From 293b3b065c5ec5d15c3087ca42a52c991d7d8235 Mon Sep 17 00:00:00 2001 From: Andy Adamson Date: Wed, 20 Jun 2012 15:03:34 -0400 Subject: NFSv4.1 do not send LAYOUTRETURN on emtpy plh_segs list 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 Signed-off-by: Trond Myklebust --- fs/nfs/pnfs.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index 3ad768f..7fbd25a 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); -- cgit v1.1