linux/fs/cachefiles/namei.c

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// 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 dentry *dentry)
{
struct inode *inode = d_backing_inode(dentry);
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);
pr_notice("cachefiles: Inode already in use: %pd (B=%lx)\n",
dentry, inode->i_ino);
}
return can_use;
}
static bool cachefiles_mark_inode_in_use(struct cachefiles_object *object,
struct dentry *dentry)
{
struct inode *inode = d_backing_inode(dentry);
bool can_use;
inode_lock(inode);
can_use = __cachefiles_mark_inode_in_use(object, dentry);
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 dentry *dentry)
{
struct inode *inode = d_backing_inode(dentry);
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 dentry *dentry)
{
struct inode *inode = d_backing_inode(dentry);
inode_lock(inode);
__cachefiles_unmark_inode_in_use(object, dentry);
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);
if (inode) {
cachefiles_do_unmark_inode_in_use(object, file->f_path.dentry);
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(&init_user_ns, 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, subdir))
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) {
inode_lock(dir->d_inode);
__cachefiles_unmark_inode_in_use(NULL, dir);
inode_unlock(dir->d_inode);
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(&init_user_ns, 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_userns = &init_user_ns,
.old_dir = d_inode(dir),
.old_dentry = rep,
.new_mnt_userns = &init_user_ns,
.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, rep);
unlock_rename(cache->graveyard, dir);
dput(grave);
_leave(" = 0");
return 0;
}
cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:50:10 +00:00
/*
* 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;
struct path path;
cachefiles: notify the user daemon when looking up cookie Fscache/CacheFiles used to serve as a local cache for a remote networking fs. A new on-demand read mode will be introduced for CacheFiles, which can boost the scenario where on-demand read semantics are needed, e.g. container image distribution. The essential difference between these two modes is seen when a cache miss occurs: In the original mode, the netfs will fetch the data from the remote server and then write it to the cache file; in on-demand read mode, fetching the data and writing it into the cache is delegated to a user daemon. As the first step, notify the user daemon when looking up cookie. In this case, an anonymous fd is sent to the user daemon, through which the user daemon can write the fetched data to the cache file. Since the user daemon may move the anonymous fd around, e.g. through dup(), an object ID uniquely identifying the cache file is also attached. Also add one advisory flag (FSCACHE_ADV_WANT_CACHE_SIZE) suggesting that the cache file size shall be retrieved at runtime. This helps the scenario where one cache file contains multiple netfs files, e.g. for the purpose of deduplication. In this case, netfs itself has no idea the size of the cache file, whilst the user daemon should give the hint on it. Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> Link: https://lore.kernel.org/r/20220509074028.74954-3-jefflexu@linux.alibaba.com Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-04-25 12:21:24 +00:00
uint64_t ni_size;
cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:50:10 +00:00
long ret;
cachefiles_begin_secure(cache, &saved_cred);
path.mnt = cache->mnt;
ret = cachefiles_inject_write_error();
if (ret == 0)
path.dentry = vfs_tmpfile(&init_user_ns, fan, S_IFREG, O_RDWR);
else
path.dentry = ERR_PTR(ret);
if (IS_ERR(path.dentry)) {
trace_cachefiles_vfs_error(object, d_inode(fan), PTR_ERR(path.dentry),
cachefiles_trace_tmpfile_error);
if (PTR_ERR(path.dentry) == -EIO)
cachefiles_io_error_obj(object, "Failed to create tmpfile");
file = ERR_CAST(path.dentry);
goto out;
}
trace_cachefiles_tmpfile(object, d_backing_inode(path.dentry));
if (!cachefiles_mark_inode_in_use(object, path.dentry)) {
file = ERR_PTR(-EBUSY);
goto out_dput;
}
cachefiles: notify the user daemon when looking up cookie Fscache/CacheFiles used to serve as a local cache for a remote networking fs. A new on-demand read mode will be introduced for CacheFiles, which can boost the scenario where on-demand read semantics are needed, e.g. container image distribution. The essential difference between these two modes is seen when a cache miss occurs: In the original mode, the netfs will fetch the data from the remote server and then write it to the cache file; in on-demand read mode, fetching the data and writing it into the cache is delegated to a user daemon. As the first step, notify the user daemon when looking up cookie. In this case, an anonymous fd is sent to the user daemon, through which the user daemon can write the fetched data to the cache file. Since the user daemon may move the anonymous fd around, e.g. through dup(), an object ID uniquely identifying the cache file is also attached. Also add one advisory flag (FSCACHE_ADV_WANT_CACHE_SIZE) suggesting that the cache file size shall be retrieved at runtime. This helps the scenario where one cache file contains multiple netfs files, e.g. for the purpose of deduplication. In this case, netfs itself has no idea the size of the cache file, whilst the user daemon should give the hint on it. Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> Link: https://lore.kernel.org/r/20220509074028.74954-3-jefflexu@linux.alibaba.com Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-04-25 12:21:24 +00:00
ret = cachefiles_ondemand_init_object(object);
if (ret < 0) {
file = ERR_PTR(ret);
goto out_unuse;
}
ni_size = object->cookie->object_size;
ni_size = round_up(ni_size, CACHEFILES_DIO_BLOCK_SIZE);
cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:50:10 +00:00
if (ni_size > 0) {
trace_cachefiles_trunc(object, d_backing_inode(path.dentry), 0, ni_size,
cachefiles_trunc_expand_tmpfile);
ret = cachefiles_inject_write_error();
if (ret == 0)
ret = vfs_truncate(&path, ni_size);
if (ret < 0) {
trace_cachefiles_vfs_error(
object, d_backing_inode(path.dentry), ret,
cachefiles_trace_trunc_error);
file = ERR_PTR(ret);
goto out_unuse;
cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:50:10 +00:00
}
}
file = open_with_fake_path(&path, O_RDWR | O_LARGEFILE | O_DIRECT,
d_backing_inode(path.dentry), cache->cache_cred);
if (IS_ERR(file)) {
trace_cachefiles_vfs_error(object, d_backing_inode(path.dentry),
PTR_ERR(file),
cachefiles_trace_open_error);
goto out_unuse;
cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:50:10 +00:00
}
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");
file = ERR_PTR(-EINVAL);
goto out_unuse;
cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:50:10 +00:00
}
goto out_dput;
out_unuse:
cachefiles_do_unmark_inode_in_use(object, path.dentry);
cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:50:10 +00:00
out_dput:
dput(path.dentry);
out:
cachefiles_end_secure(cache, saved_cred);
return file;
}
/*
* 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);
cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:50:10 +00:00
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, dentry))
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);
cachefiles: notify the user daemon when looking up cookie Fscache/CacheFiles used to serve as a local cache for a remote networking fs. A new on-demand read mode will be introduced for CacheFiles, which can boost the scenario where on-demand read semantics are needed, e.g. container image distribution. The essential difference between these two modes is seen when a cache miss occurs: In the original mode, the netfs will fetch the data from the remote server and then write it to the cache file; in on-demand read mode, fetching the data and writing it into the cache is delegated to a user daemon. As the first step, notify the user daemon when looking up cookie. In this case, an anonymous fd is sent to the user daemon, through which the user daemon can write the fetched data to the cache file. Since the user daemon may move the anonymous fd around, e.g. through dup(), an object ID uniquely identifying the cache file is also attached. Also add one advisory flag (FSCACHE_ADV_WANT_CACHE_SIZE) suggesting that the cache file size shall be retrieved at runtime. This helps the scenario where one cache file contains multiple netfs files, e.g. for the purpose of deduplication. In this case, netfs itself has no idea the size of the cache file, whilst the user daemon should give the hint on it. Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> Link: https://lore.kernel.org/r/20220509074028.74954-3-jefflexu@linux.alibaba.com Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-04-25 12:21:24 +00:00
ret = cachefiles_ondemand_init_object(object);
if (ret < 0)
goto error_fput;
cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:50:10 +00:00
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)
cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:50:10 +00:00
return cachefiles_create_file(object);
return false;
cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:50:10 +00:00
error_fput:
fput(file);
error:
cachefiles_do_unmark_inode_in_use(object, dentry);
cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:50:10 +00:00
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);
cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:50:10 +00:00
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, &init_user_ns,
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;
}