Messages in this thread Patch in this message | | | From | Miklos Szeredi <> | Subject | [PATCH 2/2] vfs: dcache: use DCACHE_DENTRY_KILLED instead of DCACHE_DISCONNECTED in d_kill() | Date | Mon, 17 Sep 2012 22:31:38 +0200 |
| |
From: Miklos Szeredi <mszeredi@suse.cz>
IBM reported a soft lockup after applying the fix for the rename_lock deadlock. Commit c83ce989 ("VFS: Fix the nfs sillyrename regression in kernel 2.6.38") was found to be the culprit.
The nfs sillyrename fix used DCACHE_DISCONNECTED to indicate that the dentry was killed. This flag can be set on non-killed dentries too, which results in infinite retries when trying to traverse the dentry tree.
This patch introduces a separate flag: DCACHE_DENTRY_KILLED, which is only set in d_kill() and makes try_to_ascend() test only this flag.
IBM reported successful test results with this patch.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: stable@vger.kernel.org --- fs/dcache.c | 4 ++-- include/linux/dcache.h | 2 ++ 2 files changed, 4 insertions(+), 2 deletions(-)
Index: linux-2.6/fs/dcache.c =================================================================== --- linux-2.6.orig/fs/dcache.c 2012-09-17 20:04:07.000000000 +0200 +++ linux-2.6/fs/dcache.c 2012-09-17 20:04:21.000000000 +0200 @@ -389,7 +389,7 @@ static struct dentry *d_kill(struct dent * Inform try_to_ascend() that we are no longer attached to the * dentry tree */ - dentry->d_flags |= DCACHE_DISCONNECTED; + dentry->d_flags |= DCACHE_DENTRY_KILLED; if (parent) spin_unlock(&parent->d_lock); dentry_iput(dentry); @@ -1048,7 +1048,7 @@ static struct dentry *try_to_ascend(stru * or deletion */ if (new != old->d_parent || - (old->d_flags & DCACHE_DISCONNECTED) || + (old->d_flags & DCACHE_DENTRY_KILLED) || (!locked && read_seqretry(&rename_lock, seq))) { spin_unlock(&new->d_lock); new = NULL; Index: linux-2.6/include/linux/dcache.h =================================================================== --- linux-2.6.orig/include/linux/dcache.h 2012-09-17 19:56:19.000000000 +0200 +++ linux-2.6/include/linux/dcache.h 2012-09-17 20:04:21.000000000 +0200 @@ -206,6 +206,8 @@ struct dentry_operations { #define DCACHE_MANAGED_DENTRY \ (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) +#define DCACHE_DENTRY_KILLED 0x100000 + extern seqlock_t rename_lock; static inline int dname_external(struct dentry *dentry)
| |