diff options
Diffstat (limited to 'block-raw-posix.c')
| -rw-r--r-- | block-raw-posix.c | 41 |
1 files changed, 17 insertions, 24 deletions
diff --git a/block-raw-posix.c b/block-raw-posix.c index 83a358cd4d..4c04dbf8da 100644 --- a/block-raw-posix.c +++ b/block-raw-posix.c @@ -73,6 +73,11 @@ #define DEBUG_BLOCK_PRINT(formatCstr, args...) #endif +/* Approximate O_DIRECT with O_DSYNC if O_DIRECT isn't available */ +#ifndef O_DIRECT +#define O_DIRECT O_DSYNC +#endif + #define FTYPE_FILE 0 #define FTYPE_CD 1 #define FTYPE_FD 2 @@ -101,9 +106,7 @@ typedef struct BDRVRawState { int fd_got_error; int fd_media_changed; #endif -#if defined(O_DIRECT) uint8_t* aligned_buf; -#endif } BDRVRawState; static int posix_aio_init(void); @@ -129,10 +132,13 @@ static int raw_open(BlockDriverState *bs, const char *filename, int flags) } if (flags & BDRV_O_CREAT) open_flags |= O_CREAT | O_TRUNC; -#ifdef O_DIRECT - if (flags & BDRV_O_DIRECT) + + /* Use O_DSYNC for write-through caching, no flags for write-back caching, + * and O_DIRECT for no caching. */ + if ((flags & BDRV_O_NOCACHE)) open_flags |= O_DIRECT; -#endif + else if (!(flags & BDRV_O_CACHE_WB)) + open_flags |= O_DSYNC; s->type = FTYPE_FILE; @@ -146,9 +152,8 @@ static int raw_open(BlockDriverState *bs, const char *filename, int flags) s->fd = fd; for (i = 0; i < RAW_FD_POOL_SIZE; i++) s->fd_pool[i] = -1; -#if defined(O_DIRECT) s->aligned_buf = NULL; - if (flags & BDRV_O_DIRECT) { + if ((flags & BDRV_O_NOCACHE)) { s->aligned_buf = qemu_memalign(512, ALIGNED_BUFFER_SIZE); if (s->aligned_buf == NULL) { ret = -errno; @@ -156,7 +161,6 @@ static int raw_open(BlockDriverState *bs, const char *filename, int flags) return ret; } } -#endif return 0; } @@ -281,7 +285,6 @@ label__raw_write__success: } -#if defined(O_DIRECT) /* * offset and count are in bytes and possibly not aligned. For files opened * with O_DIRECT, necessary alignments are ensured before calling @@ -432,12 +435,6 @@ static int raw_pwrite(BlockDriverState *bs, int64_t offset, return raw_pwrite_aligned(bs, offset, buf, count) + sum; } -#else -#define raw_pread raw_pread_aligned -#define raw_pwrite raw_pwrite_aligned -#endif - - #ifdef CONFIG_AIO /***********************************************************/ /* Unix AIO using POSIX AIO */ @@ -661,7 +658,6 @@ static BlockDriverAIOCB *raw_aio_read(BlockDriverState *bs, * If O_DIRECT is used and the buffer is not aligned fall back * to synchronous IO. */ -#if defined(O_DIRECT) BDRVRawState *s = bs->opaque; if (unlikely(s->aligned_buf != NULL && ((uintptr_t) buf % 512))) { @@ -672,7 +668,6 @@ static BlockDriverAIOCB *raw_aio_read(BlockDriverState *bs, qemu_bh_schedule(bh); return &acb->common; } -#endif acb = raw_aio_setup(bs, sector_num, buf, nb_sectors, cb, opaque); if (!acb) @@ -694,7 +689,6 @@ static BlockDriverAIOCB *raw_aio_write(BlockDriverState *bs, * If O_DIRECT is used and the buffer is not aligned fall back * to synchronous IO. */ -#if defined(O_DIRECT) BDRVRawState *s = bs->opaque; if (unlikely(s->aligned_buf != NULL && ((uintptr_t) buf % 512))) { @@ -705,7 +699,6 @@ static BlockDriverAIOCB *raw_aio_write(BlockDriverState *bs, qemu_bh_schedule(bh); return &acb->common; } -#endif acb = raw_aio_setup(bs, sector_num, (uint8_t*)buf, nb_sectors, cb, opaque); if (!acb) @@ -770,10 +763,8 @@ static void raw_close(BlockDriverState *bs) if (s->fd >= 0) { close(s->fd); s->fd = -1; -#if defined(O_DIRECT) if (s->aligned_buf != NULL) qemu_free(s->aligned_buf); -#endif } raw_close_fd_pool(s); } @@ -1003,10 +994,12 @@ static int hdev_open(BlockDriverState *bs, const char *filename, int flags) open_flags |= O_RDONLY; bs->read_only = 1; } -#ifdef O_DIRECT - if (flags & BDRV_O_DIRECT) + /* Use O_DSYNC for write-through caching, no flags for write-back caching, + * and O_DIRECT for no caching. */ + if ((flags & BDRV_O_NOCACHE)) open_flags |= O_DIRECT; -#endif + else if (!(flags & BDRV_O_CACHE_WB)) + open_flags |= O_DSYNC; s->type = FTYPE_FILE; #if defined(__linux__) |