From dfe4d3d6a6f707fff1dbfd4b8fce65e64a91b809 Mon Sep 17 00:00:00 2001 From: Tao Ma Date: Fri, 19 Mar 2010 15:04:23 +0800 Subject: [PATCH] ocfs2: Fix the update of name_offset when removing xattrs When replacing a xattr's value, in some case we wipe its name/value first and then re-add it. The wipe is done by ocfs2_xa_block_wipe_namevalue() when the xattr is in the inode or block. We currently adjust name_offset for all the entries which have (offset < name_offset). This does not adjust the entrie we're replacing. Since we are replacing the entry, we don't adjust the total entry count. When we calculate a new namevalue location, we trust the entries now-wrong offset in ocfs2_xa_get_free_start(). The solution is to also adjust the name_offset for the replaced entry, allowing ocfs2_xa_get_free_start() to calculate the new namevalue location correctly. The following script can trigger a kernel panic easily. echo 'y'|mkfs.ocfs2 --fs-features=local,xattr -b 4K $DEVICE mount -t ocfs2 $DEVICE $MNT_DIR FILE=$MNT_DIR/$RANDOM for((i=0;i<76;i++)) do string_76="a$string_76" done string_78="aa$string_76" string_82="aaaa$string_78" touch $FILE setfattr -n 'user.test1234567890' -v $string_76 $FILE setfattr -n 'user.test1234567890' -v $string_78 $FILE setfattr -n 'user.test1234567890' -v $string_82 $FILE Signed-off-by: Tao Ma Signed-off-by: Joel Becker --- fs/ocfs2/xattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index d1b0d386f6d1..82c2a0b53eb4 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -1622,7 +1622,7 @@ static void ocfs2_xa_block_wipe_namevalue(struct ocfs2_xa_loc *loc) /* Now tell xh->xh_entries about it */ for (i = 0; i < count; i++) { offset = le16_to_cpu(xh->xh_entries[i].xe_name_offset); - if (offset < namevalue_offset) + if (offset <= namevalue_offset) le16_add_cpu(&xh->xh_entries[i].xe_name_offset, namevalue_size); } -- GitLab