On Tue, Aug 10, 2021 at 06:12:19PM +0300, Amir Goldstein wrote:
> 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.
>
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
LGTM.
Reviewed-by: Matthew Bobrowski <repnop@xxxxxxxxxx>
> ---
> fs/notify/fsnotify.c | 6 +++---
> fs/notify/fsnotify.h | 15 +++++++++++++++
> fs/notify/mark.c | 24 +++++++++++++++++++++---
> include/linux/fs.h | 4 ++--
> 4 files changed, 41 insertions(+), 8 deletions(-)
>
> diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
> index 30d422b8c0fc..963e6ce75b96 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 ff2063ec6b0f..87d8a50ee803 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 2d8c46e1167d..95006d1d29ab 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 640574294216..d48d2018dfa4 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1507,8 +1507,8 @@ 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 */
> + atomic_long_t s_fsnotify_connectors;
>
> /* Being remounted read-only */
> int s_readonly_remount;
> --
> 2.32.0
>
/M
