diff mbox series

[v5,03/10] ext4: don't write back data before punch hole in nojournal mode

Message ID 20241220011637.1157197-4-yi.zhang@huaweicloud.com (mailing list archive)
State New
Headers show
Series ext4: clean up and refactor fallocate | expand

Commit Message

Zhang Yi Dec. 20, 2024, 1:16 a.m. UTC 
From: Zhang Yi <yi.zhang@huawei.com>

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>
---
 fs/ext4/inode.c | 18 +++++-------------
 1 file changed, 5 insertions(+), 13 deletions(-)
diff mbox series

Patch

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index b94cbdb82692..33f1a28177cf 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4019,17 +4019,6 @@  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 */
@@ -4091,8 +4080,11 @@  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))