diff options
author | Lachlan McIlroy <lachlan@sgi.com> | 2008-09-17 16:50:14 +1000 |
---|---|---|
committer | Lachlan McIlroy <lachlan@redback.melbourne.sgi.com> | 2008-09-17 16:50:14 +1000 |
commit | 364f358a734ddcd827c662ccbfa58ee3ac510762 (patch) | |
tree | 2af362aa418b145e0626066ed2c8b3b0918630eb /net/ipv6 | |
parent | 6efdf281777eb07fac28ac2b2d7df1e619ee6da1 (diff) |
[XFS] Prevent direct I/O from mapping extents beyond eof
With the help from some tracing I found that we try to map extents beyond
eof when doing a direct I/O read. It appears that the way to inform the
generic direct I/O path (ie do_direct_IO()) that we have breached eof is
to return an unmapped buffer from xfs_get_blocks_direct(). This will cause
do_direct_IO() to jump to the hole handling code where is will check for
eof and then abort.
This problem was found because a direct I/O read was trying to map beyond
eof and was encountering delayed allocations. The delayed allocations
beyond eof are speculative allocations and they didn't get converted when
the direct I/O flushed the file because there was only enough space in the
current AG to convert and write out the dirty pages within eof. Note that
xfs_iomap_write_allocate() wont necessarily convert all the delayed
allocation passed to it - it will return after allocating the first extent
- so if the delayed allocation extends beyond eof then it will stay that
way.
SGI-PV: 983683
SGI-Modid: xfs-linux-melb:xfs-kern:31929a
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Diffstat (limited to 'net/ipv6')
0 files changed, 0 insertions, 0 deletions