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authorLouis Rilling <louis.rilling@kerlabs.com>2008-06-20 14:09:22 +0200
committerMark Fasheh <mfasheh@suse.com>2008-07-31 16:21:13 -0700
commit9a73d78cda750f12e25eb811878f2d9dbab1bc6e (patch)
treeabdc6537d51ee4faeb41c452428f2bde72abc9c8 /fs/configfs/configfs_internal.h
parent4768e9b18dc63719209c68920d4ae52dc49b6161 (diff)
downloadop-kernel-dev-9a73d78cda750f12e25eb811878f2d9dbab1bc6e.zip
op-kernel-dev-9a73d78cda750f12e25eb811878f2d9dbab1bc6e.tar.gz
[PATCH] configfs: Fix failing symlink() making rmdir() fail
On a similar pattern as mkdir() vs rmdir(), a failing symlink() may make rmdir() fail for the symlink's parent and the symlink's target as well. failing symlink() making target's rmdir() fail: process 1: process 2: symlink("A/S" -> "B") allow_link() create_link() attach to "B" links list rmdir("B") detach_prep("B") error because of new link configfs_create_link("A", "S") error (eg -ENOMEM) failing symlink() making parent's rmdir() fail: process 1: process 2: symlink("A/D/S" -> "B") allow_link() create_link() attach to "B" links list configfs_create_link("A/D", "S") make_dirent("A/D", "S") rmdir("A") detach_prep("A") detach_prep("A/D") error because of "S" create("S") error (eg -ENOMEM) We cannot use the same solution as for mkdir() vs rmdir(), since rmdir() on the target cannot wait on the i_mutex of the new symlink's parent without risking a deadlock (with other symlink() or sys_rename()). Instead we define a global mutex protecting all configfs symlinks attachment, so that rmdir() can avoid the races above. Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com> Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Diffstat (limited to 'fs/configfs/configfs_internal.h')
-rw-r--r--fs/configfs/configfs_internal.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/configfs/configfs_internal.h b/fs/configfs/configfs_internal.h
index da015c1..5f61b26 100644
--- a/fs/configfs/configfs_internal.h
+++ b/fs/configfs/configfs_internal.h
@@ -51,6 +51,7 @@ struct configfs_dirent {
#define CONFIGFS_USET_IN_MKDIR 0x0200
#define CONFIGFS_NOT_PINNED (CONFIGFS_ITEM_ATTR)
+extern struct mutex configfs_symlink_mutex;
extern spinlock_t configfs_dirent_lock;
extern struct vfsmount * configfs_mount;
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