From 54e4a0dfa25d9365c4e80a639e80d9213eb6edbe Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Sun, 27 Nov 2016 15:12:39 -0500 Subject: [PATCH] pNFS: Fix a deadlock between read resends and layoutreturn 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 Cc: stable@vger.kernel.org # v4.0+ --- fs/nfs/flexfilelayout/flexfilelayout.c | 4 ++++ fs/nfs/pnfs.c | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c index 98ace127bf86..a5c38889e7ae 100644 --- 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 rpc_task *task, 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: diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index 259ef85f435a..206d560c74f4 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -2286,6 +2286,10 @@ void pnfs_read_resend_pnfs(struct nfs_pgio_header *hdr) 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); -- 2.20.1