This is a note to let you know that I've just added the patch titled
fsnotify: count all objects with attached connectors
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fsnotify-count-all-objects-with-attached-connectors.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8603ceadb6e3247a658fd2041168f5450d479222
Author: Amir Goldstein <amir73il@xxxxxxxxx>
Date: Tue Aug 10 18:12:19 2021 +0300
fsnotify: count all objects with attached connectors
[ Upstream commit ec44610fe2b86daef70f3f53f47d2a2542d7094f ]
Rename s_fsnotify_inode_refs to s_fsnotify_connectors and count all
objects with attached connectors, not only inodes with attached
connectors.
This will be used to optimize fsnotify() calls on sb without any
type of marks.
Link: https://lore.kernel.org/r/20210810151220.285179-4-amir73il@xxxxxxxxx
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
Reviewed-by: Matthew Bobrowski <repnop@xxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 30d422b8c0fc7..963e6ce75b961 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -87,15 +87,15 @@ static void fsnotify_unmount_inodes(struct super_block *sb)
if (iput_inode)
iput(iput_inode);
- /* Wait for outstanding inode references from connectors */
- wait_var_event(&sb->s_fsnotify_inode_refs,
- !atomic_long_read(&sb->s_fsnotify_inode_refs));
}
void fsnotify_sb_delete(struct super_block *sb)
{
fsnotify_unmount_inodes(sb);
fsnotify_clear_marks_by_sb(sb);
+ /* Wait for outstanding object references from connectors */
+ wait_var_event(&sb->s_fsnotify_connectors,
+ !atomic_long_read(&sb->s_fsnotify_connectors));
}
/*
diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h
index ff2063ec6b0f3..87d8a50ee8038 100644
--- a/fs/notify/fsnotify.h
+++ b/fs/notify/fsnotify.h
@@ -27,6 +27,21 @@ static inline struct super_block *fsnotify_conn_sb(
return container_of(conn->obj, struct super_block, s_fsnotify_marks);
}
+static inline struct super_block *fsnotify_connector_sb(
+ struct fsnotify_mark_connector *conn)
+{
+ switch (conn->type) {
+ case FSNOTIFY_OBJ_TYPE_INODE:
+ return fsnotify_conn_inode(conn)->i_sb;
+ case FSNOTIFY_OBJ_TYPE_VFSMOUNT:
+ return fsnotify_conn_mount(conn)->mnt.mnt_sb;
+ case FSNOTIFY_OBJ_TYPE_SB:
+ return fsnotify_conn_sb(conn);
+ default:
+ return NULL;
+ }
+}
+
/* destroy all events sitting in this groups notification queue */
extern void fsnotify_flush_notify(struct fsnotify_group *group);
diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index f6d1ad3ecca2a..796946eb0c2e2 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -172,7 +172,7 @@ static void fsnotify_connector_destroy_workfn(struct work_struct *work)
static void fsnotify_get_inode_ref(struct inode *inode)
{
ihold(inode);
- atomic_long_inc(&inode->i_sb->s_fsnotify_inode_refs);
+ atomic_long_inc(&inode->i_sb->s_fsnotify_connectors);
}
static void fsnotify_put_inode_ref(struct inode *inode)
@@ -180,8 +180,24 @@ static void fsnotify_put_inode_ref(struct inode *inode)
struct super_block *sb = inode->i_sb;
iput(inode);
- if (atomic_long_dec_and_test(&sb->s_fsnotify_inode_refs))
- wake_up_var(&sb->s_fsnotify_inode_refs);
+ if (atomic_long_dec_and_test(&sb->s_fsnotify_connectors))
+ wake_up_var(&sb->s_fsnotify_connectors);
+}
+
+static void fsnotify_get_sb_connectors(struct fsnotify_mark_connector *conn)
+{
+ struct super_block *sb = fsnotify_connector_sb(conn);
+
+ if (sb)
+ atomic_long_inc(&sb->s_fsnotify_connectors);
+}
+
+static void fsnotify_put_sb_connectors(struct fsnotify_mark_connector *conn)
+{
+ struct super_block *sb = fsnotify_connector_sb(conn);
+
+ if (sb && atomic_long_dec_and_test(&sb->s_fsnotify_connectors))
+ wake_up_var(&sb->s_fsnotify_connectors);
}
static void *fsnotify_detach_connector_from_object(
@@ -203,6 +219,7 @@ static void *fsnotify_detach_connector_from_object(
fsnotify_conn_sb(conn)->s_fsnotify_mask = 0;
}
+ fsnotify_put_sb_connectors(conn);
rcu_assign_pointer(*(conn->obj), NULL);
conn->obj = NULL;
conn->type = FSNOTIFY_OBJ_TYPE_DETACHED;
@@ -504,6 +521,7 @@ static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp,
inode = fsnotify_conn_inode(conn);
fsnotify_get_inode_ref(inode);
}
+ fsnotify_get_sb_connectors(conn);
/*
* cmpxchg() provides the barrier so that readers of *connp can see
diff --git a/include/linux/fs.h b/include/linux/fs.h
index cc3b6ddf58223..a9ac60d3be1d6 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1512,8 +1512,11 @@ struct super_block {
/* Number of inodes with nlink == 0 but still referenced */
atomic_long_t s_remove_count;
- /* Pending fsnotify inode refs */
- atomic_long_t s_fsnotify_inode_refs;
+ /*
+ * Number of inode/mount/sb objects that are being watched, note that
+ * inodes objects are currently double-accounted.
+ */
+ atomic_long_t s_fsnotify_connectors;
/* Being remounted read-only */
int s_readonly_remount;
