[PATCH v2 3/9] smb/client: handle smb2_set_sparse() failure in EOF-extending fallocate

[Huiwen He <huiwen.he@linux.dev>]

From: Huiwen He <hehuiwen@kylinos.cn>

An EOF-extending fallocate(mode=0) can return success while the newly
extended range remains sparse. A later write into that range may
therefore still fail with ENOSPC despite fallocate having succeeded.

CIFS clears the sparse attribute before extending EOF so that the
requested range is allocated. However, it ignores failure from
smb2_set_sparse() and continues to SetEOF.

Return the smb2_set_sparse() error without extending EOF. This prevents
CIFS from reporting successful preallocation when the server rejected
FSCTL_SET_SPARSE.

Fixes: 8bd0d701445e ("cifs: add support for fallocate mode 0 for non-sparse files")
Signed-off-by: Huiwen He <hehuiwen@kylinos.cn>
Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
---
 fs/smb/client/smb2ops.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 965a4d21dd43..f68c0df1b66e 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -3691,8 +3691,11 @@ static long smb3_simple_falloc(struct file *file, struct cifs_tcon *tcon,
 		if (rc)
 			goto out;
 
-		if (cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE)
-			smb2_set_sparse(xid, tcon, cfile, inode, false);
+		if (cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE) {
+			rc = smb2_set_sparse(xid, tcon, cfile, inode, false);
+			if (rc)
+				goto out;
+		}
 
 		new_eof = off + len;
 		rc = SMB2_set_eof(xid, tcon, cfile->fid.persistent_fid,
-- 
2.43.0