mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-08-30 14:33:24 -04:00
Code Issues Packages Projects Releases Wiki Activity

ext4: remove useless ext4_iomap_overwrite_ops

Browse Source 
ext4_iomap_overwrite_ops was introduced in commit 8cd115bdda ("ext4:
Optimize ext4 DIO overwrites"), which can optimize pure overwrite
performance by dropping the IOMAP_WRITE flag to only query the mapped
mapping information. This avoids starting a new journal handle, thereby
improving speed. Later, commit 9faac62d40 ("ext4: optimize file
overwrites") also optimized similar scenarios, but it performs the check
later, examining the mappings status only when the actual block mapping
is needed. Thus, it can handle the previous commit scenario. That means
in the case of an overwrite scenario, the condition
"offset + length <= i_size_read(inode)" in the write path must always be
true.

Therefore, it is acceptable to remove the ext4_iomap_overwrite_ops,
which will also clarify the write and read paths of ext4_iomap_begin.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://patch.msgid.link/20260105014522.1937690-5-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Zhang Yi
2026-01-05 09:45:19 +08:00
committed by Theodore Ts'o
parent 5d87c7fca2
commit 012924f0ee
3 changed files with 1 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
fs/ext4/ext4.h
View File

@@ -3911,7 +3911,6 @@ static inline void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
}
extern const struct iomap_ops ext4_iomap_ops;
extern const struct iomap_ops ext4_iomap_overwrite_ops;
extern const struct iomap_ops ext4_iomap_report_ops;
static inline int ext4_buffer_uptodate(struct buffer_head *bh)

5
fs/ext4/file.c
View File

@@ -506,7 +506,6 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
struct inode *inode = file_inode(iocb->ki_filp);
loff_t offset = iocb->ki_pos;
size_t count = iov_iter_count(from);
const struct iomap_ops *iomap_ops = &ext4_iomap_ops;
bool extend = false, unwritten = false;
bool ilock_shared = true;
int dio_flags = 0;
@@ -573,9 +572,7 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
goto out;
}
if (ilock_shared && !unwritten)
iomap_ops = &ext4_iomap_overwrite_ops;
ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
ret = iomap_dio_rw(iocb, from, &ext4_iomap_ops, &ext4_dio_write_ops,
dio_flags, NULL, 0);
if (ret == -ENOTBLK)
ret = 0;

24
fs/ext4/inode.c
View File

@@ -3829,10 +3829,6 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
}
ret = ext4_iomap_alloc(inode, &map, flags);
} else {
/*
* This can be called for overwrites path from
* ext4_iomap_overwrite_begin().
*/
ret = ext4_map_blocks(NULL, inode, &map, 0);
}
@@ -3861,30 +3857,10 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
return 0;
}
static int ext4_iomap_overwrite_begin(struct inode *inode, loff_t offset,
loff_t length, unsigned flags, struct iomap *iomap,
struct iomap *srcmap)
{
int ret;
/*
* Even for writes we don't need to allocate blocks, so just pretend
* we are reading to save overhead of starting a transaction.
*/
flags &= ~IOMAP_WRITE;
ret = ext4_iomap_begin(inode, offset, length, flags, iomap, srcmap);
WARN_ON_ONCE(!ret && iomap->type != IOMAP_MAPPED);
return ret;
}
const struct iomap_ops ext4_iomap_ops = {
.iomap_begin = ext4_iomap_begin,
};
const struct iomap_ops ext4_iomap_overwrite_ops = {
.iomap_begin = ext4_iomap_overwrite_begin,
};
static int ext4_iomap_begin_report(struct inode *inode, loff_t offset,
loff_t length, unsigned int flags,
struct iomap *iomap, struct iomap *srcmap)