From 64a318ee2af9000df482d7a125c3b3e1f1007404 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Tue, 3 Jan 2006 09:55:46 +0100 Subject: NLM: Further cancel fixes If the server receives an NLM cancel call and finds no waiting lock to cancel, then chances are the lock has already been applied, and the client just hadn't yet processed the NLM granted callback before it sent the cancel. The Open Group text, for example, perimts a server to return either success (LCK_GRANTED) or failure (LCK_DENIED) in this case. But returning an error seems more helpful; the client may be able to use it to recognize that a race has occurred and to recover from the race. So, modify the relevant functions to return an error in this case. Signed-off-by: J. Bruce Fields Signed-off-by: Trond Myklebust --- fs/lockd/svclock.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) (limited to 'fs/lockd') diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c index b56d439bad8..9cfced65d4a 100644 --- a/fs/lockd/svclock.c +++ b/fs/lockd/svclock.c @@ -227,25 +227,27 @@ failed: * It is the caller's responsibility to check whether the file * can be closed hereafter. */ -static void +static int nlmsvc_delete_block(struct nlm_block *block, int unlock) { struct file_lock *fl = &block->b_call.a_args.lock.fl; struct nlm_file *file = block->b_file; struct nlm_block **bp; + int status = 0; dprintk("lockd: deleting block %p...\n", block); /* Remove block from list */ nlmsvc_remove_block(block); - posix_unblock_lock(file->f_file, fl); + if (unlock) + status = posix_unblock_lock(file->f_file, fl); /* If the block is in the middle of a GRANT callback, * don't kill it yet. */ if (block->b_incall) { nlmsvc_insert_block(block, NLM_NEVER); block->b_done = 1; - return; + return status; } /* Remove block from file's list of blocks */ @@ -260,6 +262,7 @@ nlmsvc_delete_block(struct nlm_block *block, int unlock) nlm_release_host(block->b_host); nlmclnt_freegrantargs(&block->b_call); kfree(block); + return status; } /* @@ -270,6 +273,7 @@ int nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action) { struct nlm_block *block, *next; + /* XXX: Will everything get cleaned up if we don't unlock here? */ down(&file->f_sema); for (block = file->f_blocks; block; block = next) { @@ -439,6 +443,7 @@ u32 nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock) { struct nlm_block *block; + int status = 0; dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n", file->f_file->f_dentry->d_inode->i_sb->s_id, @@ -449,9 +454,9 @@ nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock) down(&file->f_sema); if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL) - nlmsvc_delete_block(block, 1); + status = nlmsvc_delete_block(block, 1); up(&file->f_sema); - return nlm_granted; + return status ? nlm_lck_denied : nlm_granted; } /* -- cgit v1.2.3-18-g5258