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audit: reimplement audit_trees using fsnotify rather than inotify
Simply switch audit_trees from using inotify to using fsnotify for it's inode pinning and disappearing act information. Signed-off-by: Eric Paris <eparis@redhat.com>
This commit is contained in:
Eric Paris
parent
40554c3dae
commit
28a3a7eb3b
@ -62,8 +62,9 @@
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/* listeners that hard code group numbers near the top */
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#define DNOTIFY_GROUP_NUM UINT_MAX
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#define AUDIT_WATCH_GROUP_NUM (DNOTIFY_GROUP_NUM-1)
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#define INOTIFY_GROUP_NUM (AUDIT_WATCH_GROUP_NUM-1)
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#define AUDIT_WATCH_GROUP_NUM (DNOTIFY_GROUP_NUM-1)
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#define AUDIT_TREE_GROUP_NUM (AUDIT_WATCH_GROUP_NUM-1)
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#define INOTIFY_GROUP_NUM (AUDIT_TREE_GROUP_NUM-1)
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struct fsnotify_group;
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struct fsnotify_event;
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@ -326,7 +326,7 @@ config AUDITSYSCALL
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config AUDIT_TREE
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def_bool y
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depends on AUDITSYSCALL
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select INOTIFY
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select FSNOTIFY
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menu "RCU Subsystem"
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@ -1,5 +1,5 @@
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#include "audit.h"
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#include <linux/inotify.h>
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#include <linux/fsnotify_backend.h>
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#include <linux/namei.h>
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#include <linux/mount.h>
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#include <linux/kthread.h>
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@ -22,7 +22,7 @@ struct audit_tree {
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struct audit_chunk {
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struct list_head hash;
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struct inotify_watch watch;
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struct fsnotify_mark_entry mark;
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struct list_head trees; /* with root here */
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int dead;
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int count;
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@ -59,7 +59,7 @@ static LIST_HEAD(prune_list);
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* tree is refcounted; one reference for "some rules on rules_list refer to
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* it", one for each chunk with pointer to it.
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*
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* chunk is refcounted by embedded inotify_watch + .refs (non-zero refcount
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* chunk is refcounted by embedded fsnotify_mark + .refs (non-zero refcount
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* of watch contributes 1 to .refs).
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*
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* node.index allows to get from node.list to containing chunk.
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@ -68,7 +68,7 @@ static LIST_HEAD(prune_list);
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* that makes a difference. Some.
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*/
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static struct inotify_handle *rtree_ih;
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static struct fsnotify_group *audit_tree_group;
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static struct audit_tree *alloc_tree(const char *s)
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{
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@ -111,29 +111,6 @@ const char *audit_tree_path(struct audit_tree *tree)
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return tree->pathname;
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}
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static struct audit_chunk *alloc_chunk(int count)
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{
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struct audit_chunk *chunk;
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size_t size;
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int i;
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size = offsetof(struct audit_chunk, owners) + count * sizeof(struct node);
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chunk = kzalloc(size, GFP_KERNEL);
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if (!chunk)
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return NULL;
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INIT_LIST_HEAD(&chunk->hash);
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INIT_LIST_HEAD(&chunk->trees);
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chunk->count = count;
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atomic_long_set(&chunk->refs, 1);
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for (i = 0; i < count; i++) {
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INIT_LIST_HEAD(&chunk->owners[i].list);
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chunk->owners[i].index = i;
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}
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inotify_init_watch(&chunk->watch);
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return chunk;
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}
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static void free_chunk(struct audit_chunk *chunk)
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{
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int i;
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@ -157,6 +134,35 @@ static void __put_chunk(struct rcu_head *rcu)
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audit_put_chunk(chunk);
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}
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static void audit_tree_destroy_watch(struct fsnotify_mark_entry *entry)
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{
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struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark);
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call_rcu(&chunk->head, __put_chunk);
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}
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static struct audit_chunk *alloc_chunk(int count)
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{
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struct audit_chunk *chunk;
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size_t size;
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int i;
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size = offsetof(struct audit_chunk, owners) + count * sizeof(struct node);
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chunk = kzalloc(size, GFP_KERNEL);
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if (!chunk)
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return NULL;
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INIT_LIST_HEAD(&chunk->hash);
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INIT_LIST_HEAD(&chunk->trees);
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chunk->count = count;
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atomic_long_set(&chunk->refs, 1);
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for (i = 0; i < count; i++) {
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INIT_LIST_HEAD(&chunk->owners[i].list);
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chunk->owners[i].index = i;
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}
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fsnotify_init_mark(&chunk->mark, audit_tree_destroy_watch);
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return chunk;
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}
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enum {HASH_SIZE = 128};
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static struct list_head chunk_hash_heads[HASH_SIZE];
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static __cacheline_aligned_in_smp DEFINE_SPINLOCK(hash_lock);
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@ -167,10 +173,15 @@ static inline struct list_head *chunk_hash(const struct inode *inode)
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return chunk_hash_heads + n % HASH_SIZE;
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}
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/* hash_lock is held by caller */
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/* hash_lock & entry->lock is held by caller */
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static void insert_hash(struct audit_chunk *chunk)
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{
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struct list_head *list = chunk_hash(chunk->watch.inode);
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struct fsnotify_mark_entry *entry = &chunk->mark;
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struct list_head *list;
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if (!entry->inode)
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return;
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list = chunk_hash(entry->inode);
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list_add_rcu(&chunk->hash, list);
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}
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@ -181,7 +192,8 @@ struct audit_chunk *audit_tree_lookup(const struct inode *inode)
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struct audit_chunk *p;
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list_for_each_entry_rcu(p, list, hash) {
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if (p->watch.inode == inode) {
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/* mark.inode may have gone NULL, but who cares? */
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if (p->mark.inode == inode) {
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atomic_long_inc(&p->refs);
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return p;
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}
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@ -210,38 +222,19 @@ static struct audit_chunk *find_chunk(struct node *p)
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static void untag_chunk(struct node *p)
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{
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struct audit_chunk *chunk = find_chunk(p);
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struct fsnotify_mark_entry *entry = &chunk->mark;
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struct audit_chunk *new;
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struct audit_tree *owner;
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int size = chunk->count - 1;
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int i, j;
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if (!pin_inotify_watch(&chunk->watch)) {
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/*
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* Filesystem is shutting down; all watches are getting
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* evicted, just take it off the node list for this
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* tree and let the eviction logics take care of the
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* rest.
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*/
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owner = p->owner;
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if (owner->root == chunk) {
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list_del_init(&owner->same_root);
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owner->root = NULL;
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}
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list_del_init(&p->list);
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p->owner = NULL;
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put_tree(owner);
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return;
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}
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fsnotify_get_mark(entry);
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spin_unlock(&hash_lock);
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/*
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* pin_inotify_watch() succeeded, so the watch won't go away
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* from under us.
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*/
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mutex_lock(&chunk->watch.inode->inotify_mutex);
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if (chunk->dead) {
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mutex_unlock(&chunk->watch.inode->inotify_mutex);
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spin_lock(&entry->lock);
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if (chunk->dead || !entry->inode) {
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spin_unlock(&entry->lock);
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goto out;
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}
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@ -256,16 +249,17 @@ static void untag_chunk(struct node *p)
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list_del_init(&p->list);
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list_del_rcu(&chunk->hash);
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spin_unlock(&hash_lock);
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inotify_evict_watch(&chunk->watch);
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mutex_unlock(&chunk->watch.inode->inotify_mutex);
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put_inotify_watch(&chunk->watch);
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spin_unlock(&entry->lock);
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fsnotify_destroy_mark_by_entry(entry);
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fsnotify_put_mark(entry);
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goto out;
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}
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new = alloc_chunk(size);
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if (!new)
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goto Fallback;
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if (inotify_clone_watch(&chunk->watch, &new->watch) < 0) {
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fsnotify_duplicate_mark(&new->mark, entry);
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if (fsnotify_add_mark(&new->mark, new->mark.group, new->mark.inode, 1)) {
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free_chunk(new);
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goto Fallback;
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}
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@ -298,9 +292,9 @@ static void untag_chunk(struct node *p)
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list_for_each_entry(owner, &new->trees, same_root)
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owner->root = new;
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spin_unlock(&hash_lock);
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inotify_evict_watch(&chunk->watch);
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mutex_unlock(&chunk->watch.inode->inotify_mutex);
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put_inotify_watch(&chunk->watch);
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spin_unlock(&entry->lock);
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fsnotify_destroy_mark_by_entry(entry);
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fsnotify_put_mark(entry);
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goto out;
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Fallback:
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@ -314,31 +308,33 @@ Fallback:
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p->owner = NULL;
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put_tree(owner);
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spin_unlock(&hash_lock);
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mutex_unlock(&chunk->watch.inode->inotify_mutex);
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spin_unlock(&entry->lock);
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out:
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unpin_inotify_watch(&chunk->watch);
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fsnotify_put_mark(entry);
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spin_lock(&hash_lock);
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}
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static int create_chunk(struct inode *inode, struct audit_tree *tree)
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{
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struct fsnotify_mark_entry *entry;
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struct audit_chunk *chunk = alloc_chunk(1);
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if (!chunk)
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return -ENOMEM;
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if (inotify_add_watch(rtree_ih, &chunk->watch, inode, IN_IGNORED | IN_DELETE_SELF) < 0) {
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entry = &chunk->mark;
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if (fsnotify_add_mark(entry, audit_tree_group, inode, 0)) {
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free_chunk(chunk);
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return -ENOSPC;
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}
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mutex_lock(&inode->inotify_mutex);
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spin_lock(&entry->lock);
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spin_lock(&hash_lock);
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if (tree->goner) {
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spin_unlock(&hash_lock);
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chunk->dead = 1;
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inotify_evict_watch(&chunk->watch);
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mutex_unlock(&inode->inotify_mutex);
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put_inotify_watch(&chunk->watch);
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spin_unlock(&entry->lock);
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fsnotify_destroy_mark_by_entry(entry);
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fsnotify_put_mark(entry);
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return 0;
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}
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chunk->owners[0].index = (1U << 31);
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@ -351,30 +347,33 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree)
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}
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insert_hash(chunk);
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spin_unlock(&hash_lock);
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mutex_unlock(&inode->inotify_mutex);
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spin_unlock(&entry->lock);
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return 0;
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}
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/* the first tagged inode becomes root of tree */
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static int tag_chunk(struct inode *inode, struct audit_tree *tree)
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{
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struct inotify_watch *watch;
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struct fsnotify_mark_entry *old_entry, *chunk_entry;
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struct audit_tree *owner;
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struct audit_chunk *chunk, *old;
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struct node *p;
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int n;
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if (inotify_find_watch(rtree_ih, inode, &watch) < 0)
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spin_lock(&inode->i_lock);
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old_entry = fsnotify_find_mark_entry(audit_tree_group, inode);
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spin_unlock(&inode->i_lock);
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if (!old_entry)
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return create_chunk(inode, tree);
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old = container_of(watch, struct audit_chunk, watch);
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old = container_of(old_entry, struct audit_chunk, mark);
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/* are we already there? */
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spin_lock(&hash_lock);
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for (n = 0; n < old->count; n++) {
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if (old->owners[n].owner == tree) {
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spin_unlock(&hash_lock);
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put_inotify_watch(&old->watch);
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fsnotify_put_mark(old_entry);
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return 0;
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}
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}
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@ -382,25 +381,44 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
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chunk = alloc_chunk(old->count + 1);
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if (!chunk) {
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put_inotify_watch(&old->watch);
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fsnotify_put_mark(old_entry);
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return -ENOMEM;
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}
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mutex_lock(&inode->inotify_mutex);
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if (inotify_clone_watch(&old->watch, &chunk->watch) < 0) {
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mutex_unlock(&inode->inotify_mutex);
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put_inotify_watch(&old->watch);
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chunk_entry = &chunk->mark;
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spin_lock(&old_entry->lock);
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if (!old_entry->inode) {
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/* old_entry is being shot, lets just lie */
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spin_unlock(&old_entry->lock);
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fsnotify_put_mark(old_entry);
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free_chunk(chunk);
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return -ENOENT;
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}
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fsnotify_duplicate_mark(chunk_entry, old_entry);
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if (fsnotify_add_mark(chunk_entry, chunk_entry->group, chunk_entry->inode, 1)) {
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spin_unlock(&old_entry->lock);
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free_chunk(chunk);
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fsnotify_put_mark(old_entry);
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return -ENOSPC;
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}
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/* even though we hold old_entry->lock, this is safe since chunk_entry->lock could NEVER have been grabbed before */
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spin_lock(&chunk_entry->lock);
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spin_lock(&hash_lock);
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/* we now hold old_entry->lock, chunk_entry->lock, and hash_lock */
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if (tree->goner) {
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spin_unlock(&hash_lock);
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chunk->dead = 1;
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inotify_evict_watch(&chunk->watch);
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mutex_unlock(&inode->inotify_mutex);
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put_inotify_watch(&old->watch);
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put_inotify_watch(&chunk->watch);
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spin_unlock(&chunk_entry->lock);
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spin_unlock(&old_entry->lock);
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fsnotify_destroy_mark_by_entry(chunk_entry);
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fsnotify_put_mark(chunk_entry);
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fsnotify_put_mark(old_entry);
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return 0;
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}
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list_replace_init(&old->trees, &chunk->trees);
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@ -426,10 +444,11 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
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list_add(&tree->same_root, &chunk->trees);
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}
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spin_unlock(&hash_lock);
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inotify_evict_watch(&old->watch);
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mutex_unlock(&inode->inotify_mutex);
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put_inotify_watch(&old->watch); /* pair to inotify_find_watch */
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put_inotify_watch(&old->watch); /* and kill it */
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spin_unlock(&chunk_entry->lock);
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spin_unlock(&old_entry->lock);
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fsnotify_destroy_mark_by_entry(old_entry);
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fsnotify_put_mark(old_entry); /* pair to fsnotify_find mark_entry */
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fsnotify_put_mark(old_entry); /* and kill it */
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return 0;
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}
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@ -584,7 +603,9 @@ void audit_trim_trees(void)
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spin_lock(&hash_lock);
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list_for_each_entry(node, &tree->chunks, list) {
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struct inode *inode = find_chunk(node)->watch.inode;
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struct audit_chunk *chunk = find_chunk(node);
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/* this could be NULL if the watch is dieing else where... */
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struct inode *inode = chunk->mark.inode;
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node->index |= 1U<<31;
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if (iterate_mounts(compare_root, inode, root_mnt))
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node->index &= ~(1U<<31);
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@ -846,7 +867,6 @@ void audit_kill_trees(struct list_head *list)
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* Here comes the stuff asynchronous to auditctl operations
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*/
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/* inode->inotify_mutex is locked */
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static void evict_chunk(struct audit_chunk *chunk)
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{
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struct audit_tree *owner;
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@ -885,35 +905,41 @@ static void evict_chunk(struct audit_chunk *chunk)
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mutex_unlock(&audit_filter_mutex);
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}
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static void handle_event(struct inotify_watch *watch, u32 wd, u32 mask,
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u32 cookie, const char *dname, struct inode *inode)
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static int audit_tree_handle_event(struct fsnotify_group *group, struct fsnotify_event *event)
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{
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struct audit_chunk *chunk = container_of(watch, struct audit_chunk, watch);
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if (mask & IN_IGNORED) {
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evict_chunk(chunk);
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put_inotify_watch(watch);
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}
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BUG();
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return -EOPNOTSUPP;
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}
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static void destroy_watch(struct inotify_watch *watch)
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static void audit_tree_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group)
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{
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struct audit_chunk *chunk = container_of(watch, struct audit_chunk, watch);
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call_rcu(&chunk->head, __put_chunk);
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struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark);
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evict_chunk(chunk);
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fsnotify_put_mark(entry);
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}
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static const struct inotify_operations rtree_inotify_ops = {
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.handle_event = handle_event,
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.destroy_watch = destroy_watch,
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static bool audit_tree_send_event(struct fsnotify_group *group, struct inode *inode, __u32 mask)
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{
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return 0;
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}
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static const struct fsnotify_ops audit_tree_ops = {
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.handle_event = audit_tree_handle_event,
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.should_send_event = audit_tree_send_event,
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.free_group_priv = NULL,
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.free_event_priv = NULL,
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.freeing_mark = audit_tree_freeing_mark,
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};
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static int __init audit_tree_init(void)
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{
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int i;
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rtree_ih = inotify_init(&rtree_inotify_ops);
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if (IS_ERR(rtree_ih))
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audit_panic("cannot initialize inotify handle for rectree watches");
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audit_tree_group = fsnotify_obtain_group(AUDIT_TREE_GROUP_NUM,
|
||||
0, &audit_tree_ops);
|
||||
if (IS_ERR(audit_tree_group))
|
||||
audit_panic("cannot initialize fsnotify group for rectree watches");
|
||||
|
||||
for (i = 0; i < HASH_SIZE; i++)
|
||||
INIT_LIST_HEAD(&chunk_hash_heads[i]);
|
||||
|
||||
@ -1725,7 +1725,7 @@ static inline void handle_one(const struct inode *inode)
|
||||
struct audit_tree_refs *p;
|
||||
struct audit_chunk *chunk;
|
||||
int count;
|
||||
if (likely(list_empty(&inode->inotify_watches)))
|
||||
if (likely(hlist_empty(&inode->i_fsnotify_mark_entries)))
|
||||
return;
|
||||
context = current->audit_context;
|
||||
p = context->trees;
|
||||
@ -1768,7 +1768,7 @@ retry:
|
||||
seq = read_seqbegin(&rename_lock);
|
||||
for(;;) {
|
||||
struct inode *inode = d->d_inode;
|
||||
if (inode && unlikely(!list_empty(&inode->inotify_watches))) {
|
||||
if (inode && unlikely(!hlist_empty(&inode->i_fsnotify_mark_entries))) {
|
||||
struct audit_chunk *chunk;
|
||||
chunk = audit_tree_lookup(inode);
|
||||
if (chunk) {
|
||||
|
||||
Loading…
Reference in New Issue
Block a user