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author | Paolo Bonzini <pbonzini@redhat.com> | 2013-11-22 13:39:57 +0100 |
---|---|---|
committer | Stefan Hajnoczi <stefanha@redhat.com> | 2013-12-03 15:26:49 +0100 |
commit | 97a2ae34537882df34810d538ab1f51085499d2c (patch) | |
tree | 0e38e7b3f86fc7565dae03a6e98fd606a492560f | |
parent | d0b4503ed2d8713791c38839341b023f78d1a3d9 (diff) | |
download | qemu-97a2ae34537882df34810d538ab1f51085499d2c.zip qemu-97a2ae34537882df34810d538ab1f51085499d2c.tar.gz qemu-97a2ae34537882df34810d538ab1f51085499d2c.tar.bz2 |
raw-posix: add support for write_zeroes on XFS and block devices
The code is similar to the implementation of discard and write_zeroes
with UNMAP. However, failure must be propagated up to block.c.
The stale page cache problem can be reproduced as follows:
# modprobe scsi-debug lbpws=1 lbprz=1
# ./qemu-io /dev/sdXX
qemu-io> write -P 0xcc 0 2M
qemu-io> write -z 0 1M
qemu-io> read -P 0x00 0 512
Pattern verification failed at offset 0, 512 bytes
qemu-io> read -v 0 512
00000000: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc ................
...
# ./qemu-io --cache=none /dev/sdXX
qemu-io> write -P 0xcc 0 2M
qemu-io> write -z 0 1M
qemu-io> read -P 0x00 0 512
qemu-io> read -v 0 512
00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
...
And similarly with discard instead of "write -z".
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-rw-r--r-- | block/raw-aio.h | 3 | ||||
-rw-r--r-- | block/raw-posix.c | 84 |
2 files changed, 74 insertions, 13 deletions
diff --git a/block/raw-aio.h b/block/raw-aio.h index c61f159..7ad0a8a 100644 --- a/block/raw-aio.h +++ b/block/raw-aio.h @@ -21,9 +21,10 @@ #define QEMU_AIO_IOCTL 0x0004 #define QEMU_AIO_FLUSH 0x0008 #define QEMU_AIO_DISCARD 0x0010 +#define QEMU_AIO_WRITE_ZEROES 0x0020 #define QEMU_AIO_TYPE_MASK \ (QEMU_AIO_READ|QEMU_AIO_WRITE|QEMU_AIO_IOCTL|QEMU_AIO_FLUSH| \ - QEMU_AIO_DISCARD) + QEMU_AIO_DISCARD|QEMU_AIO_WRITE_ZEROES) /* AIO flags */ #define QEMU_AIO_MISALIGNED 0x1000 diff --git a/block/raw-posix.c b/block/raw-posix.c index b3feed6..10c6b34 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -142,6 +142,7 @@ typedef struct BDRVRawState { bool is_xfs:1; #endif bool has_discard:1; + bool has_write_zeroes:1; bool discard_zeroes:1; } BDRVRawState; @@ -326,6 +327,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, #endif s->has_discard = true; + s->has_write_zeroes = true; if (fstat(s->fd, &st) < 0) { error_setg_errno(errp, errno, "Could not stat file"); @@ -344,9 +346,11 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, #ifdef __linux__ /* On Linux 3.10, BLKDISCARD leaves stale data in the page cache. Do * not rely on the contents of discarded blocks unless using O_DIRECT. + * Same for BLKZEROOUT. */ if (!(bs->open_flags & BDRV_O_NOCACHE)) { s->discard_zeroes = false; + s->has_write_zeroes = false; } #endif } @@ -702,6 +706,23 @@ static ssize_t handle_aiocb_rw(RawPosixAIOData *aiocb) } #ifdef CONFIG_XFS +static int xfs_write_zeroes(BDRVRawState *s, int64_t offset, uint64_t bytes) +{ + struct xfs_flock64 fl; + + memset(&fl, 0, sizeof(fl)); + fl.l_whence = SEEK_SET; + fl.l_start = offset; + fl.l_len = bytes; + + if (xfsctl(NULL, s->fd, XFS_IOC_ZERO_RANGE, &fl) < 0) { + DEBUG_BLOCK_PRINT("cannot write zero range (%s)\n", strerror(errno)); + return -errno; + } + + return 0; +} + static int xfs_discard(BDRVRawState *s, int64_t offset, uint64_t bytes) { struct xfs_flock64 fl; @@ -720,6 +741,42 @@ static int xfs_discard(BDRVRawState *s, int64_t offset, uint64_t bytes) } #endif +static ssize_t handle_aiocb_write_zeroes(RawPosixAIOData *aiocb) +{ + int ret = -EOPNOTSUPP; + BDRVRawState *s = aiocb->bs->opaque; + + if (s->has_write_zeroes == 0) { + return -ENOTSUP; + } + + if (aiocb->aio_type & QEMU_AIO_BLKDEV) { +#ifdef BLKZEROOUT + do { + uint64_t range[2] = { aiocb->aio_offset, aiocb->aio_nbytes }; + if (ioctl(aiocb->aio_fildes, BLKZEROOUT, range) == 0) { + return 0; + } + } while (errno == EINTR); + + ret = -errno; +#endif + } else { +#ifdef CONFIG_XFS + if (s->is_xfs) { + return xfs_write_zeroes(s, aiocb->aio_offset, aiocb->aio_nbytes); + } +#endif + } + + if (ret == -ENODEV || ret == -ENOSYS || ret == -EOPNOTSUPP || + ret == -ENOTTY) { + s->has_write_zeroes = false; + ret = -ENOTSUP; + } + return ret; +} + static ssize_t handle_aiocb_discard(RawPosixAIOData *aiocb) { int ret = -EOPNOTSUPP; @@ -804,6 +861,9 @@ static int aio_worker(void *arg) case QEMU_AIO_DISCARD: ret = handle_aiocb_discard(aiocb); break; + case QEMU_AIO_WRITE_ZEROES: + ret = handle_aiocb_write_zeroes(aiocb); + break; default: fprintf(stderr, "invalid aio request (0x%x)\n", aiocb->aio_type); ret = -EINVAL; @@ -1256,13 +1316,13 @@ static int coroutine_fn raw_co_write_zeroes( BDRVRawState *s = bs->opaque; if (!(flags & BDRV_REQ_MAY_UNMAP)) { - return -ENOTSUP; - } - if (!s->discard_zeroes) { - return -ENOTSUP; + return paio_submit_co(bs, s->fd, sector_num, NULL, nb_sectors, + QEMU_AIO_WRITE_ZEROES); + } else if (s->discard_zeroes) { + return paio_submit_co(bs, s->fd, sector_num, NULL, nb_sectors, + QEMU_AIO_DISCARD); } - return paio_submit_co(bs, s->fd, sector_num, NULL, nb_sectors, - QEMU_AIO_DISCARD); + return -ENOTSUP; } static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) @@ -1613,13 +1673,13 @@ static coroutine_fn int hdev_co_write_zeroes(BlockDriverState *bs, return rc; } if (!(flags & BDRV_REQ_MAY_UNMAP)) { - return -ENOTSUP; - } - if (!s->discard_zeroes) { - return -ENOTSUP; + return paio_submit_co(bs, s->fd, sector_num, NULL, nb_sectors, + QEMU_AIO_WRITE_ZEROES|QEMU_AIO_BLKDEV); + } else if (s->discard_zeroes) { + return paio_submit_co(bs, s->fd, sector_num, NULL, nb_sectors, + QEMU_AIO_DISCARD|QEMU_AIO_BLKDEV); } - return paio_submit_co(bs, s->fd, sector_num, NULL, nb_sectors, - QEMU_AIO_DISCARD|QEMU_AIO_BLKDEV); + return -ENOTSUP; } static int hdev_create(const char *filename, QEMUOptionParameter *options, |