lockd: always preallocate block in nlmsvc_lock()
Normally we could skip ever having to allocate a block in the case where the client asks for a non-blocking lock, or asks for a blocking lock that succeeds immediately. However we're going to want to always look up a block first in order to check whether we're revisiting a deferred lock call, and to be prepared to handle the case where the filesystem returns -EINPROGRESS--in that case we want to make sure the lock we've given the filesystem is the one embedded in the block that we'll use to track the deferred request. Signed-off-by: Marc Eshel <eshel@almaden.ibm.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
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parent
5ea0d75037
commit
f812048020
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@ -365,7 +365,7 @@ __be32
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nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
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nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
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struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
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struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
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{
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{
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struct nlm_block *block, *newblock = NULL;
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struct nlm_block *block = NULL;
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int error;
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int error;
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__be32 ret;
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__be32 ret;
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@ -378,17 +378,20 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
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wait);
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wait);
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lock->fl.fl_flags &= ~FL_SLEEP;
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again:
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/* Lock file against concurrent access */
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/* Lock file against concurrent access */
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mutex_lock(&file->f_mutex);
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mutex_lock(&file->f_mutex);
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/* Get existing block (in case client is busy-waiting) */
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/* Get existing block (in case client is busy-waiting)
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* or create new block
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*/
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block = nlmsvc_lookup_block(file, lock);
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block = nlmsvc_lookup_block(file, lock);
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if (block == NULL) {
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if (block == NULL) {
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if (newblock != NULL)
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block = nlmsvc_create_block(rqstp, file, lock, cookie);
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lock = &newblock->b_call->a_args.lock;
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ret = nlm_lck_denied_nolocks;
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} else
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if (block == NULL)
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goto out;
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lock = &block->b_call->a_args.lock;
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lock = &block->b_call->a_args.lock;
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} else
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lock->fl.fl_flags &= ~FL_SLEEP;
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error = posix_lock_file(file->f_file, &lock->fl, NULL);
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error = posix_lock_file(file->f_file, &lock->fl, NULL);
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lock->fl.fl_flags &= ~FL_SLEEP;
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lock->fl.fl_flags &= ~FL_SLEEP;
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@ -414,26 +417,11 @@ again:
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goto out;
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goto out;
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ret = nlm_lck_blocked;
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ret = nlm_lck_blocked;
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if (block != NULL)
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goto out;
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/* If we don't have a block, create and initialize it. Then
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* retry because we may have slept in kmalloc. */
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/* We have to release f_mutex as nlmsvc_create_block may try to
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* to claim it while doing host garbage collection */
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if (newblock == NULL) {
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mutex_unlock(&file->f_mutex);
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dprintk("lockd: blocking on this lock (allocating).\n");
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if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie)))
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return nlm_lck_denied_nolocks;
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goto again;
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}
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/* Append to list of blocked */
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/* Append to list of blocked */
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nlmsvc_insert_block(newblock, NLM_NEVER);
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nlmsvc_insert_block(block, NLM_NEVER);
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out:
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out:
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mutex_unlock(&file->f_mutex);
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mutex_unlock(&file->f_mutex);
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nlmsvc_release_block(newblock);
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nlmsvc_release_block(block);
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nlmsvc_release_block(block);
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dprintk("lockd: nlmsvc_lock returned %u\n", ret);
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dprintk("lockd: nlmsvc_lock returned %u\n", ret);
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return ret;
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return ret;
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