[PATCH] Fix reiserfs oops on small fs

[PATCH] Fix reiserfs oops on small fs

[Jan Kara]

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  Hello!

  Attached patch fixes oops of reiserfs on a filesystem with just one
bitmap block - current code always tries to return second bitmap even if
there's not any. Could someone review it please so that it can be merged
in mainline?
	
								Honza

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Fix block allocation code of reiserfs to give correct bitmap numbers
for small filesystems (with just one bitmap block).

Signed-off-by: Jan Kara <jack@suse.cz>

diff -rupNX /home/jack/.kerndiffexclude linux-2.6.10-rc2-mm1-3-reiserdebug/fs/reiserfs/bitmap.c linux-2.6.10-rc2-mm1-4-reisersmall/fs/reiserfs/bitmap.c
--- linux-2.6.10-rc2-mm1-3-reiserdebug/fs/reiserfs/bitmap.c	2004-11-16 16:57:33.000000000 +0100
+++ linux-2.6.10-rc2-mm1-4-reisersmall/fs/reiserfs/bitmap.c	2004-11-16 17:01:47.000000000 +0100
@@ -229,6 +229,9 @@ static int bmap_hash_id(struct super_blo
     unsigned long hash;
     unsigned bm;
 
+    /* If there is only one bitmap, we have no choice... */
+    if (SB_BMAP_NR(s) == 1)
+	return 0;
     if (id <= 2) {
 	bm = 1;
     } else {
@@ -613,7 +616,7 @@ dirid_groups (reiserfs_blocknr_hint_t *h
 	/* give a portion of the block group to metadata */
 	if (hint->inode)
 	    hash += sb->s_blocksize/2;
-	hint->search_start = hash;
+	hint->search_start = hash >= SB_BLOCK_COUNT(sb) ? SB_BLOCK_COUNT(sb)-1 : hash;
     }
 }
 
@@ -642,7 +645,7 @@ oid_groups (reiserfs_blocknr_hint_t *hin
 	    bm = bmap_hash_id(hint->inode->i_sb, oid);
 	    hash = bm * (hint->inode->i_sb->s_blocksize << 3);
 	}
-	hint->search_start = hash;
+	hint->search_start = hash >= SB_BLOCK_COUNT(hint->inode->i_sb) ? SB_BLOCK_COUNT(hint->inode->i_sb)-1 : hash;
     }
 }
 

Re: [PATCH] Fix reiserfs oops on small fs

[Chris Mason]

On Thu, 2004-11-18 at 12:49 +0100, Jan Kara wrote:
>   Hello!
> 
>   Attached patch fixes oops of reiserfs on a filesystem with just one
> bitmap block - current code always tries to return second bitmap even if
> there's not any. Could someone review it please so that it can be merged
> in mainline?

Hi Jan,

A slightly different form of this patch is in already.  Look for the
checks in bmap_hash_id.  Are you still able to reproduce this bug on
kernels newer than October 18?

-chris

Re: [PATCH] Fix reiserfs oops on small fs

[Jan Kara]

> On Thu, 2004-11-18 at 12:49 +0100, Jan Kara wrote:
> >   Hello!
> > 
> >   Attached patch fixes oops of reiserfs on a filesystem with just one
> > bitmap block - current code always tries to return second bitmap even if
> > there's not any. Could someone review it please so that it can be merged
> > in mainline?
> 
> A slightly different form of this patch is in already.  Look for the
> checks in bmap_hash_id.  Are you still able to reproduce this bug on
> kernels newer than October 18?
  Sorry. I've missed that the bug was already fixed in the other place.
It looks OK now.
								Honza

-- 
Jan Kara <jack@suse.cz>
SuSE CR Labs