7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paulo Alcantara commit 4721587f96cb8de8164f3fd203093a0875560999 upstream. cifs_remap_file_range() discarded the pagecache only for the folios overlapping the destination region, so when a clone extends the file the folio straddling the old EOF - which may hold data dirtied past EOF through an mmap - was never dropped and became visible as file content once the file was extended. Start the discard at the smaller of fstart and the old EOF. i_size is still old here, so nothing past the old EOF is flushed to the server. Fixes: c54fc3a4f375 ("cifs: Fix flushing, invalidation and file size with FICLONE") Reviewed-by: David Howells Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Christian Brauner Cc: Matthew Wilcox Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/smb/client/cifsfs.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/fs/smb/client/cifsfs.c +++ b/fs/smb/client/cifsfs.c @@ -1467,9 +1467,14 @@ static loff_t cifs_remap_file_range(stru i_size = target_inode->i_size; spin_unlock(&target_inode->i_lock); - /* Discard all the folios that overlap the destination region. */ + /* + * Discard all the folios that overlap the destination region. Start at + * the old EOF when extending so the folio straddling it, which may hold + * data written past EOF through an mmap, is dropped too. + */ cifs_dbg(FYI, "about to discard pages %llx-%llx\n", fstart, fend); - truncate_inode_pages_range(&target_inode->i_data, fstart, fend); + truncate_inode_pages_range(&target_inode->i_data, + min(fstart, i_size), fend); fscache_invalidate(cifs_inode_cookie(target_inode), NULL, i_size, 0);