diff options
| author | Roger Pau Monne <roger.pau@citrix.com> | 2014-10-21 16:03:03 +0200 |
|---|---|---|
| committer | Max Reitz <mreitz@redhat.com> | 2014-10-23 16:56:53 +0200 |
| commit | 3cad83075c7b847fe0eb6e61316fdf50984d4570 (patch) | |
| tree | a286ce1b56987c52fd99bb6dff2079d8fc75ab81 /block | |
| parent | 1b2dd0bee6bd03045b90c8a7549c8134466b2938 (diff) | |
block: char devices on FreeBSD are not behind a pager
Introduce a new flag to mark devices that require requests to be aligned and
replace the usage of BDRV_O_NOCACHE and O_DIRECT with this flag when
appropriate.
If a character device is used as a backend on a FreeBSD host set this flag
unconditionally.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/raw-posix.c | 26 |
1 files changed, 21 insertions, 5 deletions
diff --git a/block/raw-posix.c b/block/raw-posix.c index ee4ca3c01e..475cf74655 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -150,6 +150,7 @@ typedef struct BDRVRawState { bool has_discard:1; bool has_write_zeroes:1; bool discard_zeroes:1; + bool needs_alignment; #ifdef CONFIG_FIEMAP bool skip_fiemap; #endif @@ -230,7 +231,7 @@ static void raw_probe_alignment(BlockDriverState *bs, int fd, Error **errp) /* For /dev/sg devices the alignment is not really used. With buffered I/O, we don't have any restrictions. */ - if (bs->sg || !(s->open_flags & O_DIRECT)) { + if (bs->sg || !s->needs_alignment) { bs->request_alignment = 1; s->buf_align = 1; return; @@ -446,6 +447,9 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, s->has_discard = true; s->has_write_zeroes = true; + if ((bs->open_flags & BDRV_O_NOCACHE) != 0) { + s->needs_alignment = true; + } if (fstat(s->fd, &st) < 0) { error_setg_errno(errp, errno, "Could not stat file"); @@ -472,6 +476,17 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, } #endif } +#ifdef __FreeBSD__ + if (S_ISCHR(st.st_mode)) { + /* + * The file is a char device (disk), which on FreeBSD isn't behind + * a pager, so force all requests to be aligned. This is needed + * so QEMU makes sure all IO operations on the device are aligned + * to sector size, or else FreeBSD will reject them with EINVAL. + */ + s->needs_alignment = true; + } +#endif #ifdef CONFIG_XFS if (platform_test_xfs_fd(s->fd)) { @@ -1076,11 +1091,12 @@ static BlockAIOCB *raw_aio_submit(BlockDriverState *bs, return NULL; /* - * If O_DIRECT is used the buffer needs to be aligned on a sector - * boundary. Check if this is the case or tell the low-level - * driver that it needs to copy the buffer. + * Check if the underlying device requires requests to be aligned, + * and if the request we are trying to submit is aligned or not. + * If this is the case tell the low-level driver that it needs + * to copy the buffer. */ - if ((bs->open_flags & BDRV_O_NOCACHE)) { + if (s->needs_alignment) { if (!bdrv_qiov_is_aligned(bs, qiov)) { type |= QEMU_AIO_MISALIGNED; #ifdef CONFIG_LINUX_AIO |