From: Ronnie Sahlberg lsahlber@redhat.com
commit aa081859b10c5d8b19f5c525c78883a59d73c2b8 upstream.
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 Reviewed-by: Pavel Shilovsky pshilov@microsoft.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/cifs/inode.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
--- a/fs/cifs/inode.c +++ b/fs/cifs/inode.c @@ -2371,6 +2371,8 @@ cifs_setattr_nounix(struct dentry *diren 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; @@ -2417,6 +2419,20 @@ cifs_setattr_nounix(struct dentry *diren 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)