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dir.c
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/* dir.c: AFS filesystem directory handling
*
* Copyright (C) 2002, 2018 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*
* 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/fs.h>
#include <linux/namei.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <linux/ctype.h>
#include <linux/sched.h>
#include <linux/task_io_accounting_ops.h>
#include "internal.h"
#include "xdr_fs.h"
static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags);
static int afs_dir_open(struct inode *inode, struct file *file);
static int afs_readdir(struct file *file, struct dir_context *ctx);
static int afs_d_revalidate(struct dentry *dentry, unsigned int flags);
static int afs_d_delete(const struct dentry *dentry);
static int afs_lookup_one_filldir(struct dir_context *ctx, const char *name, int nlen,
loff_t fpos, u64 ino, unsigned dtype);
static int afs_lookup_filldir(struct dir_context *ctx, const char *name, int nlen,
loff_t fpos, u64 ino, unsigned dtype);
static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
bool excl);
static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode);
static int afs_rmdir(struct inode *dir, struct dentry *dentry);
static int afs_unlink(struct inode *dir, struct dentry *dentry);
static int afs_link(struct dentry *from, struct inode *dir,
struct dentry *dentry);
static int afs_symlink(struct inode *dir, struct dentry *dentry,
const char *content);
static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry,
unsigned int flags);
static int afs_dir_releasepage(struct page *page, gfp_t gfp_flags);
static void afs_dir_invalidatepage(struct page *page, unsigned int offset,
unsigned int length);
static int afs_dir_set_page_dirty(struct page *page)
{
BUG(); /* This should never happen. */
}
const struct file_operations afs_dir_file_operations = {
.open = afs_dir_open,
.release = afs_release,
.iterate_shared = afs_readdir,
.lock = afs_lock,
.llseek = generic_file_llseek,
};
const struct inode_operations afs_dir_inode_operations = {
.create = afs_create,
.lookup = afs_lookup,
.link = afs_link,
.unlink = afs_unlink,
.symlink = afs_symlink,
.mkdir = afs_mkdir,
.rmdir = afs_rmdir,
.rename = afs_rename,
.permission = afs_permission,
.getattr = afs_getattr,
.setattr = afs_setattr,
.listxattr = afs_listxattr,
};
const struct address_space_operations afs_dir_aops = {
.set_page_dirty = afs_dir_set_page_dirty,
.releasepage = afs_dir_releasepage,
.invalidatepage = afs_dir_invalidatepage,
};
const struct dentry_operations afs_fs_dentry_operations = {
.d_revalidate = afs_d_revalidate,
.d_delete = afs_d_delete,
.d_release = afs_d_release,
.d_automount = afs_d_automount,
};
struct afs_lookup_one_cookie {
struct dir_context ctx;
struct qstr name;
bool found;
struct afs_fid fid;
};
struct afs_lookup_cookie {
struct dir_context ctx;
struct qstr name;
bool found;
bool one_only;
unsigned short nr_fids;
struct afs_file_status *statuses;
struct afs_callback *callbacks;
struct afs_fid fids[50];
};
/*
* check that a directory page is valid
*/
static bool afs_dir_check_page(struct afs_vnode *dvnode, struct page *page,
loff_t i_size)
{
struct afs_xdr_dir_page *dbuf;
loff_t latter, off;
int tmp, qty;
/* Determine how many magic numbers there should be in this page, but
* we must take care because the directory may change size under us.
*/
off = page_offset(page);
if (i_size <= off)
goto checked;
latter = i_size - off;
if (latter >= PAGE_SIZE)
qty = PAGE_SIZE;
else
qty = latter;
qty /= sizeof(union afs_xdr_dir_block);
/* check them */
dbuf = kmap(page);
for (tmp = 0; tmp < qty; tmp++) {
if (dbuf->blocks[tmp].hdr.magic != AFS_DIR_MAGIC) {
printk("kAFS: %s(%lx): bad magic %d/%d is %04hx\n",
__func__, dvnode->vfs_inode.i_ino, tmp, qty,
ntohs(dbuf->blocks[tmp].hdr.magic));
trace_afs_dir_check_failed(dvnode, off, i_size);
kunmap(page);
goto error;
}
/* Make sure each block is NUL terminated so we can reasonably
* use string functions on it. The filenames in the page
* *should* be NUL-terminated anyway.
*/
((u8 *)&dbuf->blocks[tmp])[AFS_DIR_BLOCK_SIZE - 1] = 0;
}
kunmap(page);
checked:
afs_stat_v(dvnode, n_read_dir);
return true;
error:
return false;
}
/*
* 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_xdr_dir_block) != 2048);
BUILD_BUG_ON(sizeof(union afs_xdr_dirent) != 32);
if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(inode)->flags))
return -ENOENT;
return afs_open(inode, file);
}
/*
* Read the directory into the pagecache in one go, scrubbing the previous
* contents. The list of pages is returned, pinning them so that they don't
* get reclaimed during the iteration.
*/
static struct afs_read *afs_read_dir(struct afs_vnode *dvnode, struct key *key)
__acquires(&dvnode->validate_lock)
{
struct afs_read *req;
loff_t i_size;
int nr_pages, nr_inline, i, n;
int ret = -ENOMEM;
retry:
i_size = i_size_read(&dvnode->vfs_inode);
if (i_size < 2048)
return ERR_PTR(-EIO);
if (i_size > 2048 * 1024)
return ERR_PTR(-EFBIG);
_enter("%llu", i_size);
/* Get a request record to hold the page list. We want to hold it
* inline if we can, but we don't want to make an order 1 allocation.
*/
nr_pages = (i_size + PAGE_SIZE - 1) / PAGE_SIZE;
nr_inline = nr_pages;
if (nr_inline > (PAGE_SIZE - sizeof(*req)) / sizeof(struct page *))
nr_inline = 0;
req = kzalloc(sizeof(*req) + sizeof(struct page *) * nr_inline,
GFP_KERNEL);
if (!req)
return ERR_PTR(-ENOMEM);
refcount_set(&req->usage, 1);
req->nr_pages = nr_pages;
req->actual_len = i_size; /* May change */
req->len = nr_pages * PAGE_SIZE; /* We can ask for more than there is */
req->data_version = dvnode->status.data_version; /* May change */
if (nr_inline > 0) {
req->pages = req->array;
} else {
req->pages = kcalloc(nr_pages, sizeof(struct page *),
GFP_KERNEL);
if (!req->pages)
goto error;
}
/* Get a list of all the pages that hold or will hold the directory
* content. We need to fill in any gaps that we might find where the
* memory reclaimer has been at work. If there are any gaps, we will
* need to reread the entire directory contents.
*/
i = 0;
do {
n = find_get_pages_contig(dvnode->vfs_inode.i_mapping, i,
req->nr_pages - i,
req->pages + i);
_debug("find %u at %u/%u", n, i, req->nr_pages);
if (n == 0) {
gfp_t gfp = dvnode->vfs_inode.i_mapping->gfp_mask;
if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
afs_stat_v(dvnode, n_inval);
ret = -ENOMEM;
req->pages[i] = __page_cache_alloc(gfp);
if (!req->pages[i])
goto error;
ret = add_to_page_cache_lru(req->pages[i],
dvnode->vfs_inode.i_mapping,
i, gfp);
if (ret < 0)
goto error;
set_page_private(req->pages[i], 1);
SetPagePrivate(req->pages[i]);
unlock_page(req->pages[i]);
i++;
} else {
i += n;
}
} while (i < req->nr_pages);
/* If we're going to reload, we need to lock all the pages to prevent
* races.
*/
ret = -ERESTARTSYS;
if (down_read_killable(&dvnode->validate_lock) < 0)
goto error;
if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
goto success;
up_read(&dvnode->validate_lock);
if (down_write_killable(&dvnode->validate_lock) < 0)
goto error;
if (!test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags)) {
ret = afs_fetch_data(dvnode, key, req);
if (ret < 0)
goto error_unlock;
task_io_account_read(PAGE_SIZE * req->nr_pages);
if (req->len < req->file_size)
goto content_has_grown;
/* Validate the data we just read. */
ret = -EIO;
for (i = 0; i < req->nr_pages; i++)
if (!afs_dir_check_page(dvnode, req->pages[i],
req->actual_len))
goto error_unlock;
// TODO: Trim excess pages
set_bit(AFS_VNODE_DIR_VALID, &dvnode->flags);
}
downgrade_write(&dvnode->validate_lock);
success:
return req;
error_unlock:
up_write(&dvnode->validate_lock);
error:
afs_put_read(req);
_leave(" = %d", ret);
return ERR_PTR(ret);
content_has_grown:
up_write(&dvnode->validate_lock);
afs_put_read(req);
goto retry;
}
/*
* deal with one block in an AFS directory
*/
static int afs_dir_iterate_block(struct dir_context *ctx,
union afs_xdr_dir_block *block,
unsigned blkoff)
{
union afs_xdr_dirent *dire;
unsigned offset, next, curr;
size_t nlen;
int tmp;
_enter("%u,%x,%p,,",(unsigned)ctx->pos,blkoff,block);
curr = (ctx->pos - blkoff) / sizeof(union afs_xdr_dirent);
/* walk through the block, an entry at a time */
for (offset = (blkoff == 0 ? AFS_DIR_RESV_BLOCKS0 : AFS_DIR_RESV_BLOCKS);
offset < AFS_DIR_SLOTS_PER_BLOCK;
offset = next
) {
next = offset + 1;
/* skip entries marked unused in the bitmap */
if (!(block->hdr.bitmap[offset / 8] &
(1 << (offset % 8)))) {
_debug("ENT[%zu.%u]: unused",
blkoff / sizeof(union afs_xdr_dir_block), offset);
if (offset >= curr)
ctx->pos = blkoff +
next * sizeof(union afs_xdr_dirent);
continue;
}
/* got a valid entry */
dire = &block->dirents[offset];
nlen = strnlen(dire->u.name,
sizeof(*block) -
offset * sizeof(union afs_xdr_dirent));
_debug("ENT[%zu.%u]: %s %zu \"%s\"",
blkoff / sizeof(union afs_xdr_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_xdr_dirent)) {
if (next >= AFS_DIR_SLOTS_PER_BLOCK) {
_debug("ENT[%zu.%u]:"
" %u travelled beyond end dir block"
" (len %u/%zu)",
blkoff / sizeof(union afs_xdr_dir_block),
offset, next, tmp, nlen);
return -EIO;
}
if (!(block->hdr.bitmap[next / 8] &
(1 << (next % 8)))) {
_debug("ENT[%zu.%u]:"
" %u unmarked extension (len %u/%zu)",
blkoff / sizeof(union afs_xdr_dir_block),
offset, next, tmp, nlen);
return -EIO;
}
_debug("ENT[%zu.%u]: ext %u/%zu",
blkoff / sizeof(union afs_xdr_dir_block),
next, tmp, nlen);
next++;
}
/* skip if starts before the current position */
if (offset < curr)
continue;
/* found the next entry */
if (!dir_emit(ctx, dire->u.name, nlen,
ntohl(dire->u.vnode),
(ctx->actor == afs_lookup_filldir ||
ctx->actor == afs_lookup_one_filldir)?
ntohl(dire->u.unique) : DT_UNKNOWN)) {
_leave(" = 0 [full]");
return 0;
}
ctx->pos = blkoff + next * sizeof(union afs_xdr_dirent);
}
_leave(" = 1 [more]");
return 1;
}
/*
* iterate through the data blob that lists the contents of an AFS directory
*/
static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
struct key *key)
{
struct afs_vnode *dvnode = AFS_FS_I(dir);
struct afs_xdr_dir_page *dbuf;
union afs_xdr_dir_block *dblock;
struct afs_read *req;
struct page *page;
unsigned blkoff, limit;
int ret;
_enter("{%lu},%u,,", dir->i_ino, (unsigned)ctx->pos);
if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dir)->flags)) {
_leave(" = -ESTALE");
return -ESTALE;
}
req = afs_read_dir(dvnode, key);
if (IS_ERR(req))
return PTR_ERR(req);
/* round the file position up to the next entry boundary */
ctx->pos += sizeof(union afs_xdr_dirent) - 1;
ctx->pos &= ~(sizeof(union afs_xdr_dirent) - 1);
/* walk through the blocks in sequence */
ret = 0;
while (ctx->pos < req->actual_len) {
blkoff = ctx->pos & ~(sizeof(union afs_xdr_dir_block) - 1);
/* Fetch the appropriate page from the directory and re-add it
* to the LRU.
*/
page = req->pages[blkoff / PAGE_SIZE];
if (!page) {
ret = -EIO;
break;
}
mark_page_accessed(page);
limit = blkoff & ~(PAGE_SIZE - 1);
dbuf = kmap(page);
/* deal with the individual blocks stashed on this page */
do {
dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /
sizeof(union afs_xdr_dir_block)];
ret = afs_dir_iterate_block(ctx, dblock, blkoff);
if (ret != 1) {
kunmap(page);
goto out;
}
blkoff += sizeof(union afs_xdr_dir_block);
} while (ctx->pos < dir->i_size && blkoff < limit);
kunmap(page);
ret = 0;
}
out:
up_read(&dvnode->validate_lock);
afs_put_read(req);
_leave(" = %d", ret);
return ret;
}
/*
* read an AFS directory
*/
static int afs_readdir(struct file *file, struct dir_context *ctx)
{
return afs_dir_iterate(file_inode(file), ctx, afs_file_key(file));
}
/*
* Search the directory for a single name
* - if afs_dir_iterate_block() spots this function, it'll pass the FID
* uniquifier through dtype
*/
static int afs_lookup_one_filldir(struct dir_context *ctx, const char *name,
int nlen, loff_t fpos, u64 ino, unsigned dtype)
{
struct afs_lookup_one_cookie *cookie =
container_of(ctx, struct afs_lookup_one_cookie, ctx);
_enter("{%s,%u},%s,%u,,%llu,%u",
cookie->name.name, cookie->name.len, name, nlen,
(unsigned long long) ino, dtype);
/* insanity checks first */
BUILD_BUG_ON(sizeof(union afs_xdr_dir_block) != 2048);
BUILD_BUG_ON(sizeof(union afs_xdr_dirent) != 32);
if (cookie->name.len != nlen ||
memcmp(cookie->name.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;
}
/*
* Do a lookup of a single name in a directory
* - just returns the FID the dentry name maps to if found
*/
static int afs_do_lookup_one(struct inode *dir, struct dentry *dentry,
struct afs_fid *fid, struct key *key)
{
struct afs_super_info *as = dir->i_sb->s_fs_info;
struct afs_lookup_one_cookie cookie = {
.ctx.actor = afs_lookup_one_filldir,
.name = dentry->d_name,
.fid.vid = as->volume->vid
};
int ret;
_enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);
/* search the directory */
ret = afs_dir_iterate(dir, &cookie.ctx, key);
if (ret < 0) {
_leave(" = %d [iter]", ret);
return ret;
}
ret = -ENOENT;
if (!cookie.found) {
_leave(" = -ENOENT [not found]");
return -ENOENT;
}
*fid = cookie.fid;
_leave(" = 0 { vn=%u u=%u }", fid->vnode, fid->unique);
return 0;
}
/*
* 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_lookup_filldir(struct dir_context *ctx, const char *name,
int nlen, loff_t fpos, u64 ino, unsigned dtype)
{
struct afs_lookup_cookie *cookie =
container_of(ctx, struct afs_lookup_cookie, ctx);
int ret;
_enter("{%s,%u},%s,%u,,%llu,%u",
cookie->name.name, cookie->name.len, name, nlen,
(unsigned long long) ino, dtype);
/* insanity checks first */
BUILD_BUG_ON(sizeof(union afs_xdr_dir_block) != 2048);
BUILD_BUG_ON(sizeof(union afs_xdr_dirent) != 32);
if (cookie->found) {
if (cookie->nr_fids < 50) {
cookie->fids[cookie->nr_fids].vnode = ino;
cookie->fids[cookie->nr_fids].unique = dtype;
cookie->nr_fids++;
}
} else if (cookie->name.len == nlen &&
memcmp(cookie->name.name, name, nlen) == 0) {
cookie->fids[0].vnode = ino;
cookie->fids[0].unique = dtype;
cookie->found = 1;
if (cookie->one_only)
return -1;
}
ret = cookie->nr_fids >= 50 ? -1 : 0;
_leave(" = %d", ret);
return ret;
}
/*
* Do a lookup in a directory. We make use of bulk lookup to query a slew of
* files in one go and create inodes for them. The inode of the file we were
* asked for is returned.
*/
static struct inode *afs_do_lookup(struct inode *dir, struct dentry *dentry,
struct key *key)
{
struct afs_lookup_cookie *cookie;
struct afs_cb_interest *cbi = NULL;
struct afs_super_info *as = dir->i_sb->s_fs_info;
struct afs_iget_data data;
struct afs_fs_cursor fc;
struct afs_vnode *dvnode = AFS_FS_I(dir);
struct inode *inode = NULL;
int ret, i;
_enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);
cookie = kzalloc(sizeof(struct afs_lookup_cookie), GFP_KERNEL);
if (!cookie)
return ERR_PTR(-ENOMEM);
cookie->ctx.actor = afs_lookup_filldir;
cookie->name = dentry->d_name;
cookie->nr_fids = 1; /* slot 0 is saved for the fid we actually want */
read_seqlock_excl(&dvnode->cb_lock);
if (dvnode->cb_interest &&
dvnode->cb_interest->server &&
test_bit(AFS_SERVER_FL_NO_IBULK, &dvnode->cb_interest->server->flags))
cookie->one_only = true;
read_sequnlock_excl(&dvnode->cb_lock);
for (i = 0; i < 50; i++)
cookie->fids[i].vid = as->volume->vid;
/* search the directory */
ret = afs_dir_iterate(dir, &cookie->ctx, key);
if (ret < 0) {
inode = ERR_PTR(ret);
goto out;
}
inode = ERR_PTR(-ENOENT);
if (!cookie->found)
goto out;
/* Check to see if we already have an inode for the primary fid. */
data.volume = dvnode->volume;
data.fid = cookie->fids[0];
inode = ilookup5(dir->i_sb, cookie->fids[0].vnode, afs_iget5_test, &data);
if (inode)
goto out;
/* Need space for examining all the selected files */
inode = ERR_PTR(-ENOMEM);
cookie->statuses = kcalloc(cookie->nr_fids, sizeof(struct afs_file_status),
GFP_KERNEL);
if (!cookie->statuses)
goto out;
cookie->callbacks = kcalloc(cookie->nr_fids, sizeof(struct afs_callback),
GFP_KERNEL);
if (!cookie->callbacks)
goto out_s;
/* Try FS.InlineBulkStatus first. Abort codes for the individual
* lookups contained therein are stored in the reply without aborting
* the whole operation.
*/
if (cookie->one_only)
goto no_inline_bulk_status;
inode = ERR_PTR(-ERESTARTSYS);
if (afs_begin_vnode_operation(&fc, dvnode, key)) {
while (afs_select_fileserver(&fc)) {
if (test_bit(AFS_SERVER_FL_NO_IBULK,
&fc.cbi->server->flags)) {
fc.ac.abort_code = RX_INVALID_OPERATION;
fc.ac.error = -ECONNABORTED;
break;
}
afs_fs_inline_bulk_status(&fc,
afs_v2net(dvnode),
cookie->fids,
cookie->statuses,
cookie->callbacks,
cookie->nr_fids, NULL);
}
if (fc.ac.error == 0)
cbi = afs_get_cb_interest(fc.cbi);
if (fc.ac.abort_code == RX_INVALID_OPERATION)
set_bit(AFS_SERVER_FL_NO_IBULK, &fc.cbi->server->flags);
inode = ERR_PTR(afs_end_vnode_operation(&fc));
}
if (!IS_ERR(inode))
goto success;
if (fc.ac.abort_code != RX_INVALID_OPERATION)
goto out_c;
no_inline_bulk_status:
/* We could try FS.BulkStatus next, but this aborts the entire op if
* any of the lookups fails - so, for the moment, revert to
* FS.FetchStatus for just the primary fid.
*/
cookie->nr_fids = 1;
inode = ERR_PTR(-ERESTARTSYS);
if (afs_begin_vnode_operation(&fc, dvnode, key)) {
while (afs_select_fileserver(&fc)) {
afs_fs_fetch_status(&fc,
afs_v2net(dvnode),
cookie->fids,
cookie->statuses,
cookie->callbacks,
NULL);
}
if (fc.ac.error == 0)
cbi = afs_get_cb_interest(fc.cbi);
inode = ERR_PTR(afs_end_vnode_operation(&fc));
}
if (IS_ERR(inode))
goto out_c;
for (i = 0; i < cookie->nr_fids; i++)
cookie->statuses[i].abort_code = 0;
success:
/* Turn all the files into inodes and save the first one - which is the
* one we actually want.
*/
if (cookie->statuses[0].abort_code != 0)
inode = ERR_PTR(afs_abort_to_error(cookie->statuses[0].abort_code));
for (i = 0; i < cookie->nr_fids; i++) {
struct inode *ti;
if (cookie->statuses[i].abort_code != 0)
continue;
ti = afs_iget(dir->i_sb, key, &cookie->fids[i],
&cookie->statuses[i],
&cookie->callbacks[i],
cbi);
if (i == 0) {
inode = ti;
} else {
if (!IS_ERR(ti))
iput(ti);
}
}
out_c:
afs_put_cb_interest(afs_v2net(dvnode), cbi);
kfree(cookie->callbacks);
out_s:
kfree(cookie->statuses);
out:
kfree(cookie);
return inode;
}
/*
* Look up an entry in a directory with @sys substitution.
*/
static struct dentry *afs_lookup_atsys(struct inode *dir, struct dentry *dentry,
struct key *key)
{
struct afs_sysnames *subs;
struct afs_net *net = afs_i2net(dir);
struct dentry *ret;
char *buf, *p, *name;
int len, i;
_enter("");
ret = ERR_PTR(-ENOMEM);
p = buf = kmalloc(AFSNAMEMAX, GFP_KERNEL);
if (!buf)
goto out_p;
if (dentry->d_name.len > 4) {
memcpy(p, dentry->d_name.name, dentry->d_name.len - 4);
p += dentry->d_name.len - 4;
}
/* There is an ordered list of substitutes that we have to try. */
read_lock(&net->sysnames_lock);
subs = net->sysnames;
refcount_inc(&subs->usage);
read_unlock(&net->sysnames_lock);
for (i = 0; i < subs->nr; i++) {
name = subs->subs[i];
len = dentry->d_name.len - 4 + strlen(name);
if (len >= AFSNAMEMAX) {
ret = ERR_PTR(-ENAMETOOLONG);
goto out_s;
}
strcpy(p, name);
ret = lookup_one_len(buf, dentry->d_parent, len);
if (IS_ERR(ret) || d_is_positive(ret))
goto out_s;
dput(ret);
}
/* We don't want to d_add() the @sys dentry here as we don't want to
* the cached dentry to hide changes to the sysnames list.
*/
ret = NULL;
out_s:
afs_put_sysnames(subs);
kfree(buf);
out_p:
key_put(key);
return ret;
}
/*
* look up an entry in a directory
*/
static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
struct afs_vnode *dvnode = AFS_FS_I(dir);
struct inode *inode;
struct dentry *d;
struct key *key;
int ret;
_enter("{%x:%u},%p{%pd},",
dvnode->fid.vid, dvnode->fid.vnode, dentry, dentry);
ASSERTCMP(d_inode(dentry), ==, NULL);
if (dentry->d_name.len >= AFSNAMEMAX) {
_leave(" = -ENAMETOOLONG");
return ERR_PTR(-ENAMETOOLONG);
}
if (test_bit(AFS_VNODE_DELETED, &dvnode->flags)) {
_leave(" = -ESTALE");
return ERR_PTR(-ESTALE);
}
key = afs_request_key(dvnode->volume->cell);
if (IS_ERR(key)) {
_leave(" = %ld [key]", PTR_ERR(key));
return ERR_CAST(key);
}
ret = afs_validate(dvnode, key);
if (ret < 0) {
key_put(key);
_leave(" = %d [val]", ret);
return ERR_PTR(ret);
}
if (dentry->d_name.len >= 4 &&
dentry->d_name.name[dentry->d_name.len - 4] == '@' &&
dentry->d_name.name[dentry->d_name.len - 3] == 's' &&
dentry->d_name.name[dentry->d_name.len - 2] == 'y' &&
dentry->d_name.name[dentry->d_name.len - 1] == 's')
return afs_lookup_atsys(dir, dentry, key);
afs_stat_v(dvnode, n_lookup);
inode = afs_do_lookup(dir, dentry, key);
key_put(key);
if (inode == ERR_PTR(-ENOENT)) {
inode = afs_try_auto_mntpt(dentry, dir);
} else {
dentry->d_fsdata =
(void *)(unsigned long)dvnode->status.data_version;
}
d = d_splice_alias(inode, dentry);
if (!IS_ERR_OR_NULL(d))
d->d_fsdata = dentry->d_fsdata;
return d;
}
/*
* 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
*/
static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
{
struct afs_vnode *vnode, *dir;
struct afs_fid uninitialized_var(fid);
struct dentry *parent;
struct inode *inode;
struct key *key;
long dir_version, de_version;
int ret;
if (flags & LOOKUP_RCU)
return -ECHILD;
if (d_really_is_positive(dentry)) {
vnode = AFS_FS_I(d_inode(dentry));
_enter("{v={%x:%u} n=%pd fl=%lx},",
vnode->fid.vid, vnode->fid.vnode, dentry,
vnode->flags);
} else {
_enter("{neg n=%pd}", dentry);
}
key = afs_request_key(AFS_FS_S(dentry->d_sb)->volume->cell);
if (IS_ERR(key))
key = NULL;
if (d_really_is_positive(dentry)) {
inode = d_inode(dentry);
if (inode) {
vnode = AFS_FS_I(inode);
afs_validate(vnode, key);
if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
goto out_bad;
}
}
/* lock down the parent dentry so we can peer at it */
parent = dget_parent(dentry);
dir = AFS_FS_I(d_inode(parent));
/* validate the parent directory */
afs_validate(dir, key);
if (test_bit(AFS_VNODE_DELETED, &dir->flags)) {
_debug("%pd: parent dir deleted", dentry);
goto out_bad_parent;
}
/* We only need to invalidate a dentry if the server's copy changed
* behind our back. If we made the change, it's no problem. Note that
* on a 32-bit system, we only have 32 bits in the dentry to store the
* version.
*/
dir_version = (long)dir->status.data_version;
de_version = (long)dentry->d_fsdata;
if (de_version == dir_version)
goto out_valid_noupdate;
dir_version = (long)dir->invalid_before;
if (de_version - dir_version >= 0)
goto out_valid;
_debug("dir modified");
afs_stat_v(dir, n_reval);
/* search the directory for this vnode */
ret = afs_do_lookup_one(&dir->vfs_inode, dentry, &fid, key);
switch (ret) {
case 0:
/* the filename maps to something */
if (d_really_is_negative(dentry))
goto out_bad_parent;
inode = d_inode(dentry);
if (is_bad_inode(inode)) {
printk("kAFS: afs_d_revalidate: %pd2 has bad inode\n",
dentry);
goto out_bad_parent;
}
vnode = AFS_FS_I(inode);
/* if the vnode ID has changed, then the dirent points to a
* different file */
if (fid.vnode != vnode->fid.vnode) {
_debug("%pd: dirent changed [%u != %u]",
dentry, fid.vnode,
vnode->fid.vnode);
goto not_found;
}
/* if the vnode ID uniqifier has changed, then the file has
* been deleted and replaced, and the original vnode ID has
* been reused */
if (fid.unique != vnode->fid.unique) {
_debug("%pd: file deleted (uq %u -> %u I:%u)",
dentry, fid.unique,
vnode->fid.unique,
vnode->vfs_inode.i_generation);
write_seqlock(&vnode->cb_lock);
set_bit(AFS_VNODE_DELETED, &vnode->flags);
write_sequnlock(&vnode->cb_lock);
goto not_found;
}
goto out_valid;
case -ENOENT:
/* the filename is unknown */
_debug("%pd: dirent not found", dentry);
if (d_really_is_positive(dentry))
goto not_found;
goto out_valid;
default:
_debug("failed to iterate dir %pd: %d",
parent, ret);
goto out_bad_parent;
}