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| author | Daniel McNeil <daniel@osdl.org> | 2005-04-16 15:25:50 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:25:50 -0700 |
| commit | 29504ff3be784372c4e2f7e31681a3e0292c4d9a (patch) | |
| tree | 449f6598e10a1930d113fd7bbe3aa6ca37341d10 /fs/direct-io.c | |
| parent | 1f08ad02379530e1c970d3d104343b9907b4d1b4 (diff) | |
| download | linux-29504ff3be784372c4e2f7e31681a3e0292c4d9a.tar.gz linux-29504ff3be784372c4e2f7e31681a3e0292c4d9a.tar.bz2 linux-29504ff3be784372c4e2f7e31681a3e0292c4d9a.zip | |
[PATCH] Direct IO async short read fix
The direct I/O code is mapping the read request to the file system block. If
the file size was not on a block boundary, the result would show the the read
reading past EOF. This was only happening for the AIO case. The non-AIO case
truncates the result to match file size (in direct_io_worker). This patch
does the same thing for the AIO case, it truncates the result to match the
file size if the read reads past EOF.
When I/O completes the result can be truncated to match the file size
without using i_size_read(), thus the aio result now matches the number of
bytes read to the end of file.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/direct-io.c')
| -rw-r--r-- | fs/direct-io.c | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/fs/direct-io.c b/fs/direct-io.c index 5a674a0c7146..1d55e7e67342 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -66,6 +66,7 @@ struct dio { struct bio *bio; /* bio under assembly */ struct inode *inode; int rw; + loff_t i_size; /* i_size when submitted */ int lock_type; /* doesn't change */ unsigned blkbits; /* doesn't change */ unsigned blkfactor; /* When we're using an alignment which @@ -230,17 +231,29 @@ static void finished_one_bio(struct dio *dio) spin_lock_irqsave(&dio->bio_lock, flags); if (dio->bio_count == 1) { if (dio->is_async) { + ssize_t transferred; + loff_t offset; + /* * Last reference to the dio is going away. * Drop spinlock and complete the DIO. */ spin_unlock_irqrestore(&dio->bio_lock, flags); - dio_complete(dio, dio->block_in_file << dio->blkbits, - dio->result); + + /* Check for short read case */ + transferred = dio->result; + offset = dio->iocb->ki_pos; + + if ((dio->rw == READ) && + ((offset + transferred) > dio->i_size)) + transferred = dio->i_size - offset; + + dio_complete(dio, offset, transferred); + /* Complete AIO later if falling back to buffered i/o */ if (dio->result == dio->size || ((dio->rw == READ) && dio->result)) { - aio_complete(dio->iocb, dio->result, 0); + aio_complete(dio->iocb, transferred, 0); kfree(dio); return; } else { @@ -951,6 +964,7 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, dio->page_errors = 0; dio->result = 0; dio->iocb = iocb; + dio->i_size = i_size_read(inode); /* * BIO completion state. |