Commit fc837c8f authored by Sage Weil's avatar Sage Weil
Browse files

ceph: queue_cap_snap should always queue dirty context 



This simplifies the calling convention, and fixes a bug where we queue a
capsnap with a context other than i_head_snapc (the one that matches the
dirty pages).  The result was a BUG at fs/ceph/caps.c:2178 on writeback
completion when a capsnap matching the writeback snapc could not be found.

Signed-off-by: default avatarSage Weil <sage@newdream.net>
parent f5b06628

fs/ceph/snap.c

+7 −9
Original line number Diff line number Diff line
@@ -430,8 +430,7 @@ static int dup_array(u64 **dst, __le64 *src, int num) 
 * Caller must hold snap_rwsem for read (i.e., the realm topology won't

 * change).

 */

void ceph_queue_cap_snap(struct ceph_inode_info *ci,

			 struct ceph_snap_context *snapc)

void ceph_queue_cap_snap(struct ceph_inode_info *ci)

{

	struct inode *inode = &ci->vfs_inode;

	struct ceph_cap_snap *capsnap;
@@ -450,10 +449,11 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci, 
		   as no new writes are allowed to start when pending, so any

		   writes in progress now were started before the previous

		   cap_snap.  lucky us. */

		dout("queue_cap_snap %p snapc %p seq %llu used %d"

		     " already pending\n", inode, snapc, snapc->seq, used);

		dout("queue_cap_snap %p already pending\n", inode);

		kfree(capsnap);

	} else if (ci->i_wrbuffer_ref_head || (used & CEPH_CAP_FILE_WR)) {

		struct ceph_snap_context *snapc = ci->i_head_snapc;



		igrab(inode);



		atomic_set(&capsnap->nref, 1);
@@ -462,7 +462,6 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci, 
		INIT_LIST_HEAD(&capsnap->flushing_item);



		capsnap->follows = snapc->seq - 1;

		capsnap->context = ceph_get_snap_context(snapc);

		capsnap->issued = __ceph_caps_issued(ci, NULL);

		capsnap->dirty = __ceph_caps_dirty(ci);
@@ -479,7 +478,7 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci, 
		   snapshot. */

		capsnap->dirty_pages = ci->i_wrbuffer_ref_head;

		ci->i_wrbuffer_ref_head = 0;

		ceph_put_snap_context(ci->i_head_snapc);

		capsnap->context = snapc;

		ci->i_head_snapc = NULL;

		list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps);
@@ -603,7 +602,7 @@ more: 
				if (lastinode)

					iput(lastinode);

				lastinode = inode;

				ceph_queue_cap_snap(ci, realm->cached_context);

				ceph_queue_cap_snap(ci);

				spin_lock(&realm->inodes_with_caps_lock);

			}

			spin_unlock(&realm->inodes_with_caps_lock);
@@ -825,8 +824,7 @@ void ceph_handle_snap(struct ceph_mds_client *mdsc, 
			spin_unlock(&realm->inodes_with_caps_lock);

			spin_unlock(&inode->i_lock);



			ceph_queue_cap_snap(ci,

					    ci->i_snap_realm->cached_context);

			ceph_queue_cap_snap(ci);



			iput(inode);

			continue;

fs/ceph/super.h

+1 −2
Original line number Diff line number Diff line
@@ -714,8 +714,7 @@ extern int ceph_update_snap_trace(struct ceph_mds_client *m, 
extern void ceph_handle_snap(struct ceph_mds_client *mdsc,

			     struct ceph_mds_session *session,

			     struct ceph_msg *msg);

extern void ceph_queue_cap_snap(struct ceph_inode_info *ci,

				struct ceph_snap_context *snapc);

extern void ceph_queue_cap_snap(struct ceph_inode_info *ci);

extern int __ceph_finish_cap_snap(struct ceph_inode_info *ci,

				  struct ceph_cap_snap *capsnap);

extern void ceph_cleanup_empty_realms(struct ceph_mds_client *mdsc);

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