From 4f0b903ded728c505850daf2914bfc08841f0ae6 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Wed, 23 Feb 2022 17:14:37 +0200 Subject: fsnotify: fix merge with parent's ignored mask fsnotify_parent() does not consider the parent's mark at all unless the parent inode shows interest in events on children and in the specific event. So unless parent added an event to both its mark mask and ignored mask, the event will not be ignored. Fix this by declaring the interest of an object in an event when the event is in either a mark mask or ignored mask. Link: https://lore.kernel.org/r/20220223151438.790268-2-amir73il@gmail.com Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara --- fs/notify/fanotify/fanotify_user.c | 17 +++++++++-------- fs/notify/mark.c | 4 ++-- include/linux/fsnotify_backend.h | 15 +++++++++++++++ 3 files changed, 26 insertions(+), 10 deletions(-) diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 2ff6bd85ba8f..bd99430a128d 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -1003,17 +1003,18 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, __u32 mask, unsigned int flags, __u32 umask, int *destroy) { - __u32 oldmask = 0; + __u32 oldmask, newmask; /* umask bits cannot be removed by user */ mask &= ~umask; spin_lock(&fsn_mark->lock); + oldmask = fsnotify_calc_mask(fsn_mark); if (!(flags & FAN_MARK_IGNORED_MASK)) { - oldmask = fsn_mark->mask; fsn_mark->mask &= ~mask; } else { fsn_mark->ignored_mask &= ~mask; } + newmask = fsnotify_calc_mask(fsn_mark); /* * We need to keep the mark around even if remaining mask cannot * result in any events (e.g. mask == FAN_ONDIR) to support incremenal @@ -1023,7 +1024,7 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, *destroy = !((fsn_mark->mask | fsn_mark->ignored_mask) & ~umask); spin_unlock(&fsn_mark->lock); - return mask & oldmask; + return oldmask & ~newmask; } static int fanotify_remove_mark(struct fsnotify_group *group, @@ -1081,23 +1082,23 @@ static int fanotify_remove_inode_mark(struct fsnotify_group *group, } static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, - __u32 mask, - unsigned int flags) + __u32 mask, unsigned int flags) { - __u32 oldmask = -1; + __u32 oldmask, newmask; spin_lock(&fsn_mark->lock); + oldmask = fsnotify_calc_mask(fsn_mark); if (!(flags & FAN_MARK_IGNORED_MASK)) { - oldmask = fsn_mark->mask; fsn_mark->mask |= mask; } else { fsn_mark->ignored_mask |= mask; if (flags & FAN_MARK_IGNORED_SURV_MODIFY) fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY; } + newmask = fsnotify_calc_mask(fsn_mark); spin_unlock(&fsn_mark->lock); - return mask & ~oldmask; + return newmask & ~oldmask; } static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group, diff --git a/fs/notify/mark.c b/fs/notify/mark.c index 9007d6affff3..4853184f7dde 100644 --- a/fs/notify/mark.c +++ b/fs/notify/mark.c @@ -127,7 +127,7 @@ static void __fsnotify_recalc_mask(struct fsnotify_mark_connector *conn) return; hlist_for_each_entry(mark, &conn->list, obj_list) { if (mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED) - new_mask |= mark->mask; + new_mask |= fsnotify_calc_mask(mark); } *fsnotify_conn_mask_p(conn) = new_mask; } @@ -692,7 +692,7 @@ int fsnotify_add_mark_locked(struct fsnotify_mark *mark, if (ret) goto err; - if (mark->mask) + if (mark->mask || mark->ignored_mask) fsnotify_recalc_mask(mark->connector); return ret; diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index 790c31844db5..5f9c960049b0 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -601,6 +601,21 @@ extern void fsnotify_remove_queued_event(struct fsnotify_group *group, /* functions used to manipulate the marks attached to inodes */ +/* Get mask for calculating object interest taking ignored mask into account */ +static inline __u32 fsnotify_calc_mask(struct fsnotify_mark *mark) +{ + __u32 mask = mark->mask; + + if (!mark->ignored_mask) + return mask; + + /* + * If mark is interested in ignoring events on children, the object must + * show interest in those events for fsnotify_parent() to notice it. + */ + return mask | (mark->ignored_mask & ALL_FSNOTIFY_EVENTS); +} + /* Get mask of events for a list of marks */ extern __u32 fsnotify_conn_mask(struct fsnotify_mark_connector *conn); /* Calculate mask of events for a list of marks */ -- cgit v1.2.3 From 04e317ba72d07901b03399b3d1525e83424df5b3 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Wed, 23 Feb 2022 17:14:38 +0200 Subject: fsnotify: optimize FS_MODIFY events with no ignored masks fsnotify() treats FS_MODIFY events specially - it does not skip them even if the FS_MODIFY event does not apear in the object's fsnotify mask. This is because send_to_group() checks if FS_MODIFY needs to clear ignored mask of marks. The common case is that an object does not have any mark with ignored mask and in particular, that it does not have a mark with ignored mask and without the FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY flag. Set FS_MODIFY in object's fsnotify mask during fsnotify_recalc_mask() if object has a mark with an ignored mask and without the FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY flag and remove the special treatment of FS_MODIFY in fsnotify(), so that FS_MODIFY events could be optimized in the common case. Call fsnotify_recalc_mask() from fanotify after adding or removing an ignored mask from a mark without FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY or when adding the FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY flag to a mark with ignored mask (the flag cannot be removed by fanotify uapi). Performance results for doing 10000000 write(2)s to tmpfs: vanilla patched without notification mark 25.486+-1.054 24.965+-0.244 with notification mark 30.111+-0.139 26.891+-1.355 So we can see the overhead of notification subsystem has been drastically reduced. Link: https://lore.kernel.org/r/20220223151438.790268-3-amir73il@gmail.com Suggested-by: Jan Kara Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara --- fs/notify/fanotify/fanotify_user.c | 32 +++++++++++++++++++++++++------- fs/notify/fsnotify.c | 8 +++++--- include/linux/fsnotify_backend.h | 4 ++++ 3 files changed, 34 insertions(+), 10 deletions(-) diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index bd99430a128d..9b32b76a9c30 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -1081,8 +1081,28 @@ static int fanotify_remove_inode_mark(struct fsnotify_group *group, flags, umask); } +static void fanotify_mark_add_ignored_mask(struct fsnotify_mark *fsn_mark, + __u32 mask, unsigned int flags, + __u32 *removed) +{ + fsn_mark->ignored_mask |= mask; + + /* + * Setting FAN_MARK_IGNORED_SURV_MODIFY for the first time may lead to + * the removal of the FS_MODIFY bit in calculated mask if it was set + * because of an ignored mask that is now going to survive FS_MODIFY. + */ + if ((flags & FAN_MARK_IGNORED_SURV_MODIFY) && + !(fsn_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) { + fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY; + if (!(fsn_mark->mask & FS_MODIFY)) + *removed = FS_MODIFY; + } +} + static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, - __u32 mask, unsigned int flags) + __u32 mask, unsigned int flags, + __u32 *removed) { __u32 oldmask, newmask; @@ -1091,9 +1111,7 @@ static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, if (!(flags & FAN_MARK_IGNORED_MASK)) { fsn_mark->mask |= mask; } else { - fsn_mark->ignored_mask |= mask; - if (flags & FAN_MARK_IGNORED_SURV_MODIFY) - fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY; + fanotify_mark_add_ignored_mask(fsn_mark, mask, flags, removed); } newmask = fsnotify_calc_mask(fsn_mark); spin_unlock(&fsn_mark->lock); @@ -1156,7 +1174,7 @@ static int fanotify_add_mark(struct fsnotify_group *group, __kernel_fsid_t *fsid) { struct fsnotify_mark *fsn_mark; - __u32 added; + __u32 added, removed = 0; int ret = 0; mutex_lock(&group->mark_mutex); @@ -1179,8 +1197,8 @@ static int fanotify_add_mark(struct fsnotify_group *group, goto out; } - added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); - if (added & ~fsnotify_conn_mask(fsn_mark->connector)) + added = fanotify_mark_add_to_mask(fsn_mark, mask, flags, &removed); + if (removed || (added & ~fsnotify_conn_mask(fsn_mark->connector))) fsnotify_recalc_mask(fsn_mark->connector); out: diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index ab81a0776ece..494f653efbc6 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -531,11 +531,13 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir, /* - * if this is a modify event we may need to clear the ignored masks - * otherwise return if none of the marks care about this type of event. + * If this is a modify event we may need to clear some ignored masks. + * In that case, the object with ignored masks will have the FS_MODIFY + * event in its mask. + * Otherwise, return if none of the marks care about this type of event. */ test_mask = (mask & ALL_FSNOTIFY_EVENTS); - if (!(mask & FS_MODIFY) && !(test_mask & marks_mask)) + if (!(test_mask & marks_mask)) return 0; iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu); diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index 5f9c960049b0..0805b74cae44 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -609,6 +609,10 @@ static inline __u32 fsnotify_calc_mask(struct fsnotify_mark *mark) if (!mark->ignored_mask) return mask; + /* Interest in FS_MODIFY may be needed for clearing ignored mask */ + if (!(mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) + mask |= FS_MODIFY; + /* * If mark is interested in ignoring events on children, the object must * show interest in those events for fsnotify_parent() to notice it. -- cgit v1.2.3 From f92ca72b0263d601807bbd23ed25cbe6f4da89f4 Mon Sep 17 00:00:00 2001 From: Bang Li Date: Fri, 11 Mar 2022 23:12:40 +0800 Subject: fsnotify: remove redundant parameter judgment iput() has already judged the incoming parameter, so there is no need to repeat the judgment here. Link: https://lore.kernel.org/r/20220311151240.62045-1-libang.linuxer@gmail.com Signed-off-by: Bang Li Signed-off-by: Jan Kara --- fs/notify/fsnotify.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 494f653efbc6..70a8516b78bc 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -70,8 +70,7 @@ static void fsnotify_unmount_inodes(struct super_block *sb) spin_unlock(&inode->i_lock); spin_unlock(&sb->s_inode_list_lock); - if (iput_inode) - iput(iput_inode); + iput(iput_inode); /* for each watch, send FS_UNMOUNT and then remove it */ fsnotify_inode(inode, FS_UNMOUNT); @@ -85,8 +84,7 @@ static void fsnotify_unmount_inodes(struct super_block *sb) } spin_unlock(&sb->s_inode_list_lock); - if (iput_inode) - iput(iput_inode); + iput(iput_inode); } void fsnotify_sb_delete(struct super_block *sb) -- cgit v1.2.3