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-rw-r--r--fs/notify/fsnotify.c16
-rw-r--r--fs/notify/fsnotify.h9
-rw-r--r--fs/notify/mark.c32
-rw-r--r--include/linux/fs.h8
-rw-r--r--include/linux/fsnotify_backend.h17
5 files changed, 73 insertions, 9 deletions
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 503e7c75e777..fb3f36bc6ea9 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -89,11 +89,18 @@ static void fsnotify_unmount_inodes(struct super_block *sb)
void fsnotify_sb_delete(struct super_block *sb)
{
+ struct fsnotify_sb_info *sbinfo = fsnotify_sb_info(sb);
+
+ /* Were any marks ever added to any object on this sb? */
+ if (!sbinfo)
+ return;
+
fsnotify_unmount_inodes(sb);
fsnotify_clear_marks_by_sb(sb);
/* Wait for outstanding object references from connectors */
wait_var_event(fsnotify_sb_watched_objects(sb),
!atomic_long_read(fsnotify_sb_watched_objects(sb)));
+ kfree(sbinfo);
}
/*
@@ -489,6 +496,7 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
{
const struct path *path = fsnotify_data_path(data, data_type);
struct super_block *sb = fsnotify_data_sb(data, data_type);
+ struct fsnotify_sb_info *sbinfo = fsnotify_sb_info(sb);
struct fsnotify_iter_info iter_info = {};
struct mount *mnt = NULL;
struct inode *inode2 = NULL;
@@ -525,7 +533,7 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
* SRCU because we have no references to any objects and do not
* need SRCU to keep them "alive".
*/
- if (!sb->s_fsnotify_marks &&
+ if ((!sbinfo || !sbinfo->sb_marks) &&
(!mnt || !mnt->mnt_fsnotify_marks) &&
(!inode || !inode->i_fsnotify_marks) &&
(!inode2 || !inode2->i_fsnotify_marks))
@@ -552,8 +560,10 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu);
- iter_info.marks[FSNOTIFY_ITER_TYPE_SB] =
- fsnotify_first_mark(&sb->s_fsnotify_marks);
+ if (sbinfo) {
+ iter_info.marks[FSNOTIFY_ITER_TYPE_SB] =
+ fsnotify_first_mark(&sbinfo->sb_marks);
+ }
if (mnt) {
iter_info.marks[FSNOTIFY_ITER_TYPE_VFSMOUNT] =
fsnotify_first_mark(&mnt->mnt_fsnotify_marks);
diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h
index b1fec7cd8ee4..2d059f789ee3 100644
--- a/fs/notify/fsnotify.h
+++ b/fs/notify/fsnotify.h
@@ -54,6 +54,13 @@ static inline struct super_block *fsnotify_connector_sb(
return fsnotify_object_sb(conn->obj, conn->type);
}
+static inline fsnotify_connp_t *fsnotify_sb_marks(struct super_block *sb)
+{
+ struct fsnotify_sb_info *sbinfo = fsnotify_sb_info(sb);
+
+ return sbinfo ? &sbinfo->sb_marks : NULL;
+}
+
/* destroy all events sitting in this groups notification queue */
extern void fsnotify_flush_notify(struct fsnotify_group *group);
@@ -79,7 +86,7 @@ static inline void fsnotify_clear_marks_by_mount(struct vfsmount *mnt)
/* run the list of all marks associated with sb and destroy them */
static inline void fsnotify_clear_marks_by_sb(struct super_block *sb)
{
- fsnotify_destroy_marks(&sb->s_fsnotify_marks);
+ fsnotify_destroy_marks(fsnotify_sb_marks(sb));
}
/*
diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 647c49c20467..b2f5d8c9cce1 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -106,7 +106,7 @@ static fsnotify_connp_t *fsnotify_object_connp(void *obj,
case FSNOTIFY_OBJ_TYPE_VFSMOUNT:
return &real_mount(obj)->mnt_fsnotify_marks;
case FSNOTIFY_OBJ_TYPE_SB:
- return &((struct super_block *)obj)->s_fsnotify_marks;
+ return fsnotify_sb_marks(obj);
default:
return NULL;
}
@@ -569,6 +569,26 @@ int fsnotify_compare_groups(struct fsnotify_group *a, struct fsnotify_group *b)
return -1;
}
+static int fsnotify_attach_info_to_sb(struct super_block *sb)
+{
+ struct fsnotify_sb_info *sbinfo;
+
+ /* sb info is freed on fsnotify_sb_delete() */
+ sbinfo = kzalloc(sizeof(*sbinfo), GFP_KERNEL);
+ if (!sbinfo)
+ return -ENOMEM;
+
+ /*
+ * cmpxchg() provides the barrier so that callers of fsnotify_sb_info()
+ * will observe an initialized structure
+ */
+ if (cmpxchg(&sb->s_fsnotify_info, NULL, sbinfo)) {
+ /* Someone else created sbinfo for us */
+ kfree(sbinfo);
+ }
+ return 0;
+}
+
static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp,
void *obj, unsigned int obj_type)
{
@@ -640,6 +660,16 @@ static int fsnotify_add_mark_list(struct fsnotify_mark *mark, void *obj,
if (WARN_ON(!fsnotify_valid_obj_type(obj_type)))
return -EINVAL;
+ /*
+ * Attach the sb info before attaching a connector to any object on sb.
+ * The sb info will remain attached as long as sb lives.
+ */
+ if (!fsnotify_sb_info(sb)) {
+ err = fsnotify_attach_info_to_sb(sb);
+ if (err)
+ return err;
+ }
+
connp = fsnotify_object_connp(obj, obj_type);
restart:
spin_lock(&mark->lock);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 00fc429b0af0..7f40b592f711 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -73,6 +73,8 @@ struct fscrypt_inode_info;
struct fscrypt_operations;
struct fsverity_info;
struct fsverity_operations;
+struct fsnotify_mark_connector;
+struct fsnotify_sb_info;
struct fs_context;
struct fs_parameter_spec;
struct fileattr;
@@ -620,8 +622,6 @@ is_uncached_acl(struct posix_acl *acl)
#define IOP_XATTR 0x0008
#define IOP_DEFAULT_READLINK 0x0010
-struct fsnotify_mark_connector;
-
/*
* Keep mostly read-only and often accessed (especially for
* the RCU path lookup and 'stat' data) fields at the beginning
@@ -1249,7 +1249,7 @@ struct super_block {
/*
* Keep s_fs_info, s_time_gran, s_fsnotify_mask, and
- * s_fsnotify_marks together for cache efficiency. They are frequently
+ * s_fsnotify_info together for cache efficiency. They are frequently
* accessed and rarely modified.
*/
void *s_fs_info; /* Filesystem private info */
@@ -1261,7 +1261,7 @@ struct super_block {
time64_t s_time_max;
#ifdef CONFIG_FSNOTIFY
__u32 s_fsnotify_mask;
- struct fsnotify_mark_connector __rcu *s_fsnotify_marks;
+ struct fsnotify_sb_info *s_fsnotify_info;
#endif
/*
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 83004d9e07a3..c9f2b2f6b493 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -477,6 +477,23 @@ struct fsnotify_mark_connector {
struct hlist_head list;
};
+/*
+ * Container for per-sb fsnotify state (sb marks and more).
+ * Attached lazily on first marked object on the sb and freed when killing sb.
+ */
+struct fsnotify_sb_info {
+ struct fsnotify_mark_connector __rcu *sb_marks;
+};
+
+static inline struct fsnotify_sb_info *fsnotify_sb_info(struct super_block *sb)
+{
+#ifdef CONFIG_FSNOTIFY
+ return READ_ONCE(sb->s_fsnotify_info);
+#else
+ return NULL;
+#endif
+}
+
static inline atomic_long_t *fsnotify_sb_watched_objects(struct super_block *sb)
{
return &sb->s_fsnotify_connectors;
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-26 02:55:39 +0300