From 09c7938c5640a6f22bef074ca6b803dccfdb93e3 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 20 Mar 2006 13:44:38 -0500 Subject: lockd: Fix server-side lock blocking code Signed-off-by: Trond Myklebust --- fs/lockd/svclock.c | 73 ++++++++++++++++++++++++++++++------------------------ 1 file changed, 40 insertions(+), 33 deletions(-) (limited to 'fs/lockd') diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c index d50946d..1d3a74d 100644 --- a/fs/lockd/svclock.c +++ b/fs/lockd/svclock.c @@ -193,6 +193,7 @@ nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file, goto failed_free; /* Set notifier function for VFS, and init args */ + block->b_call.a_args.lock.fl.fl_flags |= FL_SLEEP; block->b_call.a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations; block->b_call.a_args.cookie = *cookie; /* see above */ @@ -228,19 +229,18 @@ failed: * can be closed hereafter. */ static int -nlmsvc_delete_block(struct nlm_block *block, int unlock) +nlmsvc_delete_block(struct nlm_block *block) { 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; + int status; dprintk("lockd: deleting block %p...\n", block); /* Remove block from list */ nlmsvc_remove_block(block); - if (unlock) - status = posix_unblock_lock(file->f_file, fl); + status = posix_unblock_lock(file->f_file, fl); /* If the block is in the middle of a GRANT callback, * don't kill it yet. */ @@ -282,7 +282,7 @@ nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action) block->b_host->h_inuse = 1; else if (action == NLM_ACT_UNLOCK) { if (host == NULL || host == block->b_host) - nlmsvc_delete_block(block, 1); + nlmsvc_delete_block(block); } } up(&file->f_sema); @@ -297,7 +297,7 @@ u32 nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, struct nlm_lock *lock, int wait, struct nlm_cookie *cookie) { - struct nlm_block *block; + struct nlm_block *block, *newblock = NULL; int error; u32 ret; @@ -310,59 +310,65 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, wait); - /* Get existing block (in case client is busy-waiting) */ - block = nlmsvc_lookup_block(file, lock, 0); - + lock->fl.fl_flags &= ~FL_SLEEP; again: /* Lock file against concurrent access */ down(&file->f_sema); + /* Get existing block (in case client is busy-waiting) */ + block = nlmsvc_lookup_block(file, lock, 0); + if (block == NULL) { + if (newblock != NULL) + lock = &newblock->b_call.a_args.lock.fl; + } else + lock = &block->b_call.a_args.lock.fl; error = posix_lock_file(file->f_file, &lock->fl); + lock->fl.fl_flags &= ~FL_SLEEP; dprintk("lockd: posix_lock_file returned %d\n", error); - if (error != -EAGAIN) { - if (block) - nlmsvc_delete_block(block, 0); - up(&file->f_sema); - - switch(-error) { + switch(error) { case 0: ret = nlm_granted; goto out; - case EDEADLK: + case -EAGAIN: + break; + case -EDEADLK: ret = nlm_deadlock; goto out; default: /* includes ENOLCK */ ret = nlm_lck_denied_nolocks; goto out; - } } - if (!wait) { - ret = nlm_lck_denied; - goto out_unlock; - } + ret = nlm_lck_denied; + if (!wait) + goto out; + + ret = nlm_lck_blocked; + if (block != NULL) + goto out; /* If we don't have a block, create and initialize it. Then * retry because we may have slept in kmalloc. */ /* We have to release f_sema as nlmsvc_create_block may try to * to claim it while doing host garbage collection */ - if (block == NULL) { + if (newblock == NULL) { up(&file->f_sema); dprintk("lockd: blocking on this lock (allocating).\n"); - if (!(block = nlmsvc_create_block(rqstp, file, lock, cookie))) + if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie))) return nlm_lck_denied_nolocks; goto again; } /* Append to list of blocked */ - nlmsvc_insert_block(block, NLM_NEVER); + nlmsvc_insert_block(newblock, NLM_NEVER); + newblock = NULL; - ret = nlm_lck_blocked; -out_unlock: - up(&file->f_sema); out: + up(&file->f_sema); + if (newblock != NULL) + nlmsvc_delete_block(newblock); dprintk("lockd: nlmsvc_lock returned %u\n", ret); return ret; } @@ -445,7 +451,7 @@ nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock) down(&file->f_sema); if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL) - status = nlmsvc_delete_block(block, 1); + status = nlmsvc_delete_block(block); up(&file->f_sema); return status ? nlm_lck_denied : nlm_granted; } @@ -519,7 +525,11 @@ nlmsvc_grant_blocked(struct nlm_block *block) } /* Try the lock operation again */ + posix_unblock_lock(file->f_file, &lock->fl); + lock->fl.fl_flags |= FL_SLEEP; error = posix_lock_file(file->f_file, &lock->fl); + lock->fl.fl_flags &= ~FL_SLEEP; + switch (error) { case 0: break; @@ -630,11 +640,8 @@ nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status } else { /* Lock is now held by client, or has been rejected. * In both cases, the block should be removed. */ + nlmsvc_delete_block(block); up(&file->f_sema); - if (status == NLM_LCK_GRANTED) - nlmsvc_delete_block(block, 0); - else - nlmsvc_delete_block(block, 1); } } nlm_release_file(file); @@ -661,7 +668,7 @@ nlmsvc_retry_blocked(void) dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n", block, block->b_when, block->b_done); if (block->b_done) - nlmsvc_delete_block(block, 0); + nlmsvc_delete_block(block); else nlmsvc_grant_blocked(block); } -- cgit v1.1