From: Zhang Yi yi.zhang@huawei.com
[ Upstream commit 43d0105e2c7523cc6b14cad65e2044e829c0a07a ]
There is no need to write back all data before punching a hole in non-journaled mode since it will be dropped soon after removing space. Therefore, the call to filemap_write_and_wait_range() can be eliminated. Besides, similar to ext4_zero_range(), we must address the case of partially punched folios when block size < page size. It is essential to remove writable userspace mappings to ensure that the folio can be faulted again during subsequent mmap write access.
In journaled mode, we need to write dirty pages out before discarding page cache in case of crash before committing the freeing data transaction, which could expose old, stale data, even if synchronization has been performed.
Signed-off-by: Zhang Yi yi.zhang@huawei.com Reviewed-by: Jan Kara jack@suse.cz Reviewed-by: Ojaswin Mujoo ojaswin@linux.ibm.com Link: https://patch.msgid.link/20241220011637.1157197-4-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ext4/inode.c | 18 +++++------------- 1 file changed, 5 insertions(+), 13 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 487d9aec56c9d..819be57bb4ecf 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3933,17 +3933,6 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
trace_ext4_punch_hole(inode, offset, length, 0);
- /* - * Write out all dirty pages to avoid race conditions - * Then release them. - */ - if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { - ret = filemap_write_and_wait_range(mapping, offset, - offset + length - 1); - if (ret) - return ret; - } - inode_lock(inode);
/* No need to punch hole beyond i_size */ @@ -4005,8 +3994,11 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length) ret = ext4_update_disksize_before_punch(inode, offset, length); if (ret) goto out_dio; - truncate_pagecache_range(inode, first_block_offset, - last_block_offset); + + ret = ext4_truncate_page_cache_block_range(inode, + first_block_offset, last_block_offset + 1); + if (ret) + goto out_dio; }
if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))