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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/symlink.c | |
| parent | fe9f387740ac7cb3b7c2fffa76807e997e6c6292 (diff) | |
| download | linux-6f61076406251626be39651d114fac412b1e0c39.tar.gz linux-6f61076406251626be39651d114fac412b1e0c39.tar.bz2 linux-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/symlink.c')
| -rw-r--r-- | fs/configfs/symlink.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/configfs/symlink.c b/fs/configfs/symlink.c index 2a731ef5f305..676c84c416da 100644 --- a/fs/configfs/symlink.c +++ b/fs/configfs/symlink.c @@ -169,7 +169,9 @@ int configfs_unlink(struct inode *dir, struct dentry *dentry) parent_item = configfs_get_config_item(dentry->d_parent); type = parent_item->ci_type; + spin_lock(&configfs_dirent_lock); list_del_init(&sd->s_sibling); + spin_unlock(&configfs_dirent_lock); configfs_drop_dentry(sd, dentry->d_parent); dput(dentry); configfs_put(sd); |