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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-22 17:07:18 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-22 17:07:18 -0700 |
| commit | a2887097f25cd38cadfc11d10769e2b349fb5eca (patch) | |
| tree | cd4adcb305365d6ba9acd2c02d4eb9d0125c6f8d /Documentation/lguest/lguest.c | |
| parent | 8abfc6e7a45eb74e51904bbae676fae008b11366 (diff) | |
| parent | 005a1d15f5a6b2bb4ada80349513effbf22b4588 (diff) | |
| download | linux-a2887097f25cd38cadfc11d10769e2b349fb5eca.tar.bz2 | |
Merge branch 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block
* 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block: (46 commits)
xen-blkfront: disable barrier/flush write support
Added blk-lib.c and blk-barrier.c was renamed to blk-flush.c
block: remove BLKDEV_IFL_WAIT
aic7xxx_old: removed unused 'req' variable
block: remove the BH_Eopnotsupp flag
block: remove the BLKDEV_IFL_BARRIER flag
block: remove the WRITE_BARRIER flag
swap: do not send discards as barriers
fat: do not send discards as barriers
ext4: do not send discards as barriers
jbd2: replace barriers with explicit flush / FUA usage
jbd2: Modify ASYNC_COMMIT code to not rely on queue draining on barrier
jbd: replace barriers with explicit flush / FUA usage
nilfs2: replace barriers with explicit flush / FUA usage
reiserfs: replace barriers with explicit flush / FUA usage
gfs2: replace barriers with explicit flush / FUA usage
btrfs: replace barriers with explicit flush / FUA usage
xfs: replace barriers with explicit flush / FUA usage
block: pass gfp_mask and flags to sb_issue_discard
dm: convey that all flushes are processed as empty
...
Diffstat (limited to 'Documentation/lguest/lguest.c')
| -rw-r--r-- | Documentation/lguest/lguest.c | 29 |
1 files changed, 9 insertions, 20 deletions
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index 8a6a8c6d4980..dc73bc54cc4e 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -1640,15 +1640,6 @@ static void blk_request(struct virtqueue *vq) off = out->sector * 512; /* - * The block device implements "barriers", where the Guest indicates - * that it wants all previous writes to occur before this write. We - * don't have a way of asking our kernel to do a barrier, so we just - * synchronize all the data in the file. Pretty poor, no? - */ - if (out->type & VIRTIO_BLK_T_BARRIER) - fdatasync(vblk->fd); - - /* * In general the virtio block driver is allowed to try SCSI commands. * It'd be nice if we supported eject, for example, but we don't. */ @@ -1680,6 +1671,13 @@ static void blk_request(struct virtqueue *vq) /* Die, bad Guest, die. */ errx(1, "Write past end %llu+%u", off, ret); } + + wlen = sizeof(*in); + *in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR); + } else if (out->type & VIRTIO_BLK_T_FLUSH) { + /* Flush */ + ret = fdatasync(vblk->fd); + verbose("FLUSH fdatasync: %i\n", ret); wlen = sizeof(*in); *in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR); } else { @@ -1703,15 +1701,6 @@ static void blk_request(struct virtqueue *vq) } } - /* - * OK, so we noted that it was pretty poor to use an fdatasync as a - * barrier. But Christoph Hellwig points out that we need a sync - * *afterwards* as well: "Barriers specify no reordering to the front - * or the back." And Jens Axboe confirmed it, so here we are: - */ - if (out->type & VIRTIO_BLK_T_BARRIER) - fdatasync(vblk->fd); - /* Finished that request. */ add_used(vq, head, wlen); } @@ -1736,8 +1725,8 @@ static void setup_block_file(const char *filename) vblk->fd = open_or_die(filename, O_RDWR|O_LARGEFILE); vblk->len = lseek64(vblk->fd, 0, SEEK_END); - /* We support barriers. */ - add_feature(dev, VIRTIO_BLK_F_BARRIER); + /* We support FLUSH. */ + add_feature(dev, VIRTIO_BLK_F_FLUSH); /* Tell Guest how many sectors this device has. */ conf.capacity = cpu_to_le64(vblk->len / 512); |