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Commit 56b38a1f authored by Trond Myklebust's avatar Trond Myklebust
Browse files

pNFS: Fix post-layoutget error handling in pnfs_update_layout() 



The non-retry error path is currently broken and ends up releasing the
reference to the layout twice. It also can end up clearing the
NFS_LAYOUT_FIRST_LAYOUTGET flag twice, causing a race.

In addition, the retry path will fail to decrement the plh_outstanding
counter.

Fixes: 183d9e7b ("pnfs: rework LAYOUTGET retry handling")
Cc: stable@vger.kernel.org # 4.7
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: default avatarJeff Layton <jlayton@redhat.com>
parent 8487c479

fs/nfs/pnfs.c

+11 −10
Original line number Diff line number Diff line
@@ -1645,6 +1645,7 @@ pnfs_update_layout(struct inode *ino, 
	lseg = send_layoutget(lo, ctx, &stateid, &arg, &timeout, gfp_flags);

	trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,

				 PNFS_UPDATE_LAYOUT_SEND_LAYOUTGET);

	atomic_dec(&lo->plh_outstanding);

	if (IS_ERR(lseg)) {

		switch(PTR_ERR(lseg)) {

		case -ERECALLCONFLICT:
@@ -1652,26 +1653,26 @@ pnfs_update_layout(struct inode *ino, 
				lseg = NULL;

			/* Fallthrough */

		case -EAGAIN:

			pnfs_put_layout_hdr(lo);

			if (first)

				pnfs_clear_first_layoutget(lo);

			if (lseg) {

				trace_pnfs_update_layout(ino, pos, count,

					iomode, lo, lseg, PNFS_UPDATE_LAYOUT_RETRY);

				goto lookup_again;

			}

			/* Fallthrough */

			break;

		default:

			if (!nfs_error_is_fatal(PTR_ERR(lseg))) {

				pnfs_layout_clear_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));

				lseg = NULL;

			}

			goto out_put_layout_hdr;

		}

		if (lseg) {

			if (first)

				pnfs_clear_first_layoutget(lo);

			trace_pnfs_update_layout(ino, pos, count,

				iomode, lo, lseg, PNFS_UPDATE_LAYOUT_RETRY);

			pnfs_put_layout_hdr(lo);

			goto lookup_again;

		}

	} else {

		pnfs_layout_clear_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));

	}



	atomic_dec(&lo->plh_outstanding);

out_put_layout_hdr:

	if (first)

		pnfs_clear_first_layoutget(lo);