[pnfs] [PATCH 22/38] [v1] pnfs: client layout cache: unlock layout around call to get_layout

[Benny Halevy]

get_layout sends an rpc to the server so the layout spinlock should be
released around the call.

Signed-off-by: Benny Halevy <bhalevy at panasas.com>
---
 fs/nfs/pnfs.c |   21 ++++++++++++++-------
 1 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 81d9800..c95659b 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -594,8 +594,6 @@ pnfs_update_layout(struct inode *ino,
 		return 0; /* Already have layout information */
 	}
 
-	res.layout.buf = NULL;
-
 	/* if get layout already failed once goto out */
 	if (nfsi->pnfs_layout_state & NFS_INO_LAYOUT_FAILED) {
 		if (unlikely(nfsi->pnfs_layout_suspend &&
@@ -609,7 +607,16 @@ pnfs_update_layout(struct inode *ino,
 		}
 	}
 
+	res.layout.buf = NULL;
+	spin_unlock(&nfsi->lo_lock);
 	result = get_layout(ino, ctx, &arg, &res);
+	spin_lock(&nfsi->lo_lock);
+
+	/* we got a reference on nfsi->current_layout hence it must never
+	 * change, even while nfsi->lo_lock was not held.
+	 */
+	BUG_ON(nfsi->current_layout != layout_new);
+
 	if (result) {
 		printk(KERN_ERR "%s: ERROR retrieving layout %d\n",
 		       __FUNCTION__, result);
@@ -636,14 +643,14 @@ pnfs_update_layout(struct inode *ino,
 			/* mark with NFS_INO_LAYOUT_FAILED */
 			break;
 		}
-		goto out;
+		goto get_out;
 	}
 
 	if (res.layout.len <= 0) {
 		printk(KERN_ERR
 		       "%s: ERROR!  Layout size is ZERO!\n", __FUNCTION__);
 		result =  -EIO;
-		goto out;
+		goto get_out;
 	}
 
 	/* Inject layout blob into I/O device driver */
@@ -653,7 +660,7 @@ pnfs_update_layout(struct inode *ino,
 		printk(KERN_ERR "%s: ERROR!  Could not inject layout (%d)\n",
 		       __FUNCTION__, result);
 		result =  -EIO;
-		goto out;
+		goto get_out;
 	}
 
 	if (res.return_on_close) {
@@ -664,14 +671,14 @@ pnfs_update_layout(struct inode *ino,
 	nfsi->current_layout = layout_new;
 
 	result = 0;
-out:
-
+get_out:
 	/* remember that get layout failed and don't try again */
 	if (result < 0)
 		nfsi->pnfs_layout_state |= NFS_INO_LAYOUT_FAILED;
 
 	/* res.layout.buf kalloc'ed by the xdr decoder? */
 	kfree(res.layout.buf);
+out:
 	put_unlock_current_layout(nfsi, layout_new);
 ret:
 	dprintk("%s end (err:%d) state 0x%lx\n",
-- 
1.5.3.3