Remove the conditional checking for out_data_len and skipping the fallocate
if it is 0. This is wrong will actually change any legitimate the fallocate
where the entire region is unallocated into a no-op.
Additionally, before allocating the range, if FALLOC_FL_KEEP_SIZE is set then
we need to clamp the length of the fallocate region as to not extend the size of the file.
Fixes: 966a3cb7c7db ("cifs: improve fallocate emulation")
Signed-off-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
---
fs/cifs/smb2ops.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 5cefb5972396..238717654e46 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -3667,11 +3667,6 @@ static int smb3_simple_fallocate_range(unsigned int xid,
(char **)&out_data, &out_data_len);
if (rc)
goto out;
- /*
- * It is already all allocated
- */
- if (out_data_len == 0)
- goto out;
buf = kzalloc(1024 * 1024, GFP_KERNEL);
if (buf == NULL) {
@@ -3794,6 +3789,24 @@ static long smb3_simple_falloc(struct file *file, struct cifs_tcon *tcon,
goto out;
}
+ if (keep_size == true) {
+ /*
+ * We can not preallocate pages beyond the end of the file
+ * in SMB2.
+ */
+ if (off >= i_size_read(inode)) {
+ rc = -EFBIG;
+ goto out;
+ }
+ /*
+ * For fallocates that are partially beyond the end of file,
+ * clamp len so we only fallocate up to the end of file.
+ */
+ if (off + len > i_size_read(inode)) {
+ len = i_size_read(inode) - off;
+ }
+ }
+
if ((keep_size == true) || (i_size_read(inode) >= off + len)) {
/*
* At this point, we are trying to fallocate an internal
--
2.30.2
