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
little tweak to be able to compile out the buffer_head based code path.
Otherwise this is just Kconfig and ifdef changes.
Signed-off-by: Christoph Hellwig <[email protected]>
---
block/fops.c | 71 +++++++++++++++++++++++++++++++-----
drivers/md/Kconfig | 1 +
fs/Kconfig | 4 ++
fs/Makefile | 2 +-
fs/adfs/Kconfig | 1 +
fs/affs/Kconfig | 1 +
fs/befs/Kconfig | 1 +
fs/bfs/Kconfig | 1 +
fs/efs/Kconfig | 1 +
fs/exfat/Kconfig | 1 +
fs/ext2/Kconfig | 1 +
fs/ext4/Kconfig | 1 +
fs/f2fs/Kconfig | 1 +
fs/fat/Kconfig | 1 +
fs/freevxfs/Kconfig | 1 +
fs/gfs2/Kconfig | 1 +
fs/hfs/Kconfig | 1 +
fs/hfsplus/Kconfig | 1 +
fs/hpfs/Kconfig | 1 +
fs/iomap/buffered-io.c | 12 ++++--
fs/isofs/Kconfig | 1 +
fs/jfs/Kconfig | 1 +
fs/minix/Kconfig | 1 +
fs/nilfs2/Kconfig | 1 +
fs/ntfs/Kconfig | 1 +
fs/ntfs3/Kconfig | 1 +
fs/ocfs2/Kconfig | 1 +
fs/omfs/Kconfig | 1 +
fs/qnx4/Kconfig | 1 +
fs/qnx6/Kconfig | 1 +
fs/reiserfs/Kconfig | 1 +
fs/sysv/Kconfig | 1 +
fs/udf/Kconfig | 1 +
fs/ufs/Kconfig | 1 +
include/linux/buffer_head.h | 32 ++++++++--------
include/trace/events/block.h | 2 +
mm/migrate.c | 4 +-
37 files changed, 125 insertions(+), 32 deletions(-)
diff --git a/block/fops.c b/block/fops.c
index 7910636f8df33b..524b8a828aad3d 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -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 +391,8 @@ 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;
+ if (IS_ENABLED(CONFIG_BUFFER_HEAD))
+ iomap->flags |= IOMAP_F_BUFFER_HEAD;
return 0;
}
@@ -408,6 +400,16 @@ 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 +455,55 @@ 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
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index b0a22e99bade37..9ee18013b1f2ab 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -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.
diff --git a/fs/Kconfig b/fs/Kconfig
index e99830c650336a..366d5d5be2784b 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -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
diff --git a/fs/Makefile b/fs/Makefile
index da21e7d0a1cf37..3cd6aa1d2ce387 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -18,7 +18,7 @@ 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/
diff --git a/fs/adfs/Kconfig b/fs/adfs/Kconfig
index 44738fed66251f..1b97058f0c4a92 100644
--- a/fs/adfs/Kconfig
+++ b/fs/adfs/Kconfig
@@ -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
diff --git a/fs/affs/Kconfig b/fs/affs/Kconfig
index 962b86374e1c15..1ae432d266c32f 100644
--- a/fs/affs/Kconfig
+++ b/fs/affs/Kconfig
@@ -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
diff --git a/fs/befs/Kconfig b/fs/befs/Kconfig
index 9550b6462b8147..5fcfc4024ffe6f 100644
--- a/fs/befs/Kconfig
+++ b/fs/befs/Kconfig
@@ -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
diff --git a/fs/bfs/Kconfig b/fs/bfs/Kconfig
index 3a757805b58568..8e7ef866b62a62 100644
--- a/fs/bfs/Kconfig
+++ b/fs/bfs/Kconfig
@@ -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
diff --git a/fs/efs/Kconfig b/fs/efs/Kconfig
index 2df1bac8b375b1..0833e533df9d53 100644
--- a/fs/efs/Kconfig
+++ b/fs/efs/Kconfig
@@ -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
diff --git a/fs/exfat/Kconfig b/fs/exfat/Kconfig
index 147edeb044691d..cbeca8e44d9b38 100644
--- a/fs/exfat/Kconfig
+++ b/fs/exfat/Kconfig
@@ -2,6 +2,7 @@
config EXFAT_FS
tristate "exFAT filesystem support"
+ select BUFFER_HEAD
select NLS
select LEGACY_DIRECT_IO
help
diff --git a/fs/ext2/Kconfig b/fs/ext2/Kconfig
index 77393fda99af09..74d98965902e16 100644
--- a/fs/ext2/Kconfig
+++ b/fs/ext2/Kconfig
@@ -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
diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
index 86699c8cab281c..e20d59221fc05b 100644
--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig
@@ -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
diff --git a/fs/f2fs/Kconfig b/fs/f2fs/Kconfig
index 03ef087537c7c4..68a1e23e1557c7 100644
--- a/fs/f2fs/Kconfig
+++ b/fs/f2fs/Kconfig
@@ -2,6 +2,7 @@
config F2FS_FS
tristate "F2FS filesystem support"
depends on BLOCK
+ select BUFFER_HEAD
select NLS
select CRYPTO
select CRYPTO_CRC32
diff --git a/fs/fat/Kconfig b/fs/fat/Kconfig
index afe83b4e717280..25fae1c83725bc 100644
--- a/fs/fat/Kconfig
+++ b/fs/fat/Kconfig
@@ -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
diff --git a/fs/freevxfs/Kconfig b/fs/freevxfs/Kconfig
index 0e2fc08f7de492..912107ebea6f40 100644
--- a/fs/freevxfs/Kconfig
+++ b/fs/freevxfs/Kconfig
@@ -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
diff --git a/fs/gfs2/Kconfig b/fs/gfs2/Kconfig
index 03c966840422ec..be7f87a8e11ae1 100644
--- a/fs/gfs2/Kconfig
+++ b/fs/gfs2/Kconfig
@@ -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
diff --git a/fs/hfs/Kconfig b/fs/hfs/Kconfig
index d985066006d588..5ea5cd8ecea9c0 100644
--- a/fs/hfs/Kconfig
+++ b/fs/hfs/Kconfig
@@ -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
diff --git a/fs/hfsplus/Kconfig b/fs/hfsplus/Kconfig
index 8034e7827a690b..8ce4a33a9ac788 100644
--- a/fs/hfsplus/Kconfig
+++ b/fs/hfsplus/Kconfig
@@ -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
diff --git a/fs/hpfs/Kconfig b/fs/hpfs/Kconfig
index ec975f4668775f..ac1e9318e65a4a 100644
--- a/fs/hpfs/Kconfig
+++ b/fs/hpfs/Kconfig
@@ -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
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 3d5042efda202a..336a9d4542c97a 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -42,6 +42,12 @@ static inline struct iomap_page *to_iomap_page(struct folio *folio)
return NULL;
}
+static inline bool iomap_use_buffer_heads(const struct iomap *iomap)
+{
+ return IS_ENABLED(CONFIG_BUFFER_HEAD) &&
+ (iomap->flags & IOMAP_F_BUFFER_HEAD);
+}
+
static struct bio_set iomap_ioend_bioset;
static struct iomap_page *
@@ -683,7 +689,7 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos,
if (srcmap->type == IOMAP_INLINE)
status = iomap_write_begin_inline(iter, folio);
- else if (srcmap->flags & IOMAP_F_BUFFER_HEAD)
+ else if (iomap_use_buffer_heads(srcmap))
status = __block_write_begin_int(folio, pos, len, NULL, srcmap);
else
status = __iomap_write_begin(iter, pos, len, folio);
@@ -753,7 +759,7 @@ static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
if (srcmap->type == IOMAP_INLINE) {
ret = iomap_write_end_inline(iter, folio, pos, copied);
- } else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) {
+ } else if (iomap_use_buffer_heads(srcmap)) {
ret = block_write_end(NULL, iter->inode->i_mapping, pos, len,
copied, &folio->page, NULL);
} else {
@@ -1256,7 +1262,7 @@ static loff_t iomap_folio_mkwrite_iter(struct iomap_iter *iter,
loff_t length = iomap_length(iter);
int ret;
- if (iter->iomap.flags & IOMAP_F_BUFFER_HEAD) {
+ if (iomap_use_buffer_heads(&iter->iomap)) {
ret = __block_write_begin_int(folio, iter->pos, length, NULL,
&iter->iomap);
if (ret)
diff --git a/fs/isofs/Kconfig b/fs/isofs/Kconfig
index 08ffd37b9bb8f6..51434f2a471b0f 100644
--- a/fs/isofs/Kconfig
+++ b/fs/isofs/Kconfig
@@ -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
diff --git a/fs/jfs/Kconfig b/fs/jfs/Kconfig
index 51e856f0e4b8d6..17488440eef1a9 100644
--- a/fs/jfs/Kconfig
+++ b/fs/jfs/Kconfig
@@ -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
diff --git a/fs/minix/Kconfig b/fs/minix/Kconfig
index de2003974ff0d0..90ddfad2a75e8f 100644
--- a/fs/minix/Kconfig
+++ b/fs/minix/Kconfig
@@ -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
diff --git a/fs/nilfs2/Kconfig b/fs/nilfs2/Kconfig
index 7d59567465e121..7dae168e346e30 100644
--- a/fs/nilfs2/Kconfig
+++ b/fs/nilfs2/Kconfig
@@ -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
diff --git a/fs/ntfs/Kconfig b/fs/ntfs/Kconfig
index f93e69a612833f..7b2509741735a9 100644
--- a/fs/ntfs/Kconfig
+++ b/fs/ntfs/Kconfig
@@ -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.
diff --git a/fs/ntfs3/Kconfig b/fs/ntfs3/Kconfig
index 96cc236f7f7bd3..cdfdf51e55d797 100644
--- a/fs/ntfs3/Kconfig
+++ b/fs/ntfs3/Kconfig
@@ -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
diff --git a/fs/ocfs2/Kconfig b/fs/ocfs2/Kconfig
index 304d12186ccd38..4a8288f7ee8697 100644
--- a/fs/ocfs2/Kconfig
+++ b/fs/ocfs2/Kconfig
@@ -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
diff --git a/fs/omfs/Kconfig b/fs/omfs/Kconfig
index 42b2ec35a05bfb..8470f6c3e64e6a 100644
--- a/fs/omfs/Kconfig
+++ b/fs/omfs/Kconfig
@@ -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
diff --git a/fs/qnx4/Kconfig b/fs/qnx4/Kconfig
index 45b5b98376c436..a2eb826e76c602 100644
--- a/fs/qnx4/Kconfig
+++ b/fs/qnx4/Kconfig
@@ -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).
diff --git a/fs/qnx6/Kconfig b/fs/qnx6/Kconfig
index 6a9d6bce158622..8e865d72204e75 100644
--- a/fs/qnx6/Kconfig
+++ b/fs/qnx6/Kconfig
@@ -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).
diff --git a/fs/reiserfs/Kconfig b/fs/reiserfs/Kconfig
index 4d22ecfe0fab65..0e6fe26458fede 100644
--- a/fs/reiserfs/Kconfig
+++ b/fs/reiserfs/Kconfig
@@ -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
diff --git a/fs/sysv/Kconfig b/fs/sysv/Kconfig
index b4e23e03fbeba3..67b3f90afbfd67 100644
--- a/fs/sysv/Kconfig
+++ b/fs/sysv/Kconfig
@@ -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
diff --git a/fs/udf/Kconfig b/fs/udf/Kconfig
index 82e8bfa2dfd989..8f7ce30d47fdce 100644
--- a/fs/udf/Kconfig
+++ b/fs/udf/Kconfig
@@ -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
diff --git a/fs/ufs/Kconfig b/fs/ufs/Kconfig
index 6d30adb6b890fc..9301e7ecd09210 100644
--- a/fs/ufs/Kconfig
+++ b/fs/ufs/Kconfig
@@ -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
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 0fcc16b7f02bb4..1ef3915cacfae2 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -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 */
@@ -196,7 +194,6 @@ void mark_buffer_write_io_error(struct buffer_head *bh);
void touch_buffer(struct buffer_head *bh);
void set_bh_page(struct buffer_head *bh,
struct page *page, unsigned long offset);
-bool try_to_free_buffers(struct folio *);
struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
bool retry);
void create_empty_buffers(struct page *, unsigned long,
@@ -207,10 +204,6 @@ 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);
void clean_bdev_aliases(struct block_device *bdev, sector_t block,
sector_t len);
static inline void clean_bdev_bh_alias(struct buffer_head *bh)
@@ -230,9 +223,6 @@ 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);
@@ -248,8 +238,6 @@ 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.
@@ -294,8 +282,6 @@ extern int buffer_migrate_folio_norefs(struct address_space *,
#define buffer_migrate_folio_norefs NULL
#endif
-void buffer_init(void);
-
/*
* inline definitions
*/
@@ -455,7 +441,20 @@ __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; }
@@ -463,9 +462,10 @@ 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 */
diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index 7f4dfbdf12a6f1..a0503f387104a1 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -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
diff --git a/mm/migrate.c b/mm/migrate.c
index db3f154446af4e..9f9a81d43fc8f2 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -692,7 +692,7 @@ 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)
@@ -850,7 +850,7 @@ 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)
--
2.39.2
>> No but the only place to add that would be in the block cache. Adding
>> that alone to the block cache doesn't fix the issue. The below patch
>> however does get us by.
>
> That's "working around the error", not fixing it ... probably the same
> root cause as your other errors; at least I'm not diving into them until
> the obvious one is fixed.
>
>> >From my readings it does't seem like readahead_folio() should always
>> return non-NULL, and also I couldn't easily verify the math is right.
>
> readahead_folio() always returns non-NULL. That's guaranteed by how
> page_cache_ra_unbounded() and page_cache_ra_order() work. It allocates
> folios, until it can't (already-present folio, ENOMEM, EOF, max batch
> size) and then calls the filesystem to make those folios uptodate,
> telling it how many folios it put in the page cache, where they start.
>
> Hm. The fact that it's coming from page_cache_ra_unbounded() makes
> me wonder if you updated this line:
>
> folio = filemap_alloc_folio(gfp_mask, 0);
>
> without updating this line:
>
> ractl->_nr_pages++;
>
> This is actually number of pages, not number of folios, so needs to be
> ractl->_nr_pages += 1 << order;
>
I already had a patch which did the following:
ractl->_nr_pages += folio_nr_pages(folio);
but the variable `i` in the loop was not updated properly (assumption of zero order folio). This now
fixes the crash:
@@ -210,7 +210,7 @@ void page_cache_ra_unbounded(struct readahead_control *ractl,
unsigned long index = readahead_index(ractl);
gfp_t gfp_mask = readahead_gfp_mask(mapping);
unsigned long i;
-
+ int order = 0;
/*
* Partway through the readahead operation, we will have added
* locked pages to the page cache, but will not yet have submitted
@@ -223,6 +223,9 @@ void page_cache_ra_unbounded(struct readahead_control *ractl,
*/
unsigned int nofs = memalloc_nofs_save();
+ if (mapping->host->i_blkbits > PAGE_SHIFT)
+ order = mapping->host->i_blkbits - PAGE_SHIFT;
+
filemap_invalidate_lock_shared(mapping);
/*
* Preallocate as many pages as we will need.
@@ -245,7 +248,7 @@ void page_cache_ra_unbounded(struct readahead_control *ractl,
continue;
}
- folio = filemap_alloc_folio(gfp_mask, 0);
+ folio = filemap_alloc_folio(gfp_mask, order);
if (!folio)
break;
if (filemap_add_folio(mapping, folio, index + i,
@@ -259,7 +262,8 @@ void page_cache_ra_unbounded(struct readahead_control *ractl,
if (i == nr_to_read - lookahead_size)
folio_set_readahead(folio);
ractl->_workingset |= folio_test_workingset(folio);
- ractl->_nr_pages++;
+ ractl->_nr_pages += folio_nr_pages(folio);
+ i += folio_nr_pages(folio) - 1;
}
> various other parts of page_cache_ra_unbounded() need to be examined
> carefully for assumptions of order-0; it's never been used for that
> before. all the large folio work has concentrated on
> page_cache_ra_order()
As you have noted here, this needs to be examined more carefully. Even though the patches fix the
crash, fio with verify option fails (i.e write and read are not giving the same output).
I think it is better to send an RFC patch series on top of Christoph's work with optional
BUFFER_HEAD to iron out some core issues/bugs.