linux/fs/cachefiles/namei.c
Christian Brauner abf08576af
fs: port vfs_*() helpers to struct mnt_idmap
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-18 17:51:45 +01:00

861 lines
22 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* CacheFiles path walking and related routines
*
* Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/fs.h>
#include <linux/namei.h>
#include "internal.h"
/*
* Mark the backing file as being a cache file if it's not already in use. The
* mark tells the culling request command that it's not allowed to cull the
* file or directory. The caller must hold the inode lock.
*/
static bool __cachefiles_mark_inode_in_use(struct cachefiles_object *object,
struct inode *inode)
{
bool can_use = false;
if (!(inode->i_flags & S_KERNEL_FILE)) {
inode->i_flags |= S_KERNEL_FILE;
trace_cachefiles_mark_active(object, inode);
can_use = true;
} else {
trace_cachefiles_mark_failed(object, inode);
}
return can_use;
}
static bool cachefiles_mark_inode_in_use(struct cachefiles_object *object,
struct inode *inode)
{
bool can_use;
inode_lock(inode);
can_use = __cachefiles_mark_inode_in_use(object, inode);
inode_unlock(inode);
return can_use;
}
/*
* Unmark a backing inode. The caller must hold the inode lock.
*/
static void __cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
struct inode *inode)
{
inode->i_flags &= ~S_KERNEL_FILE;
trace_cachefiles_mark_inactive(object, inode);
}
static void cachefiles_do_unmark_inode_in_use(struct cachefiles_object *object,
struct inode *inode)
{
inode_lock(inode);
__cachefiles_unmark_inode_in_use(object, inode);
inode_unlock(inode);
}
/*
* Unmark a backing inode and tell cachefilesd that there's something that can
* be culled.
*/
void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
struct file *file)
{
struct cachefiles_cache *cache = object->volume->cache;
struct inode *inode = file_inode(file);
cachefiles_do_unmark_inode_in_use(object, inode);
if (!test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags)) {
atomic_long_add(inode->i_blocks, &cache->b_released);
if (atomic_inc_return(&cache->f_released))
cachefiles_state_changed(cache);
}
}
/*
* get a subdirectory
*/
struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
struct dentry *dir,
const char *dirname,
bool *_is_new)
{
struct dentry *subdir;
struct path path;
int ret;
_enter(",,%s", dirname);
/* search the current directory for the element name */
inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
retry:
ret = cachefiles_inject_read_error();
if (ret == 0)
subdir = lookup_one_len(dirname, dir, strlen(dirname));
else
subdir = ERR_PTR(ret);
trace_cachefiles_lookup(NULL, dir, subdir);
if (IS_ERR(subdir)) {
trace_cachefiles_vfs_error(NULL, d_backing_inode(dir),
PTR_ERR(subdir),
cachefiles_trace_lookup_error);
if (PTR_ERR(subdir) == -ENOMEM)
goto nomem_d_alloc;
goto lookup_error;
}
_debug("subdir -> %pd %s",
subdir, d_backing_inode(subdir) ? "positive" : "negative");
/* we need to create the subdir if it doesn't exist yet */
if (d_is_negative(subdir)) {
ret = cachefiles_has_space(cache, 1, 0,
cachefiles_has_space_for_create);
if (ret < 0)
goto mkdir_error;
_debug("attempt mkdir");
path.mnt = cache->mnt;
path.dentry = dir;
ret = security_path_mkdir(&path, subdir, 0700);
if (ret < 0)
goto mkdir_error;
ret = cachefiles_inject_write_error();
if (ret == 0)
ret = vfs_mkdir(&nop_mnt_idmap, d_inode(dir), subdir, 0700);
if (ret < 0) {
trace_cachefiles_vfs_error(NULL, d_inode(dir), ret,
cachefiles_trace_mkdir_error);
goto mkdir_error;
}
trace_cachefiles_mkdir(dir, subdir);
if (unlikely(d_unhashed(subdir))) {
cachefiles_put_directory(subdir);
goto retry;
}
ASSERT(d_backing_inode(subdir));
_debug("mkdir -> %pd{ino=%lu}",
subdir, d_backing_inode(subdir)->i_ino);
if (_is_new)
*_is_new = true;
}
/* Tell rmdir() it's not allowed to delete the subdir */
inode_lock(d_inode(subdir));
inode_unlock(d_inode(dir));
if (!__cachefiles_mark_inode_in_use(NULL, d_inode(subdir))) {
pr_notice("cachefiles: Inode already in use: %pd (B=%lx)\n",
subdir, d_inode(subdir)->i_ino);
goto mark_error;
}
inode_unlock(d_inode(subdir));
/* we need to make sure the subdir is a directory */
ASSERT(d_backing_inode(subdir));
if (!d_can_lookup(subdir)) {
pr_err("%s is not a directory\n", dirname);
ret = -EIO;
goto check_error;
}
ret = -EPERM;
if (!(d_backing_inode(subdir)->i_opflags & IOP_XATTR) ||
!d_backing_inode(subdir)->i_op->lookup ||
!d_backing_inode(subdir)->i_op->mkdir ||
!d_backing_inode(subdir)->i_op->rename ||
!d_backing_inode(subdir)->i_op->rmdir ||
!d_backing_inode(subdir)->i_op->unlink)
goto check_error;
_leave(" = [%lu]", d_backing_inode(subdir)->i_ino);
return subdir;
check_error:
cachefiles_put_directory(subdir);
_leave(" = %d [check]", ret);
return ERR_PTR(ret);
mark_error:
inode_unlock(d_inode(subdir));
dput(subdir);
return ERR_PTR(-EBUSY);
mkdir_error:
inode_unlock(d_inode(dir));
dput(subdir);
pr_err("mkdir %s failed with error %d\n", dirname, ret);
return ERR_PTR(ret);
lookup_error:
inode_unlock(d_inode(dir));
ret = PTR_ERR(subdir);
pr_err("Lookup %s failed with error %d\n", dirname, ret);
return ERR_PTR(ret);
nomem_d_alloc:
inode_unlock(d_inode(dir));
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
/*
* Put a subdirectory.
*/
void cachefiles_put_directory(struct dentry *dir)
{
if (dir) {
cachefiles_do_unmark_inode_in_use(NULL, d_inode(dir));
dput(dir);
}
}
/*
* Remove a regular file from the cache.
*/
static int cachefiles_unlink(struct cachefiles_cache *cache,
struct cachefiles_object *object,
struct dentry *dir, struct dentry *dentry,
enum fscache_why_object_killed why)
{
struct path path = {
.mnt = cache->mnt,
.dentry = dir,
};
int ret;
trace_cachefiles_unlink(object, d_inode(dentry)->i_ino, why);
ret = security_path_unlink(&path, dentry);
if (ret < 0) {
cachefiles_io_error(cache, "Unlink security error");
return ret;
}
ret = cachefiles_inject_remove_error();
if (ret == 0) {
ret = vfs_unlink(&nop_mnt_idmap, d_backing_inode(dir), dentry, NULL);
if (ret == -EIO)
cachefiles_io_error(cache, "Unlink failed");
}
if (ret != 0)
trace_cachefiles_vfs_error(object, d_backing_inode(dir), ret,
cachefiles_trace_unlink_error);
return ret;
}
/*
* Delete an object representation from the cache
* - File backed objects are unlinked
* - Directory backed objects are stuffed into the graveyard for userspace to
* delete
*/
int cachefiles_bury_object(struct cachefiles_cache *cache,
struct cachefiles_object *object,
struct dentry *dir,
struct dentry *rep,
enum fscache_why_object_killed why)
{
struct dentry *grave, *trap;
struct path path, path_to_graveyard;
char nbuffer[8 + 8 + 1];
int ret;
_enter(",'%pd','%pd'", dir, rep);
if (rep->d_parent != dir) {
inode_unlock(d_inode(dir));
_leave(" = -ESTALE");
return -ESTALE;
}
/* non-directories can just be unlinked */
if (!d_is_dir(rep)) {
dget(rep); /* Stop the dentry being negated if it's only pinned
* by a file struct.
*/
ret = cachefiles_unlink(cache, object, dir, rep, why);
dput(rep);
inode_unlock(d_inode(dir));
_leave(" = %d", ret);
return ret;
}
/* directories have to be moved to the graveyard */
_debug("move stale object to graveyard");
inode_unlock(d_inode(dir));
try_again:
/* first step is to make up a grave dentry in the graveyard */
sprintf(nbuffer, "%08x%08x",
(uint32_t) ktime_get_real_seconds(),
(uint32_t) atomic_inc_return(&cache->gravecounter));
/* do the multiway lock magic */
trap = lock_rename(cache->graveyard, dir);
/* do some checks before getting the grave dentry */
if (rep->d_parent != dir || IS_DEADDIR(d_inode(rep))) {
/* the entry was probably culled when we dropped the parent dir
* lock */
unlock_rename(cache->graveyard, dir);
_leave(" = 0 [culled?]");
return 0;
}
if (!d_can_lookup(cache->graveyard)) {
unlock_rename(cache->graveyard, dir);
cachefiles_io_error(cache, "Graveyard no longer a directory");
return -EIO;
}
if (trap == rep) {
unlock_rename(cache->graveyard, dir);
cachefiles_io_error(cache, "May not make directory loop");
return -EIO;
}
if (d_mountpoint(rep)) {
unlock_rename(cache->graveyard, dir);
cachefiles_io_error(cache, "Mountpoint in cache");
return -EIO;
}
grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer));
if (IS_ERR(grave)) {
unlock_rename(cache->graveyard, dir);
trace_cachefiles_vfs_error(object, d_inode(cache->graveyard),
PTR_ERR(grave),
cachefiles_trace_lookup_error);
if (PTR_ERR(grave) == -ENOMEM) {
_leave(" = -ENOMEM");
return -ENOMEM;
}
cachefiles_io_error(cache, "Lookup error %ld", PTR_ERR(grave));
return -EIO;
}
if (d_is_positive(grave)) {
unlock_rename(cache->graveyard, dir);
dput(grave);
grave = NULL;
cond_resched();
goto try_again;
}
if (d_mountpoint(grave)) {
unlock_rename(cache->graveyard, dir);
dput(grave);
cachefiles_io_error(cache, "Mountpoint in graveyard");
return -EIO;
}
/* target should not be an ancestor of source */
if (trap == grave) {
unlock_rename(cache->graveyard, dir);
dput(grave);
cachefiles_io_error(cache, "May not make directory loop");
return -EIO;
}
/* attempt the rename */
path.mnt = cache->mnt;
path.dentry = dir;
path_to_graveyard.mnt = cache->mnt;
path_to_graveyard.dentry = cache->graveyard;
ret = security_path_rename(&path, rep, &path_to_graveyard, grave, 0);
if (ret < 0) {
cachefiles_io_error(cache, "Rename security error %d", ret);
} else {
struct renamedata rd = {
.old_mnt_idmap = &nop_mnt_idmap,
.old_dir = d_inode(dir),
.old_dentry = rep,
.new_mnt_idmap = &nop_mnt_idmap,
.new_dir = d_inode(cache->graveyard),
.new_dentry = grave,
};
trace_cachefiles_rename(object, d_inode(rep)->i_ino, why);
ret = cachefiles_inject_read_error();
if (ret == 0)
ret = vfs_rename(&rd);
if (ret != 0)
trace_cachefiles_vfs_error(object, d_inode(dir), ret,
cachefiles_trace_rename_error);
if (ret != 0 && ret != -ENOMEM)
cachefiles_io_error(cache,
"Rename failed with error %d", ret);
}
__cachefiles_unmark_inode_in_use(object, d_inode(rep));
unlock_rename(cache->graveyard, dir);
dput(grave);
_leave(" = 0");
return 0;
}
/*
* Delete a cache file.
*/
int cachefiles_delete_object(struct cachefiles_object *object,
enum fscache_why_object_killed why)
{
struct cachefiles_volume *volume = object->volume;
struct dentry *dentry = object->file->f_path.dentry;
struct dentry *fan = volume->fanout[(u8)object->cookie->key_hash];
int ret;
_enter(",OBJ%x{%pD}", object->debug_id, object->file);
/* Stop the dentry being negated if it's only pinned by a file struct. */
dget(dentry);
inode_lock_nested(d_backing_inode(fan), I_MUTEX_PARENT);
ret = cachefiles_unlink(volume->cache, object, fan, dentry, why);
inode_unlock(d_backing_inode(fan));
dput(dentry);
return ret;
}
/*
* Create a temporary file and leave it unattached and un-xattr'd until the
* time comes to discard the object from memory.
*/
struct file *cachefiles_create_tmpfile(struct cachefiles_object *object)
{
struct cachefiles_volume *volume = object->volume;
struct cachefiles_cache *cache = volume->cache;
const struct cred *saved_cred;
struct dentry *fan = volume->fanout[(u8)object->cookie->key_hash];
struct file *file;
const struct path parentpath = { .mnt = cache->mnt, .dentry = fan };
uint64_t ni_size;
long ret;
cachefiles_begin_secure(cache, &saved_cred);
ret = cachefiles_inject_write_error();
if (ret == 0) {
file = vfs_tmpfile_open(&nop_mnt_idmap, &parentpath, S_IFREG,
O_RDWR | O_LARGEFILE | O_DIRECT,
cache->cache_cred);
ret = PTR_ERR_OR_ZERO(file);
}
if (ret) {
trace_cachefiles_vfs_error(object, d_inode(fan), ret,
cachefiles_trace_tmpfile_error);
if (ret == -EIO)
cachefiles_io_error_obj(object, "Failed to create tmpfile");
goto err;
}
trace_cachefiles_tmpfile(object, file_inode(file));
/* This is a newly created file with no other possible user */
if (!cachefiles_mark_inode_in_use(object, file_inode(file)))
WARN_ON(1);
ret = cachefiles_ondemand_init_object(object);
if (ret < 0)
goto err_unuse;
ni_size = object->cookie->object_size;
ni_size = round_up(ni_size, CACHEFILES_DIO_BLOCK_SIZE);
if (ni_size > 0) {
trace_cachefiles_trunc(object, file_inode(file), 0, ni_size,
cachefiles_trunc_expand_tmpfile);
ret = cachefiles_inject_write_error();
if (ret == 0)
ret = vfs_truncate(&file->f_path, ni_size);
if (ret < 0) {
trace_cachefiles_vfs_error(
object, file_inode(file), ret,
cachefiles_trace_trunc_error);
goto err_unuse;
}
}
ret = -EINVAL;
if (unlikely(!file->f_op->read_iter) ||
unlikely(!file->f_op->write_iter)) {
fput(file);
pr_notice("Cache does not support read_iter and write_iter\n");
goto err_unuse;
}
out:
cachefiles_end_secure(cache, saved_cred);
return file;
err_unuse:
cachefiles_do_unmark_inode_in_use(object, file_inode(file));
fput(file);
err:
file = ERR_PTR(ret);
goto out;
}
/*
* Create a new file.
*/
static bool cachefiles_create_file(struct cachefiles_object *object)
{
struct file *file;
int ret;
ret = cachefiles_has_space(object->volume->cache, 1, 0,
cachefiles_has_space_for_create);
if (ret < 0)
return false;
file = cachefiles_create_tmpfile(object);
if (IS_ERR(file))
return false;
set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &object->cookie->flags);
set_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags);
_debug("create -> %pD{ino=%lu}", file, file_inode(file)->i_ino);
object->file = file;
return true;
}
/*
* Open an existing file, checking its attributes and replacing it if it is
* stale.
*/
static bool cachefiles_open_file(struct cachefiles_object *object,
struct dentry *dentry)
{
struct cachefiles_cache *cache = object->volume->cache;
struct file *file;
struct path path;
int ret;
_enter("%pd", dentry);
if (!cachefiles_mark_inode_in_use(object, d_inode(dentry))) {
pr_notice("cachefiles: Inode already in use: %pd (B=%lx)\n",
dentry, d_inode(dentry)->i_ino);
return false;
}
/* We need to open a file interface onto a data file now as we can't do
* it on demand because writeback called from do_exit() sees
* current->fs == NULL - which breaks d_path() called from ext4 open.
*/
path.mnt = cache->mnt;
path.dentry = dentry;
file = open_with_fake_path(&path, O_RDWR | O_LARGEFILE | O_DIRECT,
d_backing_inode(dentry), cache->cache_cred);
if (IS_ERR(file)) {
trace_cachefiles_vfs_error(object, d_backing_inode(dentry),
PTR_ERR(file),
cachefiles_trace_open_error);
goto error;
}
if (unlikely(!file->f_op->read_iter) ||
unlikely(!file->f_op->write_iter)) {
pr_notice("Cache does not support read_iter and write_iter\n");
goto error_fput;
}
_debug("file -> %pd positive", dentry);
ret = cachefiles_ondemand_init_object(object);
if (ret < 0)
goto error_fput;
ret = cachefiles_check_auxdata(object, file);
if (ret < 0)
goto check_failed;
object->file = file;
/* Always update the atime on an object we've just looked up (this is
* used to keep track of culling, and atimes are only updated by read,
* write and readdir but not lookup or open).
*/
touch_atime(&file->f_path);
dput(dentry);
return true;
check_failed:
fscache_cookie_lookup_negative(object->cookie);
cachefiles_unmark_inode_in_use(object, file);
fput(file);
dput(dentry);
if (ret == -ESTALE)
return cachefiles_create_file(object);
return false;
error_fput:
fput(file);
error:
cachefiles_do_unmark_inode_in_use(object, d_inode(dentry));
dput(dentry);
return false;
}
/*
* walk from the parent object to the child object through the backing
* filesystem, creating directories as we go
*/
bool cachefiles_look_up_object(struct cachefiles_object *object)
{
struct cachefiles_volume *volume = object->volume;
struct dentry *dentry, *fan = volume->fanout[(u8)object->cookie->key_hash];
int ret;
_enter("OBJ%x,%s,", object->debug_id, object->d_name);
/* Look up path "cache/vol/fanout/file". */
ret = cachefiles_inject_read_error();
if (ret == 0)
dentry = lookup_positive_unlocked(object->d_name, fan,
object->d_name_len);
else
dentry = ERR_PTR(ret);
trace_cachefiles_lookup(object, fan, dentry);
if (IS_ERR(dentry)) {
if (dentry == ERR_PTR(-ENOENT))
goto new_file;
if (dentry == ERR_PTR(-EIO))
cachefiles_io_error_obj(object, "Lookup failed");
return false;
}
if (!d_is_reg(dentry)) {
pr_err("%pd is not a file\n", dentry);
inode_lock_nested(d_inode(fan), I_MUTEX_PARENT);
ret = cachefiles_bury_object(volume->cache, object, fan, dentry,
FSCACHE_OBJECT_IS_WEIRD);
dput(dentry);
if (ret < 0)
return false;
goto new_file;
}
if (!cachefiles_open_file(object, dentry))
return false;
_leave(" = t [%lu]", file_inode(object->file)->i_ino);
return true;
new_file:
fscache_cookie_lookup_negative(object->cookie);
return cachefiles_create_file(object);
}
/*
* Attempt to link a temporary file into its rightful place in the cache.
*/
bool cachefiles_commit_tmpfile(struct cachefiles_cache *cache,
struct cachefiles_object *object)
{
struct cachefiles_volume *volume = object->volume;
struct dentry *dentry, *fan = volume->fanout[(u8)object->cookie->key_hash];
bool success = false;
int ret;
_enter(",%pD", object->file);
inode_lock_nested(d_inode(fan), I_MUTEX_PARENT);
ret = cachefiles_inject_read_error();
if (ret == 0)
dentry = lookup_one_len(object->d_name, fan, object->d_name_len);
else
dentry = ERR_PTR(ret);
if (IS_ERR(dentry)) {
trace_cachefiles_vfs_error(object, d_inode(fan), PTR_ERR(dentry),
cachefiles_trace_lookup_error);
_debug("lookup fail %ld", PTR_ERR(dentry));
goto out_unlock;
}
if (!d_is_negative(dentry)) {
if (d_backing_inode(dentry) == file_inode(object->file)) {
success = true;
goto out_dput;
}
ret = cachefiles_unlink(volume->cache, object, fan, dentry,
FSCACHE_OBJECT_IS_STALE);
if (ret < 0)
goto out_dput;
dput(dentry);
ret = cachefiles_inject_read_error();
if (ret == 0)
dentry = lookup_one_len(object->d_name, fan, object->d_name_len);
else
dentry = ERR_PTR(ret);
if (IS_ERR(dentry)) {
trace_cachefiles_vfs_error(object, d_inode(fan), PTR_ERR(dentry),
cachefiles_trace_lookup_error);
_debug("lookup fail %ld", PTR_ERR(dentry));
goto out_unlock;
}
}
ret = cachefiles_inject_read_error();
if (ret == 0)
ret = vfs_link(object->file->f_path.dentry, &nop_mnt_idmap,
d_inode(fan), dentry, NULL);
if (ret < 0) {
trace_cachefiles_vfs_error(object, d_inode(fan), ret,
cachefiles_trace_link_error);
_debug("link fail %d", ret);
} else {
trace_cachefiles_link(object, file_inode(object->file));
spin_lock(&object->lock);
/* TODO: Do we want to switch the file pointer to the new dentry? */
clear_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags);
spin_unlock(&object->lock);
success = true;
}
out_dput:
dput(dentry);
out_unlock:
inode_unlock(d_inode(fan));
_leave(" = %u", success);
return success;
}
/*
* Look up an inode to be checked or culled. Return -EBUSY if the inode is
* marked in use.
*/
static struct dentry *cachefiles_lookup_for_cull(struct cachefiles_cache *cache,
struct dentry *dir,
char *filename)
{
struct dentry *victim;
int ret = -ENOENT;
inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
victim = lookup_one_len(filename, dir, strlen(filename));
if (IS_ERR(victim))
goto lookup_error;
if (d_is_negative(victim))
goto lookup_put;
if (d_inode(victim)->i_flags & S_KERNEL_FILE)
goto lookup_busy;
return victim;
lookup_busy:
ret = -EBUSY;
lookup_put:
inode_unlock(d_inode(dir));
dput(victim);
return ERR_PTR(ret);
lookup_error:
inode_unlock(d_inode(dir));
ret = PTR_ERR(victim);
if (ret == -ENOENT)
return ERR_PTR(-ESTALE); /* Probably got retired by the netfs */
if (ret == -EIO) {
cachefiles_io_error(cache, "Lookup failed");
} else if (ret != -ENOMEM) {
pr_err("Internal error: %d\n", ret);
ret = -EIO;
}
return ERR_PTR(ret);
}
/*
* Cull an object if it's not in use
* - called only by cache manager daemon
*/
int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
char *filename)
{
struct dentry *victim;
struct inode *inode;
int ret;
_enter(",%pd/,%s", dir, filename);
victim = cachefiles_lookup_for_cull(cache, dir, filename);
if (IS_ERR(victim))
return PTR_ERR(victim);
/* check to see if someone is using this object */
inode = d_inode(victim);
inode_lock(inode);
if (inode->i_flags & S_KERNEL_FILE) {
ret = -EBUSY;
} else {
/* Stop the cache from picking it back up */
inode->i_flags |= S_KERNEL_FILE;
ret = 0;
}
inode_unlock(inode);
if (ret < 0)
goto error_unlock;
ret = cachefiles_bury_object(cache, NULL, dir, victim,
FSCACHE_OBJECT_WAS_CULLED);
if (ret < 0)
goto error;
fscache_count_culled();
dput(victim);
_leave(" = 0");
return 0;
error_unlock:
inode_unlock(d_inode(dir));
error:
dput(victim);
if (ret == -ENOENT)
return -ESTALE; /* Probably got retired by the netfs */
if (ret != -ENOMEM) {
pr_err("Internal error: %d\n", ret);
ret = -EIO;
}
_leave(" = %d", ret);
return ret;
}
/*
* Find out if an object is in use or not
* - called only by cache manager daemon
* - returns -EBUSY or 0 to indicate whether an object is in use or not
*/
int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir,
char *filename)
{
struct dentry *victim;
int ret = 0;
victim = cachefiles_lookup_for_cull(cache, dir, filename);
if (IS_ERR(victim))
return PTR_ERR(victim);
inode_unlock(d_inode(dir));
dput(victim);
return ret;
}