Commit fca4451a authored by Greg Farnum's avatar Greg Farnum Committed by Sage Weil
Browse files

ceph: preallocate flock state without locks held 



When the lock_kernel() turns into lock_flocks() and a spinlock, we won't
be able to do allocations with the lock held.  Preallocate space without
the lock, and retry if the lock state changes out from underneath us.

Signed-off-by: default avatarGreg Farnum <gregf@hq.newdream.net>
Signed-off-by: default avatarSage Weil <sage@newdream.net>
parent ac0b74d8

fs/ceph/locks.c

+15 −2
Original line number Diff line number Diff line
@@ -181,8 +181,9 @@ void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count) 
 * Encode the flock and fcntl locks for the given inode into the pagelist.

 * Format is: #fcntl locks, sequential fcntl locks, #flock locks,

 * sequential flock locks.

 * Must be called with BLK already held, and the lock numbers should have

 * been gathered under the same lock holding window.

 * Must be called with lock_flocks() already held.

 * If we encounter more of a specific lock type than expected,

 * we return the value 1.

 */

int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist,

		      int num_fcntl_locks, int num_flock_locks)
@@ -190,6 +191,8 @@ int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist, 
	struct file_lock *lock;

	struct ceph_filelock cephlock;

	int err = 0;

	int seen_fcntl = 0;

	int seen_flock = 0;



	dout("encoding %d flock and %d fcntl locks", num_flock_locks,

	     num_fcntl_locks);
@@ -198,6 +201,11 @@ int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist, 
		goto fail;

	for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {

		if (lock->fl_flags & FL_POSIX) {

			++seen_fcntl;

			if (seen_fcntl > num_fcntl_locks) {

				err = -ENOSPC;

				goto fail;

			}

			err = lock_to_ceph_filelock(lock, &cephlock);

			if (err)

				goto fail;
@@ -213,6 +221,11 @@ int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist, 
		goto fail;

	for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {

		if (lock->fl_flags & FL_FLOCK) {

			++seen_flock;

			if (seen_flock > num_flock_locks) {

				err = -ENOSPC;

				goto fail;

			}

			err = lock_to_ceph_filelock(lock, &cephlock);

			if (err)

				goto fail;

fs/ceph/mds_client.c

+29 −13
Original line number Diff line number Diff line
@@ -2365,19 +2365,35 @@ static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap, 


	if (recon_state->flock) {

		int num_fcntl_locks, num_flock_locks;

		struct ceph_pagelist_cursor trunc_point;



		ceph_pagelist_set_cursor(pagelist, &trunc_point);

		do {

			lock_kernel();

		ceph_count_locks(inode, &num_fcntl_locks, &num_flock_locks);

			ceph_count_locks(inode, &num_fcntl_locks,

					 &num_flock_locks);

			rec.v2.flock_len = (2*sizeof(u32) +

					    (num_fcntl_locks+num_flock_locks) *

					    sizeof(struct ceph_filelock));

			unlock_kernel();



			/* pre-alloc pagelist */

			ceph_pagelist_truncate(pagelist, &trunc_point);

			err = ceph_pagelist_append(pagelist, &rec, reclen);

			if (!err)

			err = ceph_encode_locks(inode, pagelist,

				err = ceph_pagelist_reserve(pagelist,

							    rec.v2.flock_len);



			/* encode locks */

			if (!err) {

				lock_kernel();

				err = ceph_encode_locks(inode,

							pagelist,

							num_fcntl_locks,

							num_flock_locks);

				unlock_kernel();

			}

		} while (err == -ENOSPC);

	} else {

		err = ceph_pagelist_append(pagelist, &rec, reclen);

	}

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