Align file accesses with cache=off (Kevin Wolf, Laurent Vivier)
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4367 c046a42c-6fe2-441c-8c8c-71466251a162
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@ -77,10 +77,10 @@
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typedef struct BDRVRawState {
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typedef struct BDRVRawState {
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int fd;
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int fd;
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int type;
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int type;
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int open_flags;
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unsigned int lseek_err_cnt;
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unsigned int lseek_err_cnt;
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#if defined(__linux__)
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#if defined(__linux__)
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/* linux floppy specific */
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/* linux floppy specific */
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int fd_open_flags;
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int64_t fd_open_time;
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int64_t fd_open_time;
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int64_t fd_error_time;
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int64_t fd_error_time;
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int fd_got_error;
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int fd_got_error;
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@ -111,6 +111,7 @@ static int raw_open(BlockDriverState *bs, const char *filename, int flags)
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open_flags |= O_DIRECT;
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open_flags |= O_DIRECT;
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#endif
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#endif
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s->open_flags = open_flags;
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s->type = FTYPE_FILE;
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s->type = FTYPE_FILE;
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fd = open(filename, open_flags, 0644);
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fd = open(filename, open_flags, 0644);
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@ -141,7 +142,14 @@ static int raw_open(BlockDriverState *bs, const char *filename, int flags)
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#endif
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#endif
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*/
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*/
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static int raw_pread(BlockDriverState *bs, int64_t offset,
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/*
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* offset and count are in bytes, but must be multiples of 512 for files
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* opened with O_DIRECT. buf must be aligned to 512 bytes then.
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*
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* This function may be called without alignment if the caller ensures
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* that O_DIRECT is not in effect.
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*/
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static int raw_pread_aligned(BlockDriverState *bs, int64_t offset,
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uint8_t *buf, int count)
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uint8_t *buf, int count)
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{
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{
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BDRVRawState *s = bs->opaque;
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BDRVRawState *s = bs->opaque;
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@ -194,7 +202,14 @@ label__raw_read__success:
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return ret;
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return ret;
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}
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}
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static int raw_pwrite(BlockDriverState *bs, int64_t offset,
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/*
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* offset and count are in bytes, but must be multiples of 512 for files
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* opened with O_DIRECT. buf must be aligned to 512 bytes then.
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*
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* This function may be called without alignment if the caller ensures
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* that O_DIRECT is not in effect.
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*/
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static int raw_pwrite_aligned(BlockDriverState *bs, int64_t offset,
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const uint8_t *buf, int count)
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const uint8_t *buf, int count)
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{
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{
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BDRVRawState *s = bs->opaque;
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BDRVRawState *s = bs->opaque;
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@ -230,6 +245,67 @@ label__raw_write__success:
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return ret;
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return ret;
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}
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}
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#ifdef O_DIRECT
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/*
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* offset and count are in bytes and possibly not aligned. For files opened
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* with O_DIRECT, necessary alignments are ensured before calling
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* raw_pread_aligned to do the actual read.
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*/
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static int raw_pread(BlockDriverState *bs, int64_t offset,
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uint8_t *buf, int count)
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{
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BDRVRawState *s = bs->opaque;
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if (unlikely((s->open_flags & O_DIRECT) &&
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(offset % 512 || count % 512 || (uintptr_t) buf % 512))) {
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int ret;
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// Temporarily disable O_DIRECT for unaligned access
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fcntl(s->fd, F_SETFL, s->open_flags & ~O_DIRECT);
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ret = raw_pread_aligned(bs, offset, buf, count);
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fcntl(s->fd, F_SETFL, s->open_flags);
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return ret;
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} else {
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return raw_pread_aligned(bs, offset, buf, count);
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}
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}
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/*
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* offset and count are in bytes and possibly not aligned. For files opened
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* with O_DIRECT, necessary alignments are ensured before calling
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* raw_pwrite_aligned to do the actual write.
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*/
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static int raw_pwrite(BlockDriverState *bs, int64_t offset,
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const uint8_t *buf, int count)
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{
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BDRVRawState *s = bs->opaque;
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if (unlikely((s->open_flags & O_DIRECT) &&
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(offset % 512 || count % 512 || (uintptr_t) buf % 512))) {
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int ret;
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// Temporarily disable O_DIRECT for unaligned access
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fcntl(s->fd, F_SETFL, s->open_flags & ~O_DIRECT);
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ret = raw_pwrite_aligned(bs, offset, buf, count);
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fcntl(s->fd, F_SETFL, s->open_flags);
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return ret;
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} else {
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return raw_pwrite_aligned(bs, offset, buf, count);
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}
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}
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#else
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#define raw_pread raw_pread_aligned
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#define raw_pwrite raw_pwrite_aligned
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#endif
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/***********************************************************/
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/***********************************************************/
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/* Unix AIO using POSIX AIO */
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/* Unix AIO using POSIX AIO */
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@ -402,10 +478,26 @@ static BlockDriverAIOCB *raw_aio_read(BlockDriverState *bs,
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BlockDriverCompletionFunc *cb, void *opaque)
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BlockDriverCompletionFunc *cb, void *opaque)
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{
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{
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RawAIOCB *acb;
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RawAIOCB *acb;
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BDRVRawState *s = bs->opaque;
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/*
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* If O_DIRECT is used and the buffer is not aligned fall back
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* to synchronous IO.
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*/
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if (unlikely((s->open_flags & O_DIRECT) && ((uintptr_t) buf % 512))) {
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int ret;
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acb = qemu_aio_get(bs, cb, opaque);
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ret = raw_pread(bs, 512 * sector_num, buf, 512 * nb_sectors);
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acb->common.cb(acb->common.opaque, ret);
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qemu_aio_release(acb);
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return &acb->common;
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}
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acb = raw_aio_setup(bs, sector_num, buf, nb_sectors, cb, opaque);
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acb = raw_aio_setup(bs, sector_num, buf, nb_sectors, cb, opaque);
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if (!acb)
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if (!acb)
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return NULL;
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return NULL;
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if (aio_read(&acb->aiocb) < 0) {
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if (aio_read(&acb->aiocb) < 0) {
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qemu_aio_release(acb);
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qemu_aio_release(acb);
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return NULL;
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return NULL;
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@ -418,6 +510,21 @@ static BlockDriverAIOCB *raw_aio_write(BlockDriverState *bs,
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BlockDriverCompletionFunc *cb, void *opaque)
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BlockDriverCompletionFunc *cb, void *opaque)
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{
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{
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RawAIOCB *acb;
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RawAIOCB *acb;
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BDRVRawState *s = bs->opaque;
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/*
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* If O_DIRECT is used and the buffer is not aligned fall back
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* to synchronous IO.
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*/
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if (unlikely((s->open_flags & O_DIRECT) && ((uintptr_t) buf % 512))) {
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int ret;
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acb = qemu_aio_get(bs, cb, opaque);
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ret = raw_pwrite(bs, 512 * sector_num, buf, 512 * nb_sectors);
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acb->common.cb(acb->common.opaque, ret);
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qemu_aio_release(acb);
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return &acb->common;
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}
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acb = raw_aio_setup(bs, sector_num, (uint8_t*)buf, nb_sectors, cb, opaque);
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acb = raw_aio_setup(bs, sector_num, (uint8_t*)buf, nb_sectors, cb, opaque);
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if (!acb)
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if (!acb)
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@ -679,7 +786,7 @@ static int hdev_open(BlockDriverState *bs, const char *filename, int flags)
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s->type = FTYPE_CD;
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s->type = FTYPE_CD;
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} else if (strstart(filename, "/dev/fd", NULL)) {
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} else if (strstart(filename, "/dev/fd", NULL)) {
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s->type = FTYPE_FD;
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s->type = FTYPE_FD;
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s->fd_open_flags = open_flags;
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s->open_flags = open_flags;
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/* open will not fail even if no floppy is inserted */
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/* open will not fail even if no floppy is inserted */
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open_flags |= O_NONBLOCK;
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open_flags |= O_NONBLOCK;
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} else if (strstart(filename, "/dev/sg", NULL)) {
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} else if (strstart(filename, "/dev/sg", NULL)) {
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@ -734,7 +841,7 @@ static int fd_open(BlockDriverState *bs)
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#endif
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#endif
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return -EIO;
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return -EIO;
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}
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}
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s->fd = open(bs->filename, s->fd_open_flags);
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s->fd = open(bs->filename, s->open_flags);
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if (s->fd < 0) {
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if (s->fd < 0) {
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s->fd_error_time = qemu_get_clock(rt_clock);
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s->fd_error_time = qemu_get_clock(rt_clock);
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s->fd_got_error = 1;
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s->fd_got_error = 1;
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@ -831,7 +938,7 @@ static int raw_eject(BlockDriverState *bs, int eject_flag)
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close(s->fd);
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close(s->fd);
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s->fd = -1;
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s->fd = -1;
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}
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}
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fd = open(bs->filename, s->fd_open_flags | O_NONBLOCK);
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fd = open(bs->filename, s->open_flags | O_NONBLOCK);
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if (fd >= 0) {
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if (fd >= 0) {
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if (ioctl(fd, FDEJECT, 0) < 0)
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if (ioctl(fd, FDEJECT, 0) < 0)
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perror("FDEJECT");
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perror("FDEJECT");
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