From: Andy Adamson <andros@xxxxxxxxxx>
mark_matching_lsegs_invalid() resets the mds_threshold counters and can
dereference the layout hdr on an initial empty plh_segs list. It returns 0 both
in the case of an initial empty list and in a non-emtpy list that was cleared
by calls to mark_lseg_invalid.
Don't send a LAYOUTRETURN if the list was initially empty.
Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
---
fs/nfs/pnfs.c | 23 +++++++++++++++++++----
1 files changed, 19 insertions(+), 4 deletions(-)
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 3dfd0a6..2669710 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -651,7 +651,14 @@ out_err_free:
return NULL;
}
-/* Initiates a LAYOUTRETURN(FILE) */
+/*
+ * Initiates a LAYOUTRETURN(FILE), and removes the pnfs_layout_hdr
+ * when the layout segment list is empty.
+ *
+ * Note that a pnfs_layout_hdr can exist with an empty layout segment
+ * list when LAYOUTGET has failed, or when LAYOUTGET succeeded, but the
+ * deviceid is marked invalid.
+ */
int
_pnfs_return_layout(struct inode *ino)
{
@@ -660,7 +667,7 @@ _pnfs_return_layout(struct inode *ino)
LIST_HEAD(tmp_list);
struct nfs4_layoutreturn *lrp;
nfs4_stateid stateid;
- int status = 0;
+ int status = 0, empty;
dprintk("NFS: %s for inode %lu\n", __func__, ino->i_ino);
@@ -668,13 +675,21 @@ _pnfs_return_layout(struct inode *ino)
lo = nfsi->layout;
if (!lo || pnfs_test_layout_returned(lo)) {
spin_unlock(&ino->i_lock);
- dprintk("%s: no layout to return\n", __func__);
- return status;
+ dprintk("NFS: %s no layout to return\n", __func__);
+ goto out;
}
stateid = nfsi->layout->plh_stateid;
/* Reference matched in nfs4_layoutreturn_release */
get_layout_hdr(lo);
+ empty = list_empty(&lo->plh_segs);
mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
+ /* Don't send a LAYOUTRETURN if list was initially empty */
+ if (empty) {
+ spin_unlock(&ino->i_lock);
+ put_layout_hdr(lo);
+ dprintk("NFS: %s no layout segments to return\n", __func__);
+ goto out;
+ }
lo->plh_block_lgets++;
pnfs_mark_layout_returned(lo);
spin_unlock(&ino->i_lock);
--
1.7.6.4
--
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