cifs: flush before set-info if we have writeable handles
diff mbox series

Message ID 20190718221211.22429-1-lsahlber@redhat.com
State New
Headers show
Series
  • cifs: flush before set-info if we have writeable handles
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Commit Message

Ronnie Sahlberg July 18, 2019, 10:12 p.m. UTC
Servers can defer destaging any data and updating the mtime until close().
This means that if we do a setinfo to modify the mtime while other handles
are open for write the server may overwrite our setinfo timestamps when
if flushes the file on close() of the writeable handle.

To solve this we add an explicit flush when the mtime is about to
be updated.

This fixes "cp -p" to preserve mtime when copying a file onto an SMB2 share.

CC: Stable <stable@vger.kernel.org>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
 fs/cifs/inode.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

Patch
diff mbox series

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 1bffe029fb66..56ca4b8ccaba 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -2406,6 +2406,8 @@  cifs_setattr_nounix(struct dentry *direntry, struct iattr *attrs)
 	struct inode *inode = d_inode(direntry);
 	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 	struct cifsInodeInfo *cifsInode = CIFS_I(inode);
+	struct cifsFileInfo *wfile;
+	struct cifs_tcon *tcon;
 	char *full_path = NULL;
 	int rc = -EACCES;
 	__u32 dosattr = 0;
@@ -2452,6 +2454,20 @@  cifs_setattr_nounix(struct dentry *direntry, struct iattr *attrs)
 	mapping_set_error(inode->i_mapping, rc);
 	rc = 0;
 
+	if (attrs->ia_valid & ATTR_MTIME) {
+		rc = cifs_get_writable_file(cifsInode, false, &wfile);
+		if (!rc) {
+			tcon = tlink_tcon(wfile->tlink);
+			rc = tcon->ses->server->ops->flush(xid, tcon, &wfile->fid);
+			cifsFileInfo_put(wfile);
+			if (rc)
+				return rc;
+		} else if (rc != -EBADF)
+			return rc;
+		else
+			rc = 0;
+	}
+
 	if (attrs->ia_valid & ATTR_SIZE) {
 		rc = cifs_set_file_size(inode, attrs, xid, full_path);
 		if (rc != 0)