Merge tag 'nfs-for-4.4-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client bugfixes from Trond Myklebust:
 "Highlights include:

  Stable patches:
   - Fix a NFSv4 callback identifier leak that was also causing client
     crashes
   - Fix NFSv4 callback decoding issues when incoming requests are
     truncated
   - Don't declare the attribute cache valid when we call
     nfs_update_inode with an empty attribute structure.
   - Resend LAYOUTGET when there is a race that changes the seqid

  Bugfixes:
   - Fix a number of issues with the NFSv4.2 CLONE ioctl()
   - Properly set NFS v4.2 NFSDBG_FACILITY
   - NFSv4 referrals are broken; Cleanup FATTR4_WORD0_FS_LOCATIONS after
     decoding success
   - Use sliding delay when LAYOUTGET gets NFS4ERR_DELAY
   - Ensure that attrcache is revalidated after a SETATTR"

* tag 'nfs-for-4.4-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  nfs4: resend LAYOUTGET when there is a race that changes the seqid
  nfs: if we have no valid attrs, then don't declare the attribute cache valid
  nfs: ensure that attrcache is revalidated after a SETATTR
  nfs4: limit callback decoding to received bytes
  nfs4: start callback_ident at idr 1
  nfs: use sliding delay when LAYOUTGET gets NFS4ERR_DELAY
  NFS4: Cleanup FATTR4_WORD0_FS_LOCATIONS after decoding success
  NFS: Properly set NFS v4.2 NFSDBG_FACILITY
  nfs: reduce the amount of ifdefs for v4.2 in nfs4file.c
  nfs: use btrfs ioctl defintions for clone
  nfs: allow intra-file CLONE
  nfs: offer native ioctls even if CONFIG_COMPAT is set
  nfs: pass on count for CLONE operations

1 files changed, 31 insertions, 25 deletions

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 93496c059837..5a8ae2125b50 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -872,33 +872,38 @@ send_layoutget(struct pnfs_layout_hdr *lo,
 
 	dprintk("--> %s\n", __func__);
 
-	lgp = kzalloc(sizeof(*lgp), gfp_flags);
-	if (lgp == NULL)
-		return NULL;
+	/*
+	 * 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;
 
-	i_size = i_size_read(ino);
+		lseg = nfs4_proc_layoutget(lgp, gfp_flags);
+	} while (lseg == ERR_PTR(-EAGAIN));
 
-	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;
-
-	/* 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_layoutget *lgp)
 		/* 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);