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authorLouis Rilling <Louis.Rilling@kerlabs.com>2008-06-16 19:00:59 +0200
committerMark Fasheh <mfasheh@suse.com>2008-07-14 13:57:16 -0700
commit5301a77da2da1e4c22573e0e8d394a653b8ad9f9 (patch)
treec2a6186510c3a4502d923cf3f5d445fa821cb277 /fs/configfs/dir.c
parent6f61076406251626be39651d114fac412b1e0c39 (diff)
downloadop-kernel-dev-5301a77da2da1e4c22573e0e8d394a653b8ad9f9.zip
op-kernel-dev-5301a77da2da1e4c22573e0e8d394a653b8ad9f9.tar.gz
configfs: Protect configfs_dirent s_links list mutations
Symlinks to a config_item are listed under its configfs_dirent s_links, but the list mutations are not protected by any common lock. This patch uses the configfs_dirent_lock spinlock to add the necessary protection. Note: we should also protect the list_empty() test in configfs_detach_prep() but 1/ the lock should not be released immediately because nothing would prevent the list from being filled after a successful list_empty() test, making the problem tricky, 2/ this will be solved by the rmdir() vs rename() deadlock bugfix. Signed-off-by: Louis Rilling <Louis.Rilling@kerlabs.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
Diffstat (limited to 'fs/configfs/dir.c')
-rw-r--r--fs/configfs/dir.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 2619f48..a08e5c2 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -37,10 +37,11 @@
DECLARE_RWSEM(configfs_rename_sem);
/*
* Protects mutations of configfs_dirent linkage together with proper i_mutex
+ * Also protects mutations of symlinks linkage to target configfs_dirent
* Mutators of configfs_dirent linkage must *both* have the proper inode locked
* and configfs_dirent_lock locked, in that order.
- * This allows one to safely traverse configfs_dirent trees without having to
- * lock inodes.
+ * This allows one to safely traverse configfs_dirent trees and symlinks without
+ * having to lock inodes.
*/
DEFINE_SPINLOCK(configfs_dirent_lock);
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