From 54e4a0dfa25d9365c4e80a639e80d9213eb6edbe Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Sun, 27 Nov 2016 15:12:39 -0500 Subject: 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/pnfs.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'fs/nfs/pnfs.c') 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); -- cgit v1.2.3