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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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Christoph Hellwig
da9baa5470
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>
89 lines
2.5 KiB
C
89 lines
2.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (c) 2014-2026 Christoph Hellwig.
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*
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* Support for exportfs-based layout grants for direct block device access.
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*/
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#ifndef LINUX_EXPORTFS_BLOCK_H
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#define LINUX_EXPORTFS_BLOCK_H 1
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#include <linux/blkdev.h>
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#include <linux/exportfs.h>
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#include <linux/fs.h>
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struct inode;
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struct iomap;
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struct super_block;
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/*
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* There are the two types of block-style layout support:
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* - In-band implies a device identified by a unique cookie inside the actual
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* device address space checked by the ->get_uuid method as used by the pNFS
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* block layout. This is a bit dangerous and deprecated.
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* - Out of band implies identification by out of band unique identifiers
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* specified by the storage protocol, which is much safer and used by the
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* pNFS SCSI/NVMe layouts.
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*/
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typedef unsigned int __bitwise expfs_block_layouts_t;
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#define EXPFS_BLOCK_FLAG(__bit) \
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((__force expfs_block_layouts_t)(1u << __bit))
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#define EXPFS_BLOCK_IN_BAND_ID EXPFS_BLOCK_FLAG(0)
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#define EXPFS_BLOCK_OUT_OF_BAND_ID EXPFS_BLOCK_FLAG(1)
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struct exportfs_block_ops {
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/*
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* Returns the EXPFS_BLOCK_* bitmap of supported layout types.
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*/
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expfs_block_layouts_t (*layouts_supported)(struct super_block *sb);
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/*
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* Get the in-band device unique signature exposed to clients.
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*/
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int (*get_uuid)(struct super_block *sb, u8 *buf, u32 *len, u64 *offset);
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/*
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* Map blocks for direct block access.
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* If @write is %true, also allocate the blocks for the range if needed.
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*/
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int (*map_blocks)(struct inode *inode, loff_t offset, u64 len,
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struct iomap *iomap, bool write,
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u32 *device_generation);
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/*
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* Commit blocks previously handed out by ->map_blocks and written to by
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* the client.
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*/
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int (*commit_blocks)(struct inode *inode, struct iomap *iomaps,
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int nr_iomaps, loff_t new_size);
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};
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static inline bool
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exportfs_bdev_supports_out_of_band_id(struct block_device *bdev)
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{
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return bdev->bd_disk->fops->pr_ops &&
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bdev->bd_disk->fops->get_unique_id;
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}
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#ifdef CONFIG_EXPORTFS_BLOCK_OPS
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static inline expfs_block_layouts_t
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exportfs_layouts_supported(struct super_block *sb)
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{
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const struct exportfs_block_ops *bops = sb->s_export_op->block_ops;
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if (!bops ||
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!bops->layouts_supported ||
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WARN_ON_ONCE(!bops->map_blocks) ||
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WARN_ON_ONCE(!bops->commit_blocks))
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return 0;
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return bops->layouts_supported(sb);
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}
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#else
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static inline expfs_block_layouts_t
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exportfs_layouts_supported(struct super_block *sb)
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{
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return 0;
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}
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#endif /* CONFIG_EXPORTFS_BLOCK_OPS */
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#endif /* LINUX_EXPORTFS_BLOCK_H */
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