aboutsummaryrefslogtreecommitdiff
path: root/fs/notify/inode_mark.c
diff options
context:
space:
mode:
authorEric Paris <eparis@redhat.com>2009-05-21 17:01:54 -0400
committerEric Paris <eparis@redhat.com>2009-06-11 14:57:54 -0400
commit1ef5f13c6c8acd3fd10db9f1743f3b4cf30a4abb (patch)
treeb42f8aa8f74e598e47c114fc5141a8566a92d859 /fs/notify/inode_mark.c
parente4aff117368cfdd3567ee41844d216d079b55173 (diff)
downloadlinux-1ef5f13c6c8acd3fd10db9f1743f3b4cf30a4abb.tar.gz
fsnotify: fsnotify marks on inodes pin them in core
This patch pins any inodes with an fsnotify mark in core. The idea is that as soon as the mark is removed from the inode->fsnotify_mark_entries list the inode will be iput. In reality is doesn't quite work exactly this way. The igrab will happen when the mark is added to an inode, but the iput will happen when the inode pointer is NULL'd inside the mark. It's possible that 2 racing things will try to remove the mark from different directions. One may try to remove the mark because of an explicit request and one might try to remove it because the inode was deleted. It's possible that the removal because of inode deletion will remove the mark from the inode's list, but the removal by explicit request will actually set entry->inode == NULL; and call the iput. This is safe. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/notify/inode_mark.c')
-rw-r--r--fs/notify/inode_mark.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index a39534845b2..282150f74cf 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -204,6 +204,8 @@ void fsnotify_destroy_mark_by_entry(struct fsnotify_mark_entry *entry)
*/
+ iput(inode);
+
/*
* it's possible that this group tried to destroy itself, but this
* this mark was simultaneously being freed by inode. If that's the
@@ -306,6 +308,10 @@ int fsnotify_add_mark(struct fsnotify_mark_entry *entry,
struct fsnotify_mark_entry *lentry;
int ret = 0;
+ inode = igrab(inode);
+ if (unlikely(!inode))
+ return -EINVAL;
+
/*
* LOCKING ORDER!!!!
* entry->lock
@@ -337,6 +343,7 @@ int fsnotify_add_mark(struct fsnotify_mark_entry *entry,
if (lentry) {
ret = -EEXIST;
+ iput(inode);
fsnotify_put_mark(lentry);
} else {
__fsnotify_update_child_dentry_flags(inode);