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Commit 6f60f889 authored by Yan, Zheng's avatar Yan, Zheng Committed by Sage Weil
Browse files

ceph: fix freeing inode vs removing session caps race 



remove_session_caps() uses iterate_session_caps() to remove caps,
but iterate_session_caps() skips inodes that are being deleted.
So session->s_nr_caps can be non-zero after iterate_session_caps()
return.

We can fix the issue by waiting until deletions are complete.
__wait_on_freeing_inode() is designed for the job, but it is not
exported, so we use lookup inode function to access it.

Signed-off-by: default avatarYan, Zheng <zheng.z.yan@intel.com>
parent 4d1829a5

fs/ceph/inode.c

+8 −0
Original line number Diff line number Diff line
@@ -61,6 +61,14 @@ struct inode *ceph_get_inode(struct super_block *sb, struct ceph_vino vino) 
	return inode;

}



struct inode *ceph_lookup_inode(struct super_block *sb, struct ceph_vino vino)

{

	struct inode *inode;

	ino_t t = ceph_vino_to_ino(vino);

	inode = ilookup5_nowait(sb, t, ceph_ino_compare, &vino);

	return inode;

}



/*

 * get/constuct snapdir inode for a given directory

 */

fs/ceph/mds_client.c

+31 −0
Original line number Diff line number Diff line
@@ -1031,6 +1031,37 @@ static void remove_session_caps(struct ceph_mds_session *session) 
{

	dout("remove_session_caps on %p\n", session);

	iterate_session_caps(session, remove_session_caps_cb, NULL);



	spin_lock(&session->s_cap_lock);

	if (session->s_nr_caps > 0) {

		struct super_block *sb = session->s_mdsc->fsc->sb;

		struct inode *inode;

		struct ceph_cap *cap, *prev = NULL;

		struct ceph_vino vino;

		/*

		 * iterate_session_caps() skips inodes that are being

		 * deleted, we need to wait until deletions are complete.

		 * __wait_on_freeing_inode() is designed for the job,

		 * but it is not exported, so use lookup inode function

		 * to access it.

		 */

		while (!list_empty(&session->s_caps)) {

			cap = list_entry(session->s_caps.next,

					 struct ceph_cap, session_caps);

			if (cap == prev)

				break;

			prev = cap;

			vino = cap->ci->i_vino;

			spin_unlock(&session->s_cap_lock);



			inode = ceph_lookup_inode(sb, vino);

			iput(inode);



			spin_lock(&session->s_cap_lock);

		}

	}

	spin_unlock(&session->s_cap_lock);



	BUG_ON(session->s_nr_caps > 0);

	BUG_ON(!list_empty(&session->s_cap_flushing));

	cleanup_cap_releases(session);

fs/ceph/super.h

+2 −0
Original line number Diff line number Diff line
@@ -677,6 +677,8 @@ extern void ceph_destroy_inode(struct inode *inode); 


extern struct inode *ceph_get_inode(struct super_block *sb,

				    struct ceph_vino vino);

extern struct inode *ceph_lookup_inode(struct super_block *sb,

				       struct ceph_vino vino);

extern struct inode *ceph_get_snapdir(struct inode *parent);

extern int ceph_fill_file_size(struct inode *inode, int issued,

			       u32 truncate_seq, u64 truncate_size, u64 size);