From 565277f63c616e11c37309a1e98c052d18ebbb55 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 15 Oct 2007 18:17:53 -0400 Subject: NFS: Fix a race in sillyrename lookup() and sillyrename() can race one another because the sillyrename() completion cannot take the parent directory's inode->i_mutex since the latter may be held by whoever is calling dput(). We therefore have little option but to add extra locking to ensure that nfs_lookup() and nfs_atomic_open() do not race with the sillyrename completion. If somebody has looked up the sillyrenamed file in the meantime, we just transfer the sillydelete information to the new dentry. Please refer to the bug-report at http://bugzilla.linux-nfs.org/show_bug.cgi?id=150 Signed-off-by: Trond Myklebust --- fs/nfs/nfs4proc.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'fs/nfs/nfs4proc.c') diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index cb99fd90a9ac..2cb3b8b71ee7 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -1372,6 +1372,7 @@ out_close: struct dentry * nfs4_atomic_open(struct inode *dir, struct dentry *dentry, struct nameidata *nd) { + struct dentry *parent; struct path path = { .mnt = nd->mnt, .dentry = dentry, @@ -1394,6 +1395,9 @@ nfs4_atomic_open(struct inode *dir, struct dentry *dentry, struct nameidata *nd) cred = rpcauth_lookupcred(NFS_CLIENT(dir)->cl_auth, 0); if (IS_ERR(cred)) return (struct dentry *)cred; + parent = dentry->d_parent; + /* Protect against concurrent sillydeletes */ + nfs_block_sillyrename(parent); state = nfs4_do_open(dir, &path, nd->intent.open.flags, &attr, cred); put_rpccred(cred); if (IS_ERR(state)) { @@ -1401,12 +1405,14 @@ nfs4_atomic_open(struct inode *dir, struct dentry *dentry, struct nameidata *nd) d_add(dentry, NULL); nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); } + nfs_unblock_sillyrename(parent); return (struct dentry *)state; } res = d_add_unique(dentry, igrab(state->inode)); if (res != NULL) path.dentry = res; nfs_set_verifier(path.dentry, nfs_save_change_attribute(dir)); + nfs_unblock_sillyrename(parent); nfs4_intent_set_file(nd, &path, state); return res; } -- cgit v1.2.2