hulk inclusion category: perf bugzilla: 188836, https://gitee.com/openeuler/kernel/issues/I7AYNZ

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This reverts commit 5193a88ea78c9d4a61752443cd7e7457eeeed3c6. This commit may cause performance degradation, so it is being reverted temporarily.

Signed-off-by: Baokun Li libaokun1@huawei.com --- V1->V2: Modify patch description. V2->V3: Add maillist kernel@openeuler.org. V3->V4: subscribe kernel@openeuler.org.

fs/ext4/file.c | 34 ++++++++++++---------------------- 1 file changed, 12 insertions(+), 22 deletions(-)

diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 43076e72cd76..aeb169354a53 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -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);