From 19e03c570e6099ffaf24e5628d4fe1a8acbe820d Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Tue, 23 Dec 2008 15:21:44 -0500 Subject: [PATCH] NFSv4: Ensure that file unlock requests don't conflict with state recovery The unlock path is currently failing to take the nfs_client->cl_sem read lock, and hence the recovery path may see locks disappear from underneath it. Also ensure that it takes the nfs_inode->rwsem read lock so that it there is no conflict with delegation recalls. Signed-off-by: Trond Myklebust --- fs/nfs/nfs4proc.c | 26 ++++++++++++++++---------- fs/nfs/nfs4state.c | 4 ++++ 2 files changed, 20 insertions(+), 10 deletions(-) diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 660c5dcfb0a..aec4e47c462 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -3273,6 +3273,8 @@ static struct rpc_task *nfs4_do_unlck(struct file_lock *fl, static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock *request) { + struct nfs_client *clp = state->owner->so_client; + struct nfs_inode *nfsi = NFS_I(state->inode); struct nfs_seqid *seqid; struct nfs4_lock_state *lsp; struct rpc_task *task; @@ -3282,8 +3284,15 @@ static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock * status = nfs4_set_lock_state(state, request); /* Unlock _before_ we do the RPC call */ request->fl_flags |= FL_EXISTS; - if (do_vfs_lock(request->fl_file, request) == -ENOENT) + down_read(&clp->cl_sem); + down_read(&nfsi->rwsem); + if (do_vfs_lock(request->fl_file, request) == -ENOENT) { + up_read(&nfsi->rwsem); + up_read(&clp->cl_sem); goto out; + } + up_read(&nfsi->rwsem); + up_read(&clp->cl_sem); if (status != 0) goto out; /* Is this a delegated lock? */ @@ -3510,6 +3519,7 @@ static int nfs4_lock_expired(struct nfs4_state *state, struct file_lock *request static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock *request) { struct nfs_client *clp = state->owner->so_client; + struct nfs_inode *nfsi = NFS_I(state->inode); unsigned char fl_flags = request->fl_flags; int status; @@ -3522,18 +3532,13 @@ static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock if (status < 0) goto out; down_read(&clp->cl_sem); + down_read(&nfsi->rwsem); if (test_bit(NFS_DELEGATED_STATE, &state->flags)) { - struct nfs_inode *nfsi = NFS_I(state->inode); /* Yes: cache locks! */ - down_read(&nfsi->rwsem); /* ...but avoid races with delegation recall... */ - if (test_bit(NFS_DELEGATED_STATE, &state->flags)) { - request->fl_flags = fl_flags & ~FL_SLEEP; - status = do_vfs_lock(request->fl_file, request); - up_read(&nfsi->rwsem); - goto out_unlock; - } - up_read(&nfsi->rwsem); + request->fl_flags = fl_flags & ~FL_SLEEP; + status = do_vfs_lock(request->fl_file, request); + goto out_unlock; } status = _nfs4_do_setlk(state, cmd, request, 0); if (status != 0) @@ -3543,6 +3548,7 @@ static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock if (do_vfs_lock(request->fl_file, request) < 0) printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__); out_unlock: + up_read(&nfsi->rwsem); up_read(&clp->cl_sem); out: request->fl_flags = fl_flags; diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index beade5570b5..16c9fbdf97b 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -849,9 +849,11 @@ static int nfs4_state_mark_reclaim_nograce(struct nfs_client *clp, struct nfs4_s static int nfs4_reclaim_locks(struct nfs4_state *state, const struct nfs4_state_recovery_ops *ops) { struct inode *inode = state->inode; + struct nfs_inode *nfsi = NFS_I(inode); struct file_lock *fl; int status = 0; + down_write(&nfsi->rwsem); for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK))) continue; @@ -874,8 +876,10 @@ static int nfs4_reclaim_locks(struct nfs4_state *state, const struct nfs4_state_ goto out_err; } } + up_write(&nfsi->rwsem); return 0; out_err: + up_write(&nfsi->rwsem); return status; } -- 2.41.0