[PATCH] ntfs: not change 0-byte $DATA attribute to non-resident

[Hyunchul Lee <hyc.lee@gmail.com>]

When ntfs_resident_attr_resize() cannot grow a resident attribute in
place, it retries after converting other resident attributes to
non-resident to free space in the MFT recrord.

Do not select zero-length resident $DATA attributes for this conversion.
fsck treats 0-byte non-resident $DATA attribute as corruptions.

Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
---
 fs/ntfs/attrib.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c
index 9d676375f25c..2872b4ce1835 100644
--- a/fs/ntfs/attrib.c
+++ b/fs/ntfs/attrib.c
@@ -4537,10 +4537,12 @@ static int ntfs_resident_attr_resize(struct ntfs_inode *attr_ni, const s64 newsi
 	while (!(err = ntfs_attr_lookup(AT_UNUSED, NULL, 0, 0, 0, NULL, 0, ctx))) {
 		struct inode *tvi;
 		struct attr_record *a;
+		u32 value_len;
 
 		a = ctx->attr;
 		if (a->non_resident || a->type == AT_ATTRIBUTE_LIST)
 			continue;
+		value_len = le32_to_cpu(a->data.resident.value_length);
 
 		if (ntfs_attr_can_be_non_resident(vol, a->type))
 			continue;
@@ -4552,6 +4554,8 @@ static int ntfs_resident_attr_resize(struct ntfs_inode *attr_ni, const s64 newsi
 		if (le32_to_cpu(a->length) <= (sizeof(struct attr_record) - sizeof(s64)) +
 				((a->name_length * sizeof(__le16) + 7) & ~7) + 8)
 			continue;
+		if (a->type == AT_DATA && !value_len)
+			continue;
 
 		if (a->type == AT_DATA)
 			tvi = ntfs_iget(sb, base_ni->mft_no);
@@ -4564,8 +4568,7 @@ static int ntfs_resident_attr_resize(struct ntfs_inode *attr_ni, const s64 newsi
 			continue;
 		}
 
-		if (ntfs_attr_make_non_resident(NTFS_I(tvi),
-		    le32_to_cpu(ctx->attr->data.resident.value_length))) {
+		if (ntfs_attr_make_non_resident(NTFS_I(tvi), value_len)) {
 			iput(tvi);
 			continue;
 		}

---
base-commit: 47a20013412ac44a71be899c206a2dc71c7a5dd9
change-id: 20260528-f-0-byte-data-ff696b1bacf6

Best regards,
-- 
Thanks,
Hyunchul