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Commit 6070e0c1 authored by Yan, Zheng's avatar Yan, Zheng Committed by Sage Weil
Browse files

ceph: don't early drop Fw cap 



ceph_aio_write() has an optimization that marks CEPH_CAP_FILE_WR
cap dirty before data is copied to page cache and inode size is
updated. The optimization avoids slow cap revocation caused by
balance_dirty_pages(), but introduces inode size update race. If
ceph_check_caps() flushes the dirty cap before the inode size is
updated, MDS can miss the new inode size. So just remove the
optimization.

Signed-off-by: default avatarYan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: default avatarGreg Farnum <greg@inktank.com>
parent 7971bd92

fs/ceph/file.c

+17 −25
Original line number Diff line number Diff line
@@ -724,9 +724,12 @@ static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov, 
	if (ceph_snap(inode) != CEPH_NOSNAP)

		return -EROFS;



	sb_start_write(inode->i_sb);

retry_snap:

	if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL))

		return -ENOSPC;

	if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL)) {

		ret = -ENOSPC;

		goto out;

	}

	__ceph_do_pending_vmtruncate(inode);

	dout("aio_write %p %llx.%llx %llu~%u getting caps. i_size %llu\n",

	     inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
@@ -750,29 +753,10 @@ static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov, 
		ret = ceph_sync_write(file, iov->iov_base, iov->iov_len,

			&iocb->ki_pos);

	} else {

		/*

		 * buffered write; drop Fw early to avoid slow

		 * revocation if we get stuck on balance_dirty_pages

		 */

		int dirty;



		spin_lock(&ci->i_ceph_lock);

		dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);

		spin_unlock(&ci->i_ceph_lock);

		ceph_put_cap_refs(ci, got);



		ret = generic_file_aio_write(iocb, iov, nr_segs, pos);

		if ((ret >= 0 || ret == -EIOCBQUEUED) &&

		    ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host)

		     || ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {

			err = vfs_fsync_range(file, pos, pos + ret - 1, 1);

			if (err < 0)

				ret = err;

		}



		if (dirty)

			__mark_inode_dirty(inode, dirty);

		goto out;

		mutex_lock(&inode->i_mutex);

		ret = __generic_file_aio_write(iocb, iov, nr_segs,

					       &iocb->ki_pos);

		mutex_unlock(&inode->i_mutex);

	}



	if (ret >= 0) {
@@ -790,12 +774,20 @@ static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov, 
	     ceph_cap_string(got));

	ceph_put_cap_refs(ci, got);



	if (ret >= 0 &&

	    ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host) ||

	     ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {

		err = vfs_fsync_range(file, pos, pos + ret - 1, 1);

		if (err < 0)

			ret = err;

	}

out:

	if (ret == -EOLDSNAPC) {

		dout("aio_write %p %llx.%llx %llu~%u got EOLDSNAPC, retrying\n",

		     inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len);

		goto retry_snap;

	}

	sb_end_write(inode->i_sb);



	return ret;

}