Re: reiser4progs: possible off-by-one in librepair/twig_scan.c?

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On 06/20/2014 01:18 AM, Ivan Shapovalov wrote:
I've got a strange fsck complaint while testing the rewritten discard.
The fsck log is here (not line-wrapped):

====LOG====

$ fsck.reiser4 /dev/disk/by-label/linux-build
*******************************************************************
This is an EXPERIMENTAL version of fsck.reiser4. Read README first.
*******************************************************************

Fscking the /dev/disk/by-label/linux-build block device.
Will check the consistency of the Reiser4 SuperBlock.
Will check the consistency of the Reiser4 FileSystem.
Continue?
(Yes/No): y
***** fsck.reiser4 started at Fri Jun 20 02:49:22 2014
Reiser4 fs was detected on /dev/disk/by-label/linux-build.
Master super block (16):
magic:          ReIsEr4
blksize:        4096
format:         0x0 (format40)
uuid:           73831051-68e1-4848-b9ea-83f9703558b6
label:          linux-build
Format super block (17):
plugin:         format40
description:    Disk-format plugin.
version:        0
magic:          ReIsEr40FoRmAt
mkfs id:        0x143b8ccd
flushes:        0
blocks:         2621440
free blocks:    542951
root block:     69897
tail policy:    0x2 (smart)
next oid:       0x21c6d1
file count:     182200
tree height:    4
key policy:     LARGE
CHECKING THE STORAGE TREE
         Read nodes 239320
         Nodes left in the tree 239320
                 Leaves of them 236133, Twigs of them 3136
         Time interval: Fri Jun 20 02:49:22 2014 - Fri Jun 20 02:49:29 2014
CHECKING EXTENT REGIONS.
FSCK: extent40_repair.c: 96: extent40_check_layout: Node (2618486), item (9), unit (10), [20d7ef:4(FB):766d6c696e757a:20da66:0]: points out of the fs, region [2621239..2621439].
         Read twigs 3136
         Invaid extent pointers 1
         Time interval: Fri Jun 20 02:49:29 2014 - Fri Jun 20 02:49:29 2014
CHECKING THE SEMANTIC TREE
         Found 189973 objects (some could be encountered more then once).
         Time interval: Fri Jun 20 02:49:29 2014 - Fri Jun 20 02:49:33 2014
FSCK: repair.c: 550: repair_sem_fini: On-disk used block bitmap and really used block bitmap differ.
***** fsck.reiser4 finished at Fri Jun 20 02:49:33 2014
Closing fs...done

1 fatal corruptions were detected in FileSystem. Run with --build-fs option to fix them.

====END LOG====

This seems invalid to me: why a [2621239; 2621439] region would be invalid
in a filesystem with 2621440 blocks?
Also, the file in question is intact and does not appear to be corrupted,
because this is my current vmlinuz. :)

The following patch against reiser4progs shows precise location of this check.

diff --git a/librepair/twig_scan.c b/librepair/twig_scan.c
index 39b747c..ca8607a 100644
--- a/librepair/twig_scan.c
+++ b/librepair/twig_scan.c
@@ -19,7 +19,7 @@ static errno_t cb_item_region_check(blk_t start, uint64_t count, void *data) {
  	/* This must be fixed at the first pass. */
  	if (start >= ts->bm_met->total ||
  	    count > ts->bm_met->total ||
-	    start >= ts->bm_met->total - count)
+	    start > ts->bm_met->total - count)
  	{
  		ts->stat.bad_unfm_ptrs++;
  		return RE_FATAL;

Sometimes our fsck is overly suspicious ;)
Does this fix help, BTW?
Thanks!
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