Bug 519471 - ext4 bitmap allocator must limit blocks to < 2^32
Summary: ext4 bitmap allocator must limit blocks to < 2^32
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: kernel
Version: 6.0
Hardware: All
OS: Linux
Target Milestone: rc
: ---
Assignee: Eric Sandeen
QA Contact: Igor Zhang
Depends On:
Blocks: 534150
TreeView+ depends on / blocked
Reported: 2009-08-26 18:06 UTC by Valerie Aurora Henson
Modified: 2010-11-15 14:24 UTC (History)
4 users (show)

Fixed In Version: kernel-2.6.32-1.el6
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2010-11-15 14:24:29 UTC

Attachments (Terms of Use)

System ID Priority Status Summary Last Updated
Linux Kernel 9502 None None None Never

Description Valerie Aurora Henson 2009-08-26 18:06:07 UTC
This is a tracking bug for an ext4 kernel bugzilla:


Comment 2 RHEL Product and Program Management 2009-08-26 18:46:30 UTC
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux major release.  Product Management has requested further
review of this request by Red Hat Engineering, for potential inclusion in a Red
Hat Enterprise Linux Major release.  This request is not yet committed for

Comment 3 Eric Sandeen 2009-11-13 22:15:14 UTC
Upstream in 2.6.32:

commit fb0a387dcdcd21aab1b09ee7fd80b7c979bdbbfd
Author: Eric Sandeen <sandeen@redhat.com>
Date:   Wed Sep 16 14:45:10 2009 -0400

    ext4: limit block allocations for indirect-block files to < 2^32
    Today, the ext4 allocator will happily allocate blocks past
    2^32 for indirect-block files, which results in the block
    numbers getting truncated, and corruption ensues.
    This patch limits such allocations to < 2^32, and adds
    BUG_ONs if we do get blocks larger than that.
    This should address RH Bug 519471, ext4 bitmap allocator
    must limit blocks to < 2^32
    * ext4_find_goal() is modified to choose a goal < UINT_MAX,
      so that our starting point is in an acceptable range.
    * ext4_xattr_block_set() is modified such that the goal block
      is < UINT_MAX, as above.
    * ext4_mb_regular_allocator() is modified so that the group
      search does not continue into groups which are too high
    * ext4_mb_use_preallocated() has a check that we don't use
      preallocated space which is too far out
    * ext4_alloc_blocks() and ext4_xattr_block_set() add some BUG_ONs
    No attempt has been made to limit inode locations to < 2^32,
    so we may wind up with blocks far from their inodes.  Doing
    this much already will lead to some odd ENOSPC issues when the
    "lower 32" gets full, and further restricting inodes could
    make that even weirder.
    For high inodes, choosing a goal of the original, % UINT_MAX,
    may be a bit odd, but then we're in an odd situation anyway,
    and I don't know of a better heuristic.
    Signed-off-by: Eric Sandeen <sandeen@redhat.com>
    Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

Comment 5 Igor Zhang 2010-09-30 06:39:28 UTC
There are no separate patches for this bug in kernel-2.6.32-1.el6.
Sanity Check the corresponding code in kernel-2.6.32-73.el6 and make comparison with kernel-2.6.32-1.el6.
Two BUG_ONs in inode.c are replaced by as much as following code:
	if (unlikely(current_block + ar.len > EXT4_MAX_BLOCK_FILE_PHYS)) {
				 "current_block %llu + ar.len %d > %d!",
				 current_block, ar.len,
		*err = -EIO;
		goto failed_out;

The last BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS) in xattr.c is still there.

Comment 6 releng-rhel@redhat.com 2010-11-15 14:24:29 UTC
Red Hat Enterprise Linux 6.0 is now available and should resolve
the problem described in this bug report. This report is therefore being closed
with a resolution of CURRENTRELEASE. You may reopen this bug report if the
solution does not work for you.

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