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author | Louis Rilling <louis.rilling@kerlabs.com> | 2008-06-20 14:09:22 +0200 |
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committer | Mark Fasheh <mfasheh@suse.com> | 2008-07-31 16:21:13 -0700 |
commit | 9a73d78cda750f12e25eb811878f2d9dbab1bc6e (patch) | |
tree | abdc6537d51ee4faeb41c452428f2bde72abc9c8 /fs/configfs/configfs_internal.h | |
parent | 4768e9b18dc63719209c68920d4ae52dc49b6161 (diff) | |
download | op-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.h | 1 |
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; |