From: "Yan, Zheng" <zyan@redhat.com>
Date: Mon, 14 Aug 2017 10:50:50 +0800
Subject: ceph: fix -EOLDSNAPC handling
Git-commit: a5cd74ad388c1318554e24820b77ce335a27e0ef
Patch-mainline: v4.14-rc1
References: FATE#324714

Need to drop cap reference before retry. Besides, it's better to
redo file write checks for each retry because we re-lock inode.

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Luis Henriques <lhenriques@suse.com>
---
 fs/ceph/file.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 0e8986c69639..1ce80f66e9e5 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1309,6 +1309,7 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (!prealloc_cf)
 		return -ENOMEM;
 
+retry_snap:
 	inode_lock(inode);
 
 	/* We can write back this queue in page reclaim */
@@ -1340,7 +1341,6 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 			goto out;
 	}
 
-retry_snap:
 	/* FIXME: not complete since it doesn't account for being at quota */
 	if (ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL)) {
 		err = -ENOSPC;
@@ -1389,14 +1389,6 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 							 &prealloc_cf);
 		else
 			written = ceph_sync_write(iocb, &data, pos, snapc);
-		if (written == -EOLDSNAPC) {
-			dout("aio_write %p %llx.%llx %llu~%u"
-				"got EOLDSNAPC, retrying\n",
-				inode, ceph_vinop(inode),
-				pos, (unsigned)count);
-			inode_lock(inode);
-			goto retry_snap;
-		}
 		if (written > 0)
 			iov_iter_advance(from, written);
 		ceph_put_snap_context(snapc);
@@ -1430,10 +1422,15 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	     ceph_cap_string(got));
 	ceph_put_cap_refs(ci, got);
 
+	if (written == -EOLDSNAPC) {
+		dout("aio_write %p %llx.%llx %llu~%u" "got EOLDSNAPC, retrying\n",
+		     inode, ceph_vinop(inode), pos, (unsigned)count);
+		goto retry_snap;
+	}
+
 	if (written >= 0) {
 		if (ceph_osdmap_flag(osdc, CEPH_OSDMAP_NEARFULL))
 			iocb->ki_flags |= IOCB_DSYNC;
-
 		written = generic_write_sync(iocb, written);
 	}