When punch hole success, we also can read old data from file:
# strace -e trace=pread64,fallocate xfs_io -f -c "pread 20 40" \
-c "fpunch 20 40" -c"pread 20 40" file
pread64(3, " version 5.8.0-rc1+"..., 40, 20) = 40
fallocate(3, FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE, 20, 40) = 0
pread64(3, " version 5.8.0-rc1+"..., 40, 20) = 40
CIFS implements the fallocate(FALLOCATE_FL_PUNCH_HOLE) with send SMB
ioctl(FSCTL_SET_ZERO_DATA) to server. It just set the range of the
remote file to zero, but local page caches not updated, then the
local page caches inconsistent with server.
So, we need to remove the page caches before send the SMB
ioctl(FSCTL_SET_ZERO_DATA) to server.
Suggested-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@xxxxxxxxxx>
---
fs/cifs/smb2ops.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 250b51aca514..478178468d52 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -3258,6 +3258,12 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
return rc;
}
+ /*
+ * We implement the punch hole through ioctl, so we need remove the page
+ * caches first, otherwise the data may be inconsistent with the server.
+ */
+ truncate_pagecache_range(inode, offset, offset + len - 1);
+
cifs_dbg(FYI, "Offset %lld len %lld\n", offset, len);
fsctl_buf.FileOffset = cpu_to_le64(offset);
--
2.25.4
