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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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a8b0026847
... and fix the directory locking documentation and proof of correctness. Holding ->s_vfs_rename_mutex *almost* prevents ->d_parent changes; the case where we really don't want it is splicing the root of disconnected tree to somewhere. In other words, ->s_vfs_rename_mutex is sufficient to stabilize "X is an ancestor of Y" only if X and Y are already in the same tree. Otherwise it can go from false to true, and one can construct a deadlock on that. Make lock_two_directories() report an error in such case and update the callers of lock_rename()/lock_rename_child() to handle such errors. And yes, such conditions are not impossible to create ;-/ Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
865 lines
22 KiB
C
865 lines
22 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* CacheFiles path walking and related routines
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*
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* Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/fs.h>
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#include <linux/namei.h>
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#include "internal.h"
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/*
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* Mark the backing file as being a cache file if it's not already in use. The
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* mark tells the culling request command that it's not allowed to cull the
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* file or directory. The caller must hold the inode lock.
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*/
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static bool __cachefiles_mark_inode_in_use(struct cachefiles_object *object,
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struct inode *inode)
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{
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bool can_use = false;
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if (!(inode->i_flags & S_KERNEL_FILE)) {
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inode->i_flags |= S_KERNEL_FILE;
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trace_cachefiles_mark_active(object, inode);
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can_use = true;
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} else {
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trace_cachefiles_mark_failed(object, inode);
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}
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return can_use;
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}
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static bool cachefiles_mark_inode_in_use(struct cachefiles_object *object,
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struct inode *inode)
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{
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bool can_use;
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inode_lock(inode);
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can_use = __cachefiles_mark_inode_in_use(object, inode);
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inode_unlock(inode);
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return can_use;
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}
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/*
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* Unmark a backing inode. The caller must hold the inode lock.
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*/
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static void __cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
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struct inode *inode)
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{
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inode->i_flags &= ~S_KERNEL_FILE;
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trace_cachefiles_mark_inactive(object, inode);
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}
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static void cachefiles_do_unmark_inode_in_use(struct cachefiles_object *object,
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struct inode *inode)
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{
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inode_lock(inode);
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__cachefiles_unmark_inode_in_use(object, inode);
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inode_unlock(inode);
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}
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/*
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* Unmark a backing inode and tell cachefilesd that there's something that can
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* be culled.
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*/
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void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
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struct file *file)
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{
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struct cachefiles_cache *cache = object->volume->cache;
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struct inode *inode = file_inode(file);
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cachefiles_do_unmark_inode_in_use(object, inode);
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if (!test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags)) {
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atomic_long_add(inode->i_blocks, &cache->b_released);
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if (atomic_inc_return(&cache->f_released))
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cachefiles_state_changed(cache);
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}
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}
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/*
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* get a subdirectory
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*/
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struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
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struct dentry *dir,
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const char *dirname,
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bool *_is_new)
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{
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struct dentry *subdir;
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struct path path;
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int ret;
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_enter(",,%s", dirname);
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/* search the current directory for the element name */
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inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
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retry:
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ret = cachefiles_inject_read_error();
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if (ret == 0)
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subdir = lookup_one_len(dirname, dir, strlen(dirname));
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else
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subdir = ERR_PTR(ret);
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trace_cachefiles_lookup(NULL, dir, subdir);
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if (IS_ERR(subdir)) {
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trace_cachefiles_vfs_error(NULL, d_backing_inode(dir),
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PTR_ERR(subdir),
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cachefiles_trace_lookup_error);
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if (PTR_ERR(subdir) == -ENOMEM)
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goto nomem_d_alloc;
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goto lookup_error;
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}
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_debug("subdir -> %pd %s",
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subdir, d_backing_inode(subdir) ? "positive" : "negative");
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/* we need to create the subdir if it doesn't exist yet */
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if (d_is_negative(subdir)) {
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ret = cachefiles_has_space(cache, 1, 0,
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cachefiles_has_space_for_create);
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if (ret < 0)
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goto mkdir_error;
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_debug("attempt mkdir");
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path.mnt = cache->mnt;
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path.dentry = dir;
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ret = security_path_mkdir(&path, subdir, 0700);
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if (ret < 0)
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goto mkdir_error;
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ret = cachefiles_inject_write_error();
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if (ret == 0)
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ret = vfs_mkdir(&nop_mnt_idmap, d_inode(dir), subdir, 0700);
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if (ret < 0) {
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trace_cachefiles_vfs_error(NULL, d_inode(dir), ret,
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cachefiles_trace_mkdir_error);
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goto mkdir_error;
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}
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trace_cachefiles_mkdir(dir, subdir);
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if (unlikely(d_unhashed(subdir))) {
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cachefiles_put_directory(subdir);
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goto retry;
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}
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ASSERT(d_backing_inode(subdir));
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_debug("mkdir -> %pd{ino=%lu}",
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subdir, d_backing_inode(subdir)->i_ino);
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if (_is_new)
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*_is_new = true;
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}
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/* Tell rmdir() it's not allowed to delete the subdir */
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inode_lock(d_inode(subdir));
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inode_unlock(d_inode(dir));
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if (!__cachefiles_mark_inode_in_use(NULL, d_inode(subdir))) {
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pr_notice("cachefiles: Inode already in use: %pd (B=%lx)\n",
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subdir, d_inode(subdir)->i_ino);
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goto mark_error;
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}
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inode_unlock(d_inode(subdir));
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/* we need to make sure the subdir is a directory */
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ASSERT(d_backing_inode(subdir));
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if (!d_can_lookup(subdir)) {
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pr_err("%s is not a directory\n", dirname);
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ret = -EIO;
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goto check_error;
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}
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ret = -EPERM;
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if (!(d_backing_inode(subdir)->i_opflags & IOP_XATTR) ||
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!d_backing_inode(subdir)->i_op->lookup ||
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!d_backing_inode(subdir)->i_op->mkdir ||
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!d_backing_inode(subdir)->i_op->rename ||
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!d_backing_inode(subdir)->i_op->rmdir ||
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!d_backing_inode(subdir)->i_op->unlink)
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goto check_error;
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_leave(" = [%lu]", d_backing_inode(subdir)->i_ino);
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return subdir;
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check_error:
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cachefiles_put_directory(subdir);
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_leave(" = %d [check]", ret);
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return ERR_PTR(ret);
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mark_error:
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inode_unlock(d_inode(subdir));
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dput(subdir);
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return ERR_PTR(-EBUSY);
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mkdir_error:
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inode_unlock(d_inode(dir));
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dput(subdir);
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pr_err("mkdir %s failed with error %d\n", dirname, ret);
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return ERR_PTR(ret);
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lookup_error:
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inode_unlock(d_inode(dir));
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ret = PTR_ERR(subdir);
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pr_err("Lookup %s failed with error %d\n", dirname, ret);
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return ERR_PTR(ret);
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nomem_d_alloc:
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inode_unlock(d_inode(dir));
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_leave(" = -ENOMEM");
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return ERR_PTR(-ENOMEM);
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}
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/*
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* Put a subdirectory.
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*/
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void cachefiles_put_directory(struct dentry *dir)
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{
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if (dir) {
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cachefiles_do_unmark_inode_in_use(NULL, d_inode(dir));
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dput(dir);
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}
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}
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/*
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* Remove a regular file from the cache.
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*/
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static int cachefiles_unlink(struct cachefiles_cache *cache,
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struct cachefiles_object *object,
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struct dentry *dir, struct dentry *dentry,
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enum fscache_why_object_killed why)
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{
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struct path path = {
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.mnt = cache->mnt,
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.dentry = dir,
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};
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int ret;
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trace_cachefiles_unlink(object, d_inode(dentry)->i_ino, why);
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ret = security_path_unlink(&path, dentry);
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if (ret < 0) {
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cachefiles_io_error(cache, "Unlink security error");
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return ret;
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}
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ret = cachefiles_inject_remove_error();
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if (ret == 0) {
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ret = vfs_unlink(&nop_mnt_idmap, d_backing_inode(dir), dentry, NULL);
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if (ret == -EIO)
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cachefiles_io_error(cache, "Unlink failed");
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}
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if (ret != 0)
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trace_cachefiles_vfs_error(object, d_backing_inode(dir), ret,
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cachefiles_trace_unlink_error);
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return ret;
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}
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/*
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* Delete an object representation from the cache
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* - File backed objects are unlinked
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* - Directory backed objects are stuffed into the graveyard for userspace to
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* delete
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*/
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int cachefiles_bury_object(struct cachefiles_cache *cache,
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struct cachefiles_object *object,
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struct dentry *dir,
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struct dentry *rep,
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enum fscache_why_object_killed why)
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{
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struct dentry *grave, *trap;
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struct path path, path_to_graveyard;
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char nbuffer[8 + 8 + 1];
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int ret;
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_enter(",'%pd','%pd'", dir, rep);
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if (rep->d_parent != dir) {
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inode_unlock(d_inode(dir));
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_leave(" = -ESTALE");
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return -ESTALE;
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}
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/* non-directories can just be unlinked */
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if (!d_is_dir(rep)) {
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dget(rep); /* Stop the dentry being negated if it's only pinned
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* by a file struct.
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*/
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ret = cachefiles_unlink(cache, object, dir, rep, why);
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dput(rep);
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inode_unlock(d_inode(dir));
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_leave(" = %d", ret);
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return ret;
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}
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/* directories have to be moved to the graveyard */
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_debug("move stale object to graveyard");
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inode_unlock(d_inode(dir));
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try_again:
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/* first step is to make up a grave dentry in the graveyard */
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sprintf(nbuffer, "%08x%08x",
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(uint32_t) ktime_get_real_seconds(),
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(uint32_t) atomic_inc_return(&cache->gravecounter));
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/* do the multiway lock magic */
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trap = lock_rename(cache->graveyard, dir);
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if (IS_ERR(trap))
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return PTR_ERR(trap);
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/* do some checks before getting the grave dentry */
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if (rep->d_parent != dir || IS_DEADDIR(d_inode(rep))) {
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/* the entry was probably culled when we dropped the parent dir
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* lock */
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unlock_rename(cache->graveyard, dir);
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_leave(" = 0 [culled?]");
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return 0;
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}
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if (!d_can_lookup(cache->graveyard)) {
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unlock_rename(cache->graveyard, dir);
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cachefiles_io_error(cache, "Graveyard no longer a directory");
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return -EIO;
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}
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if (trap == rep) {
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unlock_rename(cache->graveyard, dir);
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cachefiles_io_error(cache, "May not make directory loop");
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return -EIO;
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}
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if (d_mountpoint(rep)) {
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unlock_rename(cache->graveyard, dir);
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cachefiles_io_error(cache, "Mountpoint in cache");
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return -EIO;
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}
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grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer));
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if (IS_ERR(grave)) {
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unlock_rename(cache->graveyard, dir);
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trace_cachefiles_vfs_error(object, d_inode(cache->graveyard),
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PTR_ERR(grave),
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cachefiles_trace_lookup_error);
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if (PTR_ERR(grave) == -ENOMEM) {
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_leave(" = -ENOMEM");
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return -ENOMEM;
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}
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cachefiles_io_error(cache, "Lookup error %ld", PTR_ERR(grave));
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return -EIO;
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}
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if (d_is_positive(grave)) {
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unlock_rename(cache->graveyard, dir);
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dput(grave);
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grave = NULL;
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cond_resched();
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goto try_again;
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}
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if (d_mountpoint(grave)) {
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unlock_rename(cache->graveyard, dir);
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dput(grave);
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cachefiles_io_error(cache, "Mountpoint in graveyard");
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return -EIO;
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}
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/* target should not be an ancestor of source */
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if (trap == grave) {
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unlock_rename(cache->graveyard, dir);
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dput(grave);
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cachefiles_io_error(cache, "May not make directory loop");
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return -EIO;
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}
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/* attempt the rename */
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path.mnt = cache->mnt;
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path.dentry = dir;
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path_to_graveyard.mnt = cache->mnt;
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path_to_graveyard.dentry = cache->graveyard;
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ret = security_path_rename(&path, rep, &path_to_graveyard, grave, 0);
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if (ret < 0) {
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cachefiles_io_error(cache, "Rename security error %d", ret);
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} else {
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struct renamedata rd = {
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.old_mnt_idmap = &nop_mnt_idmap,
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.old_dir = d_inode(dir),
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.old_dentry = rep,
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.new_mnt_idmap = &nop_mnt_idmap,
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.new_dir = d_inode(cache->graveyard),
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.new_dentry = grave,
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};
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trace_cachefiles_rename(object, d_inode(rep)->i_ino, why);
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ret = cachefiles_inject_read_error();
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if (ret == 0)
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ret = vfs_rename(&rd);
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if (ret != 0)
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trace_cachefiles_vfs_error(object, d_inode(dir), ret,
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cachefiles_trace_rename_error);
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if (ret != 0 && ret != -ENOMEM)
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cachefiles_io_error(cache,
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"Rename failed with error %d", ret);
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}
|
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|
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__cachefiles_unmark_inode_in_use(object, d_inode(rep));
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unlock_rename(cache->graveyard, dir);
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dput(grave);
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_leave(" = 0");
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return 0;
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}
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|
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/*
|
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* Delete a cache file.
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*/
|
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int cachefiles_delete_object(struct cachefiles_object *object,
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enum fscache_why_object_killed why)
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{
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struct cachefiles_volume *volume = object->volume;
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struct dentry *dentry = object->file->f_path.dentry;
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struct dentry *fan = volume->fanout[(u8)object->cookie->key_hash];
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int ret;
|
|
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_enter(",OBJ%x{%pD}", object->debug_id, object->file);
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|
|
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/* Stop the dentry being negated if it's only pinned by a file struct. */
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dget(dentry);
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|
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inode_lock_nested(d_backing_inode(fan), I_MUTEX_PARENT);
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ret = cachefiles_unlink(volume->cache, object, fan, dentry, why);
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inode_unlock(d_backing_inode(fan));
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dput(dentry);
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return ret;
|
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}
|
|
|
|
/*
|
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* Create a temporary file and leave it unattached and un-xattr'd until the
|
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* time comes to discard the object from memory.
|
|
*/
|
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struct file *cachefiles_create_tmpfile(struct cachefiles_object *object)
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|
{
|
|
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];
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struct file *file;
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const struct path parentpath = { .mnt = cache->mnt, .dentry = fan };
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uint64_t ni_size;
|
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long ret;
|
|
|
|
|
|
cachefiles_begin_secure(cache, &saved_cred);
|
|
|
|
ret = cachefiles_inject_write_error();
|
|
if (ret == 0) {
|
|
file = kernel_tmpfile_open(&nop_mnt_idmap, &parentpath,
|
|
S_IFREG | 0600,
|
|
O_RDWR | O_LARGEFILE | O_DIRECT,
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cache->cache_cred);
|
|
ret = PTR_ERR_OR_ZERO(file);
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|
}
|
|
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 = kernel_file_open(&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;
|
|
|
|
clear_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &object->cookie->flags);
|
|
|
|
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;
|
|
}
|