未验证 提交 b83bcc7b 编写于 作者: O openeuler-ci-bot 提交者: Gitee

!919 Revert "ext4: dio take shared inode lock when overwriting preallocated blocks"

Merge Pull Request from: @ci-robot 
 
PR sync from:  Baokun Li <libaokun1@huawei.com>
 https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/thread/TMNW5KJPDRL5VBVVST3Y343U5DVD4WWG/ 
 
 
Link:https://gitee.com/openeuler/kernel/pulls/919 

Reviewed-by: zhangyi (F) <yi.zhang@huawei.com> 
Reviewed-by: Jialin Zhang <zhangjialin11@huawei.com> 
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> 
......@@ -190,9 +190,8 @@ ext4_extending_io(struct inode *inode, loff_t offset, size_t len)
return false;
}
/* Is IO overwriting allocated or initialized blocks? */
static bool ext4_overwrite_io(struct inode *inode,
loff_t pos, loff_t len, bool *unwritten)
/* Is IO overwriting allocated and initialized blocks? */
static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
{
struct ext4_map_blocks map;
unsigned int blkbits = inode->i_blkbits;
......@@ -206,15 +205,12 @@ static bool ext4_overwrite_io(struct inode *inode,
blklen = map.m_len;
err = ext4_map_blocks(NULL, inode, &map, 0);
if (err != blklen)
return false;
/*
* 'err==len' means that all of the blocks have been preallocated,
* regardless of whether they have been initialized or not. We need to
* check m_flags to distinguish the unwritten extents.
* regardless of whether they have been initialized or not. To exclude
* unwritten extents, we need to check m_flags.
*/
*unwritten = !(map.m_flags & EXT4_MAP_MAPPED);
return true;
return err == blklen && (map.m_flags & EXT4_MAP_MAPPED);
}
static ssize_t ext4_generic_write_checks(struct kiocb *iocb,
......@@ -425,16 +421,11 @@ static const struct iomap_dio_ops ext4_dio_write_ops = {
* - For extending writes case we don't take the shared lock, since it requires
* updating inode i_disksize and/or orphan handling with exclusive lock.
*
* - shared locking will only be true mostly with overwrites, including
* initialized blocks and unwritten blocks. For overwrite unwritten blocks
* we protect splitting extents by i_data_sem in ext4_inode_info, so we can
* also release exclusive i_rwsem lock.
*
* - Otherwise we will switch to exclusive i_rwsem lock.
* - shared locking will only be true mostly with overwrites. Otherwise we will
* switch to exclusive i_rwsem lock.
*/
static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
bool *ilock_shared, bool *extend,
bool *unwritten)
bool *ilock_shared, bool *extend)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
......@@ -458,7 +449,7 @@ static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
* in file_modified().
*/
if (*ilock_shared && (!IS_NOSEC(inode) || *extend ||
!ext4_overwrite_io(inode, offset, count, unwritten))) {
!ext4_overwrite_io(inode, offset, count))) {
if (iocb->ki_flags & IOCB_NOWAIT) {
ret = -EAGAIN;
goto out;
......@@ -490,7 +481,7 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
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, unaligned_io = false, unwritten = false;
bool extend = false, unaligned_io = false;
bool ilock_shared = true;
/*
......@@ -533,8 +524,7 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
return ext4_buffered_write_iter(iocb, from);
}
ret = ext4_dio_write_checks(iocb, from,
&ilock_shared, &extend, &unwritten);
ret = ext4_dio_write_checks(iocb, from, &ilock_shared, &extend);
if (ret <= 0)
return ret;
......@@ -584,7 +574,7 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
ext4_journal_stop(handle);
}
if (ilock_shared && !unwritten)
if (ilock_shared)
iomap_ops = &ext4_iomap_overwrite_ops;
ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
is_sync_kiocb(iocb) || unaligned_io || extend);
......
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