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authorTrond Myklebust <trond.myklebust@primarydata.com>2016-11-27 15:12:39 -0500
committerTrond Myklebust <trond.myklebust@primarydata.com>2016-12-01 17:21:38 -0500
commit54e4a0dfa25d9365c4e80a639e80d9213eb6edbe (patch)
tree5d1004f5fc0f7e1529e323524eda755e69ec08bd /fs/nfs/pnfs.c
parent9a837856cf612d83e9ede7081972a2fa78de6921 (diff)
downloadlinux-54e4a0dfa25d9365c4e80a639e80d9213eb6edbe.tar.gz
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 <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.0+
Diffstat (limited to 'fs/nfs/pnfs.c')
-rw-r--r--fs/nfs/pnfs.c4
1 files changed, 4 insertions, 0 deletions
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);