[PATCH v4 2/9] ext4: skip tail block zeroing for inline data files

[Zhang Yi]

From: Zhang Yi <yi.zhang@xxxxxxxxxx>

ext4_block_zero_eof() is called from ext4_write_checks() on every
append write beyond EOF. For inline data files, ext4_get_block()
returns -ERANGE when ext4_load_tail_bh() looks up the tail block.
However, this error is currently ignored because the return value
of ext4_get_block() in ext4_load_tail_bh() is discarded.

Before we fix ext4_load_tail_bh() to properly propagate the error,
skip the zeroing for inline data inodes to avoid unnecessary
failures or confusion.

Fixes: 3f60efd65412d ("ext4: zero post-EOF partial block before appending write")
Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
---
 fs/ext4/inode.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 7b2face041ef..3ce925ca0769 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4218,6 +4218,14 @@ int ext4_block_zero_eof(struct inode *inode, loff_t from, loff_t end)
 	offset = from & (blocksize - 1);
 	if (!offset || from >= end)
 		return 0;
+	/*
+	 * Inline data has no tail block to zero out.  Note that a race with
+	 * ext4_page_mkwrite() converting inline data to an extent without
+	 * holding i_rwsem is safe, as that path zeroes the full block before
+	 * copying in the inline data.
+	 */
+	if (ext4_has_inline_data(inode))
+		return 0;
 	/* If we are processing an encrypted inode during orphan list handling */
 	if (IS_ENCRYPTED(inode) && !fscrypt_has_encryption_key(inode))
 		return 0;
-- 
2.52.0