xfs: avoid overflow of attr3 leaf block headers with 64k blocks
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- v2 Latest3 patches 0 repliesNew
- v12 patches 4 repliesSuperseded
Changes in v2 from the cover letter
- Created separate firstused conversion helpers to isolate the overflow management to a single point.
- Added patch 3/3 to kill an unnecessary overflow check.
- Comment cleanups, additions.
Patches in v2 No applies recorded yet
| # | Subject and files | Size | Replies | Applied |
|---|---|---|---|---|
| 1/3 | xfs: pass attr geometry to attr leaf header conversion functionsfs/ fs/ fs/ +1 more | +46 | 0 replies | |
| 2/3 | xfs: use larger in-core attr firstused field and detect overflowfs/ fs/ | +92 | 0 replies | |
| 3/3 | xfs: kill unnecessary firstused overflow check on attr3 leaf removalfs/ | +1 | 0 replies |
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Cover letter [PATCH v2 0/3] xfs: avoid overflow of attr3 leaf block headers with 64k blocks
Hi all,
Here's v2 of the series previously posted here:
http://oss.sgi.com/archives/xfs/2015-02/msg00516.html
This version incorporates the feedback from v1 to use separate helpers for firstused conversion. I've also added a 3rd patch to kill what looks like a (now unnecessary) overflow check.
To give a little more context... it appears that this overflow might have been handled previously in the attr code by reducing the firstused value by the required offset alignment and leaking the last few bytes of the block. In fact, xfs_attr3_leaf_create() used to have a similar check that was removed in:
517c22207b04 xfs: add CRCs to attr leaf blocks
... so I suspect that introduced the regression. Both of those !firstused checks appear to exist as of the original git import. Unfortunately, I haven't seen them documented anywhere, but I can't think of any other purpose for them.
Finally, I took a quick look at userspace... First, this depends on xfs_da_geometry, which is not yet available there. So I suspect this will depend on a larger xfsprogs update. IIRC, something of that nature is pending or in progress..?
Second, from what I can see, nothing functional actually needs to change. xfs_repair already does the correct thing by using a larger type to compute firstused. It's written directly to the on-disk header and will overflow at 64k, but that naturally results in the correct value of 0 on-disk. We should definitely make the code explicit, but this is resolved simply by updating the conversion functions in libxfs.
Thoughts, reviews, flames appreciated...
Brian
v2:
- Created separate firstused conversion helpers to isolate the overflow management to a single point.
- Added patch 3/3 to kill an unnecessary overflow check.
- Comment cleanups, additions.
Brian Foster (3):
xfs: pass attr geometry to attr leaf header conversion functions
xfs: use larger in-core attr firstused field and detect overflow
xfs: kill unnecessary firstused overflow check on attr3 leaf removal
fs/xfs/libxfs/xfs_attr_leaf.c | 150 ++++++++++++++++++++++++++++++++---------- fs/xfs/libxfs/xfs_attr_leaf.h | 6 +- fs/xfs/libxfs/xfs_da_format.h | 14 +++- fs/xfs/xfs_attr_inactive.c | 3 +- fs/xfs/xfs_attr_list.c | 9 ++- 5 files changed, 139 insertions(+), 43 deletions(-)
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