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authorTrond Myklebust <trond.myklebust@primarydata.com>2018-03-07 14:49:06 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-03-15 10:57:00 +0100
commit0fa7083df3994b0bbc748240f6044d6561d30e7f (patch)
tree48ef1e63562f53a8c9787633ed7838b9cedad869
parentff32fd5e2dce7d7e8ae90735bd5a387224811272 (diff)
pNFS: Prevent the layout header refcount going to zero in pnfs_roc()
commit 9c6376ebddad585da4238532dd6d90ae23ffee67 upstream. Ensure that we hold a reference to the layout header when processing the pNFS return-on-close so that the refcount value does not inadvertently go to zero. Reported-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Cc: stable@vger.kernel.org # v4.10+ Tested-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/nfs/pnfs.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index eb098ccfefd5..b99200828d08 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -292,8 +292,11 @@ pnfs_detach_layout_hdr(struct pnfs_layout_hdr *lo)
void
pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo)
{
- struct inode *inode = lo->plh_inode;
+ struct inode *inode;
+ if (!lo)
+ return;
+ inode = lo->plh_inode;
pnfs_layoutreturn_before_put_layout_hdr(lo);
if (refcount_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) {
@@ -1241,10 +1244,12 @@ retry:
spin_lock(&ino->i_lock);
lo = nfsi->layout;
if (!lo || !pnfs_layout_is_valid(lo) ||
- test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags))
+ test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
+ lo = NULL;
goto out_noroc;
+ }
+ pnfs_get_layout_hdr(lo);
if (test_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags)) {
- pnfs_get_layout_hdr(lo);
spin_unlock(&ino->i_lock);
wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN,
TASK_UNINTERRUPTIBLE);
@@ -1312,10 +1317,12 @@ out_noroc:
struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
if (ld->prepare_layoutreturn)
ld->prepare_layoutreturn(args);
+ pnfs_put_layout_hdr(lo);
return true;
}
if (layoutreturn)
pnfs_send_layoutreturn(lo, &stateid, iomode, true);
+ pnfs_put_layout_hdr(lo);
return false;
}