From e911d8af87dba7642138f4320ca3db80629989f2 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 14 Mar 2017 14:48:00 +0100 Subject: fsnotify: Make fsnotify_mark_connector hold inode reference Currently inode reference is held by fsnotify marks. Change the rules so that inode reference is held by fsnotify_mark_connector structure whenever the list is non-empty. This simplifies the code and is more logical. Reviewed-by: Miklos Szeredi Reviewed-by: Amir Goldstein Signed-off-by: Jan Kara --- fs/notify/fsnotify.h | 4 +--- fs/notify/inode_mark.c | 30 +++++------------------------- fs/notify/mark.c | 17 ++++++----------- include/linux/fsnotify_backend.h | 12 ++++++------ 4 files changed, 18 insertions(+), 45 deletions(-) diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h index dd1a6798c9cd..1a2aec65ebd8 100644 --- a/fs/notify/fsnotify.h +++ b/fs/notify/fsnotify.h @@ -21,8 +21,6 @@ extern u32 fsnotify_recalc_mask(struct fsnotify_mark_connector *conn); extern int fsnotify_compare_groups(struct fsnotify_group *a, struct fsnotify_group *b); -extern void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *fsn_mark, - __u32 mask); /* Add mark to a proper place in mark list */ extern int fsnotify_add_mark_list(struct fsnotify_mark_connector **connp, struct fsnotify_mark *mark, @@ -40,7 +38,7 @@ extern int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark, /* vfsmount specific destruction of a mark */ extern void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark); /* inode specific destruction of a mark */ -extern void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark); +extern struct inode *fsnotify_destroy_inode_mark(struct fsnotify_mark *mark); /* Find mark belonging to given group in the list of marks */ extern struct fsnotify_mark *fsnotify_find_mark( struct fsnotify_mark_connector *conn, diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c index 1644ba09efd4..c3873b6920e7 100644 --- a/fs/notify/inode_mark.c +++ b/fs/notify/inode_mark.c @@ -43,9 +43,10 @@ void fsnotify_recalc_inode_mask(struct inode *inode) __fsnotify_update_child_dentry_flags(inode); } -void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark) +struct inode *fsnotify_destroy_inode_mark(struct fsnotify_mark *mark) { struct inode *inode = mark->connector->inode; + bool empty; BUG_ON(!mutex_is_locked(&mark->group->mark_mutex)); assert_spin_locked(&mark->lock); @@ -53,6 +54,7 @@ void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark) spin_lock(&inode->i_lock); hlist_del_init_rcu(&mark->obj_list); + empty = hlist_empty(&mark->connector->list); mark->connector = NULL; /* @@ -62,6 +64,8 @@ void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark) */ inode->i_fsnotify_mask = fsnotify_recalc_mask(inode->i_fsnotify_marks); spin_unlock(&inode->i_lock); + + return empty ? inode : NULL; } /* @@ -88,30 +92,6 @@ struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, return mark; } -/* - * If we are setting a mark mask on an inode mark we should pin the inode - * in memory. - */ -void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *mark, - __u32 mask) -{ - struct inode *inode; - - assert_spin_locked(&mark->lock); - - if (mask && mark->connector && - !(mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) { - mark->flags |= FSNOTIFY_MARK_FLAG_OBJECT_PINNED; - inode = igrab(mark->connector->inode); - /* - * we shouldn't be able to get here if the inode wasn't - * already safely held in memory. But bug in case it - * ever is wrong. - */ - BUG_ON(!inode); - } -} - /* * Attach an initialized mark to a given inode. * These marks may be used for the fsnotify backend to determine which diff --git a/fs/notify/mark.c b/fs/notify/mark.c index 3d6e7a8e58be..8a15c64fbe80 100644 --- a/fs/notify/mark.c +++ b/fs/notify/mark.c @@ -142,10 +142,9 @@ void fsnotify_detach_mark(struct fsnotify_mark *mark) mark->flags &= ~FSNOTIFY_MARK_FLAG_ATTACHED; - if (mark->connector->flags & FSNOTIFY_OBJ_TYPE_INODE) { - inode = mark->connector->inode; - fsnotify_destroy_inode_mark(mark); - } else if (mark->connector->flags & FSNOTIFY_OBJ_TYPE_VFSMOUNT) + if (mark->connector->flags & FSNOTIFY_OBJ_TYPE_INODE) + inode = fsnotify_destroy_inode_mark(mark); + else if (mark->connector->flags & FSNOTIFY_OBJ_TYPE_VFSMOUNT) fsnotify_destroy_vfsmount_mark(mark); else BUG(); @@ -160,7 +159,7 @@ void fsnotify_detach_mark(struct fsnotify_mark *mark) spin_unlock(&mark->lock); - if (inode && (mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) + if (inode) iput(inode); atomic_dec(&group->num_marks); @@ -274,9 +273,6 @@ void fsnotify_set_mark_mask_locked(struct fsnotify_mark *mark, __u32 mask) assert_spin_locked(&mark->lock); mark->mask = mask; - - if (mark->connector && mark->connector->flags & FSNOTIFY_OBJ_TYPE_INODE) - fsnotify_set_inode_mark_mask_locked(mark, mask); } void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask) @@ -375,6 +371,8 @@ int fsnotify_add_mark_list(struct fsnotify_mark_connector **connp, /* is mark the first mark? */ if (hlist_empty(&conn->list)) { hlist_add_head_rcu(&mark->obj_list, &conn->list); + if (inode) + __iget(inode); goto added; } @@ -441,9 +439,6 @@ int fsnotify_add_mark_locked(struct fsnotify_mark *mark, } else { BUG(); } - - /* this will pin the object if appropriate */ - fsnotify_set_mark_mask_locked(mark, mark->mask); spin_unlock(&mark->lock); if (inode) diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index 06f9a2cc1463..96333fb09309 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -196,8 +196,9 @@ struct fsnotify_group { /* * Inode / vfsmount point to this structure which tracks all marks attached to - * the inode / vfsmount. The structure is freed only when inode / vfsmount gets - * freed. + * the inode / vfsmount. The reference to inode / vfsmount is held by this + * structure whenever the list is non-empty. The structure is freed only when + * inode / vfsmount gets freed. */ struct fsnotify_mark_connector { #define FSNOTIFY_OBJ_TYPE_INODE 0x01 @@ -245,10 +246,9 @@ struct fsnotify_mark { struct fsnotify_mark_connector *connector; /* Events types to ignore [mark->lock, group->mark_mutex] */ __u32 ignored_mask; -#define FSNOTIFY_MARK_FLAG_OBJECT_PINNED 0x04 -#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY 0x08 -#define FSNOTIFY_MARK_FLAG_ALIVE 0x10 -#define FSNOTIFY_MARK_FLAG_ATTACHED 0x20 +#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY 0x01 +#define FSNOTIFY_MARK_FLAG_ALIVE 0x02 +#define FSNOTIFY_MARK_FLAG_ATTACHED 0x04 unsigned int flags; /* flags [mark->lock] */ void (*free_mark)(struct fsnotify_mark *mark); /* called on final put+free */ }; -- cgit v1.2.3