From d2f277e26f521ccf6fb438463b41dba6123caabe Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Sun, 17 Mar 2024 20:41:45 +0200 Subject: fsnotify: rename fsnotify_{get,put}_sb_connectors() Instead of counting the number of connectors in an sb, we would like to count the number of watched objects per priority group. As a start, create an accessor fsnotify_sb_watched_objects() to s_fsnotify_connectors and rename the fsnotify_{get,put}_sb_connectors() helpers to fsnotify_{get,put}_sb_watchers() to better describes the counter. Increment the counter at the end of fsnotify_attach_connector_to_object() if connector was attached instead of decrementing it on race to connect. This is fine, because fsnotify_delete_sb() cannot be running in parallel to fsnotify_attach_connector_to_object() which requires a reference to a filesystem object. Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Message-Id: <20240317184154.1200192-2-amir73il@gmail.com> --- include/linux/fsnotify.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/fsnotify.h') diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h index 1a9de119a0f7..e470bb67c9a3 100644 --- a/include/linux/fsnotify.h +++ b/include/linux/fsnotify.h @@ -20,7 +20,7 @@ /* Are there any inode/mount/sb objects that are being watched at all? */ static inline bool fsnotify_sb_has_watchers(struct super_block *sb) { - return atomic_long_read(&sb->s_fsnotify_connectors); + return atomic_long_read(fsnotify_sb_watched_objects(sb)); } /* -- cgit v1.2.3 From cb5d4f48c10445c97a22af0bd8b9cf0ed6cc8036 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Sun, 17 Mar 2024 20:41:52 +0200 Subject: fsnotify: move s_fsnotify_connectors into fsnotify_sb_info Move the s_fsnotify_connectors counter into the per-sb fsnotify state. Suggested-by: Christian Brauner Signed-off-by: Amir Goldstein Reviewed-by: Christian Brauner Signed-off-by: Jan Kara Message-Id: <20240317184154.1200192-9-amir73il@gmail.com> --- include/linux/fs.h | 6 ------ include/linux/fsnotify.h | 8 +++++++- include/linux/fsnotify_backend.h | 7 ++++++- 3 files changed, 13 insertions(+), 8 deletions(-) (limited to 'include/linux/fsnotify.h') diff --git a/include/linux/fs.h b/include/linux/fs.h index 7f40b592f711..c36c2f8fdbe3 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1302,12 +1302,6 @@ struct super_block { /* Number of inodes with nlink == 0 but still referenced */ atomic_long_t s_remove_count; - /* - * Number of inode/mount/sb objects that are being watched, note that - * inodes objects are currently double-accounted. - */ - atomic_long_t s_fsnotify_connectors; - /* Read-only state of the superblock is being changed */ int s_readonly_remount; diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h index e470bb67c9a3..48dc65702415 100644 --- a/include/linux/fsnotify.h +++ b/include/linux/fsnotify.h @@ -20,7 +20,13 @@ /* Are there any inode/mount/sb objects that are being watched at all? */ static inline bool fsnotify_sb_has_watchers(struct super_block *sb) { - return atomic_long_read(fsnotify_sb_watched_objects(sb)); + struct fsnotify_sb_info *sbinfo = fsnotify_sb_info(sb); + + /* Were any marks ever added to any object on this sb? */ + if (!sbinfo) + return false; + + return atomic_long_read(&sbinfo->watched_objects); } /* diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index c9f2b2f6b493..ec592aeadfa3 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -483,6 +483,11 @@ struct fsnotify_mark_connector { */ struct fsnotify_sb_info { struct fsnotify_mark_connector __rcu *sb_marks; + /* + * Number of inode/mount/sb objects that are being watched in this sb. + * Note that inodes objects are currently double-accounted. + */ + atomic_long_t watched_objects; }; static inline struct fsnotify_sb_info *fsnotify_sb_info(struct super_block *sb) @@ -496,7 +501,7 @@ static inline struct fsnotify_sb_info *fsnotify_sb_info(struct super_block *sb) static inline atomic_long_t *fsnotify_sb_watched_objects(struct super_block *sb) { - return &sb->s_fsnotify_connectors; + return &fsnotify_sb_info(sb)->watched_objects; } /* -- cgit v1.2.3 From a5e57b4d370c6d320e5bfb0c919fe00aee29e039 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Sun, 17 Mar 2024 20:41:54 +0200 Subject: fsnotify: optimize the case of no permission event watchers Commit e43de7f0862b ("fsnotify: optimize the case of no marks of any type") optimized the case where there are no fsnotify watchers on any of the filesystem's objects. It is quite common for a system to have a single local filesystem and it is quite common for the system to have some inotify watches on some config files or directories, so the optimization of no marks at all is often not in effect. Permission event watchers, which require high priority group are more rare, so optimizing the case of no marks og high priority groups can improve performance for more systems, especially for performance sensitive io workloads. Count per-sb watched objects by high priority groups and use that the optimize out the call to __fsnotify_parent() and fsnotify() in fsnotify permission hooks. Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Message-Id: <20240317184154.1200192-11-amir73il@gmail.com> --- fs/notify/fsnotify.c | 3 +++ fs/notify/mark.c | 30 +++++++++++++++++++++++++++--- include/linux/fsnotify.h | 19 ++++++++++++++++--- include/linux/fsnotify_backend.h | 11 ++++++++--- 4 files changed, 54 insertions(+), 9 deletions(-) (limited to 'include/linux/fsnotify.h') diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index fb3f36bc6ea9..2ae965ef37e8 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -100,6 +100,9 @@ void fsnotify_sb_delete(struct super_block *sb) /* Wait for outstanding object references from connectors */ wait_var_event(fsnotify_sb_watched_objects(sb), !atomic_long_read(fsnotify_sb_watched_objects(sb))); + WARN_ON(fsnotify_sb_has_priority_watchers(sb, FSNOTIFY_PRIO_CONTENT)); + WARN_ON(fsnotify_sb_has_priority_watchers(sb, + FSNOTIFY_PRIO_PRE_CONTENT)); kfree(sbinfo); } diff --git a/fs/notify/mark.c b/fs/notify/mark.c index b2f5d8c9cce1..c3eefa70633c 100644 --- a/fs/notify/mark.c +++ b/fs/notify/mark.c @@ -161,13 +161,36 @@ static void fsnotify_put_inode_ref(struct inode *inode) static void fsnotify_update_sb_watchers(struct super_block *sb, struct fsnotify_mark_connector *conn) { + struct fsnotify_sb_info *sbinfo = fsnotify_sb_info(sb); bool is_watched = conn->flags & FSNOTIFY_CONN_FLAG_IS_WATCHED; - bool has_marks = conn->obj && !hlist_empty(&conn->list); + struct fsnotify_mark *first_mark = NULL; + unsigned int highest_prio = 0; - if (has_marks && !is_watched) { + if (conn->obj) + first_mark = hlist_entry_safe(conn->list.first, + struct fsnotify_mark, obj_list); + if (first_mark) + highest_prio = first_mark->group->priority; + if (WARN_ON(highest_prio >= __FSNOTIFY_PRIO_NUM)) + highest_prio = 0; + + /* + * If the highest priority of group watching this object is prio, + * then watched object has a reference on counters [0..prio]. + * Update priority >= 1 watched objects counters. + */ + for (unsigned int p = conn->prio + 1; p <= highest_prio; p++) + atomic_long_inc(&sbinfo->watched_objects[p]); + for (unsigned int p = conn->prio; p > highest_prio; p--) + atomic_long_dec(&sbinfo->watched_objects[p]); + conn->prio = highest_prio; + + /* Update priority >= 0 (a.k.a total) watched objects counter */ + BUILD_BUG_ON(FSNOTIFY_PRIO_NORMAL != 0); + if (first_mark && !is_watched) { conn->flags |= FSNOTIFY_CONN_FLAG_IS_WATCHED; fsnotify_get_sb_watched_objects(sb); - } else if (!has_marks && is_watched) { + } else if (!first_mark && is_watched) { conn->flags &= ~FSNOTIFY_CONN_FLAG_IS_WATCHED; fsnotify_put_sb_watched_objects(sb); } @@ -600,6 +623,7 @@ static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp, spin_lock_init(&conn->lock); INIT_HLIST_HEAD(&conn->list); conn->flags = 0; + conn->prio = 0; conn->type = obj_type; conn->obj = obj; diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h index 48dc65702415..4da80e92f804 100644 --- a/include/linux/fsnotify.h +++ b/include/linux/fsnotify.h @@ -17,8 +17,9 @@ #include #include -/* Are there any inode/mount/sb objects that are being watched at all? */ -static inline bool fsnotify_sb_has_watchers(struct super_block *sb) +/* Are there any inode/mount/sb objects watched with priority prio or above? */ +static inline bool fsnotify_sb_has_priority_watchers(struct super_block *sb, + int prio) { struct fsnotify_sb_info *sbinfo = fsnotify_sb_info(sb); @@ -26,7 +27,13 @@ static inline bool fsnotify_sb_has_watchers(struct super_block *sb) if (!sbinfo) return false; - return atomic_long_read(&sbinfo->watched_objects); + return atomic_long_read(&sbinfo->watched_objects[prio]); +} + +/* Are there any inode/mount/sb objects that are being watched at all? */ +static inline bool fsnotify_sb_has_watchers(struct super_block *sb) +{ + return fsnotify_sb_has_priority_watchers(sb, 0); } /* @@ -109,6 +116,12 @@ static inline int fsnotify_file(struct file *file, __u32 mask) return 0; path = &file->f_path; + /* Permission events require group prio >= FSNOTIFY_PRIO_CONTENT */ + if (mask & ALL_FSNOTIFY_PERM_EVENTS && + !fsnotify_sb_has_priority_watchers(path->dentry->d_sb, + FSNOTIFY_PRIO_CONTENT)) + return 0; + return fsnotify_parent(path->dentry, mask, path, FSNOTIFY_EVENT_PATH); } diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index fc38587d8564..7f1ab8264e41 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -468,7 +468,8 @@ FSNOTIFY_ITER_FUNCS(sb, SB) */ struct fsnotify_mark_connector { spinlock_t lock; - unsigned short type; /* Type of object [lock] */ + unsigned char type; /* Type of object [lock] */ + unsigned char prio; /* Highest priority group */ #define FSNOTIFY_CONN_FLAG_IS_WATCHED 0x01 #define FSNOTIFY_CONN_FLAG_HAS_IREF 0x02 unsigned short flags; /* flags [lock] */ @@ -490,8 +491,12 @@ struct fsnotify_sb_info { /* * Number of inode/mount/sb objects that are being watched in this sb. * Note that inodes objects are currently double-accounted. + * + * The value in watched_objects[prio] is the number of objects that are + * watched by groups of priority >= prio, so watched_objects[0] is the + * total number of watched objects in this sb. */ - atomic_long_t watched_objects; + atomic_long_t watched_objects[__FSNOTIFY_PRIO_NUM]; }; static inline struct fsnotify_sb_info *fsnotify_sb_info(struct super_block *sb) @@ -505,7 +510,7 @@ static inline struct fsnotify_sb_info *fsnotify_sb_info(struct super_block *sb) static inline atomic_long_t *fsnotify_sb_watched_objects(struct super_block *sb) { - return &fsnotify_sb_info(sb)->watched_objects; + return &fsnotify_sb_info(sb)->watched_objects[0]; } /* -- cgit v1.2.3