diff options
| author | Miklos Szeredi <mszeredi@suse.cz> | 2012-09-17 22:31:38 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2012-10-10 03:30:48 +0100 |
| commit | 2ebf56f3e471e0c5a831d74b5cdfe735523188f7 (patch) | |
| tree | e2dd3ca56e390817aa375b793fda0343fdecaae3 | |
| parent | 937882c09a3f906f6d70e0098715b28473d64709 (diff) | |
vfs: dcache: use DCACHE_DENTRY_KILLED instead of DCACHE_DISCONNECTED in d_kill()
commit b161dfa6937ae46d50adce8a7c6b12233e96e7bd upstream.
IBM reported a soft lockup after applying the fix for the rename_lock
deadlock. Commit c83ce989cb5f ("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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | fs/dcache.c | 4 | ||||
| -rw-r--r-- | include/linux/dcache.h | 2 |
2 files changed, 4 insertions, 2 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index eb723d31704..d20dc2b700c 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -311,7 +311,7 @@ static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent) * 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); @@ -968,7 +968,7 @@ static struct dentry *try_to_ascend(struct dentry *old, int locked, unsigned seq * 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; diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 4eb8c80c04c..1dfe974fb9f 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -219,6 +219,8 @@ 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) |