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author | Hugh Dickins <hughd@google.com> | 2011-05-11 22:13:38 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-12 01:50:45 (GMT) |
commit | 59a16ead572330deb38e5848151d30ed1af754bc (patch) | |
tree | 792b1f35e11e0f49170b0d306d45706de54afeae /include/trace | |
parent | 778dd893ae785c5fd505dac30b5fc40aae188bf1 (diff) | |
download | linux-59a16ead572330deb38e5848151d30ed1af754bc.tar.xz |
tmpfs: fix spurious ENOSPC when racing with unswap
Testing the shmem_swaplist replacements for igrab() revealed another bug:
writes to /dev/loop0 on a tmpfs file which fills its filesystem were
sometimes failing with "Buffer I/O error"s.
These came from ENOSPC failures of shmem_getpage(), when racing with
swapoff: the same could happen when racing with another shmem_getpage(),
pulling the page in from swap in between our find_lock_page() and our
taking the info->lock (though not in the single-threaded loop case).
This is unacceptable, and surprising that I've not noticed it before:
it dates back many years, but (presumably) was made a lot easier to
reproduce in 2.6.36, which sited a page preallocation in the race window.
Fix it by rechecking the page cache before settling on an ENOSPC error.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/trace')
0 files changed, 0 insertions, 0 deletions