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fs: add CONFIG_BUFFER_HEAD

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Add a new config option that controls building the buffer_head code, and
select it from all file systems and stacking drivers that need it.

For the block device nodes and alternative iomap based buffered I/O path
is provided when buffer_head support is not enabled, and iomap needs a
a small tweak to define the IOMAP_F_BUFFER_HEAD flag to 0 to not call
into the buffer_head code when it doesn't exist.

Otherwise this is just Kconfig and ifdef changes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20230801172201.1923299-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2023-08-01 19:22:01 +02:00 committed by Jens Axboe
parent 487c607df7
commit 925c86a19b
37 changed files with 119 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

70
block/fops.c
View File

@ -24,15 +24,6 @@ static inline struct inode *bdev_file_inode(struct file *file)
return file->f_mapping->host;
}
static int blkdev_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh, int create)
{
bh->b_bdev = I_BDEV(inode);
bh->b_blocknr = iblock;
set_buffer_mapped(bh);
return 0;
}
static blk_opf_t dio_bio_write_op(struct kiocb *iocb)
{
blk_opf_t opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
@ -400,7 +391,7 @@ static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
iomap->type = IOMAP_MAPPED;
iomap->addr = iomap->offset;
iomap->length = isize - iomap->offset;
iomap->flags |= IOMAP_F_BUFFER_HEAD;
iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */
return 0;
}
@ -408,6 +399,16 @@ static const struct iomap_ops blkdev_iomap_ops = {
.iomap_begin = blkdev_iomap_begin,
};
#ifdef CONFIG_BUFFER_HEAD
static int blkdev_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh, int create)
{
bh->b_bdev = I_BDEV(inode);
bh->b_blocknr = iblock;
set_buffer_mapped(bh);
return 0;
}
static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
{
return block_write_full_page(page, blkdev_get_block, wbc);
@ -453,6 +454,55 @@ const struct address_space_operations def_blk_aops = {
.migrate_folio = buffer_migrate_folio_norefs,
.is_dirty_writeback = buffer_check_dirty_writeback,
};
#else /* CONFIG_BUFFER_HEAD */
static int blkdev_read_folio(struct file *file, struct folio *folio)
{
return iomap_read_folio(folio, &blkdev_iomap_ops);
}
static void blkdev_readahead(struct readahead_control *rac)
{
iomap_readahead(rac, &blkdev_iomap_ops);
}
static int blkdev_map_blocks(struct iomap_writepage_ctx *wpc,
struct inode *inode, loff_t offset)
{
loff_t isize = i_size_read(inode);
if (WARN_ON_ONCE(offset >= isize))
return -EIO;
if (offset >= wpc->iomap.offset &&
offset < wpc->iomap.offset + wpc->iomap.length)
return 0;
return blkdev_iomap_begin(inode, offset, isize - offset,
IOMAP_WRITE, &wpc->iomap, NULL);
}
static const struct iomap_writeback_ops blkdev_writeback_ops = {
.map_blocks = blkdev_map_blocks,
};
static int blkdev_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct iomap_writepage_ctx wpc = { };
return iomap_writepages(mapping, wbc, &wpc, &blkdev_writeback_ops);
}
const struct address_space_operations def_blk_aops = {
.dirty_folio = filemap_dirty_folio,
.release_folio = iomap_release_folio,
.invalidate_folio = iomap_invalidate_folio,
.read_folio = blkdev_read_folio,
.readahead = blkdev_readahead,
.writepages = blkdev_writepages,
.is_partially_uptodate = iomap_is_partially_uptodate,
.error_remove_page = generic_error_remove_page,
.migrate_folio = filemap_migrate_folio,
};
#endif /* CONFIG_BUFFER_HEAD */
/*
* for a block special file file_inode(file)->i_size is zero

1
drivers/md/Kconfig
View File

@ -15,6 +15,7 @@ if MD
config BLK_DEV_MD
tristate "RAID support"
select BLOCK_HOLDER_DEPRECATED if SYSFS
select BUFFER_HEAD
# BLOCK_LEGACY_AUTOLOAD requirement should be removed
# after relevant mdadm enhancements - to make "names=yes"
# the default - are widely available.

4
fs/Kconfig
View File

@ -18,8 +18,12 @@ config VALIDATE_FS_PARSER
config FS_IOMAP
bool
config BUFFER_HEAD
bool
# old blockdev_direct_IO implementation. Use iomap for new code instead
config LEGACY_DIRECT_IO
depends on BUFFER_HEAD
bool
if BLOCK

2
fs/Makefile
View File

@ -17,7 +17,7 @@ obj-y := open.o read_write.o file_table.o super.o \
fs_types.o fs_context.o fs_parser.o fsopen.o init.o \
kernel_read_file.o mnt_idmapping.o remap_range.o
obj-$(CONFIG_BLOCK) += buffer.o mpage.o
obj-$(CONFIG_BUFFER_HEAD) += buffer.o mpage.o
obj-$(CONFIG_PROC_FS) += proc_namespace.o
obj-$(CONFIG_LEGACY_DIRECT_IO) += direct-io.o
obj-y += notify/

1
fs/adfs/Kconfig
View File

@ -2,6 +2,7 @@
config ADFS_FS
tristate "ADFS file system support"
depends on BLOCK
select BUFFER_HEAD
help
The Acorn Disc Filing System is the standard file system of the
RiscOS operating system which runs on Acorn's ARM-based Risc PC

1
fs/affs/Kconfig
View File

@ -2,6 +2,7 @@
config AFFS_FS
tristate "Amiga FFS file system support"
depends on BLOCK
select BUFFER_HEAD
select LEGACY_DIRECT_IO
help
The Fast File System (FFS) is the common file system used on hard

1
fs/befs/Kconfig
View File

@ -2,6 +2,7 @@
config BEFS_FS
tristate "BeOS file system (BeFS) support (read only)"
depends on BLOCK
select BUFFER_HEAD
select NLS
help
The BeOS File System (BeFS) is the native file system of Be, Inc's

1
fs/bfs/Kconfig
View File

@ -2,6 +2,7 @@
config BFS_FS
tristate "BFS file system support"
depends on BLOCK
select BUFFER_HEAD
help
Boot File System (BFS) is a file system used under SCO UnixWare to
allow the bootloader access to the kernel image and other important

1
fs/efs/Kconfig
View File

@ -2,6 +2,7 @@
config EFS_FS
tristate "EFS file system support (read only)"
depends on BLOCK
select BUFFER_HEAD
help
EFS is an older file system used for non-ISO9660 CD-ROMs and hard
disk partitions by SGI's IRIX operating system (IRIX 6.0 and newer

1
fs/exfat/Kconfig
View File

@ -2,6 +2,7 @@
config EXFAT_FS
tristate "exFAT filesystem support"
select BUFFER_HEAD
select NLS
select LEGACY_DIRECT_IO
help

1
fs/ext2/Kconfig
View File

@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
config EXT2_FS
tristate "Second extended fs support"
select BUFFER_HEAD
select FS_IOMAP
select LEGACY_DIRECT_IO
help

1
fs/ext4/Kconfig
View File

@ -28,6 +28,7 @@ config EXT3_FS_SECURITY
config EXT4_FS
tristate "The Extended 4 (ext4) filesystem"
select BUFFER_HEAD
select JBD2
select CRC16
select CRYPTO

1
fs/f2fs/Kconfig
View File

@ -2,6 +2,7 @@
config F2FS_FS
tristate "F2FS filesystem support"
depends on BLOCK
select BUFFER_HEAD
select NLS
select CRYPTO
select CRYPTO_CRC32

1
fs/fat/Kconfig
View File

@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
config FAT_FS
tristate
select BUFFER_HEAD
select NLS
select LEGACY_DIRECT_IO
help

1
fs/freevxfs/Kconfig
View File

@ -2,6 +2,7 @@
config VXFS_FS
tristate "FreeVxFS file system support (VERITAS VxFS(TM) compatible)"
depends on BLOCK
select BUFFER_HEAD
help
FreeVxFS is a file system driver that support the VERITAS VxFS(TM)
file system format. VERITAS VxFS(TM) is the standard file system

1
fs/gfs2/Kconfig
View File

@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
config GFS2_FS
tristate "GFS2 file system support"
select BUFFER_HEAD
select FS_POSIX_ACL
select CRC32
select LIBCRC32C

1
fs/hfs/Kconfig
View File

@ -2,6 +2,7 @@
config HFS_FS
tristate "Apple Macintosh file system support"
depends on BLOCK
select BUFFER_HEAD
select NLS
select LEGACY_DIRECT_IO
help

1
fs/hfsplus/Kconfig
View File

@ -2,6 +2,7 @@
config HFSPLUS_FS
tristate "Apple Extended HFS file system support"
depends on BLOCK
select BUFFER_HEAD
select NLS
select NLS_UTF8
select LEGACY_DIRECT_IO

1
fs/hpfs/Kconfig
View File

@ -2,6 +2,7 @@
config HPFS_FS
tristate "OS/2 HPFS file system support"
depends on BLOCK
select BUFFER_HEAD
select FS_IOMAP
help
OS/2 is IBM's operating system for PC's, the same as Warp, and HPFS

1
fs/isofs/Kconfig
View File

@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
config ISO9660_FS
tristate "ISO 9660 CDROM file system support"
select BUFFER_HEAD
help
This is the standard file system used on CD-ROMs. It was previously
known as "High Sierra File System" and is called "hsfs" on other

1
fs/jfs/Kconfig
View File

@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
config JFS_FS
tristate "JFS filesystem support"
select BUFFER_HEAD
select NLS
select CRC32
select LEGACY_DIRECT_IO

1
fs/minix/Kconfig
View File

@ -2,6 +2,7 @@
config MINIX_FS
tristate "Minix file system support"
depends on BLOCK
select BUFFER_HEAD
help
Minix is a simple operating system used in many classes about OS's.
The minix file system (method to organize files on a hard disk

1
fs/nilfs2/Kconfig
View File

@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
config NILFS2_FS
tristate "NILFS2 file system support"
select BUFFER_HEAD
select CRC32
select LEGACY_DIRECT_IO
help

1
fs/ntfs/Kconfig
View File

@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
config NTFS_FS
tristate "NTFS file system support"
select BUFFER_HEAD
select NLS
help
NTFS is the file system of Microsoft Windows NT, 2000, XP and 2003.

1
fs/ntfs3/Kconfig
View File

@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
config NTFS3_FS
tristate "NTFS Read-Write file system support"
select BUFFER_HEAD
select NLS
select LEGACY_DIRECT_IO
help

1
fs/ocfs2/Kconfig
View File

@ -2,6 +2,7 @@
config OCFS2_FS
tristate "OCFS2 file system support"
depends on INET && SYSFS && CONFIGFS_FS
select BUFFER_HEAD
select JBD2
select CRC32
select QUOTA

1
fs/omfs/Kconfig
View File

@ -2,6 +2,7 @@
config OMFS_FS
tristate "SonicBlue Optimized MPEG File System support"
depends on BLOCK
select BUFFER_HEAD
select CRC_ITU_T
help
This is the proprietary file system used by the Rio Karma music

1
fs/qnx4/Kconfig
View File

@ -2,6 +2,7 @@
config QNX4FS_FS
tristate "QNX4 file system support (read only)"
depends on BLOCK
select BUFFER_HEAD
help
This is the file system used by the real-time operating systems
QNX 4 and QNX 6 (the latter is also called QNX RTP).

1
fs/qnx6/Kconfig
View File

@ -2,6 +2,7 @@
config QNX6FS_FS
tristate "QNX6 file system support (read only)"
depends on BLOCK && CRC32
select BUFFER_HEAD
help
This is the file system used by the real-time operating systems
QNX 6 (also called QNX RTP).

1
fs/reiserfs/Kconfig
View File

@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
config REISERFS_FS
tristate "Reiserfs support (deprecated)"
select BUFFER_HEAD
select CRC32
select LEGACY_DIRECT_IO
help

1
fs/sysv/Kconfig
View File

@ -2,6 +2,7 @@
config SYSV_FS
tristate "System V/Xenix/V7/Coherent file system support"
depends on BLOCK
select BUFFER_HEAD
help
SCO, Xenix and Coherent are commercial Unix systems for Intel
machines, and Version 7 was used on the DEC PDP-11. Saying Y

1
fs/udf/Kconfig
View File

@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
config UDF_FS
tristate "UDF file system support"
select BUFFER_HEAD
select CRC_ITU_T
select NLS
select LEGACY_DIRECT_IO

1
fs/ufs/Kconfig
View File

@ -2,6 +2,7 @@
config UFS_FS
tristate "UFS file system support (read only)"
depends on BLOCK
select BUFFER_HEAD
help
BSD and derivate versions of Unix (such as SunOS, FreeBSD, NetBSD,
OpenBSD and NeXTstep) use a file system called UFS. Some System V

32
include/linux/buffer_head.h
View File

@ -16,8 +16,6 @@
#include <linux/wait.h>
#include <linux/atomic.h>
#ifdef CONFIG_BLOCK
enum bh_state_bits {
BH_Uptodate, /* Contains valid data */
BH_Dirty, /* Is dirty */
@ -198,7 +196,6 @@ void set_bh_page(struct buffer_head *bh,
struct page *page, unsigned long offset);
void folio_set_bh(struct buffer_head *bh, struct folio *folio,
unsigned long offset);
bool try_to_free_buffers(struct folio *);
struct buffer_head *folio_alloc_buffers(struct folio *folio, unsigned long size,
bool retry);
struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
@ -213,10 +210,6 @@ void end_buffer_async_write(struct buffer_head *bh, int uptodate);
/* Things to do with buffers at mapping->private_list */
void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode);
int inode_has_buffers(struct inode *);
void invalidate_inode_buffers(struct inode *);
int remove_inode_buffers(struct inode *inode);
int sync_mapping_buffers(struct address_space *mapping);
int generic_buffers_fsync_noflush(struct file *file, loff_t start, loff_t end,
bool datasync);
int generic_buffers_fsync(struct file *file, loff_t start, loff_t end,
@ -240,9 +233,6 @@ void __bforget(struct buffer_head *);
void __breadahead(struct block_device *, sector_t block, unsigned int size);
struct buffer_head *__bread_gfp(struct block_device *,
sector_t block, unsigned size, gfp_t gfp);
void invalidate_bh_lrus(void);
void invalidate_bh_lrus_cpu(void);
bool has_bh_in_lru(int cpu, void *dummy);
struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
void free_buffer_head(struct buffer_head * bh);
void unlock_buffer(struct buffer_head *bh);
@ -258,8 +248,6 @@ int __bh_read(struct buffer_head *bh, blk_opf_t op_flags, bool wait);
void __bh_read_batch(int nr, struct buffer_head *bhs[],
blk_opf_t op_flags, bool force_lock);
extern int buffer_heads_over_limit;
/*
* Generic address_space_operations implementations for buffer_head-backed
* address_spaces.
@ -304,8 +292,6 @@ extern int buffer_migrate_folio_norefs(struct address_space *,
#define buffer_migrate_folio_norefs NULL
#endif
void buffer_init(void);
/*
* inline definitions
*/
@ -465,7 +451,20 @@ __bread(struct block_device *bdev, sector_t block, unsigned size)
bool block_dirty_folio(struct address_space *mapping, struct folio *folio);
#else /* CONFIG_BLOCK */
#ifdef CONFIG_BUFFER_HEAD
void buffer_init(void);
bool try_to_free_buffers(struct folio *folio);
int inode_has_buffers(struct inode *inode);
void invalidate_inode_buffers(struct inode *inode);
int remove_inode_buffers(struct inode *inode);
int sync_mapping_buffers(struct address_space *mapping);
void invalidate_bh_lrus(void);
void invalidate_bh_lrus_cpu(void);
bool has_bh_in_lru(int cpu, void *dummy);
extern int buffer_heads_over_limit;
#else /* CONFIG_BUFFER_HEAD */
static inline void buffer_init(void) {}
static inline bool try_to_free_buffers(struct folio *folio) { return true; }
@ -473,9 +472,10 @@ static inline int inode_has_buffers(struct inode *inode) { return 0; }
static inline void invalidate_inode_buffers(struct inode *inode) {}
static inline int remove_inode_buffers(struct inode *inode) { return 1; }
static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; }
static inline void invalidate_bh_lrus(void) {}
static inline void invalidate_bh_lrus_cpu(void) {}
static inline bool has_bh_in_lru(int cpu, void *dummy) { return false; }
#define buffer_heads_over_limit 0
#endif /* CONFIG_BLOCK */
#endif /* CONFIG_BUFFER_HEAD */
#endif /* _LINUX_BUFFER_HEAD_H */

4
include/linux/iomap.h
View File

@ -58,7 +58,11 @@ struct vm_fault;
#define IOMAP_F_DIRTY (1U << 1)
#define IOMAP_F_SHARED (1U << 2)
#define IOMAP_F_MERGED (1U << 3)
#ifdef CONFIG_BUFFER_HEAD
#define IOMAP_F_BUFFER_HEAD (1U << 4)
#else
#define IOMAP_F_BUFFER_HEAD 0
#endif /* CONFIG_BUFFER_HEAD */
#define IOMAP_F_XATTR (1U << 5)
/*

2
include/trace/events/block.h
View File

@ -12,6 +12,7 @@
#define RWBS_LEN 8
#ifdef CONFIG_BUFFER_HEAD
DECLARE_EVENT_CLASS(block_buffer,
TP_PROTO(struct buffer_head *bh),
@ -61,6 +62,7 @@ DEFINE_EVENT(block_buffer, block_dirty_buffer,
TP_ARGS(bh)
);
#endif /* CONFIG_BUFFER_HEAD */
/**
* block_rq_requeue - place block IO request back on a queue

4
mm/migrate.c
View File

@ -684,7 +684,7 @@ int migrate_folio(struct address_space *mapping, struct folio *dst,
}
EXPORT_SYMBOL(migrate_folio);
#ifdef CONFIG_BLOCK
#ifdef CONFIG_BUFFER_HEAD
/* Returns true if all buffers are successfully locked */
static bool buffer_migrate_lock_buffers(struct buffer_head *head,
enum migrate_mode mode)
@ -837,7 +837,7 @@ int buffer_migrate_folio_norefs(struct address_space *mapping,
return __buffer_migrate_folio(mapping, dst, src, mode, true);
}
EXPORT_SYMBOL_GPL(buffer_migrate_folio_norefs);
#endif
#endif /* CONFIG_BUFFER_HEAD */
int filemap_migrate_folio(struct address_space *mapping,
struct folio *dst, struct folio *src, enum migrate_mode mode)