This is a note to let you know that I've just added the patch titled pNFS: Fix a deadlock between read resends and layoutreturn to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: pnfs-fix-a-deadlock-between-read-resends-and-layoutreturn.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 54e4a0dfa25d9365c4e80a639e80d9213eb6edbe Mon Sep 17 00:00:00 2001 From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> Date: Sun, 27 Nov 2016 15:12:39 -0500 Subject: pNFS: Fix a deadlock between read resends and layoutreturn From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> commit 54e4a0dfa25d9365c4e80a639e80d9213eb6edbe upstream. We must not call nfs_pageio_init_read() on a new nfs_pageio_descriptor while holding a reference to a layout segment, as that can deadlock pnfs_update_layout(). Fixes: d67ae825a59d6 ("pnfs/flexfiles: Add the FlexFile Layout Driver") Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/nfs/flexfilelayout/flexfilelayout.c | 4 ++++ fs/nfs/pnfs.c | 4 ++++ 2 files changed, 8 insertions(+) --- a/fs/nfs/flexfilelayout/flexfilelayout.c +++ b/fs/nfs/flexfilelayout/flexfilelayout.c @@ -28,6 +28,9 @@ static struct group_info *ff_zero_group; +static void ff_layout_read_record_layoutstats_done(struct rpc_task *task, + struct nfs_pgio_header *hdr); + static struct pnfs_layout_hdr * ff_layout_alloc_layout_hdr(struct inode *inode, gfp_t gfp_flags) { @@ -1293,6 +1296,7 @@ static int ff_layout_read_done_cb(struct hdr->pgio_mirror_idx + 1, &hdr->pgio_mirror_idx)) goto out_eagain; + ff_layout_read_record_layoutstats_done(task, hdr); pnfs_read_resend_pnfs(hdr); return task->tk_status; case -NFS4ERR_RESET_TO_MDS: --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -2293,6 +2293,10 @@ void pnfs_read_resend_pnfs(struct nfs_pg struct nfs_pageio_descriptor pgio; if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) { + /* Prevent deadlocks with layoutreturn! */ + pnfs_put_lseg(hdr->lseg); + hdr->lseg = NULL; + nfs_pageio_init_read(&pgio, hdr->inode, false, hdr->completion_ops); hdr->task.tk_status = nfs_pageio_resend(&pgio, hdr); Patches currently in stable-queue which might be from trond.myklebust@xxxxxxxxxxxxxxx are queue-4.9/pnfs-fix-a-deadlock-between-read-resends-and-layoutreturn.patch queue-4.9/pnfs-don-t-clear-the-layout-stateid-if-a-layout-return-is-outstanding.patch queue-4.9/sunrpc-fix-refcounting-problems-with-auth_gss-messages.patch queue-4.9/pnfs-on-error-do-not-send-layoutget-until-the-layoutreturn-has-completed.patch queue-4.9/pnfs-clear-nfs_layout_return_requested-when-invalidating-the-layout-stateid.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html