FAILED: patch "[PATCH] nfsd: don't offer flexfiles layouts when NFSv3 isn't being" failed to apply to 6.18-stable tree

FAILED: patch "[PATCH] nfsd: don't offer flexfiles layouts when NFSv3 isn't being" failed to apply to 6.18-stable tree

[gregkh]

The patch below does not apply to the 6.18-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x 5d28b2c920d9d9d3c45b41769342ad785eb372a7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026110409-glaucoma-strongman-8f52@gregkh' --subject-prefix 'PATCH 6.18.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 5d28b2c920d9d9d3c45b41769342ad785eb372a7 Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton@kernel.org>
Date: Fri, 4 Sep 2026 12:11:37 -0400
Subject: [PATCH] nfsd: don't offer flexfiles layouts when NFSv3 isn't being
 served

The flexfiles layout driver hands out a deviceinfo that names this server
as an NFSv3 DS (flexfilelayout.c hardcodes da->version = 3). With v3
disabled, the client can't talk to the DS: it loops on v3 NULL calls that
the server answers with PROG_MISMATCH, and I/O hangs in D state.

Skip LAYOUT_FLEX_FILES in nfsd4_setup_layout_type() unless v3 is enabled.

Reported-by: Benji Wiebe <itsme@benjiwiebe.com>
Closes: https://lore.kernel.org/linux-nfs/c734eeb8-8486-4491-bb4d-b9656cbaffbe@app.fastmail.com/
Fixes: 9b9960a0ca47 ("nfsd: Add a super simple flex file server")
Cc: stable@vger.kernel.org
Assisted-by: LLM
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260904-pnfs-ff-v1-1-5f502cf25401@kernel.org
Signed-off-by: Chuck Lever <cel@kernel.org>

diff --git a/fs/nfsd/nfs4layouts.c b/fs/nfsd/nfs4layouts.c
index 4187202f9acc..12acb68cbc3b 100644
--- a/fs/nfsd/nfs4layouts.c
+++ b/fs/nfsd/nfs4layouts.c
@@ -128,10 +128,12 @@ nfsd4_set_deviceid(struct nfsd4_deviceid *id, const struct svc_fh *fhp,
 
 void nfsd4_setup_layout_type(struct svc_export *exp)
 {
+	struct nfsd_net *nn = net_generic(exp->cd->net, nfsd_net_id);
 	struct super_block *sb = exp->ex_path.mnt->mnt_sb;
 	expfs_block_layouts_t block_supported = exportfs_layouts_supported(sb);
 
-	if (IS_ENABLED(CONFIG_NFSD_FLEXFILELAYOUT))
+	if (IS_ENABLED(CONFIG_NFSD_FLEXFILELAYOUT) &&
+	    nfsd_vers(nn, 3, NFSD_TEST))
 		exp->ex_layout_types |= 1 << LAYOUT_FLEX_FILES;
 	if (IS_ENABLED(CONFIG_NFSD_BLOCKLAYOUT) &&
 	    (block_supported & EXPFS_BLOCK_IN_BAND_ID))

[PATCH 6.18.y 1/5] NFSD/blocklayout: Extract extent mapping from proc_layoutget

[Sasha Levin]

From: Sergey Bashirov <sergeybashirov@gmail.com>

[ Upstream commit a1dce715c64d4376321b5534366ae48fd7d14bcc ]

No changes in functionality. Split the proc_layoutget function to
create a helper function that maps single extent to the requested
range. This helper function is then used to implement support for
multiple extents per LAYOUTGET.

Signed-off-by: Sergey Bashirov <sergeybashirov@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Stable-dep-of: 5d28b2c920d9 ("nfsd: don't offer flexfiles layouts when NFSv3 isn't being served")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfsd/blocklayout.c | 115 ++++++++++++++++++++++++------------------
 1 file changed, 66 insertions(+), 49 deletions(-)

diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c
index e9512c34c9dcf..8f6478d88ea22 100644
--- a/fs/nfsd/blocklayout.c
+++ b/fs/nfsd/blocklayout.c
@@ -17,68 +17,44 @@
 #define NFSDDBG_FACILITY	NFSDDBG_PNFS
 
 
+/*
+ * Get an extent from the file system that starts at offset or below
+ * and may be shorter than the requested length.
+ */
 static __be32
-nfsd4_block_proc_layoutget(struct svc_rqst *rqstp, struct inode *inode,
-		const struct svc_fh *fhp, struct nfsd4_layoutget *args)
+nfsd4_block_map_extent(struct inode *inode, const struct svc_fh *fhp,
+		u64 offset, u64 length, u32 iomode, u64 minlength,
+		struct pnfs_block_extent *bex)
 {
-	struct nfsd4_layout_seg *seg = &args->lg_seg;
 	struct super_block *sb = inode->i_sb;
-	u64 length;
-	u32 block_size = i_blocksize(inode);
-	struct pnfs_block_extent *bex;
 	struct iomap iomap;
 	u32 device_generation = 0;
 	int error;
 
-	if (locks_in_grace(SVC_NET(rqstp)))
-		return nfserr_grace;
-
-	if (seg->offset & (block_size - 1)) {
-		dprintk("pnfsd: I/O misaligned\n");
-		goto out_layoutunavailable;
-	}
-
-	/*
-	 * Some clients barf on non-zero block numbers for NONE or INVALID
-	 * layouts, so make sure to zero the whole structure.
-	 */
-	error = -ENOMEM;
-	bex = kzalloc(sizeof(*bex), GFP_KERNEL);
-	if (!bex)
-		goto out_error;
-	args->lg_content = bex;
-
-	error = sb->s_export_op->map_blocks(inode, seg->offset, seg->length,
-					    &iomap, seg->iomode != IOMODE_READ,
-					    &device_generation);
+	error = sb->s_export_op->map_blocks(inode, offset, length, &iomap,
+			iomode != IOMODE_READ, &device_generation);
 	if (error) {
 		if (error == -ENXIO)
-			goto out_layoutunavailable;
-		goto out_error;
-	}
-
-	length = iomap.offset + iomap.length - seg->offset;
-	if (length < args->lg_minlength) {
-		dprintk("pnfsd: extent smaller than minlength\n");
-		goto out_layoutunavailable;
+			return nfserr_layoutunavailable;
+		return nfserrno(error);
 	}
 
 	switch (iomap.type) {
 	case IOMAP_MAPPED:
-		if (seg->iomode == IOMODE_READ)
+		if (iomode == IOMODE_READ)
 			bex->es = PNFS_BLOCK_READ_DATA;
 		else
 			bex->es = PNFS_BLOCK_READWRITE_DATA;
 		bex->soff = iomap.addr;
 		break;
 	case IOMAP_UNWRITTEN:
-		if (seg->iomode & IOMODE_RW) {
+		if (iomode & IOMODE_RW) {
 			/*
 			 * Crack monkey special case from section 2.3.1.
 			 */
-			if (args->lg_minlength == 0) {
+			if (minlength == 0) {
 				dprintk("pnfsd: no soup for you!\n");
-				goto out_layoutunavailable;
+				return nfserr_layoutunavailable;
 			}
 
 			bex->es = PNFS_BLOCK_INVALID_DATA;
@@ -87,7 +63,7 @@ nfsd4_block_proc_layoutget(struct svc_rqst *rqstp, struct inode *inode,
 		}
 		fallthrough;
 	case IOMAP_HOLE:
-		if (seg->iomode == IOMODE_READ) {
+		if (iomode == IOMODE_READ) {
 			bex->es = PNFS_BLOCK_NONE_DATA;
 			break;
 		}
@@ -95,27 +71,68 @@ nfsd4_block_proc_layoutget(struct svc_rqst *rqstp, struct inode *inode,
 	case IOMAP_DELALLOC:
 	default:
 		WARN(1, "pnfsd: filesystem returned %d extent\n", iomap.type);
-		goto out_layoutunavailable;
+		return nfserr_layoutunavailable;
 	}
 
 	error = nfsd4_set_deviceid(&bex->vol_id, fhp, device_generation);
 	if (error)
-		goto out_error;
+		return nfserrno(error);
+
 	bex->foff = iomap.offset;
 	bex->len = iomap.length;
+	return nfs_ok;
+}
+
+static __be32
+nfsd4_block_proc_layoutget(struct svc_rqst *rqstp, struct inode *inode,
+		const struct svc_fh *fhp, struct nfsd4_layoutget *args)
+{
+	struct nfsd4_layout_seg *seg = &args->lg_seg;
+	struct pnfs_block_extent *bex;
+	u64 length;
+	u32 block_size = i_blocksize(inode);
+	__be32 nfserr;
+
+	if (locks_in_grace(SVC_NET(rqstp)))
+		return nfserr_grace;
 
-	seg->offset = iomap.offset;
-	seg->length = iomap.length;
+	nfserr = nfserr_layoutunavailable;
+	if (seg->offset & (block_size - 1)) {
+		dprintk("pnfsd: I/O misaligned\n");
+		goto out_error;
+	}
+
+	/*
+	 * Some clients barf on non-zero block numbers for NONE or INVALID
+	 * layouts, so make sure to zero the whole structure.
+	 */
+	nfserr = nfserrno(-ENOMEM);
+	bex = kzalloc(sizeof(*bex), GFP_KERNEL);
+	if (!bex)
+		goto out_error;
+	args->lg_content = bex;
+
+	nfserr = nfsd4_block_map_extent(inode, fhp, seg->offset, seg->length,
+			seg->iomode, args->lg_minlength, bex);
+	if (nfserr != nfs_ok)
+		goto out_error;
+
+	nfserr = nfserr_layoutunavailable;
+	length = bex->foff + bex->len - seg->offset;
+	if (length < args->lg_minlength) {
+		dprintk("pnfsd: extent smaller than minlength\n");
+		goto out_error;
+	}
+
+	seg->offset = bex->foff;
+	seg->length = bex->len;
 
 	dprintk("GET: 0x%llx:0x%llx %d\n", bex->foff, bex->len, bex->es);
-	return 0;
+	return nfs_ok;
 
 out_error:
 	seg->length = 0;
-	return nfserrno(error);
-out_layoutunavailable:
-	seg->length = 0;
-	return nfserr_layoutunavailable;
+	return nfserr;
 }
 
 static __be32
-- 
2.53.0

[PATCH 6.18.y 2/5] exportfs: Complete kernel-doc for struct export_operations

[Sasha Levin]

From: André Almeida <andrealmeid@igalia.com>

[ Upstream commit 7a6f811e2c06d656996776771f0498df129a0cc2 ]

Write down the missing members definitions for struct export_operations,
using as a reference the commit messages that created the members.

Signed-off-by: André Almeida <andrealmeid@igalia.com>
Link: https://patch.msgid.link/20260112-tonyk-fs_uuid-v1-3-acc1889de772@igalia.com
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Stable-dep-of: 5d28b2c920d9 ("nfsd: don't offer flexfiles layouts when NFSv3 isn't being served")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/exportfs.h | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index f0cf2714ec52d..0dc1bae9e1654 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -201,7 +201,7 @@ struct handle_to_path_ctx {
  * @commit_metadata: commit metadata changes to stable storage
  *
  * See Documentation/filesystems/nfs/exporting.rst for details on how to use
- * this interface correctly.
+ * this interface correctly and the definition of the flags.
  *
  * encode_fh:
  *    @encode_fh should store in the file handle fragment @fh (using at most
@@ -252,6 +252,19 @@ struct handle_to_path_ctx {
  * commit_metadata:
  *    @commit_metadata should commit metadata changes to stable storage.
  *
+ * @get_uuid:
+ *    Get a filesystem unique signature exposed to clients.
+ *
+ * @map_blocks:
+ *    Map and, if necessary, allocate blocks for a layout.
+ *
+ * @commit_blocks:
+ *    Commit blocks in a layout once the client is done with them.
+ *
+ * @flags:
+ *    Allows the filesystem to communicate to nfsd that it may want to do things
+ *    differently when dealing with it.
+ *
  * Locking rules:
  *    get_parent is called with child->d_inode->i_rwsem down
  *    get_name is not (which is possibly inconsistent)
-- 
2.53.0

[PATCH 6.18.y 3/5] exportfs: split out the ops for layout-based block device access

[Sasha Levin]

From: Christoph Hellwig <hch@lst.de>

[ Upstream commit d5758c31a81bcd9d5ac8a7456549b05df3579068 ]

The support to grant layouts for direct block device access works
at a very different layer than the rest of exports.  Split the methods
for it into a separate struct, and move that into a separate header
to better split things out.  The pointer to the new operation vector
is kept in export_operations to avoid bloating the super_block.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260423181854.743150-3-cel@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Stable-dep-of: 5d28b2c920d9 ("nfsd: don't offer flexfiles layouts when NFSv3 isn't being served")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 MAINTAINERS                    |  2 +-
 fs/nfsd/blocklayout.c          | 14 ++++++------
 fs/nfsd/nfs4layouts.c          |  9 ++++----
 fs/xfs/xfs_export.c            |  4 +---
 fs/xfs/xfs_pnfs.c              | 12 ++++++++---
 fs/xfs/xfs_pnfs.h              | 11 +++++-----
 include/linux/exportfs.h       | 25 +++++++---------------
 include/linux/exportfs_block.h | 39 ++++++++++++++++++++++++++++++++++
 8 files changed, 74 insertions(+), 42 deletions(-)
 create mode 100644 include/linux/exportfs_block.h

diff --git a/MAINTAINERS b/MAINTAINERS
index f5ea8588244c9..5821d97ae3304 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9606,7 +9606,7 @@ S:	Supported
 F:	Documentation/filesystems/nfs/exporting.rst
 F:	fs/exportfs/
 F:	fs/fhandle.c
-F:	include/linux/exportfs.h
+F:	include/linux/exportfs*.h
 
 FILESYSTEMS [IDMAPPED MOUNTS]
 M:	Christian Brauner <brauner@kernel.org>
diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c
index 8f6478d88ea22..ac1312fd1c457 100644
--- a/fs/nfsd/blocklayout.c
+++ b/fs/nfsd/blocklayout.c
@@ -2,7 +2,7 @@
 /*
  * Copyright (c) 2014-2016 Christoph Hellwig.
  */
-#include <linux/exportfs.h>
+#include <linux/exportfs_block.h>
 #include <linux/iomap.h>
 #include <linux/slab.h>
 #include <linux/pr.h>
@@ -31,8 +31,8 @@ nfsd4_block_map_extent(struct inode *inode, const struct svc_fh *fhp,
 	u32 device_generation = 0;
 	int error;
 
-	error = sb->s_export_op->map_blocks(inode, offset, length, &iomap,
-			iomode != IOMODE_READ, &device_generation);
+	error = sb->s_export_op->block_ops->map_blocks(inode, offset, length,
+			&iomap, iomode != IOMODE_READ, &device_generation);
 	if (error) {
 		if (error == -ENXIO)
 			return nfserr_layoutunavailable;
@@ -154,8 +154,8 @@ nfsd4_block_commit_blocks(struct inode *inode, struct nfsd4_layoutcommit *lcp,
 		iattr.ia_size = lcp->lc_newsize;
 	}
 
-	error = inode->i_sb->s_export_op->commit_blocks(inode, iomaps,
-			nr_iomaps, &iattr);
+	error = inode->i_sb->s_export_op->block_ops->commit_blocks(inode,
+			iomaps, nr_iomaps, &iattr);
 	kfree(iomaps);
 	return nfserrno(error);
 }
@@ -178,8 +178,8 @@ nfsd4_block_get_device_info_simple(struct super_block *sb,
 
 	b->type = PNFS_BLOCK_VOLUME_SIMPLE;
 	b->simple.sig_len = PNFS_BLOCK_UUID_LEN;
-	return sb->s_export_op->get_uuid(sb, b->simple.sig, &b->simple.sig_len,
-			&b->simple.offset);
+	return sb->s_export_op->block_ops->get_uuid(sb, b->simple.sig,
+			&b->simple.sig_len, &b->simple.offset);
 }
 
 static __be32
diff --git a/fs/nfsd/nfs4layouts.c b/fs/nfsd/nfs4layouts.c
index 2121ef26e7a98..6b6f55ae0472d 100644
--- a/fs/nfsd/nfs4layouts.c
+++ b/fs/nfsd/nfs4layouts.c
@@ -3,6 +3,7 @@
  * Copyright (c) 2014 Christoph Hellwig.
  */
 #include <linux/blkdev.h>
+#include <linux/exportfs_block.h>
 #include <linux/kmod.h>
 #include <linux/file.h>
 #include <linux/jhash.h>
@@ -127,6 +128,7 @@ void nfsd4_setup_layout_type(struct svc_export *exp)
 {
 #if defined(CONFIG_NFSD_BLOCKLAYOUT) || defined(CONFIG_NFSD_SCSILAYOUT)
 	struct super_block *sb = exp->ex_path.mnt->mnt_sb;
+	const struct exportfs_block_ops *bops = sb->s_export_op->block_ops;
 #endif
 
 	if (!(exp->ex_flags & NFSEXP_PNFS))
@@ -136,14 +138,11 @@ void nfsd4_setup_layout_type(struct svc_export *exp)
 	exp->ex_layout_types |= 1 << LAYOUT_FLEX_FILES;
 #endif
 #ifdef CONFIG_NFSD_BLOCKLAYOUT
-	if (sb->s_export_op->get_uuid &&
-	    sb->s_export_op->map_blocks &&
-	    sb->s_export_op->commit_blocks)
+	if (bops && bops->get_uuid && bops->map_blocks && bops->commit_blocks)
 		exp->ex_layout_types |= 1 << LAYOUT_BLOCK_VOLUME;
 #endif
 #ifdef CONFIG_NFSD_SCSILAYOUT
-	if (sb->s_export_op->map_blocks &&
-	    sb->s_export_op->commit_blocks &&
+	if (bops && bops->map_blocks && bops->commit_blocks &&
 	    sb->s_bdev &&
 	    sb->s_bdev->bd_disk->fops->pr_ops &&
 	    sb->s_bdev->bd_disk->fops->get_unique_id)
diff --git a/fs/xfs/xfs_export.c b/fs/xfs/xfs_export.c
index 201489d3de089..f64e035cacb55 100644
--- a/fs/xfs/xfs_export.c
+++ b/fs/xfs/xfs_export.c
@@ -244,8 +244,6 @@ const struct export_operations xfs_export_operations = {
 	.get_parent		= xfs_fs_get_parent,
 	.commit_metadata	= xfs_fs_nfs_commit_metadata,
 #ifdef CONFIG_EXPORTFS_BLOCK_OPS
-	.get_uuid		= xfs_fs_get_uuid,
-	.map_blocks		= xfs_fs_map_blocks,
-	.commit_blocks		= xfs_fs_commit_blocks,
+	.block_ops		= &xfs_export_block_ops,
 #endif
 };
diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c
index afe7497012d4c..c685995b69d7e 100644
--- a/fs/xfs/xfs_pnfs.c
+++ b/fs/xfs/xfs_pnfs.c
@@ -49,7 +49,7 @@ xfs_break_leased_layouts(
  * Get a unique ID including its location so that the client can identify
  * the exported device.
  */
-int
+static int
 xfs_fs_get_uuid(
 	struct super_block	*sb,
 	u8			*buf,
@@ -104,7 +104,7 @@ xfs_fs_map_update_inode(
 /*
  * Get a layout for the pNFS client.
  */
-int
+static int
 xfs_fs_map_blocks(
 	struct inode		*inode,
 	loff_t			offset,
@@ -252,7 +252,7 @@ xfs_pnfs_validate_isize(
  * to manually flush the cache here similar to what the fsync code path does
  * for datasyncs on files that have no dirty metadata.
  */
-int
+static int
 xfs_fs_commit_blocks(
 	struct inode		*inode,
 	struct iomap		*maps,
@@ -332,3 +332,9 @@ xfs_fs_commit_blocks(
 	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
 	return error;
 }
+
+const struct exportfs_block_ops xfs_export_block_ops = {
+	.get_uuid		= xfs_fs_get_uuid,
+	.map_blocks		= xfs_fs_map_blocks,
+	.commit_blocks		= xfs_fs_commit_blocks,
+};
diff --git a/fs/xfs/xfs_pnfs.h b/fs/xfs/xfs_pnfs.h
index 940c6c2ad88c5..bf43b2009e4cc 100644
--- a/fs/xfs/xfs_pnfs.h
+++ b/fs/xfs/xfs_pnfs.h
@@ -2,13 +2,9 @@
 #ifndef _XFS_PNFS_H
 #define _XFS_PNFS_H 1
 
-#ifdef CONFIG_EXPORTFS_BLOCK_OPS
-int xfs_fs_get_uuid(struct super_block *sb, u8 *buf, u32 *len, u64 *offset);
-int xfs_fs_map_blocks(struct inode *inode, loff_t offset, u64 length,
-		struct iomap *iomap, bool write, u32 *device_generation);
-int xfs_fs_commit_blocks(struct inode *inode, struct iomap *maps, int nr_maps,
-		struct iattr *iattr);
+#include <linux/exportfs_block.h>
 
+#ifdef CONFIG_EXPORTFS_BLOCK_OPS
 int xfs_break_leased_layouts(struct inode *inode, uint *iolock,
 		bool *did_unlock);
 #else
@@ -18,4 +14,7 @@ xfs_break_leased_layouts(struct inode *inode, uint *iolock, bool *did_unlock)
 	return 0;
 }
 #endif /* CONFIG_EXPORTFS_BLOCK_OPS */
+
+extern const struct exportfs_block_ops xfs_export_block_ops;
+
 #endif /* _XFS_PNFS_H */
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index 0dc1bae9e1654..dfeadad435a60 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -6,9 +6,8 @@
 #include <linux/path.h>
 
 struct dentry;
-struct iattr;
+struct exportfs_block_ops;
 struct inode;
-struct iomap;
 struct super_block;
 struct vfsmount;
 
@@ -252,19 +251,13 @@ struct handle_to_path_ctx {
  * commit_metadata:
  *    @commit_metadata should commit metadata changes to stable storage.
  *
- * @get_uuid:
- *    Get a filesystem unique signature exposed to clients.
- *
- * @map_blocks:
- *    Map and, if necessary, allocate blocks for a layout.
- *
- * @commit_blocks:
- *    Commit blocks in a layout once the client is done with them.
- *
  * @flags:
  *    Allows the filesystem to communicate to nfsd that it may want to do things
  *    differently when dealing with it.
  *
+ * @block_ops:
+ *    Operations for layout grants to block on the underlying device.
+ *
  * Locking rules:
  *    get_parent is called with child->d_inode->i_rwsem down
  *    get_name is not (which is possibly inconsistent)
@@ -282,12 +275,6 @@ struct export_operations {
 	struct dentry * (*get_parent)(struct dentry *child);
 	int (*commit_metadata)(struct inode *inode);
 
-	int (*get_uuid)(struct super_block *sb, u8 *buf, u32 *len, u64 *offset);
-	int (*map_blocks)(struct inode *inode, loff_t offset,
-			  u64 len, struct iomap *iomap,
-			  bool write, u32 *device_generation);
-	int (*commit_blocks)(struct inode *inode, struct iomap *iomaps,
-			     int nr_iomaps, struct iattr *iattr);
 	int (*permission)(struct handle_to_path_ctx *ctx, unsigned int oflags);
 	struct file * (*open)(const struct path *path, unsigned int oflags);
 #define	EXPORT_OP_NOWCC			(0x1) /* don't collect v3 wcc data */
@@ -300,6 +287,10 @@ struct export_operations {
 #define EXPORT_OP_FLUSH_ON_CLOSE	(0x20) /* fs flushes file data on close */
 #define EXPORT_OP_NOLOCKS		(0x40) /* no file locking support */
 	unsigned long	flags;
+
+#ifdef CONFIG_EXPORTFS_BLOCK_OPS
+	const struct exportfs_block_ops *block_ops;
+#endif
 };
 
 /**
diff --git a/include/linux/exportfs_block.h b/include/linux/exportfs_block.h
new file mode 100644
index 0000000000000..1f52fea8e4dce
--- /dev/null
+++ b/include/linux/exportfs_block.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2014-2026 Christoph Hellwig.
+ *
+ * Support for exportfs-based layout grants for direct block device access.
+ */
+#ifndef LINUX_EXPORTFS_BLOCK_H
+#define LINUX_EXPORTFS_BLOCK_H 1
+
+#include <linux/types.h>
+
+struct iattr;
+struct inode;
+struct iomap;
+struct super_block;
+
+struct exportfs_block_ops {
+	/*
+	 * Get the in-band device unique signature exposed to clients.
+	 */
+	int (*get_uuid)(struct super_block *sb, u8 *buf, u32 *len, u64 *offset);
+
+	/*
+	 * Map blocks for direct block access.
+	 * If @write is %true, also allocate the blocks for the range if needed.
+	 */
+	int (*map_blocks)(struct inode *inode, loff_t offset, u64 len,
+			struct iomap *iomap, bool write,
+			u32 *device_generation);
+
+	/*
+	 * Commit blocks previously handed out by ->map_blocks and written to by
+	 * the client.
+	 */
+	int (*commit_blocks)(struct inode *inode, struct iomap *iomaps,
+			int nr_iomaps, struct iattr *iattr);
+};
+
+#endif /* LINUX_EXPORTFS_BLOCK_H */
-- 
2.53.0

[PATCH 6.18.y 4/5] exportfs,nfsd: rework checking for layout-based block device access support

[Sasha Levin]

From: Christoph Hellwig <hch@lst.de>

[ Upstream commit da9baa5470dcb077a7c9806f0925c60b530c470b ]

Currently NFSD hard codes checking support for block-style layouts.
Lift the checks into a file system-helper and provide a exportfs-level
helper to implement the typical checks.

This prepares for supporting block layout export of multiple devices
per file system.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260423181854.743150-5-cel@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Stable-dep-of: 5d28b2c920d9 ("nfsd: don't offer flexfiles layouts when NFSv3 isn't being served")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfsd/export.c               |  3 +-
 fs/nfsd/nfs4layouts.c          | 26 +++++------------
 fs/xfs/xfs_pnfs.c              | 13 +++++++++
 include/linux/exportfs_block.h | 52 +++++++++++++++++++++++++++++++++-
 4 files changed, 73 insertions(+), 21 deletions(-)

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index 2a1499f2ad196..e33843a937dd6 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -722,7 +722,8 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
 			goto out4;
 		err = 0;
 
-		nfsd4_setup_layout_type(&exp);
+		if (exp.ex_flags & NFSEXP_PNFS)
+			nfsd4_setup_layout_type(&exp);
 	}
 
 	expp = svc_export_lookup(&exp);
diff --git a/fs/nfsd/nfs4layouts.c b/fs/nfsd/nfs4layouts.c
index 6b6f55ae0472d..c2d435c99bf5e 100644
--- a/fs/nfsd/nfs4layouts.c
+++ b/fs/nfsd/nfs4layouts.c
@@ -2,7 +2,6 @@
 /*
  * Copyright (c) 2014 Christoph Hellwig.
  */
-#include <linux/blkdev.h>
 #include <linux/exportfs_block.h>
 #include <linux/kmod.h>
 #include <linux/file.h>
@@ -126,28 +125,17 @@ nfsd4_set_deviceid(struct nfsd4_deviceid *id, const struct svc_fh *fhp,
 
 void nfsd4_setup_layout_type(struct svc_export *exp)
 {
-#if defined(CONFIG_NFSD_BLOCKLAYOUT) || defined(CONFIG_NFSD_SCSILAYOUT)
 	struct super_block *sb = exp->ex_path.mnt->mnt_sb;
-	const struct exportfs_block_ops *bops = sb->s_export_op->block_ops;
-#endif
-
-	if (!(exp->ex_flags & NFSEXP_PNFS))
-		return;
+	expfs_block_layouts_t block_supported = exportfs_layouts_supported(sb);
 
-#ifdef CONFIG_NFSD_FLEXFILELAYOUT
-	exp->ex_layout_types |= 1 << LAYOUT_FLEX_FILES;
-#endif
-#ifdef CONFIG_NFSD_BLOCKLAYOUT
-	if (bops && bops->get_uuid && bops->map_blocks && bops->commit_blocks)
+	if (IS_ENABLED(CONFIG_NFSD_FLEXFILELAYOUT))
+		exp->ex_layout_types |= 1 << LAYOUT_FLEX_FILES;
+	if (IS_ENABLED(CONFIG_NFSD_BLOCKLAYOUT) &&
+	    (block_supported & EXPFS_BLOCK_IN_BAND_ID))
 		exp->ex_layout_types |= 1 << LAYOUT_BLOCK_VOLUME;
-#endif
-#ifdef CONFIG_NFSD_SCSILAYOUT
-	if (bops && bops->map_blocks && bops->commit_blocks &&
-	    sb->s_bdev &&
-	    sb->s_bdev->bd_disk->fops->pr_ops &&
-	    sb->s_bdev->bd_disk->fops->get_unique_id)
+	if (IS_ENABLED(CONFIG_NFSD_SCSILAYOUT) &&
+	    (block_supported & EXPFS_BLOCK_OUT_OF_BAND_ID))
 		exp->ex_layout_types |= 1 << LAYOUT_SCSI;
-#endif
 }
 
 void nfsd4_close_layout(struct nfs4_layout_stateid *ls)
diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c
index c685995b69d7e..1b0b739571612 100644
--- a/fs/xfs/xfs_pnfs.c
+++ b/fs/xfs/xfs_pnfs.c
@@ -13,6 +13,7 @@
 #include "xfs_bmap.h"
 #include "xfs_iomap.h"
 #include "xfs_pnfs.h"
+#include <linux/exportfs_block.h>
 
 /*
  * Ensure that we do not have any outstanding pNFS layouts that can be used by
@@ -45,6 +46,17 @@ xfs_break_leased_layouts(
 	return error;
 }
 
+static expfs_block_layouts_t
+xfs_fs_layouts_supported(
+	struct super_block	*sb)
+{
+	expfs_block_layouts_t	supported = EXPFS_BLOCK_IN_BAND_ID;
+
+	if (exportfs_bdev_supports_out_of_band_id(sb->s_bdev))
+		supported |= EXPFS_BLOCK_OUT_OF_BAND_ID;
+	return supported;
+}
+
 /*
  * Get a unique ID including its location so that the client can identify
  * the exported device.
@@ -334,6 +346,7 @@ xfs_fs_commit_blocks(
 }
 
 const struct exportfs_block_ops xfs_export_block_ops = {
+	.layouts_supported	= xfs_fs_layouts_supported,
 	.get_uuid		= xfs_fs_get_uuid,
 	.map_blocks		= xfs_fs_map_blocks,
 	.commit_blocks		= xfs_fs_commit_blocks,
diff --git a/include/linux/exportfs_block.h b/include/linux/exportfs_block.h
index 1f52fea8e4dce..92f990d190bba 100644
--- a/include/linux/exportfs_block.h
+++ b/include/linux/exportfs_block.h
@@ -7,14 +7,36 @@
 #ifndef LINUX_EXPORTFS_BLOCK_H
 #define LINUX_EXPORTFS_BLOCK_H 1
 
-#include <linux/types.h>
+#include <linux/blkdev.h>
+#include <linux/exportfs.h>
+#include <linux/fs.h>
 
 struct iattr;
 struct inode;
 struct iomap;
 struct super_block;
 
+/*
+ * There are the two types of block-style layout support:
+ *  - In-band implies a device identified by a unique cookie inside the actual
+ *    device address space checked by the ->get_uuid method as used by the pNFS
+ *    block layout.  This is a bit dangerous and deprecated.
+ *  - Out of band implies identification by out of band unique identifiers
+ *    specified by the storage protocol, which is much safer and used by the
+ *    pNFS SCSI/NVMe layouts.
+ */
+typedef unsigned int __bitwise expfs_block_layouts_t;
+#define EXPFS_BLOCK_FLAG(__bit) \
+	((__force expfs_block_layouts_t)(1u << __bit))
+#define EXPFS_BLOCK_IN_BAND_ID		EXPFS_BLOCK_FLAG(0)
+#define EXPFS_BLOCK_OUT_OF_BAND_ID	EXPFS_BLOCK_FLAG(1)
+
 struct exportfs_block_ops {
+	/*
+	 * Returns the EXPFS_BLOCK_* bitmap of supported layout types.
+	 */
+	expfs_block_layouts_t (*layouts_supported)(struct super_block *sb);
+
 	/*
 	 * Get the in-band device unique signature exposed to clients.
 	 */
@@ -36,4 +58,32 @@ struct exportfs_block_ops {
 			int nr_iomaps, struct iattr *iattr);
 };
 
+static inline bool
+exportfs_bdev_supports_out_of_band_id(struct block_device *bdev)
+{
+	return bdev->bd_disk->fops->pr_ops &&
+		bdev->bd_disk->fops->get_unique_id;
+}
+
+#ifdef CONFIG_EXPORTFS_BLOCK_OPS
+static inline expfs_block_layouts_t
+exportfs_layouts_supported(struct super_block *sb)
+{
+	const struct exportfs_block_ops *bops = sb->s_export_op->block_ops;
+
+	if (!bops ||
+	    !bops->layouts_supported ||
+	    WARN_ON_ONCE(!bops->map_blocks) ||
+	    WARN_ON_ONCE(!bops->commit_blocks))
+		return 0;
+	return bops->layouts_supported(sb);
+}
+#else
+static inline expfs_block_layouts_t
+exportfs_layouts_supported(struct super_block *sb)
+{
+	return 0;
+}
+#endif /* CONFIG_EXPORTFS_BLOCK_OPS */
+
 #endif /* LINUX_EXPORTFS_BLOCK_H */
-- 
2.53.0

[PATCH 6.18.y 5/5] nfsd: don't offer flexfiles layouts when NFSv3 isn't being served

[Sasha Levin]

From: Jeff Layton <jlayton@kernel.org>

[ Upstream commit 5d28b2c920d9d9d3c45b41769342ad785eb372a7 ]

The flexfiles layout driver hands out a deviceinfo that names this server
as an NFSv3 DS (flexfilelayout.c hardcodes da->version = 3). With v3
disabled, the client can't talk to the DS: it loops on v3 NULL calls that
the server answers with PROG_MISMATCH, and I/O hangs in D state.

Skip LAYOUT_FLEX_FILES in nfsd4_setup_layout_type() unless v3 is enabled.

Reported-by: Benji Wiebe <itsme@benjiwiebe.com>
Closes: https://lore.kernel.org/linux-nfs/c734eeb8-8486-4491-bb4d-b9656cbaffbe@app.fastmail.com/
Fixes: 9b9960a0ca47 ("nfsd: Add a super simple flex file server")
Cc: stable@vger.kernel.org
Assisted-by: LLM
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260904-pnfs-ff-v1-1-5f502cf25401@kernel.org
Signed-off-by: Chuck Lever <cel@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfsd/nfs4layouts.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4layouts.c b/fs/nfsd/nfs4layouts.c
index c2d435c99bf5e..8ec980c69bec5 100644
--- a/fs/nfsd/nfs4layouts.c
+++ b/fs/nfsd/nfs4layouts.c
@@ -125,10 +125,12 @@ nfsd4_set_deviceid(struct nfsd4_deviceid *id, const struct svc_fh *fhp,
 
 void nfsd4_setup_layout_type(struct svc_export *exp)
 {
+	struct nfsd_net *nn = net_generic(exp->cd->net, nfsd_net_id);
 	struct super_block *sb = exp->ex_path.mnt->mnt_sb;
 	expfs_block_layouts_t block_supported = exportfs_layouts_supported(sb);
 
-	if (IS_ENABLED(CONFIG_NFSD_FLEXFILELAYOUT))
+	if (IS_ENABLED(CONFIG_NFSD_FLEXFILELAYOUT) &&
+	    nfsd_vers(nn, 3, NFSD_TEST))
 		exp->ex_layout_types |= 1 << LAYOUT_FLEX_FILES;
 	if (IS_ENABLED(CONFIG_NFSD_BLOCKLAYOUT) &&
 	    (block_supported & EXPFS_BLOCK_IN_BAND_ID))
-- 
2.53.0