[PATCH 3/6] direct-io: do not merge logically non-contiguous requests
in [Kernel]
|
Prev: [PATCH 1/6] fs: allow short direct-io reads to be completed via buffered IO V2
Next: Fix uninitialized spinlock of printk_ratelimited()
From: Josef Bacik on 19 May 2010 16:30 Btrfs cannot handle having logically non-contiguous requests submitted. For example if you have Logical: [0-4095][HOLE][8192-12287] Physical: [0-4095] [4096-8191] Normally the DIO code would put these into the same BIO's. The problem is we need to know exactly what offset is associated with what BIO so we can do our checksumming and unlocking properly, so putting them in the same BIO doesn't work. So add another check where we submit the current BIO if the physical blocks are not contigous OR the logical blocks are not contiguous. Signed-off-by: Josef Bacik <josef(a)redhat.com> --- fs/direct-io.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletions(-) diff --git a/fs/direct-io.c b/fs/direct-io.c index 21ec032..03a3ed4 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -623,10 +623,15 @@ static int dio_send_cur_page(struct dio *dio) int ret = 0; if (dio->bio) { + loff_t cur_offset = dio->block_in_file << dio->blkbits; + loff_t bio_next_offset = dio->logical_offset_in_bio + + dio->bio->bi_size; + /* * See whether this new request is contiguous with the old */ - if (dio->final_block_in_bio != dio->cur_page_block) + if (dio->final_block_in_bio != dio->cur_page_block || + cur_offset != bio_next_offset) dio_bio_submit(dio); /* * Submit now if the underlying fs is about to perform a -- 1.6.6.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |