdir,
};
const 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_offset(page);
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_mapping_page(dir->i_mapping, index, 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);
BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
BUILD_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_path.dentry->d_inode->i_ino);
fpos = file->f_pos;
ret = afs_dir_iterate(file->f_path.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, u64 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 */
BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
BUILD_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() */
