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| author |   Louis Rilling <Louis.Rilling@kerlabs.com> | 2008-06-16 19:00:58 +0200 |
|---|---|---|
| committer |   Mark Fasheh <mfasheh@suse.com> | 2008-07-14 13:57:15 -0700 |
| commit | 6f61076406251626be39651d114fac412b1e0c39 (patch) | |
| tree | d7adb1de212cfb7ead490b448bf75ce3b3b91c9c /fs/configfs/inode.c | |
| parent | ocfs2: Don't snprintf() without a format. (diff) | |
| download | linux-dev-6f61076406251626be39651d114fac412b1e0c39.tar.xz linux-dev-6f61076406251626be39651d114fac412b1e0c39.zip | |
configfs: Introduce configfs_dirent_lock
This patch introduces configfs_dirent_lock spinlock to protect configfs_dirent
traversals against linkage mutations (add/del/move). This will allow
configfs_detach_prep() to avoid locking i_mutexes.
Locking rules for configfs_dirent linkage mutations are the same plus the
requirement of taking configfs_dirent_lock. For configfs_dirent walking, one can
either take appropriate i_mutex as before, or take configfs_dirent_lock.
The spinlock could actually be a mutex, but the critical sections are either
O(1) or should not be too long (default groups walking in last patch).
ChangeLog:
- Clarify the comment on configfs_dirent_lock usage
- Move sd->s_element init before linking the new dirent
- In lseek(), do not release configfs_dirent_lock before the dirent is
relinked.
Signed-off-by: Louis Rilling <Louis.Rilling@kerlabs.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Diffstat (limited to 'fs/configfs/inode.c')
| -rw-r--r-- | fs/configfs/inode.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c index b9a1d810346d..4803ccc94480 100644 --- a/fs/configfs/inode.c +++ b/fs/configfs/inode.c @@ -247,7 +247,9 @@ void configfs_hash_and_remove(struct dentry * dir, const char * name) if (!sd->s_element) continue; if (!strcmp(configfs_get_name(sd), name)) { + spin_lock(&configfs_dirent_lock); list_del_init(&sd->s_sibling); + spin_unlock(&configfs_dirent_lock); configfs_drop_dentry(sd, dir); configfs_put(sd); break; |