From 5f125c5e6be24c8d216a4d3c623dc73d742c8c86 Mon Sep 17 00:00:00 2001 From: Rostislav Date: Sat, 21 Jul 2018 12:57:09 +0300 Subject: Fix readdir() bug when a non-zero offset is specified in filler (#269) The bug occurs when a filesystem client reads a directory until the end, seeks using seekdir() to some valid non-zero position and calls readdir(). A valid 'struct dirent *' is expected, but NULL is returned instead. Pseudocode demonstrating the bug: DIR *dp = opendir("some_dir"); struct dirent *de = readdir(dp); /* Get offset of the second entry */ long offset = telldir(dp); /* Read directory until the end */ while (de) de = readdir(de); seekdir(dp, offset); de = readdir(dp); /* de must contain the second entry, but NULL is returned instead */ The reason of the bug is that when the end of directory is reached, the kernel calls FUSE_READDIR op with an offset at the end of directory, so the filesystem's .readdir callback never calls the filler function, and we end up with dh->filled set to 1. After seekdir(), FUSE_READDIR is called again with a new offset, but this time the filesystem's .readdir callback is never called, and an empty reply is returned. Fix by setting dh->filled to 1 only when zero offsets are given to filler function. --- ChangeLog.rst | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'ChangeLog.rst') diff --git a/ChangeLog.rst b/ChangeLog.rst index cf5450e..9ba0263 100644 --- a/ChangeLog.rst +++ b/ChangeLog.rst @@ -1,3 +1,11 @@ +libfuse 3.2.5 +========================== + +* Added a test of `seekdir` to test_syscalls. +* Fixed `readdir` bug when non-zero offsets are given to filler and the + filesystem client, after reading a whole directory, re-reads it from a + non-zero offset e. g. by calling `seekdir` followed by `readdir`. + libfuse 3.2.4 (2018-07-11) ========================== -- cgit v1.2.3