This is a note to let you know that I've just added the patch titled
nfs4: resend LAYOUTGET when there is a race that changes the seqid
to the 4.3-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:
nfs4-resend-layoutget-when-there-is-a-race-that-changes-the-seqid.patch
and it can be found in the queue-4.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4f2e9dce0c6348a95eaa56ade9bab18572221088 Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
Date: Wed, 25 Nov 2015 13:43:14 -0500
Subject: nfs4: resend LAYOUTGET when there is a race that changes the seqid
From: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
commit 4f2e9dce0c6348a95eaa56ade9bab18572221088 upstream.
pnfs_layout_process will check the returned layout stateid against what
the kernel has in-core. If it turns out that the stateid we received is
older, then we should resend the LAYOUTGET instead of falling back to
MDS I/O.
Signed-off-by: Jeff Layton <jeff.layton@xxxxxxxxxxxxxxx>
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nfs/pnfs.c | 56 +++++++++++++++++++++++++++++++-------------------------
1 file changed, 31 insertions(+), 25 deletions(-)
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -872,33 +872,38 @@ send_layoutget(struct pnfs_layout_hdr *l
dprintk("--> %s\n", __func__);
- lgp = kzalloc(sizeof(*lgp), gfp_flags);
- if (lgp == NULL)
- return NULL;
-
- i_size = i_size_read(ino);
+ /*
+ * Synchronously retrieve layout information from server and
+ * store in lseg. If we race with a concurrent seqid morphing
+ * op, then re-send the LAYOUTGET.
+ */
+ do {
+ lgp = kzalloc(sizeof(*lgp), gfp_flags);
+ if (lgp == NULL)
+ return NULL;
+
+ i_size = i_size_read(ino);
+
+ lgp->args.minlength = PAGE_CACHE_SIZE;
+ if (lgp->args.minlength > range->length)
+ lgp->args.minlength = range->length;
+ if (range->iomode == IOMODE_READ) {
+ if (range->offset >= i_size)
+ lgp->args.minlength = 0;
+ else if (i_size - range->offset < lgp->args.minlength)
+ lgp->args.minlength = i_size - range->offset;
+ }
+ lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE;
+ lgp->args.range = *range;
+ lgp->args.type = server->pnfs_curr_ld->id;
+ lgp->args.inode = ino;
+ lgp->args.ctx = get_nfs_open_context(ctx);
+ lgp->gfp_flags = gfp_flags;
+ lgp->cred = lo->plh_lc_cred;
- lgp->args.minlength = PAGE_CACHE_SIZE;
- if (lgp->args.minlength > range->length)
- lgp->args.minlength = range->length;
- if (range->iomode == IOMODE_READ) {
- if (range->offset >= i_size)
- lgp->args.minlength = 0;
- else if (i_size - range->offset < lgp->args.minlength)
- lgp->args.minlength = i_size - range->offset;
- }
- lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE;
- lgp->args.range = *range;
- lgp->args.type = server->pnfs_curr_ld->id;
- lgp->args.inode = ino;
- lgp->args.ctx = get_nfs_open_context(ctx);
- lgp->gfp_flags = gfp_flags;
- lgp->cred = lo->plh_lc_cred;
+ lseg = nfs4_proc_layoutget(lgp, gfp_flags);
+ } while (lseg == ERR_PTR(-EAGAIN));
- /* Synchronously retrieve layout information from server and
- * store in lseg.
- */
- lseg = nfs4_proc_layoutget(lgp, gfp_flags);
if (IS_ERR(lseg)) {
switch (PTR_ERR(lseg)) {
case -ENOMEM:
@@ -1687,6 +1692,7 @@ pnfs_layout_process(struct nfs4_layoutge
/* existing state ID, make sure the sequence number matches. */
if (pnfs_layout_stateid_blocked(lo, &res->stateid)) {
dprintk("%s forget reply due to sequence\n", __func__);
+ status = -EAGAIN;
goto out_forget_reply;
}
pnfs_set_layout_stateid(lo, &res->stateid, false);
Patches currently in stable-queue which might be from jlayton@xxxxxxxxxxxxxxx are
queue-4.3/nfs-if-we-have-no-valid-attrs-then-don-t-declare-the-attribute-cache-valid.patch
queue-4.3/nfsd-serialize-state-seqid-morphing-operations.patch
queue-4.3/nfs4-resend-layoutget-when-there-is-a-race-that-changes-the-seqid.patch
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