From 925d1132a03e33cb8f29a0057300d023b4f1be23 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Fri, 4 Sep 2015 15:43:09 -0700 Subject: [PATCH] fsnotify: remove mark->free_list Free list is used when all marks on given inode / mount should be destroyed when inode / mount is going away. However we can free all of the marks without using a special list with some care. Signed-off-by: Jan Kara Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/notify/fsnotify.c | 1 - fs/notify/fsnotify.h | 21 +++++++++++++++------ fs/notify/inode_mark.c | 20 -------------------- fs/notify/mark.c | 40 +++++++++++++++++++++++++--------------- fs/notify/vfsmount_mark.c | 19 ------------------- include/linux/fsnotify_backend.h | 2 -- 6 files changed, 40 insertions(+), 63 deletions(-) diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index d675e76..db39de2 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -26,7 +26,6 @@ #include #include "fsnotify.h" -#include "../mount.h" /* * Clear all of the marks on an inode when it is being evicted from core diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h index 13a00be..b44c68a 100644 --- a/fs/notify/fsnotify.h +++ b/fs/notify/fsnotify.h @@ -6,6 +6,8 @@ #include #include +#include "../mount.h" + /* destroy all events sitting in this groups notification queue */ extern void fsnotify_flush_notify(struct fsnotify_group *group); @@ -38,15 +40,22 @@ extern int fsnotify_add_vfsmount_mark(struct fsnotify_mark *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); -/* Destroy all marks in the given list */ -extern void fsnotify_destroy_marks(struct list_head *to_free); /* Find mark belonging to given group in the list of marks */ extern struct fsnotify_mark *fsnotify_find_mark(struct hlist_head *head, struct fsnotify_group *group); -/* run the list of all marks associated with inode and flag them to be freed */ -extern void fsnotify_clear_marks_by_inode(struct inode *inode); -/* run the list of all marks associated with vfsmount and flag them to be freed */ -extern void fsnotify_clear_marks_by_mount(struct vfsmount *mnt); +/* Destroy all marks in the given list protected by 'lock' */ +extern void fsnotify_destroy_marks(struct hlist_head *head, spinlock_t *lock); +/* run the list of all marks associated with inode and destroy them */ +static inline void fsnotify_clear_marks_by_inode(struct inode *inode) +{ + fsnotify_destroy_marks(&inode->i_fsnotify_marks, &inode->i_lock); +} +/* run the list of all marks associated with vfsmount and destroy them */ +static inline void fsnotify_clear_marks_by_mount(struct vfsmount *mnt) +{ + fsnotify_destroy_marks(&real_mount(mnt)->mnt_fsnotify_marks, + &mnt->mnt_root->d_lock); +} /* * update the dentry->d_flags of all of inode's children to indicate if inode cares * about events that happen to its children. diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c index 3daf513..474a3ce1 100644 --- a/fs/notify/inode_mark.c +++ b/fs/notify/inode_mark.c @@ -65,26 +65,6 @@ void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark) } /* - * Given an inode, destroy all of the marks associated with that inode. - */ -void fsnotify_clear_marks_by_inode(struct inode *inode) -{ - struct fsnotify_mark *mark; - struct hlist_node *n; - LIST_HEAD(free_list); - - spin_lock(&inode->i_lock); - hlist_for_each_entry_safe(mark, n, &inode->i_fsnotify_marks, obj_list) { - list_add(&mark->free_list, &free_list); - hlist_del_init_rcu(&mark->obj_list); - fsnotify_get_mark(mark); - } - spin_unlock(&inode->i_lock); - - fsnotify_destroy_marks(&free_list); -} - -/* * Given a group clear all of the inode marks associated with that group. */ void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group) diff --git a/fs/notify/mark.c b/fs/notify/mark.c index 39ddcaf..3b2d1ba 100644 --- a/fs/notify/mark.c +++ b/fs/notify/mark.c @@ -203,24 +203,34 @@ void fsnotify_destroy_mark(struct fsnotify_mark *mark, mutex_unlock(&group->mark_mutex); } -/* - * Destroy all marks in the given list. The marks must be already detached from - * the original inode / vfsmount. - */ -void fsnotify_destroy_marks(struct list_head *to_free) +void fsnotify_destroy_marks(struct hlist_head *head, spinlock_t *lock) { - struct fsnotify_mark *mark, *lmark; - struct fsnotify_group *group; - - list_for_each_entry_safe(mark, lmark, to_free, free_list) { - spin_lock(&mark->lock); - fsnotify_get_group(mark->group); - group = mark->group; - spin_unlock(&mark->lock); + struct fsnotify_mark *mark; - fsnotify_destroy_mark(mark, group); + while (1) { + /* + * We have to be careful since we can race with e.g. + * fsnotify_clear_marks_by_group() and once we drop 'lock', + * mark can get removed from the obj_list and destroyed. But + * we are holding mark reference so mark cannot be freed and + * calling fsnotify_destroy_mark() more than once is fine. + */ + spin_lock(lock); + if (hlist_empty(head)) { + spin_unlock(lock); + break; + } + mark = hlist_entry(head->first, struct fsnotify_mark, obj_list); + /* + * We don't update i_fsnotify_mask / mnt_fsnotify_mask here + * since inode / mount is going away anyway. So just remove + * mark from the list. + */ + hlist_del_init_rcu(&mark->obj_list); + fsnotify_get_mark(mark); + spin_unlock(lock); + fsnotify_destroy_mark(mark, mark->group); fsnotify_put_mark(mark); - fsnotify_put_group(group); } } diff --git a/fs/notify/vfsmount_mark.c b/fs/notify/vfsmount_mark.c index 326b148..a8fcab6 100644 --- a/fs/notify/vfsmount_mark.c +++ b/fs/notify/vfsmount_mark.c @@ -28,25 +28,6 @@ #include #include "fsnotify.h" -#include "../mount.h" - -void fsnotify_clear_marks_by_mount(struct vfsmount *mnt) -{ - struct fsnotify_mark *mark; - struct hlist_node *n; - struct mount *m = real_mount(mnt); - LIST_HEAD(free_list); - - spin_lock(&mnt->mnt_root->d_lock); - hlist_for_each_entry_safe(mark, n, &m->mnt_fsnotify_marks, obj_list) { - list_add(&mark->free_list, &free_list); - hlist_del_init_rcu(&mark->obj_list); - fsnotify_get_mark(mark); - } - spin_unlock(&mnt->mnt_root->d_lock); - - fsnotify_destroy_marks(&free_list); -} void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group) { diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index dd6ddb02..f044fe3 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -225,8 +225,6 @@ struct fsnotify_mark { spinlock_t lock; /* List of marks for inode / vfsmount [obj_lock] */ struct hlist_node obj_list; - /* tmp list used when freeing this mark */ - struct list_head free_list; union { /* Object pointer [mark->lock, group->mark_mutex] */ struct inode *inode; /* inode this mark is associated with */ struct vfsmount *mnt; /* vfsmount this mark is associated with */ -- 2.7.4