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| author | Sage Weil <sage@newdream.net> | 2011-07-26 20:30:15 +0200 |
|---|---|---|
| committer | Sage Weil <sage@newdream.net> | 2011-07-26 20:30:15 +0200 |
| commit | 48d0cbd1242aac969560ef8b90f26ee3b09a6a5c (patch) | |
| tree | 228a26f8ee7d555d67c6a00e5346f3b558a2e48c | |
| parent | ceph: set dir complete frag after adding capability (diff) | |
| download | linux-48d0cbd1242aac969560ef8b90f26ee3b09a6a5c.tar.xz linux-48d0cbd1242aac969560ef8b90f26ee3b09a6a5c.zip | |
ceph: handle racing calls to ceph_init_dentry
The ->lookup() and prepopulate_readdir() callers are working with unhashed
dentries, so we don't have to worry. The export.c callers, though, need
to initialize something they got back from d_obtain_alias() and are
potentially racing with other callers. Make sure we don't return unless
the dentry is properly initialized (by us or someone else).
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
| -rw-r--r-- | fs/ceph/dir.c | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c index f39a409db0ea..883c9546111d 100644 --- a/fs/ceph/dir.c +++ b/fs/ceph/dir.c @@ -40,14 +40,6 @@ int ceph_init_dentry(struct dentry *dentry) if (dentry->d_fsdata) return 0; - if (dentry->d_parent == NULL || /* nfs fh_to_dentry */ - ceph_snap(dentry->d_parent->d_inode) == CEPH_NOSNAP) - d_set_d_op(dentry, &ceph_dentry_ops); - else if (ceph_snap(dentry->d_parent->d_inode) == CEPH_SNAPDIR) - d_set_d_op(dentry, &ceph_snapdir_dentry_ops); - else - d_set_d_op(dentry, &ceph_snap_dentry_ops); - di = kmem_cache_alloc(ceph_dentry_cachep, GFP_NOFS | __GFP_ZERO); if (!di) return -ENOMEM; /* oh well */ @@ -58,10 +50,21 @@ int ceph_init_dentry(struct dentry *dentry) kmem_cache_free(ceph_dentry_cachep, di); goto out_unlock; } + + if (dentry->d_parent == NULL || /* nfs fh_to_dentry */ + ceph_snap(dentry->d_parent->d_inode) == CEPH_NOSNAP) + d_set_d_op(dentry, &ceph_dentry_ops); + else if (ceph_snap(dentry->d_parent->d_inode) == CEPH_SNAPDIR) + d_set_d_op(dentry, &ceph_snapdir_dentry_ops); + else + d_set_d_op(dentry, &ceph_snap_dentry_ops); + di->dentry = dentry; di->lease_session = NULL; - dentry->d_fsdata = di; dentry->d_time = jiffies; + /* avoid reordering d_fsdata setup so that the check above is safe */ + smp_mb(); + dentry->d_fsdata = di; ceph_dentry_lru_add(dentry); out_unlock: spin_unlock(&dentry->d_lock); |