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author | Jan Kara <jack@suse.cz> | 2015-11-30 10:15:42 -0700 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-01-31 11:23:40 -0800 |
commit | 8885e7f3d76a9d42eb4fd97a3cfc5a8ac7f6f2ff (patch) | |
tree | cceff0ddff5b223e42979c1278026aa6a8890b24 /samples | |
parent | b824d64b153a9683aed6730e9f093a7102c36799 (diff) | |
download | lwn-8885e7f3d76a9d42eb4fd97a3cfc5a8ac7f6f2ff.tar.gz lwn-8885e7f3d76a9d42eb4fd97a3cfc5a8ac7f6f2ff.zip |
direct-io: Fix negative return from dio read beyond eof
commit 74cedf9b6c603f2278a05bc91b140b32b434d0b5 upstream.
Assume a filesystem with 4KB blocks. When a file has size 1000 bytes and
we issue direct IO read at offset 1024, blockdev_direct_IO() reads the
tail of the last block and the logic for handling short DIO reads in
dio_complete() results in a return value -24 (1000 - 1024) which
obviously confuses userspace.
Fix the problem by bailing out early once we sample i_size and can
reliably check that direct IO read starts beyond i_size.
Reported-by: Avi Kivity <avi@scylladb.com>
Fixes: 9fe55eea7e4b444bafc42fa0000cc2d1d2847275
CC: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'samples')
0 files changed, 0 insertions, 0 deletions