* [PATCH 6.18.y 3/5] exportfs: split out the ops for layout-based block device access
2026-11-06 1:53 ` [PATCH 6.18.y 1/5] NFSD/blocklayout: Extract extent mapping from proc_layoutget Sasha Levin
2026-11-06 1:53 ` [PATCH 6.18.y 2/5] exportfs: Complete kernel-doc for struct export_operations Sasha Levin
@ 2026-11-06 1:53 ` Sasha Levin
2026-11-06 1:53 ` [PATCH 6.18.y 4/5] exportfs,nfsd: rework checking for layout-based block device access support Sasha Levin
2026-11-06 1:53 ` [PATCH 6.18.y 5/5] nfsd: don't offer flexfiles layouts when NFSv3 isn't being served Sasha Levin
3 siblings, 0 replies; 6+ messages in thread
From: Sasha Levin @ 2026-11-06 1:53 UTC (permalink / raw)
To: stable
Cc: Christoph Hellwig, Jeff Layton, Chuck Lever, Christian Brauner,
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
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 6.18.y 4/5] exportfs,nfsd: rework checking for layout-based block device access support
2026-11-06 1:53 ` [PATCH 6.18.y 1/5] NFSD/blocklayout: Extract extent mapping from proc_layoutget Sasha Levin
2026-11-06 1:53 ` [PATCH 6.18.y 2/5] exportfs: Complete kernel-doc for struct export_operations Sasha Levin
2026-11-06 1:53 ` [PATCH 6.18.y 3/5] exportfs: split out the ops for layout-based block device access Sasha Levin
@ 2026-11-06 1:53 ` Sasha Levin
2026-11-06 1:53 ` [PATCH 6.18.y 5/5] nfsd: don't offer flexfiles layouts when NFSv3 isn't being served Sasha Levin
3 siblings, 0 replies; 6+ messages in thread
From: Sasha Levin @ 2026-11-06 1:53 UTC (permalink / raw)
To: stable
Cc: Christoph Hellwig, Jeff Layton, Chuck Lever, Christian Brauner,
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
^ permalink raw reply related [flat|nested] 6+ messages in thread