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-rw-r--r--fs/cachefiles/internal.h1
-rw-r--r--fs/cachefiles/namei.c98
-rw-r--r--fs/cachefiles/security.c4
3 files changed, 91 insertions, 12 deletions
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index f7c255f9c624..a8cd821226da 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -34,6 +34,7 @@ struct cachefiles_object {
loff_t i_size; /* object size */
unsigned long flags;
#define CACHEFILES_OBJECT_ACTIVE 0 /* T if marked active */
+#define CACHEFILES_OBJECT_BURIED 1 /* T if preemptively buried */
atomic_t usage; /* object usage count */
uint8_t type; /* object type */
uint8_t new; /* T if object new */
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index d5db84a1ee0d..f4a7840bf42c 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -93,6 +93,59 @@ static noinline void cachefiles_printk_object(struct cachefiles_object *object,
}
/*
+ * mark the owner of a dentry, if there is one, to indicate that that dentry
+ * has been preemptively deleted
+ * - the caller must hold the i_mutex on the dentry's parent as required to
+ * call vfs_unlink(), vfs_rmdir() or vfs_rename()
+ */
+static void cachefiles_mark_object_buried(struct cachefiles_cache *cache,
+ struct dentry *dentry)
+{
+ struct cachefiles_object *object;
+ struct rb_node *p;
+
+ _enter(",'%*.*s'",
+ dentry->d_name.len, dentry->d_name.len, dentry->d_name.name);
+
+ write_lock(&cache->active_lock);
+
+ p = cache->active_nodes.rb_node;
+ while (p) {
+ object = rb_entry(p, struct cachefiles_object, active_node);
+ if (object->dentry > dentry)
+ p = p->rb_left;
+ else if (object->dentry < dentry)
+ p = p->rb_right;
+ else
+ goto found_dentry;
+ }
+
+ write_unlock(&cache->active_lock);
+ _leave(" [no owner]");
+ return;
+
+ /* found the dentry for */
+found_dentry:
+ kdebug("preemptive burial: OBJ%x [%s] %p",
+ object->fscache.debug_id,
+ fscache_object_states[object->fscache.state],
+ dentry);
+
+ if (object->fscache.state < FSCACHE_OBJECT_DYING) {
+ printk(KERN_ERR "\n");
+ printk(KERN_ERR "CacheFiles: Error:"
+ " Can't preemptively bury live object\n");
+ cachefiles_printk_object(object, NULL);
+ } else if (test_and_set_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) {
+ printk(KERN_ERR "CacheFiles: Error:"
+ " Object already preemptively buried\n");
+ }
+
+ write_unlock(&cache->active_lock);
+ _leave(" [owner marked]");
+}
+
+/*
* record the fact that an object is now active
*/
static int cachefiles_mark_object_active(struct cachefiles_cache *cache,
@@ -219,7 +272,8 @@ requeue:
*/
static int cachefiles_bury_object(struct cachefiles_cache *cache,
struct dentry *dir,
- struct dentry *rep)
+ struct dentry *rep,
+ bool preemptive)
{
struct dentry *grave, *trap;
char nbuffer[8 + 8 + 1];
@@ -229,11 +283,16 @@ static int cachefiles_bury_object(struct cachefiles_cache *cache,
dir->d_name.len, dir->d_name.len, dir->d_name.name,
rep->d_name.len, rep->d_name.len, rep->d_name.name);
+ _debug("remove %p from %p", rep, dir);
+
/* non-directories can just be unlinked */
if (!S_ISDIR(rep->d_inode->i_mode)) {
_debug("unlink stale object");
ret = vfs_unlink(dir->d_inode, rep);
+ if (preemptive)
+ cachefiles_mark_object_buried(cache, rep);
+
mutex_unlock(&dir->d_inode->i_mutex);
if (ret == -EIO)
@@ -325,6 +384,9 @@ try_again:
if (ret != 0 && ret != -ENOMEM)
cachefiles_io_error(cache, "Rename failed with error %d", ret);
+ if (preemptive)
+ cachefiles_mark_object_buried(cache, rep);
+
unlock_rename(cache->graveyard, dir);
dput(grave);
_leave(" = 0");
@@ -340,7 +402,7 @@ int cachefiles_delete_object(struct cachefiles_cache *cache,
struct dentry *dir;
int ret;
- _enter(",{%p}", object->dentry);
+ _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry);
ASSERT(object->dentry);
ASSERT(object->dentry->d_inode);
@@ -350,15 +412,25 @@ int cachefiles_delete_object(struct cachefiles_cache *cache,
mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
- /* we need to check that our parent is _still_ our parent - it may have
- * been renamed */
- if (dir == object->dentry->d_parent) {
- ret = cachefiles_bury_object(cache, dir, object->dentry);
- } else {
- /* it got moved, presumably by cachefilesd culling it, so it's
- * no longer in the key path and we can ignore it */
+ if (test_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) {
+ /* object allocation for the same key preemptively deleted this
+ * object's file so that it could create its own file */
+ _debug("object preemptively buried");
mutex_unlock(&dir->d_inode->i_mutex);
ret = 0;
+ } else {
+ /* we need to check that our parent is _still_ our parent - it
+ * may have been renamed */
+ if (dir == object->dentry->d_parent) {
+ ret = cachefiles_bury_object(cache, dir,
+ object->dentry, false);
+ } else {
+ /* it got moved, presumably by cachefilesd culling it,
+ * so it's no longer in the key path and we can ignore
+ * it */
+ mutex_unlock(&dir->d_inode->i_mutex);
+ ret = 0;
+ }
}
dput(dir);
@@ -381,7 +453,9 @@ int cachefiles_walk_to_object(struct cachefiles_object *parent,
const char *name;
int ret, nlen;
- _enter("{%p},,%s,", parent->dentry, key);
+ _enter("OBJ%x{%p},OBJ%x,%s,",
+ parent->fscache.debug_id, parent->dentry,
+ object->fscache.debug_id, key);
cache = container_of(parent->fscache.cache,
struct cachefiles_cache, cache);
@@ -509,7 +583,7 @@ lookup_again:
* mutex) */
object->dentry = NULL;
- ret = cachefiles_bury_object(cache, dir, next);
+ ret = cachefiles_bury_object(cache, dir, next, true);
dput(next);
next = NULL;
@@ -828,7 +902,7 @@ int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
/* actually remove the victim (drops the dir mutex) */
_debug("bury");
- ret = cachefiles_bury_object(cache, dir, victim);
+ ret = cachefiles_bury_object(cache, dir, victim, false);
if (ret < 0)
goto error;
diff --git a/fs/cachefiles/security.c b/fs/cachefiles/security.c
index b5808cdb2232..039b5011d83b 100644
--- a/fs/cachefiles/security.c
+++ b/fs/cachefiles/security.c
@@ -77,6 +77,8 @@ static int cachefiles_check_cache_dir(struct cachefiles_cache *cache,
/*
* check the security details of the on-disk cache
* - must be called with security override in force
+ * - must return with a security override in force - even in the case of an
+ * error
*/
int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
struct dentry *root,
@@ -99,6 +101,8 @@ int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
* which create files */
ret = set_create_files_as(new, root->d_inode);
if (ret < 0) {
+ abort_creds(new);
+ cachefiles_begin_secure(cache, _saved_cred);
_leave(" = %d [cfa]", ret);
return ret;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-23 05:02:55 +0000