direct-io: Fix negative return from dio read beyond eof

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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: 9fe55eea7e
CC: stable@vger.kernel.org
CC: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>

...

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Jan Kara 2015-11-30 10:15:42 -07:00 • committed by Jens Axboe

parent bf4e6b4e75

commit 74cedf9b6c

1 changed files with 9 additions and 1 deletions

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fs/direct-io.c

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