| Message ID | 1365581513-3475-6-git-send-email-wdongxu@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
On Wed, Apr 10, 2013 at 04:11:52PM +0800, Dong Xu Wang wrote: > + header.cluster_bits = ffs(cluster_size) - 1; > + if (header.cluster_bits < MIN_CLUSTER_BITS || > + header.cluster_bits > MAX_CLUSTER_BITS || > + (1 << header.cluster_bits) != cluster_size) { > + error_report( > + "Cluster size must be a power of two between %d and %dk", > + 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); > + return -EINVAL; > + } > + > + header.header_size = MAX(cluster_size, DEFAULT_HEADER_SIZE); Indentation. > + if (backing_filename) { > + header.backing_offset = sizeof(header); > + header.backing_size = strlen(backing_filename); > + > + if (!backing_fmt) { > + backing_bs = bdrv_new("image"); > + ret = bdrv_open(backing_bs, backing_filename, NULL, > + BDRV_O_RDWR | BDRV_O_CACHE_WB, NULL); > + if (ret < 0) { > + return ret; backing_bs is leaked. > + ret = bdrv_file_open(&bs, filename, NULL, BDRV_O_RDWR); > + if (ret < 0) { > + return ret; > + } > + snprintf(header.backing_fmt, sizeof(header.backing_fmt), "%s", > + backing_fmt ? backing_fmt : ""); > + snprintf(header.image_fmt, sizeof(header.image_fmt), "%s", > + image_format ? image_format : "raw"); snprintf() doesn't have the semantics in the add-cow specification: " 44 - 59: backing file format Format of backing file. It will be filled with 0 if backing file name offset is 0. If backing file name offset is non-empty, it must be non-empty. It is coded in free-form ASCII, and is not NUL-terminated. Zero padded on the right. 60 - 75: image file format Format of image file. It must be non-empty. It is coded in free-form ASCII, and is not NUL-terminated. Zero padded on the right." strncpy() does the zero padding and doesn't NUL-terminate if the max buffer size is used. > + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { > + snprintf(bs->backing_format, sizeof(bs->backing_format), > + "%s", s->header.backing_fmt); s->header.backing_fmt is not NUL-terminated so using snprintf() is inappropriate (could it read beyond the end of .backing_fmt?). > + } > + > + if (s->header.cluster_bits < MIN_CLUSTER_BITS || > + s->header.cluster_bits > MAX_CLUSTER_BITS) { > + ret = -EINVAL; > + goto fail; > + } > + > + s->cluster_size = 1 << s->header.cluster_bits; > + if (s->header.header_size != MAX(s->cluster_size, DEFAULT_HEADER_SIZE)) { > + char buf[64]; > + snprintf(buf, sizeof(buf), "Header size: %d", %u or PRIu32 since header_size is uint32_t. This avoids compiler or code scanner warnings. > + s->image_hd = bdrv_new(""); > + ret = bdrv_open(s->image_hd, image_filename, NULL, flags, > + bdrv_find_format(s->header.image_fmt)); Cannot use image_fmt as a string since it is not NUL-terminated. > +static coroutine_fn int add_cow_co_writev(BlockDriverState *bs, > + int64_t sector_num, > + int remaining_sectors, > + QEMUIOVector *qiov) > +{ > + BDRVAddCowState *s = bs->opaque; > + int ret = 0, i; > + QEMUIOVector hd_qiov; > + uint8_t *table; > + uint64_t offset; > + int mask = s->cluster_sectors - 1; > + int cluster_mask = s->cluster_size - 1; > + > + qemu_co_mutex_lock(&s->lock); > + qemu_iovec_init(&hd_qiov, qiov->niov); > + ret = bdrv_co_writev(s->image_hd, sector_num, > + remaining_sectors, qiov); All writes are serialized. This means write performance will be very poor for multi-threaded workloads. qcow2 tracks allocating writes and allows them to execute at the same time if they do not overlap clusters. > + > + if (ret < 0) { > + goto fail; > + } > + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { > + /* Copy content of unmodified sectors */ > + if (!is_cluster_head(sector_num, s->cluster_sectors) > + && !is_allocated(bs, sector_num)) { > + ret = copy_sectors(bs, sector_num & ~mask, sector_num); > + if (ret < 0) { > + goto fail; > + } > + } > + > + if (!is_cluster_tail(sector_num + remaining_sectors - 1, > + s->cluster_sectors) > + && !is_allocated(bs, sector_num + remaining_sectors - 1)) { > + ret = copy_sectors(bs, sector_num + remaining_sectors, > + ((sector_num + remaining_sectors) | mask) + 1); > + if (ret < 0) { > + goto fail; > + } > + } This trashes the cluster when remaining_sectors = 0, sector_num = cluster_sectors, and sector cluster_sectors - 1 is unallocated. Probably best to return early when remaining_sectors == 0. > + > + for (i = sector_num / s->cluster_sectors; > + i <= (sector_num + remaining_sectors - 1) / s->cluster_sectors; > + i++) { > + offset = s->header.header_size > + + (offset_in_bitmap(i * s->cluster_sectors, > + s->cluster_sectors) & (~cluster_mask)); > + ret = block_cache_get(bs, s->bitmap_cache, offset, (void **)&table); > + if (ret < 0) { > + goto fail; > + } > + if ((table[i / 8] & (1 << (i % 8))) == 0) { > + table[i / 8] |= (1 << (i % 8)); i is based on sector_num while table[] starts at offset, not sector 0. The index expression i / 8 leads to out-of-bounds accesses. I think you forgot to & (s->cluster_sectors - 1). > +static coroutine_fn int add_cow_co_flush(BlockDriverState *bs) > +{ > + BDRVAddCowState *s = bs->opaque; > + int ret; > + > + qemu_co_mutex_lock(&s->lock); > + if (s->bitmap_cache) { > + ret = block_cache_flush(bs, s->bitmap_cache); > + if (ret < 0) { > + return ret; > + } > + } > + ret = bdrv_flush(s->image_hd); This is the wrong way around. We must flush image_hd first so that valid data is on disk. Then we can flush bitmap_cache to mark the clusters allocated. Beyond explicit flushes you also need to make sure that image_hd is flushed *before* bitmap_cache tables are written out (e.g. cache eviction when the cache becomes full). It seems this code is missing. Also please use bdrv_co_flush() instead of bdrv_flush() in add_cow_co_flush() since this is a coroutine function. > diff --git a/block/block-cache.c b/block/block-cache.c > index 3544691..4824632 100644 > --- a/block/block-cache.c > +++ b/block/block-cache.c > @@ -130,7 +130,7 @@ static int block_cache_entry_flush(BlockDriverState *bs, BlockCache *c, int i) > } else if (c->table_type == BLOCK_TABLE_L2) { > BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); > } else if (c->table_type == BLOCK_TABLE_BITMAP) { > - BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE); > + BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); > } > > ret = bdrv_pwrite(bs->file, c->entries[i].offset, > @@ -265,7 +265,7 @@ static int block_cache_do_get(BlockDriverState *bs, BlockCache *c, > if (c->table_type == BLOCK_TABLE_L2) { > BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); > } else if (c->table_type == BLOCK_TABLE_BITMAP) { > - BLKDBG_EVENT(bs->file, BLKDBG_COW_READ); > + BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); > } > > ret = bdrv_pread(bs->file, offset, c->entries[i].table, I commented on this in the previous patch. Please squash this fix into the previous patch. > diff --git a/block/qcow2.h b/block/qcow2.h > index e7f6aec..a4e514b 100644 > --- a/block/qcow2.h > +++ b/block/qcow2.h > @@ -98,6 +98,9 @@ typedef struct QCowSnapshot { > uint64_t vm_clock_nsec; > } QCowSnapshot; > > +struct BlockCache; > +typedef struct BlockCache BlockCache; > + > typedef struct Qcow2UnknownHeaderExtension { > uint32_t magic; > uint32_t len; > @@ -389,7 +392,4 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name); > void qcow2_free_snapshots(BlockDriverState *bs); > int qcow2_read_snapshots(BlockDriverState *bs); > > -/* qcow2-cache.c functions */ > - > - More qcow2-cache.c move cleanups? Please squash into the previous patch.
On 2013/4/18 18:03, Stefan Hajnoczi wrote: > On Wed, Apr 10, 2013 at 04:11:52PM +0800, Dong Xu Wang wrote: >> + header.cluster_bits = ffs(cluster_size) - 1; >> + if (header.cluster_bits < MIN_CLUSTER_BITS || >> + header.cluster_bits > MAX_CLUSTER_BITS || >> + (1 << header.cluster_bits) != cluster_size) { >> + error_report( >> + "Cluster size must be a power of two between %d and %dk", >> + 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); >> + return -EINVAL; >> + } >> + >> + header.header_size = MAX(cluster_size, DEFAULT_HEADER_SIZE); > > Indentation. > okay. >> + if (backing_filename) { >> + header.backing_offset = sizeof(header); >> + header.backing_size = strlen(backing_filename); >> + >> + if (!backing_fmt) { >> + backing_bs = bdrv_new("image"); >> + ret = bdrv_open(backing_bs, backing_filename, NULL, >> + BDRV_O_RDWR | BDRV_O_CACHE_WB, NULL); >> + if (ret < 0) { >> + return ret; > > backing_bs is leaked. Okay. will fix. > >> + ret = bdrv_file_open(&bs, filename, NULL, BDRV_O_RDWR); >> + if (ret < 0) { >> + return ret; >> + } >> + snprintf(header.backing_fmt, sizeof(header.backing_fmt), "%s", >> + backing_fmt ? backing_fmt : ""); >> + snprintf(header.image_fmt, sizeof(header.image_fmt), "%s", >> + image_format ? image_format : "raw"); > > snprintf() doesn't have the semantics in the add-cow specification: > > " 44 - 59: backing file format > Format of backing file. It will be filled with > 0 if backing file name offset is 0. If backing > file name offset is non-empty, it must be > non-empty. It is coded in free-form ASCII, and > is not NUL-terminated. Zero padded on the right. > > 60 - 75: image file format > Format of image file. It must be non-empty. It > is coded in free-form ASCII, and is not > NUL-terminated. Zero padded on the right." > > strncpy() does the zero padding and doesn't NUL-terminate if the max buffer > size is used. > Okay. >> + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { >> + snprintf(bs->backing_format, sizeof(bs->backing_format), >> + "%s", s->header.backing_fmt); > > s->header.backing_fmt is not NUL-terminated so using snprintf() is > inappropriate (could it read beyond the end of .backing_fmt?). > Okay. >> + } >> + >> + if (s->header.cluster_bits < MIN_CLUSTER_BITS || >> + s->header.cluster_bits > MAX_CLUSTER_BITS) { >> + ret = -EINVAL; >> + goto fail; >> + } >> + >> + s->cluster_size = 1 << s->header.cluster_bits; >> + if (s->header.header_size != MAX(s->cluster_size, DEFAULT_HEADER_SIZE)) { >> + char buf[64]; >> + snprintf(buf, sizeof(buf), "Header size: %d", > > %u or PRIu32 since header_size is uint32_t. This avoids compiler or > code scanner warnings. > Okay. >> + s->image_hd = bdrv_new(""); >> + ret = bdrv_open(s->image_hd, image_filename, NULL, flags, >> + bdrv_find_format(s->header.image_fmt)); > > Cannot use image_fmt as a string since it is not NUL-terminated. > Okay. >> +static coroutine_fn int add_cow_co_writev(BlockDriverState *bs, >> + int64_t sector_num, >> + int remaining_sectors, >> + QEMUIOVector *qiov) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + int ret = 0, i; >> + QEMUIOVector hd_qiov; >> + uint8_t *table; >> + uint64_t offset; >> + int mask = s->cluster_sectors - 1; >> + int cluster_mask = s->cluster_size - 1; >> + >> + qemu_co_mutex_lock(&s->lock); >> + qemu_iovec_init(&hd_qiov, qiov->niov); >> + ret = bdrv_co_writev(s->image_hd, sector_num, >> + remaining_sectors, qiov); > > All writes are serialized. This means write performance will be very > poor for multi-threaded workloads. > > qcow2 tracks allocating writes and allows them to execute at the same > time if they do not overlap clusters. > Okay, will refer qcow2 related code. >> + >> + if (ret < 0) { >> + goto fail; >> + } >> + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { >> + /* Copy content of unmodified sectors */ >> + if (!is_cluster_head(sector_num, s->cluster_sectors) >> + && !is_allocated(bs, sector_num)) { >> + ret = copy_sectors(bs, sector_num & ~mask, sector_num); >> + if (ret < 0) { >> + goto fail; >> + } >> + } >> + >> + if (!is_cluster_tail(sector_num + remaining_sectors - 1, >> + s->cluster_sectors) >> + && !is_allocated(bs, sector_num + remaining_sectors - 1)) { >> + ret = copy_sectors(bs, sector_num + remaining_sectors, >> + ((sector_num + remaining_sectors) | mask) + 1); >> + if (ret < 0) { >> + goto fail; >> + } >> + } > > This trashes the cluster when remaining_sectors = 0, sector_num = > cluster_sectors, and sector cluster_sectors - 1 is unallocated. > > Probably best to return early when remaining_sectors == 0. > Okay. >> + >> + for (i = sector_num / s->cluster_sectors; >> + i <= (sector_num + remaining_sectors - 1) / s->cluster_sectors; >> + i++) { >> + offset = s->header.header_size >> + + (offset_in_bitmap(i * s->cluster_sectors, >> + s->cluster_sectors) & (~cluster_mask)); >> + ret = block_cache_get(bs, s->bitmap_cache, offset, (void **)&table); >> + if (ret < 0) { >> + goto fail; >> + } >> + if ((table[i / 8] & (1 << (i % 8))) == 0) { >> + table[i / 8] |= (1 << (i % 8)); > > i is based on sector_num while table[] starts at offset, not sector 0. > The index expression i / 8 leads to out-of-bounds accesses. > > I think you forgot to & (s->cluster_sectors - 1). > Okay. >> +static coroutine_fn int add_cow_co_flush(BlockDriverState *bs) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + int ret; >> + >> + qemu_co_mutex_lock(&s->lock); >> + if (s->bitmap_cache) { >> + ret = block_cache_flush(bs, s->bitmap_cache); >> + if (ret < 0) { >> + return ret; >> + } >> + } >> + ret = bdrv_flush(s->image_hd); > > This is the wrong way around. We must flush image_hd first so that > valid data is on disk. Then we can flush bitmap_cache to mark the > clusters allocated. > > Beyond explicit flushes you also need to make sure that image_hd is > flushed *before* bitmap_cache tables are written out (e.g. cache > eviction when the cache becomes full). It seems this code is missing. > > Also please use bdrv_co_flush() instead of bdrv_flush() in > add_cow_co_flush() since this is a coroutine function. > Okay. >> diff --git a/block/block-cache.c b/block/block-cache.c >> index 3544691..4824632 100644 >> --- a/block/block-cache.c >> +++ b/block/block-cache.c >> @@ -130,7 +130,7 @@ static int block_cache_entry_flush(BlockDriverState *bs, BlockCache *c, int i) >> } else if (c->table_type == BLOCK_TABLE_L2) { >> BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); >> } else if (c->table_type == BLOCK_TABLE_BITMAP) { >> - BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE); >> + BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); >> } >> >> ret = bdrv_pwrite(bs->file, c->entries[i].offset, >> @@ -265,7 +265,7 @@ static int block_cache_do_get(BlockDriverState *bs, BlockCache *c, >> if (c->table_type == BLOCK_TABLE_L2) { >> BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); >> } else if (c->table_type == BLOCK_TABLE_BITMAP) { >> - BLKDBG_EVENT(bs->file, BLKDBG_COW_READ); >> + BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); >> } >> >> ret = bdrv_pread(bs->file, offset, c->entries[i].table, > > I commented on this in the previous patch. Please squash this fix into > the previous patch. > Okay. >> diff --git a/block/qcow2.h b/block/qcow2.h >> index e7f6aec..a4e514b 100644 >> --- a/block/qcow2.h >> +++ b/block/qcow2.h >> @@ -98,6 +98,9 @@ typedef struct QCowSnapshot { >> uint64_t vm_clock_nsec; >> } QCowSnapshot; >> >> +struct BlockCache; >> +typedef struct BlockCache BlockCache; >> + >> typedef struct Qcow2UnknownHeaderExtension { >> uint32_t magic; >> uint32_t len; >> @@ -389,7 +392,4 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name); >> void qcow2_free_snapshots(BlockDriverState *bs); >> int qcow2_read_snapshots(BlockDriverState *bs); >> >> -/* qcow2-cache.c functions */ >> - >> - > > More qcow2-cache.c move cleanups? Please squash into the previous > patch. Okay. > >
On Thu, Apr 18, 2013 at 6:03 PM, Stefan Hajnoczi <stefanha@gmail.com> wrote: > On Wed, Apr 10, 2013 at 04:11:52PM +0800, Dong Xu Wang wrote: >> + header.cluster_bits = ffs(cluster_size) - 1; >> + if (header.cluster_bits < MIN_CLUSTER_BITS || >> + header.cluster_bits > MAX_CLUSTER_BITS || >> + (1 << header.cluster_bits) != cluster_size) { >> + error_report( >> + "Cluster size must be a power of two between %d and %dk", >> + 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); >> + return -EINVAL; >> + } >> + >> + header.header_size = MAX(cluster_size, DEFAULT_HEADER_SIZE); > > Indentation. > >> + if (backing_filename) { >> + header.backing_offset = sizeof(header); >> + header.backing_size = strlen(backing_filename); >> + >> + if (!backing_fmt) { >> + backing_bs = bdrv_new("image"); >> + ret = bdrv_open(backing_bs, backing_filename, NULL, >> + BDRV_O_RDWR | BDRV_O_CACHE_WB, NULL); >> + if (ret < 0) { >> + return ret; > > backing_bs is leaked. > >> + ret = bdrv_file_open(&bs, filename, NULL, BDRV_O_RDWR); >> + if (ret < 0) { >> + return ret; >> + } >> + snprintf(header.backing_fmt, sizeof(header.backing_fmt), "%s", >> + backing_fmt ? backing_fmt : ""); >> + snprintf(header.image_fmt, sizeof(header.image_fmt), "%s", >> + image_format ? image_format : "raw"); > > snprintf() doesn't have the semantics in the add-cow specification: > > " 44 - 59: backing file format > Format of backing file. It will be filled with > 0 if backing file name offset is 0. If backing > file name offset is non-empty, it must be > non-empty. It is coded in free-form ASCII, and > is not NUL-terminated. Zero padded on the right. > > 60 - 75: image file format > Format of image file. It must be non-empty. It > is coded in free-form ASCII, and is not > NUL-terminated. Zero padded on the right." > > strncpy() does the zero padding and doesn't NUL-terminate if the max buffer > size is used. > >> + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { >> + snprintf(bs->backing_format, sizeof(bs->backing_format), >> + "%s", s->header.backing_fmt); > > s->header.backing_fmt is not NUL-terminated so using snprintf() is > inappropriate (could it read beyond the end of .backing_fmt?). > >> + } >> + >> + if (s->header.cluster_bits < MIN_CLUSTER_BITS || >> + s->header.cluster_bits > MAX_CLUSTER_BITS) { >> + ret = -EINVAL; >> + goto fail; >> + } >> + >> + s->cluster_size = 1 << s->header.cluster_bits; >> + if (s->header.header_size != MAX(s->cluster_size, DEFAULT_HEADER_SIZE)) { >> + char buf[64]; >> + snprintf(buf, sizeof(buf), "Header size: %d", > > %u or PRIu32 since header_size is uint32_t. This avoids compiler or > code scanner warnings. > >> + s->image_hd = bdrv_new(""); >> + ret = bdrv_open(s->image_hd, image_filename, NULL, flags, >> + bdrv_find_format(s->header.image_fmt)); > > Cannot use image_fmt as a string since it is not NUL-terminated. > >> +static coroutine_fn int add_cow_co_writev(BlockDriverState *bs, >> + int64_t sector_num, >> + int remaining_sectors, >> + QEMUIOVector *qiov) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + int ret = 0, i; >> + QEMUIOVector hd_qiov; >> + uint8_t *table; >> + uint64_t offset; >> + int mask = s->cluster_sectors - 1; >> + int cluster_mask = s->cluster_size - 1; >> + >> + qemu_co_mutex_lock(&s->lock); >> + qemu_iovec_init(&hd_qiov, qiov->niov); >> + ret = bdrv_co_writev(s->image_hd, sector_num, >> + remaining_sectors, qiov); > > All writes are serialized. This means write performance will be very > poor for multi-threaded workloads. > > qcow2 tracks allocating writes and allows them to execute at the same > time if they do not overlap clusters. > >> + >> + if (ret < 0) { >> + goto fail; >> + } >> + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { >> + /* Copy content of unmodified sectors */ >> + if (!is_cluster_head(sector_num, s->cluster_sectors) >> + && !is_allocated(bs, sector_num)) { >> + ret = copy_sectors(bs, sector_num & ~mask, sector_num); >> + if (ret < 0) { >> + goto fail; >> + } >> + } >> + >> + if (!is_cluster_tail(sector_num + remaining_sectors - 1, >> + s->cluster_sectors) >> + && !is_allocated(bs, sector_num + remaining_sectors - 1)) { >> + ret = copy_sectors(bs, sector_num + remaining_sectors, >> + ((sector_num + remaining_sectors) | mask) + 1); >> + if (ret < 0) { >> + goto fail; >> + } >> + } > > This trashes the cluster when remaining_sectors = 0, sector_num = > cluster_sectors, and sector cluster_sectors - 1 is unallocated. > > Probably best to return early when remaining_sectors == 0. > >> + >> + for (i = sector_num / s->cluster_sectors; >> + i <= (sector_num + remaining_sectors - 1) / s->cluster_sectors; >> + i++) { >> + offset = s->header.header_size >> + + (offset_in_bitmap(i * s->cluster_sectors, >> + s->cluster_sectors) & (~cluster_mask)); >> + ret = block_cache_get(bs, s->bitmap_cache, offset, (void **)&table); >> + if (ret < 0) { >> + goto fail; >> + } >> + if ((table[i / 8] & (1 << (i % 8))) == 0) { >> + table[i / 8] |= (1 << (i % 8)); > > i is based on sector_num while table[] starts at offset, not sector 0. > The index expression i / 8 leads to out-of-bounds accesses. > > I think you forgot to & (s->cluster_sectors - 1). > >> +static coroutine_fn int add_cow_co_flush(BlockDriverState *bs) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + int ret; >> + >> + qemu_co_mutex_lock(&s->lock); >> + if (s->bitmap_cache) { >> + ret = block_cache_flush(bs, s->bitmap_cache); >> + if (ret < 0) { >> + return ret; >> + } >> + } >> + ret = bdrv_flush(s->image_hd); > > This is the wrong way around. We must flush image_hd first so that > valid data is on disk. Then we can flush bitmap_cache to mark the > clusters allocated. > > Beyond explicit flushes you also need to make sure that image_hd is > flushed *before* bitmap_cache tables are written out (e.g. cache > eviction when the cache becomes full). It seems this code is missing. > Hi Stefan, how can I make sure image_hd "flush" operation completed before I write bitmap_cache tables? Is there any functions I can use? Thank you. > Also please use bdrv_co_flush() instead of bdrv_flush() in > add_cow_co_flush() since this is a coroutine function. > >> diff --git a/block/block-cache.c b/block/block-cache.c >> index 3544691..4824632 100644 >> --- a/block/block-cache.c >> +++ b/block/block-cache.c >> @@ -130,7 +130,7 @@ static int block_cache_entry_flush(BlockDriverState *bs, BlockCache *c, int i) >> } else if (c->table_type == BLOCK_TABLE_L2) { >> BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); >> } else if (c->table_type == BLOCK_TABLE_BITMAP) { >> - BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE); >> + BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); >> } >> >> ret = bdrv_pwrite(bs->file, c->entries[i].offset, >> @@ -265,7 +265,7 @@ static int block_cache_do_get(BlockDriverState *bs, BlockCache *c, >> if (c->table_type == BLOCK_TABLE_L2) { >> BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); >> } else if (c->table_type == BLOCK_TABLE_BITMAP) { >> - BLKDBG_EVENT(bs->file, BLKDBG_COW_READ); >> + BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); >> } >> >> ret = bdrv_pread(bs->file, offset, c->entries[i].table, > > I commented on this in the previous patch. Please squash this fix into > the previous patch. > >> diff --git a/block/qcow2.h b/block/qcow2.h >> index e7f6aec..a4e514b 100644 >> --- a/block/qcow2.h >> +++ b/block/qcow2.h >> @@ -98,6 +98,9 @@ typedef struct QCowSnapshot { >> uint64_t vm_clock_nsec; >> } QCowSnapshot; >> >> +struct BlockCache; >> +typedef struct BlockCache BlockCache; >> + >> typedef struct Qcow2UnknownHeaderExtension { >> uint32_t magic; >> uint32_t len; >> @@ -389,7 +392,4 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name); >> void qcow2_free_snapshots(BlockDriverState *bs); >> int qcow2_read_snapshots(BlockDriverState *bs); >> >> -/* qcow2-cache.c functions */ >> - >> - > > More qcow2-cache.c move cleanups? Please squash into the previous > patch. >
On Thu, May 09, 2013 at 02:24:20PM +0800, Dong Xu Wang wrote: > On Thu, Apr 18, 2013 at 6:03 PM, Stefan Hajnoczi <stefanha@gmail.com> wrote: > > On Wed, Apr 10, 2013 at 04:11:52PM +0800, Dong Xu Wang wrote: > >> +static coroutine_fn int add_cow_co_flush(BlockDriverState *bs) > >> +{ > >> + BDRVAddCowState *s = bs->opaque; > >> + int ret; > >> + > >> + qemu_co_mutex_lock(&s->lock); > >> + if (s->bitmap_cache) { > >> + ret = block_cache_flush(bs, s->bitmap_cache); > >> + if (ret < 0) { > >> + return ret; > >> + } > >> + } > >> + ret = bdrv_flush(s->image_hd); > > > > This is the wrong way around. We must flush image_hd first so that > > valid data is on disk. Then we can flush bitmap_cache to mark the > > clusters allocated. > > > > Beyond explicit flushes you also need to make sure that image_hd is > > flushed *before* bitmap_cache tables are written out (e.g. cache > > eviction when the cache becomes full). It seems this code is missing. > > > Hi Stefan, how can I make sure image_hd "flush" operation completed before > I write bitmap_cache tables? Is there any functions I can use? You could extend the block cache like this: block_cache_add_dependency_func(BlockCache *c, int (*dependency_fn)(BlockCache *c, void *opaque), void *opaque); Then add-cow would register a custom dependency function that flushes image_hd. A hackier way of achieving the same thing is to instantiate an image_hd_cache and set a dependency from the bitmap_cache on the image_hd_cache. The image_hd_cache actually has no cache entries, but it uses image_hd and will flush it. Stefan
On Wed, Apr 10, 2013 at 04:11:52PM +0800, Dong Xu Wang wrote: > add-cow file format core code. It use block-cache.c as cache code. > It lacks of snapshot_blkdev support. > > Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com> > --- > v17-v18: > 1) use error_report, not fprintf. > 2) remove version field from header. > 3) header_size is MAX(cluster_size, 4096). > 4) introduce s->cluster_sectors. > 5) use BLKDBG_L2_LOAD/UPDATE. > > v16->v17: > 1) Use stringify. > > v15->v16: > 1) Judge if opts is null in add_cow_create function. > block/Makefile.objs | 1 + > block/add-cow.c | 741 ++++++++++++++++++++++++++++++++++++++++++++++ > block/block-cache.c | 4 +- > block/qcow2.h | 6 +- > include/block/block_int.h | 2 + > 5 files changed, 749 insertions(+), 5 deletions(-) > create mode 100644 block/add-cow.c > > diff --git a/block/Makefile.objs b/block/Makefile.objs > index 4fe81dc..69cbb09 100644 > --- a/block/Makefile.objs > +++ b/block/Makefile.objs > @@ -1,6 +1,7 @@ > block-obj-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vvfat.o > block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o > block-obj-y += block-cache.o > +block-obj-y += add-cow.o > block-obj-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o > block-obj-y += qed-check.o > block-obj-y += parallels.o blkdebug.o blkverify.o > diff --git a/block/add-cow.c b/block/add-cow.c > new file mode 100644 > index 0000000..904b008 > --- /dev/null > +++ b/block/add-cow.c > @@ -0,0 +1,741 @@ > +/* > + * QEMU ADD-COW Disk Format > + * > + * Copyright IBM, Corp. 2012 > + * > + * Authors: > + * Dong Xu Wang <wdongxu@linux.vnet.ibm.com> > + * > + * This work is licensed under the terms of the GNU LGPL, version 2 or later. > + * See the COPYING.LIB file in the top-level directory. > + * > + */ > + > +#include "qemu-common.h" > +#include "block/block_int.h" > +#include "qemu/module.h" > +#include "block/block-cache.h" > + > +#define ACOW_CLUSTER_SIZE 65536 > +enum { > + /* compat_features bit */ > + ACOW_F_ALL_ALLOCATED = 0X01, > + > + /* none feature bit used now */ > + ACOW_FEATURE_MASK = 0, > + > + ACOW_MAGIC = 'A' | 'C' << 8 | 'O' << 16 | 'W' << 24, > + ACOW_CACHE_SIZE = 16, > + DEFAULT_HEADER_SIZE = 4096, > + MIN_CLUSTER_BITS = 9, > + MAX_CLUSTER_BITS = 21, > +}; > + > +typedef struct AddCowHeader { > + uint32_t magic; > + > + uint32_t backing_offset; > + uint32_t backing_size; > + uint32_t image_offset; > + uint32_t image_size; > + > + uint32_t cluster_bits; > + uint64_t features; > + uint64_t compat_features; > + uint32_t header_size; > + > + char backing_fmt[16]; > + char image_fmt[16]; > +} QEMU_PACKED AddCowHeader; > + > +typedef struct BDRVAddCowState { > + BlockDriverState *image_hd; > + CoMutex lock; > + int cluster_size; > + int cluster_sectors; > + BlockCache *bitmap_cache; > + uint64_t bitmap_size; > + AddCowHeader header; > + char backing_fmt[16]; > + char image_fmt[16]; > +} BDRVAddCowState; > + > +/* Convert sector_num to offset in bitmap */ > +static inline int64_t offset_in_bitmap(int64_t sector_num, > + int64_t cluster_sectors) > +{ > + int64_t cluster_num = sector_num / cluster_sectors; > + return cluster_num / 8; > +} > + > +static inline bool is_cluster_head(int64_t sector_num, > + int64_t cluster_sectors) > +{ > + return sector_num % cluster_sectors == 0; > +} > + > +static inline bool is_cluster_tail(int64_t sector_num, > + int64_t cluster_sectors) > +{ > + return (sector_num + 1) % cluster_sectors == 0; > +} > + > +static void add_cow_header_le_to_cpu(const AddCowHeader *le, AddCowHeader *cpu) > +{ > + cpu->magic = le32_to_cpu(le->magic); > + > + cpu->backing_offset = le32_to_cpu(le->backing_offset); > + cpu->backing_size = le32_to_cpu(le->backing_size); > + cpu->image_offset = le32_to_cpu(le->image_offset); > + cpu->image_size = le32_to_cpu(le->image_size); > + > + cpu->cluster_bits = le32_to_cpu(le->cluster_bits); > + cpu->features = le64_to_cpu(le->features); > + cpu->compat_features = le64_to_cpu(le->compat_features); > + cpu->header_size = le32_to_cpu(le->header_size); > + > + memcpy(cpu->backing_fmt, le->backing_fmt, sizeof(cpu->backing_fmt)); > + memcpy(cpu->image_fmt, le->image_fmt, sizeof(cpu->image_fmt)); > +} > + > +static void add_cow_header_cpu_to_le(const AddCowHeader *cpu, AddCowHeader *le) > +{ > + le->magic = cpu_to_le32(cpu->magic); > + > + le->backing_offset = cpu_to_le32(cpu->backing_offset); > + le->backing_size = cpu_to_le32(cpu->backing_size); > + le->image_offset = cpu_to_le32(cpu->image_offset); > + le->image_size = cpu_to_le32(cpu->image_size); > + > + le->cluster_bits = cpu_to_le32(cpu->cluster_bits); > + le->features = cpu_to_le64(cpu->features); > + le->compat_features = cpu_to_le64(cpu->compat_features); > + le->header_size = cpu_to_le32(cpu->header_size); > + memcpy(le->backing_fmt, cpu->backing_fmt, sizeof(le->backing_fmt)); > + memcpy(le->image_fmt, cpu->image_fmt, sizeof(le->image_fmt)); > +} > + > +static int add_cow_probe(const uint8_t *buf, int buf_size, const char *filename) > +{ > + const AddCowHeader *header = (const AddCowHeader *)buf; > + > + if (buf_size < sizeof(*header)) { > + return 0; > + } > + if (le32_to_cpu(header->magic) == ACOW_MAGIC) { > + return 100; > + } > + return 0; > +} > + > +static int add_cow_create(const char *filename, QemuOpts *opts) > +{ > + AddCowHeader header = { > + .magic = ACOW_MAGIC, > + .features = 0, > + .compat_features = 0, > + }; > + AddCowHeader le_header; > + int64_t image_len = 0; > + const char *backing_filename = NULL, *backing_fmt = NULL; > + const char *image_filename = NULL, *image_format = NULL; > + size_t cluster_size = ACOW_CLUSTER_SIZE; > + BlockDriverState *bs, *backing_bs; > + BlockDriver *drv = bdrv_find_format("add-cow"); > + int ret; > + > + image_len = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); > + backing_filename = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); > + backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); > + image_filename = qemu_opt_get(opts, BLOCK_OPT_IMAGE_FILE); > + image_format = qemu_opt_get(opts, BLOCK_OPT_IMAGE_FMT); > + cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, > + ACOW_CLUSTER_SIZE); > + > + header.cluster_bits = ffs(cluster_size) - 1; > + if (header.cluster_bits < MIN_CLUSTER_BITS || > + header.cluster_bits > MAX_CLUSTER_BITS || > + (1 << header.cluster_bits) != cluster_size) { > + error_report( > + "Cluster size must be a power of two between %d and %dk", > + 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); > + return -EINVAL; > + } > + > + header.header_size = MAX(cluster_size, DEFAULT_HEADER_SIZE); > + if (backing_filename) { > + header.backing_offset = sizeof(header); > + header.backing_size = strlen(backing_filename); > + > + if (!backing_fmt) { > + backing_bs = bdrv_new("image"); > + ret = bdrv_open(backing_bs, backing_filename, NULL, > + BDRV_O_RDWR | BDRV_O_CACHE_WB, NULL); > + if (ret < 0) { > + return ret; > + } > + backing_fmt = bdrv_get_format_name(backing_bs); > + bdrv_delete(backing_bs); > + } > + } else { > + header.compat_features |= ACOW_F_ALL_ALLOCATED; > + } > + > + if (image_filename) { > + header.image_offset = sizeof(header) + header.backing_size; > + header.image_size = strlen(image_filename); > + } else { > + error_report("Error: image_file should be given."); > + return -EINVAL; > + } > + > + if (backing_filename && !strcmp(backing_filename, image_filename)) { > + error_report("Error: Trying to create an image with the " > + "same backing file name as the image file name"); > + return -EINVAL; > + } > + > + if (!strcmp(filename, image_filename)) { > + error_report("Error: Trying to create an image with the " > + "same filename as the image file name"); > + return -EINVAL; > + } > + > + if (header.image_offset + header.image_size > header.header_size) { > + error_report("image_file name or backing_file name too long."); > + return -ENOSPC; > + } > + > + ret = bdrv_file_open(&bs, image_filename, NULL, 0); > + if (ret < 0) { > + return ret; > + } > + bdrv_close(bs); > + > + ret = bdrv_create_file(filename, NULL); > + if (ret < 0) { > + return ret; > + } > + > + ret = bdrv_file_open(&bs, filename, NULL, BDRV_O_RDWR); > + if (ret < 0) { > + return ret; > + } > + snprintf(header.backing_fmt, sizeof(header.backing_fmt), "%s", > + backing_fmt ? backing_fmt : ""); > + snprintf(header.image_fmt, sizeof(header.image_fmt), "%s", > + image_format ? image_format : "raw"); > + add_cow_header_cpu_to_le(&header, &le_header); > + ret = bdrv_pwrite(bs, 0, &le_header, sizeof(le_header)); > + if (ret < 0) { > + bdrv_delete(bs); > + return ret; > + } > + > + ret = bdrv_pwrite(bs, header.image_offset, image_filename, > + header.image_size); > + if (ret < 0) { > + bdrv_delete(bs); > + return ret; > + } > + > + if (backing_filename) { > + ret = bdrv_pwrite(bs, header.backing_offset, backing_filename, > + header.backing_size); > + if (ret < 0) { > + bdrv_delete(bs); > + return ret; > + } > + } > + bdrv_close(bs); > + > + ret = bdrv_open(bs, filename, NULL, BDRV_O_RDWR | BDRV_O_NO_FLUSH, drv); > + if (ret < 0) { > + bdrv_delete(bs); > + return ret; > + } > + > + ret = bdrv_truncate(bs, image_len); > + bdrv_delete(bs); > + return ret; > +} > + > +static int add_cow_open(BlockDriverState *bs, QDict *options, int flags) > +{ > + char image_filename[PATH_MAX]; > + char tmp_name[PATH_MAX]; > + int ret; > + int sector_per_byte; > + BDRVAddCowState *s = bs->opaque; > + AddCowHeader le_header; > + char backing_filename[PATH_MAX]; > + > + ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header)); > + if (ret < 0) { > + goto fail; > + } > + > + add_cow_header_le_to_cpu(&le_header, &s->header); > + > + if (s->header.magic != ACOW_MAGIC) { > + ret = -EINVAL; > + goto fail; > + } > + > + if (s->header.features & ~ACOW_FEATURE_MASK) { > + char buf[64]; > + snprintf(buf, sizeof(buf), "Feature Flags: %" PRIx64, > + s->header.features & ~ACOW_FEATURE_MASK); > + qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, > + bs->device_name, "add-cow", buf); > + return -ENOTSUP; > + } > + > + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { > + snprintf(bs->backing_format, sizeof(bs->backing_format), > + "%s", s->header.backing_fmt); > + } > + > + if (s->header.cluster_bits < MIN_CLUSTER_BITS || > + s->header.cluster_bits > MAX_CLUSTER_BITS) { > + ret = -EINVAL; > + goto fail; > + } > + > + s->cluster_size = 1 << s->header.cluster_bits; > + if (s->header.header_size != MAX(s->cluster_size, DEFAULT_HEADER_SIZE)) { > + char buf[64]; > + snprintf(buf, sizeof(buf), "Header size: %d", > + s->header.header_size); > + qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, > + bs->device_name, "add-cow", buf); > + return -ENOTSUP; > + } > + > + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { > + ret = bdrv_read_string(bs->file, s->header.backing_offset, > + s->header.backing_size, > + bs->backing_file, > + sizeof(bs->backing_file)); > + if (ret < 0) { > + goto fail; > + } > + } > + > + ret = bdrv_read_string(bs->file, s->header.image_offset, > + s->header.image_size, tmp_name, > + sizeof(tmp_name)); > + if (ret < 0) { > + goto fail; > + } > + > + if (path_has_protocol(tmp_name)) { > + pstrcpy(image_filename, sizeof(image_filename), tmp_name); > + } else { > + path_combine(image_filename, sizeof(image_filename), > + bs->filename, tmp_name); > + } > + bdrv_get_full_backing_filename(bs, backing_filename, > + sizeof(backing_filename)); > + if (!strcmp(backing_filename, image_filename)) { > + error_report("Error: backing file and image file are same: %s\n", > + backing_filename); > + ret = EINVAL; > + goto fail; > + } > + s->image_hd = bdrv_new(""); > + ret = bdrv_open(s->image_hd, image_filename, NULL, flags, > + bdrv_find_format(s->header.image_fmt)); > + if (ret < 0) { > + bdrv_delete(s->image_hd); > + goto fail; > + } > + > + bs->total_sectors = bdrv_getlength(s->image_hd) / BDRV_SECTOR_SIZE; > + s->cluster_sectors = s->cluster_size / BDRV_SECTOR_SIZE; > + sector_per_byte = s->cluster_sectors * 8; > + s->bitmap_size = > + (bs->total_sectors + sector_per_byte - 1) / sector_per_byte; > + s->bitmap_cache = block_cache_create(bs, ACOW_CACHE_SIZE, > + s->cluster_size, > + BLOCK_TABLE_BITMAP); > + qemu_co_mutex_init(&s->lock); > + return 0; > +fail: > + return ret; > +} > + > +static void add_cow_close(BlockDriverState *bs) > +{ > + BDRVAddCowState *s = bs->opaque; > + if (s->bitmap_cache) { > + block_cache_destroy(bs, s->bitmap_cache); > + } > + bdrv_delete(s->image_hd); > +} > + > +static bool is_allocated(BlockDriverState *bs, int64_t sector_num) > +{ > + BDRVAddCowState *s = bs->opaque; > + int64_t cluster_num = sector_num / s->cluster_sectors; > + uint8_t *table = NULL; > + bool val = false; > + int ret; > + > + uint64_t offset = s->header.header_size + > + (offset_in_bitmap(sector_num, s->cluster_sectors) > + & (~(s->cluster_size - 1))); > + ret = block_cache_get(bs, s->bitmap_cache, offset, (void **)&table); > + if (ret < 0) { > + return ret; > + } > + > + val = table[cluster_num / 8 % s->cluster_size] & (1 << (cluster_num % 8)); > + ret = block_cache_put(bs, s->bitmap_cache, (void **)&table); > + if (ret < 0) { > + return ret; > + } > + return val; > +} > + > +static coroutine_fn int add_cow_is_allocated(BlockDriverState *bs, > + int64_t sector_num, int nb_sectors, int *num_same) > +{ > + BDRVAddCowState *s = bs->opaque; > + int changed; > + > + if (nb_sectors == 0) { > + *num_same = 0; > + return 0; > + } > + > + if (s->header.compat_features & ACOW_F_ALL_ALLOCATED) { > + *num_same = nb_sectors; > + return 1; > + } > + changed = is_allocated(bs, sector_num); > + > + for (*num_same = 1; *num_same < nb_sectors; (*num_same)++) { > + if (is_allocated(bs, sector_num + *num_same) != changed) { > + break; > + } > + } > + return changed; > +} > + > +static int add_cow_backing_read(BlockDriverState *bs, QEMUIOVector *qiov, > + int64_t sector_num, int nb_sectors) > +{ > + int n1; > + if ((sector_num + nb_sectors) <= bs->total_sectors) { > + return nb_sectors; > + } > + if (sector_num >= bs->total_sectors) { > + n1 = 0; > + } else { > + n1 = bs->total_sectors - sector_num; > + } > + > + qemu_iovec_memset(qiov, BDRV_SECTOR_SIZE * n1, > + 0, BDRV_SECTOR_SIZE * (nb_sectors - n1)); > + > + return n1; > +} > + > +static coroutine_fn int add_cow_co_readv(BlockDriverState *bs, > + int64_t sector_num, > + int remaining_sectors, > + QEMUIOVector *qiov) > +{ > + BDRVAddCowState *s = bs->opaque; > + int cur_nr_sectors; > + uint64_t bytes_done = 0; > + QEMUIOVector hd_qiov; > + int n1, ret = 0; > + > + qemu_iovec_init(&hd_qiov, qiov->niov); > + qemu_co_mutex_lock(&s->lock); > + while (remaining_sectors != 0) { > + cur_nr_sectors = remaining_sectors; > + if (add_cow_is_allocated(bs, sector_num, cur_nr_sectors, > + &cur_nr_sectors)) { > + qemu_iovec_reset(&hd_qiov); > + qemu_iovec_concat(&hd_qiov, qiov, bytes_done, > + cur_nr_sectors * BDRV_SECTOR_SIZE); > + qemu_co_mutex_unlock(&s->lock); > + ret = bdrv_co_readv(s->image_hd, sector_num, > + cur_nr_sectors, &hd_qiov); > + qemu_co_mutex_lock(&s->lock); > + if (ret < 0) { > + goto fail; > + } > + } else { > + if (bs->backing_hd) { > + qemu_iovec_reset(&hd_qiov); > + qemu_iovec_concat(&hd_qiov, qiov, bytes_done, > + cur_nr_sectors * BDRV_SECTOR_SIZE); > + n1 = add_cow_backing_read(bs->backing_hd, &hd_qiov, > + sector_num, cur_nr_sectors); > + if (n1 > 0) { > + qemu_co_mutex_unlock(&s->lock); > + ret = bdrv_co_readv(bs->backing_hd, sector_num, > + cur_nr_sectors, &hd_qiov); > + qemu_co_mutex_lock(&s->lock); > + if (ret < 0) { > + goto fail; > + } > + } > + } else { > + qemu_iovec_memset(&hd_qiov, 0, 0, > + BDRV_SECTOR_SIZE * cur_nr_sectors); > + } > + } > + remaining_sectors -= cur_nr_sectors; > + sector_num += cur_nr_sectors; > + bytes_done += cur_nr_sectors * BDRV_SECTOR_SIZE; > + } > +fail: > + qemu_co_mutex_unlock(&s->lock); > + qemu_iovec_destroy(&hd_qiov); > + return ret; > +} > + > +static int coroutine_fn copy_sectors(BlockDriverState *bs, > + int n_start, int n_end) > +{ > + BDRVAddCowState *s = bs->opaque; > + QEMUIOVector qiov; > + struct iovec iov; > + int n, ret; > + > + n = n_end - n_start; > + if (n <= 0) { > + return 0; > + } > + > + iov.iov_len = n * BDRV_SECTOR_SIZE; > + iov.iov_base = qemu_blockalign(bs, iov.iov_len); > + > + qemu_iovec_init_external(&qiov, &iov, 1); > + > + ret = bdrv_co_readv(bs->backing_hd, n_start, n, &qiov); > + if (ret < 0) { > + goto out; > + } > + ret = bdrv_co_writev(s->image_hd, n_start, n, &qiov); > + if (ret < 0) { > + goto out; > + } > + > + ret = 0; > +out: > + qemu_vfree(iov.iov_base); > + return ret; > +} > + > +static coroutine_fn int add_cow_co_writev(BlockDriverState *bs, > + int64_t sector_num, > + int remaining_sectors, > + QEMUIOVector *qiov) > +{ > + BDRVAddCowState *s = bs->opaque; > + int ret = 0, i; > + QEMUIOVector hd_qiov; > + uint8_t *table; > + uint64_t offset; > + int mask = s->cluster_sectors - 1; > + int cluster_mask = s->cluster_size - 1; > + > + qemu_co_mutex_lock(&s->lock); > + qemu_iovec_init(&hd_qiov, qiov->niov); > + ret = bdrv_co_writev(s->image_hd, sector_num, > + remaining_sectors, qiov); > + > + if (ret < 0) { > + goto fail; > + } > + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { > + /* Copy content of unmodified sectors */ > + if (!is_cluster_head(sector_num, s->cluster_sectors) > + && !is_allocated(bs, sector_num)) { > + ret = copy_sectors(bs, sector_num & ~mask, sector_num); > + if (ret < 0) { > + goto fail; > + } > + } > + > + if (!is_cluster_tail(sector_num + remaining_sectors - 1, > + s->cluster_sectors) > + && !is_allocated(bs, sector_num + remaining_sectors - 1)) { > + ret = copy_sectors(bs, sector_num + remaining_sectors, > + ((sector_num + remaining_sectors) | mask) + 1); > + if (ret < 0) { > + goto fail; > + } > + } > + > + for (i = sector_num / s->cluster_sectors; > + i <= (sector_num + remaining_sectors - 1) / s->cluster_sectors; > + i++) { > + offset = s->header.header_size > + + (offset_in_bitmap(i * s->cluster_sectors, > + s->cluster_sectors) & (~cluster_mask)); > + ret = block_cache_get(bs, s->bitmap_cache, offset, (void **)&table); > + if (ret < 0) { > + goto fail; > + } > + if ((table[i / 8] & (1 << (i % 8))) == 0) { > + table[i / 8] |= (1 << (i % 8)); > + block_cache_entry_mark_dirty(s->bitmap_cache, table); > + } > + > + ret = block_cache_put(bs, s->bitmap_cache, (void **) &table); > + if (ret < 0) { > + goto fail; > + } > + } > + } > + ret = 0; > +fail: > + qemu_co_mutex_unlock(&s->lock); > + qemu_iovec_destroy(&hd_qiov); > + return ret; > +} > + > +static int bdrv_add_cow_truncate(BlockDriverState *bs, int64_t size) > +{ > + BDRVAddCowState *s = bs->opaque; > + int sector_per_byte = s->cluster_sectors * 8; > + int ret; > + int64_t bitmap_size = > + (size / BDRV_SECTOR_SIZE + sector_per_byte - 1) / sector_per_byte; > + bitmap_size = (bitmap_size + s->cluster_size - 1) > + & (~(s->cluster_size - 1)); > + > + ret = bdrv_truncate(bs->file, s->header.header_size + bitmap_size); > + if (ret < 0) { > + return ret; > + } > + > + ret = bdrv_truncate(s->image_hd, size); > + if (ret < 0) { > + return ret; > + } > + return 0; > +} > + > +static int add_cow_reopen_prepare(BDRVReopenState *state, > + BlockReopenQueue *queue, Error **errp) > +{ > + BDRVAddCowState *s; > + int ret = -1; > + > + assert(state != NULL); > + assert(state->bs != NULL); > + > + if (queue == NULL) { > + error_set(errp, ERROR_CLASS_GENERIC_ERROR, > + "No reopen queue for add-cow"); > + goto exit; > + } > + > + s = state->bs->opaque; > + > + assert(s != NULL); > + > + > + bdrv_reopen_queue(queue, s->image_hd, state->flags); > + ret = 0; > + > +exit: > + return ret; > +} > + > + > +static coroutine_fn int add_cow_co_flush(BlockDriverState *bs) > +{ > + BDRVAddCowState *s = bs->opaque; > + int ret; > + > + qemu_co_mutex_lock(&s->lock); > + if (s->bitmap_cache) { > + ret = block_cache_flush(bs, s->bitmap_cache); > + if (ret < 0) { > + return ret; > + } > + } > + ret = bdrv_flush(s->image_hd); > + qemu_co_mutex_unlock(&s->lock); > + return ret; > +} > + > +static int add_cow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) > +{ > + BDRVAddCowState *s = bs->opaque; > + bdi->cluster_size = s->cluster_size; > + return 0; > +} > + > +static QemuOptsList add_cow_create_opts = { > + .name = "add-cow-create-opts", > + .head = QTAILQ_HEAD_INITIALIZER(add_cow_create_opts.head), > + .desc = { > + { > + .name = BLOCK_OPT_SIZE, > + .type = QEMU_OPT_SIZE, > + .help = "Virtual disk size" > + }, > + { > + .name = BLOCK_OPT_BACKING_FILE, > + .type = QEMU_OPT_STRING, > + .help = "File name of a base image" > + }, > + { > + .name = BLOCK_OPT_BACKING_FMT, > + .type = QEMU_OPT_STRING, > + .help = "Image format of the base image" > + }, > + { > + .name = BLOCK_OPT_IMAGE_FILE, > + .type = QEMU_OPT_STRING, > + .help = "File name of a image file" > + }, > + { > + .name = BLOCK_OPT_IMAGE_FMT, > + .type = QEMU_OPT_STRING, > + .help = "Image format of the image file" > + }, > + { > + .name = BLOCK_OPT_CLUSTER_SIZE, > + .type = QEMU_OPT_SIZE, > + .help = "add-cow cluster size", > + .def_value_str = stringify(ACOW_CLUSTER_SIZE) Hi Dong, .def_value_str is undefined - it looks like this series is dependent on: [PATCH V14 1/6] add def_value_str in QemuOptDesc struct and rewrite qemu_opts_print In that 6-part series, patches 2,4,5 are also dependent on the above patch. Should these series be combined? You did mention in the header that this uses QemuOpts, but until I applied and tried compiling, it wasn't obvious (at least to me) the external patch dependency above. Thanks, Jeff > + }, > + { /* end of list */ } > + } > +}; > + > +static BlockDriver bdrv_add_cow = { > + .format_name = "add-cow", > + .instance_size = sizeof(BDRVAddCowState), > + .bdrv_probe = add_cow_probe, > + .bdrv_open = add_cow_open, > + .bdrv_close = add_cow_close, > + .bdrv_create = add_cow_create, > + .bdrv_co_readv = add_cow_co_readv, > + .bdrv_co_writev = add_cow_co_writev, > + .bdrv_truncate = bdrv_add_cow_truncate, > + .bdrv_co_is_allocated = add_cow_is_allocated, > + .bdrv_reopen_prepare = add_cow_reopen_prepare, > + .bdrv_get_info = add_cow_get_info, > + > + .bdrv_create_opts = &add_cow_create_opts, > + .bdrv_co_flush_to_os = add_cow_co_flush, > +}; > + > +static void bdrv_add_cow_init(void) > +{ > + bdrv_register(&bdrv_add_cow); > +} > + > +block_init(bdrv_add_cow_init); > diff --git a/block/block-cache.c b/block/block-cache.c > index 3544691..4824632 100644 > --- a/block/block-cache.c > +++ b/block/block-cache.c > @@ -130,7 +130,7 @@ static int block_cache_entry_flush(BlockDriverState *bs, BlockCache *c, int i) > } else if (c->table_type == BLOCK_TABLE_L2) { > BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); > } else if (c->table_type == BLOCK_TABLE_BITMAP) { > - BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE); > + BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); > } > > ret = bdrv_pwrite(bs->file, c->entries[i].offset, > @@ -265,7 +265,7 @@ static int block_cache_do_get(BlockDriverState *bs, BlockCache *c, > if (c->table_type == BLOCK_TABLE_L2) { > BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); > } else if (c->table_type == BLOCK_TABLE_BITMAP) { > - BLKDBG_EVENT(bs->file, BLKDBG_COW_READ); > + BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); > } > > ret = bdrv_pread(bs->file, offset, c->entries[i].table, > diff --git a/block/qcow2.h b/block/qcow2.h > index e7f6aec..a4e514b 100644 > --- a/block/qcow2.h > +++ b/block/qcow2.h > @@ -98,6 +98,9 @@ typedef struct QCowSnapshot { > uint64_t vm_clock_nsec; > } QCowSnapshot; > > +struct BlockCache; > +typedef struct BlockCache BlockCache; > + > typedef struct Qcow2UnknownHeaderExtension { > uint32_t magic; > uint32_t len; > @@ -389,7 +392,4 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name); > void qcow2_free_snapshots(BlockDriverState *bs); > int qcow2_read_snapshots(BlockDriverState *bs); > > -/* qcow2-cache.c functions */ > - > - > #endif > diff --git a/include/block/block_int.h b/include/block/block_int.h > index a44a9ac..b9eb9b8 100644 > --- a/include/block/block_int.h > +++ b/include/block/block_int.h > @@ -57,6 +57,8 @@ > #define BLOCK_OPT_COMPAT_LEVEL "compat" > #define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts" > #define BLOCK_OPT_ADAPTER_TYPE "adapter_type" > +#define BLOCK_OPT_IMAGE_FILE "image_file" > +#define BLOCK_OPT_IMAGE_FMT "image_fmt" > > typedef struct BdrvTrackedRequest BdrvTrackedRequest; > > -- > 1.7.11.7 > >
On 2013/5/13 23:07, Jeff Cody wrote: > On Wed, Apr 10, 2013 at 04:11:52PM +0800, Dong Xu Wang wrote: >> add-cow file format core code. It use block-cache.c as cache code. >> It lacks of snapshot_blkdev support. >> >> Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com> >> --- >> v17-v18: >> 1) use error_report, not fprintf. >> 2) remove version field from header. >> 3) header_size is MAX(cluster_size, 4096). >> 4) introduce s->cluster_sectors. >> 5) use BLKDBG_L2_LOAD/UPDATE. >> >> v16->v17: >> 1) Use stringify. >> >> v15->v16: >> 1) Judge if opts is null in add_cow_create function. >> block/Makefile.objs | 1 + >> block/add-cow.c | 741 ++++++++++++++++++++++++++++++++++++++++++++++ >> block/block-cache.c | 4 +- >> block/qcow2.h | 6 +- >> include/block/block_int.h | 2 + >> 5 files changed, 749 insertions(+), 5 deletions(-) >> create mode 100644 block/add-cow.c >> >> diff --git a/block/Makefile.objs b/block/Makefile.objs >> index 4fe81dc..69cbb09 100644 >> --- a/block/Makefile.objs >> +++ b/block/Makefile.objs >> @@ -1,6 +1,7 @@ >> block-obj-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vvfat.o >> block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o >> block-obj-y += block-cache.o >> +block-obj-y += add-cow.o >> block-obj-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o >> block-obj-y += qed-check.o >> block-obj-y += parallels.o blkdebug.o blkverify.o >> diff --git a/block/add-cow.c b/block/add-cow.c >> new file mode 100644 >> index 0000000..904b008 >> --- /dev/null >> +++ b/block/add-cow.c >> @@ -0,0 +1,741 @@ >> +/* >> + * QEMU ADD-COW Disk Format >> + * >> + * Copyright IBM, Corp. 2012 >> + * >> + * Authors: >> + * Dong Xu Wang <wdongxu@linux.vnet.ibm.com> >> + * >> + * This work is licensed under the terms of the GNU LGPL, version 2 or later. >> + * See the COPYING.LIB file in the top-level directory. >> + * >> + */ >> + >> +#include "qemu-common.h" >> +#include "block/block_int.h" >> +#include "qemu/module.h" >> +#include "block/block-cache.h" >> + >> +#define ACOW_CLUSTER_SIZE 65536 >> +enum { >> + /* compat_features bit */ >> + ACOW_F_ALL_ALLOCATED = 0X01, >> + >> + /* none feature bit used now */ >> + ACOW_FEATURE_MASK = 0, >> + >> + ACOW_MAGIC = 'A' | 'C' << 8 | 'O' << 16 | 'W' << 24, >> + ACOW_CACHE_SIZE = 16, >> + DEFAULT_HEADER_SIZE = 4096, >> + MIN_CLUSTER_BITS = 9, >> + MAX_CLUSTER_BITS = 21, >> +}; >> + >> +typedef struct AddCowHeader { >> + uint32_t magic; >> + >> + uint32_t backing_offset; >> + uint32_t backing_size; >> + uint32_t image_offset; >> + uint32_t image_size; >> + >> + uint32_t cluster_bits; >> + uint64_t features; >> + uint64_t compat_features; >> + uint32_t header_size; >> + >> + char backing_fmt[16]; >> + char image_fmt[16]; >> +} QEMU_PACKED AddCowHeader; >> + >> +typedef struct BDRVAddCowState { >> + BlockDriverState *image_hd; >> + CoMutex lock; >> + int cluster_size; >> + int cluster_sectors; >> + BlockCache *bitmap_cache; >> + uint64_t bitmap_size; >> + AddCowHeader header; >> + char backing_fmt[16]; >> + char image_fmt[16]; >> +} BDRVAddCowState; >> + >> +/* Convert sector_num to offset in bitmap */ >> +static inline int64_t offset_in_bitmap(int64_t sector_num, >> + int64_t cluster_sectors) >> +{ >> + int64_t cluster_num = sector_num / cluster_sectors; >> + return cluster_num / 8; >> +} >> + >> +static inline bool is_cluster_head(int64_t sector_num, >> + int64_t cluster_sectors) >> +{ >> + return sector_num % cluster_sectors == 0; >> +} >> + >> +static inline bool is_cluster_tail(int64_t sector_num, >> + int64_t cluster_sectors) >> +{ >> + return (sector_num + 1) % cluster_sectors == 0; >> +} >> + >> +static void add_cow_header_le_to_cpu(const AddCowHeader *le, AddCowHeader *cpu) >> +{ >> + cpu->magic = le32_to_cpu(le->magic); >> + >> + cpu->backing_offset = le32_to_cpu(le->backing_offset); >> + cpu->backing_size = le32_to_cpu(le->backing_size); >> + cpu->image_offset = le32_to_cpu(le->image_offset); >> + cpu->image_size = le32_to_cpu(le->image_size); >> + >> + cpu->cluster_bits = le32_to_cpu(le->cluster_bits); >> + cpu->features = le64_to_cpu(le->features); >> + cpu->compat_features = le64_to_cpu(le->compat_features); >> + cpu->header_size = le32_to_cpu(le->header_size); >> + >> + memcpy(cpu->backing_fmt, le->backing_fmt, sizeof(cpu->backing_fmt)); >> + memcpy(cpu->image_fmt, le->image_fmt, sizeof(cpu->image_fmt)); >> +} >> + >> +static void add_cow_header_cpu_to_le(const AddCowHeader *cpu, AddCowHeader *le) >> +{ >> + le->magic = cpu_to_le32(cpu->magic); >> + >> + le->backing_offset = cpu_to_le32(cpu->backing_offset); >> + le->backing_size = cpu_to_le32(cpu->backing_size); >> + le->image_offset = cpu_to_le32(cpu->image_offset); >> + le->image_size = cpu_to_le32(cpu->image_size); >> + >> + le->cluster_bits = cpu_to_le32(cpu->cluster_bits); >> + le->features = cpu_to_le64(cpu->features); >> + le->compat_features = cpu_to_le64(cpu->compat_features); >> + le->header_size = cpu_to_le32(cpu->header_size); >> + memcpy(le->backing_fmt, cpu->backing_fmt, sizeof(le->backing_fmt)); >> + memcpy(le->image_fmt, cpu->image_fmt, sizeof(le->image_fmt)); >> +} >> + >> +static int add_cow_probe(const uint8_t *buf, int buf_size, const char *filename) >> +{ >> + const AddCowHeader *header = (const AddCowHeader *)buf; >> + >> + if (buf_size < sizeof(*header)) { >> + return 0; >> + } >> + if (le32_to_cpu(header->magic) == ACOW_MAGIC) { >> + return 100; >> + } >> + return 0; >> +} >> + >> +static int add_cow_create(const char *filename, QemuOpts *opts) >> +{ >> + AddCowHeader header = { >> + .magic = ACOW_MAGIC, >> + .features = 0, >> + .compat_features = 0, >> + }; >> + AddCowHeader le_header; >> + int64_t image_len = 0; >> + const char *backing_filename = NULL, *backing_fmt = NULL; >> + const char *image_filename = NULL, *image_format = NULL; >> + size_t cluster_size = ACOW_CLUSTER_SIZE; >> + BlockDriverState *bs, *backing_bs; >> + BlockDriver *drv = bdrv_find_format("add-cow"); >> + int ret; >> + >> + image_len = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); >> + backing_filename = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); >> + backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); >> + image_filename = qemu_opt_get(opts, BLOCK_OPT_IMAGE_FILE); >> + image_format = qemu_opt_get(opts, BLOCK_OPT_IMAGE_FMT); >> + cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, >> + ACOW_CLUSTER_SIZE); >> + >> + header.cluster_bits = ffs(cluster_size) - 1; >> + if (header.cluster_bits < MIN_CLUSTER_BITS || >> + header.cluster_bits > MAX_CLUSTER_BITS || >> + (1 << header.cluster_bits) != cluster_size) { >> + error_report( >> + "Cluster size must be a power of two between %d and %dk", >> + 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); >> + return -EINVAL; >> + } >> + >> + header.header_size = MAX(cluster_size, DEFAULT_HEADER_SIZE); >> + if (backing_filename) { >> + header.backing_offset = sizeof(header); >> + header.backing_size = strlen(backing_filename); >> + >> + if (!backing_fmt) { >> + backing_bs = bdrv_new("image"); >> + ret = bdrv_open(backing_bs, backing_filename, NULL, >> + BDRV_O_RDWR | BDRV_O_CACHE_WB, NULL); >> + if (ret < 0) { >> + return ret; >> + } >> + backing_fmt = bdrv_get_format_name(backing_bs); >> + bdrv_delete(backing_bs); >> + } >> + } else { >> + header.compat_features |= ACOW_F_ALL_ALLOCATED; >> + } >> + >> + if (image_filename) { >> + header.image_offset = sizeof(header) + header.backing_size; >> + header.image_size = strlen(image_filename); >> + } else { >> + error_report("Error: image_file should be given."); >> + return -EINVAL; >> + } >> + >> + if (backing_filename && !strcmp(backing_filename, image_filename)) { >> + error_report("Error: Trying to create an image with the " >> + "same backing file name as the image file name"); >> + return -EINVAL; >> + } >> + >> + if (!strcmp(filename, image_filename)) { >> + error_report("Error: Trying to create an image with the " >> + "same filename as the image file name"); >> + return -EINVAL; >> + } >> + >> + if (header.image_offset + header.image_size > header.header_size) { >> + error_report("image_file name or backing_file name too long."); >> + return -ENOSPC; >> + } >> + >> + ret = bdrv_file_open(&bs, image_filename, NULL, 0); >> + if (ret < 0) { >> + return ret; >> + } >> + bdrv_close(bs); >> + >> + ret = bdrv_create_file(filename, NULL); >> + if (ret < 0) { >> + return ret; >> + } >> + >> + ret = bdrv_file_open(&bs, filename, NULL, BDRV_O_RDWR); >> + if (ret < 0) { >> + return ret; >> + } >> + snprintf(header.backing_fmt, sizeof(header.backing_fmt), "%s", >> + backing_fmt ? backing_fmt : ""); >> + snprintf(header.image_fmt, sizeof(header.image_fmt), "%s", >> + image_format ? image_format : "raw"); >> + add_cow_header_cpu_to_le(&header, &le_header); >> + ret = bdrv_pwrite(bs, 0, &le_header, sizeof(le_header)); >> + if (ret < 0) { >> + bdrv_delete(bs); >> + return ret; >> + } >> + >> + ret = bdrv_pwrite(bs, header.image_offset, image_filename, >> + header.image_size); >> + if (ret < 0) { >> + bdrv_delete(bs); >> + return ret; >> + } >> + >> + if (backing_filename) { >> + ret = bdrv_pwrite(bs, header.backing_offset, backing_filename, >> + header.backing_size); >> + if (ret < 0) { >> + bdrv_delete(bs); >> + return ret; >> + } >> + } >> + bdrv_close(bs); >> + >> + ret = bdrv_open(bs, filename, NULL, BDRV_O_RDWR | BDRV_O_NO_FLUSH, drv); >> + if (ret < 0) { >> + bdrv_delete(bs); >> + return ret; >> + } >> + >> + ret = bdrv_truncate(bs, image_len); >> + bdrv_delete(bs); >> + return ret; >> +} >> + >> +static int add_cow_open(BlockDriverState *bs, QDict *options, int flags) >> +{ >> + char image_filename[PATH_MAX]; >> + char tmp_name[PATH_MAX]; >> + int ret; >> + int sector_per_byte; >> + BDRVAddCowState *s = bs->opaque; >> + AddCowHeader le_header; >> + char backing_filename[PATH_MAX]; >> + >> + ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header)); >> + if (ret < 0) { >> + goto fail; >> + } >> + >> + add_cow_header_le_to_cpu(&le_header, &s->header); >> + >> + if (s->header.magic != ACOW_MAGIC) { >> + ret = -EINVAL; >> + goto fail; >> + } >> + >> + if (s->header.features & ~ACOW_FEATURE_MASK) { >> + char buf[64]; >> + snprintf(buf, sizeof(buf), "Feature Flags: %" PRIx64, >> + s->header.features & ~ACOW_FEATURE_MASK); >> + qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, >> + bs->device_name, "add-cow", buf); >> + return -ENOTSUP; >> + } >> + >> + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { >> + snprintf(bs->backing_format, sizeof(bs->backing_format), >> + "%s", s->header.backing_fmt); >> + } >> + >> + if (s->header.cluster_bits < MIN_CLUSTER_BITS || >> + s->header.cluster_bits > MAX_CLUSTER_BITS) { >> + ret = -EINVAL; >> + goto fail; >> + } >> + >> + s->cluster_size = 1 << s->header.cluster_bits; >> + if (s->header.header_size != MAX(s->cluster_size, DEFAULT_HEADER_SIZE)) { >> + char buf[64]; >> + snprintf(buf, sizeof(buf), "Header size: %d", >> + s->header.header_size); >> + qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, >> + bs->device_name, "add-cow", buf); >> + return -ENOTSUP; >> + } >> + >> + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { >> + ret = bdrv_read_string(bs->file, s->header.backing_offset, >> + s->header.backing_size, >> + bs->backing_file, >> + sizeof(bs->backing_file)); >> + if (ret < 0) { >> + goto fail; >> + } >> + } >> + >> + ret = bdrv_read_string(bs->file, s->header.image_offset, >> + s->header.image_size, tmp_name, >> + sizeof(tmp_name)); >> + if (ret < 0) { >> + goto fail; >> + } >> + >> + if (path_has_protocol(tmp_name)) { >> + pstrcpy(image_filename, sizeof(image_filename), tmp_name); >> + } else { >> + path_combine(image_filename, sizeof(image_filename), >> + bs->filename, tmp_name); >> + } >> + bdrv_get_full_backing_filename(bs, backing_filename, >> + sizeof(backing_filename)); >> + if (!strcmp(backing_filename, image_filename)) { >> + error_report("Error: backing file and image file are same: %s\n", >> + backing_filename); >> + ret = EINVAL; >> + goto fail; >> + } >> + s->image_hd = bdrv_new(""); >> + ret = bdrv_open(s->image_hd, image_filename, NULL, flags, >> + bdrv_find_format(s->header.image_fmt)); >> + if (ret < 0) { >> + bdrv_delete(s->image_hd); >> + goto fail; >> + } >> + >> + bs->total_sectors = bdrv_getlength(s->image_hd) / BDRV_SECTOR_SIZE; >> + s->cluster_sectors = s->cluster_size / BDRV_SECTOR_SIZE; >> + sector_per_byte = s->cluster_sectors * 8; >> + s->bitmap_size = >> + (bs->total_sectors + sector_per_byte - 1) / sector_per_byte; >> + s->bitmap_cache = block_cache_create(bs, ACOW_CACHE_SIZE, >> + s->cluster_size, >> + BLOCK_TABLE_BITMAP); >> + qemu_co_mutex_init(&s->lock); >> + return 0; >> +fail: >> + return ret; >> +} >> + >> +static void add_cow_close(BlockDriverState *bs) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + if (s->bitmap_cache) { >> + block_cache_destroy(bs, s->bitmap_cache); >> + } >> + bdrv_delete(s->image_hd); >> +} >> + >> +static bool is_allocated(BlockDriverState *bs, int64_t sector_num) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + int64_t cluster_num = sector_num / s->cluster_sectors; >> + uint8_t *table = NULL; >> + bool val = false; >> + int ret; >> + >> + uint64_t offset = s->header.header_size + >> + (offset_in_bitmap(sector_num, s->cluster_sectors) >> + & (~(s->cluster_size - 1))); >> + ret = block_cache_get(bs, s->bitmap_cache, offset, (void **)&table); >> + if (ret < 0) { >> + return ret; >> + } >> + >> + val = table[cluster_num / 8 % s->cluster_size] & (1 << (cluster_num % 8)); >> + ret = block_cache_put(bs, s->bitmap_cache, (void **)&table); >> + if (ret < 0) { >> + return ret; >> + } >> + return val; >> +} >> + >> +static coroutine_fn int add_cow_is_allocated(BlockDriverState *bs, >> + int64_t sector_num, int nb_sectors, int *num_same) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + int changed; >> + >> + if (nb_sectors == 0) { >> + *num_same = 0; >> + return 0; >> + } >> + >> + if (s->header.compat_features & ACOW_F_ALL_ALLOCATED) { >> + *num_same = nb_sectors; >> + return 1; >> + } >> + changed = is_allocated(bs, sector_num); >> + >> + for (*num_same = 1; *num_same < nb_sectors; (*num_same)++) { >> + if (is_allocated(bs, sector_num + *num_same) != changed) { >> + break; >> + } >> + } >> + return changed; >> +} >> + >> +static int add_cow_backing_read(BlockDriverState *bs, QEMUIOVector *qiov, >> + int64_t sector_num, int nb_sectors) >> +{ >> + int n1; >> + if ((sector_num + nb_sectors) <= bs->total_sectors) { >> + return nb_sectors; >> + } >> + if (sector_num >= bs->total_sectors) { >> + n1 = 0; >> + } else { >> + n1 = bs->total_sectors - sector_num; >> + } >> + >> + qemu_iovec_memset(qiov, BDRV_SECTOR_SIZE * n1, >> + 0, BDRV_SECTOR_SIZE * (nb_sectors - n1)); >> + >> + return n1; >> +} >> + >> +static coroutine_fn int add_cow_co_readv(BlockDriverState *bs, >> + int64_t sector_num, >> + int remaining_sectors, >> + QEMUIOVector *qiov) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + int cur_nr_sectors; >> + uint64_t bytes_done = 0; >> + QEMUIOVector hd_qiov; >> + int n1, ret = 0; >> + >> + qemu_iovec_init(&hd_qiov, qiov->niov); >> + qemu_co_mutex_lock(&s->lock); >> + while (remaining_sectors != 0) { >> + cur_nr_sectors = remaining_sectors; >> + if (add_cow_is_allocated(bs, sector_num, cur_nr_sectors, >> + &cur_nr_sectors)) { >> + qemu_iovec_reset(&hd_qiov); >> + qemu_iovec_concat(&hd_qiov, qiov, bytes_done, >> + cur_nr_sectors * BDRV_SECTOR_SIZE); >> + qemu_co_mutex_unlock(&s->lock); >> + ret = bdrv_co_readv(s->image_hd, sector_num, >> + cur_nr_sectors, &hd_qiov); >> + qemu_co_mutex_lock(&s->lock); >> + if (ret < 0) { >> + goto fail; >> + } >> + } else { >> + if (bs->backing_hd) { >> + qemu_iovec_reset(&hd_qiov); >> + qemu_iovec_concat(&hd_qiov, qiov, bytes_done, >> + cur_nr_sectors * BDRV_SECTOR_SIZE); >> + n1 = add_cow_backing_read(bs->backing_hd, &hd_qiov, >> + sector_num, cur_nr_sectors); >> + if (n1 > 0) { >> + qemu_co_mutex_unlock(&s->lock); >> + ret = bdrv_co_readv(bs->backing_hd, sector_num, >> + cur_nr_sectors, &hd_qiov); >> + qemu_co_mutex_lock(&s->lock); >> + if (ret < 0) { >> + goto fail; >> + } >> + } >> + } else { >> + qemu_iovec_memset(&hd_qiov, 0, 0, >> + BDRV_SECTOR_SIZE * cur_nr_sectors); >> + } >> + } >> + remaining_sectors -= cur_nr_sectors; >> + sector_num += cur_nr_sectors; >> + bytes_done += cur_nr_sectors * BDRV_SECTOR_SIZE; >> + } >> +fail: >> + qemu_co_mutex_unlock(&s->lock); >> + qemu_iovec_destroy(&hd_qiov); >> + return ret; >> +} >> + >> +static int coroutine_fn copy_sectors(BlockDriverState *bs, >> + int n_start, int n_end) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + QEMUIOVector qiov; >> + struct iovec iov; >> + int n, ret; >> + >> + n = n_end - n_start; >> + if (n <= 0) { >> + return 0; >> + } >> + >> + iov.iov_len = n * BDRV_SECTOR_SIZE; >> + iov.iov_base = qemu_blockalign(bs, iov.iov_len); >> + >> + qemu_iovec_init_external(&qiov, &iov, 1); >> + >> + ret = bdrv_co_readv(bs->backing_hd, n_start, n, &qiov); >> + if (ret < 0) { >> + goto out; >> + } >> + ret = bdrv_co_writev(s->image_hd, n_start, n, &qiov); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + ret = 0; >> +out: >> + qemu_vfree(iov.iov_base); >> + return ret; >> +} >> + >> +static coroutine_fn int add_cow_co_writev(BlockDriverState *bs, >> + int64_t sector_num, >> + int remaining_sectors, >> + QEMUIOVector *qiov) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + int ret = 0, i; >> + QEMUIOVector hd_qiov; >> + uint8_t *table; >> + uint64_t offset; >> + int mask = s->cluster_sectors - 1; >> + int cluster_mask = s->cluster_size - 1; >> + >> + qemu_co_mutex_lock(&s->lock); >> + qemu_iovec_init(&hd_qiov, qiov->niov); >> + ret = bdrv_co_writev(s->image_hd, sector_num, >> + remaining_sectors, qiov); >> + >> + if (ret < 0) { >> + goto fail; >> + } >> + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { >> + /* Copy content of unmodified sectors */ >> + if (!is_cluster_head(sector_num, s->cluster_sectors) >> + && !is_allocated(bs, sector_num)) { >> + ret = copy_sectors(bs, sector_num & ~mask, sector_num); >> + if (ret < 0) { >> + goto fail; >> + } >> + } >> + >> + if (!is_cluster_tail(sector_num + remaining_sectors - 1, >> + s->cluster_sectors) >> + && !is_allocated(bs, sector_num + remaining_sectors - 1)) { >> + ret = copy_sectors(bs, sector_num + remaining_sectors, >> + ((sector_num + remaining_sectors) | mask) + 1); >> + if (ret < 0) { >> + goto fail; >> + } >> + } >> + >> + for (i = sector_num / s->cluster_sectors; >> + i <= (sector_num + remaining_sectors - 1) / s->cluster_sectors; >> + i++) { >> + offset = s->header.header_size >> + + (offset_in_bitmap(i * s->cluster_sectors, >> + s->cluster_sectors) & (~cluster_mask)); >> + ret = block_cache_get(bs, s->bitmap_cache, offset, (void **)&table); >> + if (ret < 0) { >> + goto fail; >> + } >> + if ((table[i / 8] & (1 << (i % 8))) == 0) { >> + table[i / 8] |= (1 << (i % 8)); >> + block_cache_entry_mark_dirty(s->bitmap_cache, table); >> + } >> + >> + ret = block_cache_put(bs, s->bitmap_cache, (void **) &table); >> + if (ret < 0) { >> + goto fail; >> + } >> + } >> + } >> + ret = 0; >> +fail: >> + qemu_co_mutex_unlock(&s->lock); >> + qemu_iovec_destroy(&hd_qiov); >> + return ret; >> +} >> + >> +static int bdrv_add_cow_truncate(BlockDriverState *bs, int64_t size) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + int sector_per_byte = s->cluster_sectors * 8; >> + int ret; >> + int64_t bitmap_size = >> + (size / BDRV_SECTOR_SIZE + sector_per_byte - 1) / sector_per_byte; >> + bitmap_size = (bitmap_size + s->cluster_size - 1) >> + & (~(s->cluster_size - 1)); >> + >> + ret = bdrv_truncate(bs->file, s->header.header_size + bitmap_size); >> + if (ret < 0) { >> + return ret; >> + } >> + >> + ret = bdrv_truncate(s->image_hd, size); >> + if (ret < 0) { >> + return ret; >> + } >> + return 0; >> +} >> + >> +static int add_cow_reopen_prepare(BDRVReopenState *state, >> + BlockReopenQueue *queue, Error **errp) >> +{ >> + BDRVAddCowState *s; >> + int ret = -1; >> + >> + assert(state != NULL); >> + assert(state->bs != NULL); >> + >> + if (queue == NULL) { >> + error_set(errp, ERROR_CLASS_GENERIC_ERROR, >> + "No reopen queue for add-cow"); >> + goto exit; >> + } >> + >> + s = state->bs->opaque; >> + >> + assert(s != NULL); >> + >> + >> + bdrv_reopen_queue(queue, s->image_hd, state->flags); >> + ret = 0; >> + >> +exit: >> + return ret; >> +} >> + >> + >> +static coroutine_fn int add_cow_co_flush(BlockDriverState *bs) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + int ret; >> + >> + qemu_co_mutex_lock(&s->lock); >> + if (s->bitmap_cache) { >> + ret = block_cache_flush(bs, s->bitmap_cache); >> + if (ret < 0) { >> + return ret; >> + } >> + } >> + ret = bdrv_flush(s->image_hd); >> + qemu_co_mutex_unlock(&s->lock); >> + return ret; >> +} >> + >> +static int add_cow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) >> +{ >> + BDRVAddCowState *s = bs->opaque; >> + bdi->cluster_size = s->cluster_size; >> + return 0; >> +} >> + >> +static QemuOptsList add_cow_create_opts = { >> + .name = "add-cow-create-opts", >> + .head = QTAILQ_HEAD_INITIALIZER(add_cow_create_opts.head), >> + .desc = { >> + { >> + .name = BLOCK_OPT_SIZE, >> + .type = QEMU_OPT_SIZE, >> + .help = "Virtual disk size" >> + }, >> + { >> + .name = BLOCK_OPT_BACKING_FILE, >> + .type = QEMU_OPT_STRING, >> + .help = "File name of a base image" >> + }, >> + { >> + .name = BLOCK_OPT_BACKING_FMT, >> + .type = QEMU_OPT_STRING, >> + .help = "Image format of the base image" >> + }, >> + { >> + .name = BLOCK_OPT_IMAGE_FILE, >> + .type = QEMU_OPT_STRING, >> + .help = "File name of a image file" >> + }, >> + { >> + .name = BLOCK_OPT_IMAGE_FMT, >> + .type = QEMU_OPT_STRING, >> + .help = "Image format of the image file" >> + }, >> + { >> + .name = BLOCK_OPT_CLUSTER_SIZE, >> + .type = QEMU_OPT_SIZE, >> + .help = "add-cow cluster size", >> + .def_value_str = stringify(ACOW_CLUSTER_SIZE) > > Hi Dong, > > .def_value_str is undefined - it looks like this series is dependent > on: > > [PATCH V14 1/6] add def_value_str in QemuOptDesc struct and rewrite qemu_opts_print > > In that 6-part series, patches 2,4,5 are also dependent on the above > patch. Should these series be combined? > > You did mention in the header that this uses QemuOpts, but until I > applied and tried compiling, it wasn't obvious (at least to me) the > external patch dependency above. > Ah, yes, I wish QemuOpts patches will be merged first, so add-cow is based on them, so .. > Thanks, > Jeff > > >> + }, >> + { /* end of list */ } >> + } >> +}; >> + >> +static BlockDriver bdrv_add_cow = { >> + .format_name = "add-cow", >> + .instance_size = sizeof(BDRVAddCowState), >> + .bdrv_probe = add_cow_probe, >> + .bdrv_open = add_cow_open, >> + .bdrv_close = add_cow_close, >> + .bdrv_create = add_cow_create, >> + .bdrv_co_readv = add_cow_co_readv, >> + .bdrv_co_writev = add_cow_co_writev, >> + .bdrv_truncate = bdrv_add_cow_truncate, >> + .bdrv_co_is_allocated = add_cow_is_allocated, >> + .bdrv_reopen_prepare = add_cow_reopen_prepare, >> + .bdrv_get_info = add_cow_get_info, >> + >> + .bdrv_create_opts = &add_cow_create_opts, >> + .bdrv_co_flush_to_os = add_cow_co_flush, >> +}; >> + >> +static void bdrv_add_cow_init(void) >> +{ >> + bdrv_register(&bdrv_add_cow); >> +} >> + >> +block_init(bdrv_add_cow_init); >> diff --git a/block/block-cache.c b/block/block-cache.c >> index 3544691..4824632 100644 >> --- a/block/block-cache.c >> +++ b/block/block-cache.c >> @@ -130,7 +130,7 @@ static int block_cache_entry_flush(BlockDriverState *bs, BlockCache *c, int i) >> } else if (c->table_type == BLOCK_TABLE_L2) { >> BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); >> } else if (c->table_type == BLOCK_TABLE_BITMAP) { >> - BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE); >> + BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); >> } >> >> ret = bdrv_pwrite(bs->file, c->entries[i].offset, >> @@ -265,7 +265,7 @@ static int block_cache_do_get(BlockDriverState *bs, BlockCache *c, >> if (c->table_type == BLOCK_TABLE_L2) { >> BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); >> } else if (c->table_type == BLOCK_TABLE_BITMAP) { >> - BLKDBG_EVENT(bs->file, BLKDBG_COW_READ); >> + BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); >> } >> >> ret = bdrv_pread(bs->file, offset, c->entries[i].table, >> diff --git a/block/qcow2.h b/block/qcow2.h >> index e7f6aec..a4e514b 100644 >> --- a/block/qcow2.h >> +++ b/block/qcow2.h >> @@ -98,6 +98,9 @@ typedef struct QCowSnapshot { >> uint64_t vm_clock_nsec; >> } QCowSnapshot; >> >> +struct BlockCache; >> +typedef struct BlockCache BlockCache; >> + >> typedef struct Qcow2UnknownHeaderExtension { >> uint32_t magic; >> uint32_t len; >> @@ -389,7 +392,4 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name); >> void qcow2_free_snapshots(BlockDriverState *bs); >> int qcow2_read_snapshots(BlockDriverState *bs); >> >> -/* qcow2-cache.c functions */ >> - >> - >> #endif >> diff --git a/include/block/block_int.h b/include/block/block_int.h >> index a44a9ac..b9eb9b8 100644 >> --- a/include/block/block_int.h >> +++ b/include/block/block_int.h >> @@ -57,6 +57,8 @@ >> #define BLOCK_OPT_COMPAT_LEVEL "compat" >> #define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts" >> #define BLOCK_OPT_ADAPTER_TYPE "adapter_type" >> +#define BLOCK_OPT_IMAGE_FILE "image_file" >> +#define BLOCK_OPT_IMAGE_FMT "image_fmt" >> >> typedef struct BdrvTrackedRequest BdrvTrackedRequest; >> >> -- >> 1.7.11.7 >> >> > >
diff --git a/block/Makefile.objs b/block/Makefile.objs index 4fe81dc..69cbb09 100644 --- a/block/Makefile.objs +++ b/block/Makefile.objs @@ -1,6 +1,7 @@ block-obj-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vvfat.o block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o block-obj-y += block-cache.o +block-obj-y += add-cow.o block-obj-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o block-obj-y += qed-check.o block-obj-y += parallels.o blkdebug.o blkverify.o diff --git a/block/add-cow.c b/block/add-cow.c new file mode 100644 index 0000000..904b008 --- /dev/null +++ b/block/add-cow.c @@ -0,0 +1,741 @@ +/* + * QEMU ADD-COW Disk Format + * + * Copyright IBM, Corp. 2012 + * + * Authors: + * Dong Xu Wang <wdongxu@linux.vnet.ibm.com> + * + * This work is licensed under the terms of the GNU LGPL, version 2 or later. + * See the COPYING.LIB file in the top-level directory. + * + */ + +#include "qemu-common.h" +#include "block/block_int.h" +#include "qemu/module.h" +#include "block/block-cache.h" + +#define ACOW_CLUSTER_SIZE 65536 +enum { + /* compat_features bit */ + ACOW_F_ALL_ALLOCATED = 0X01, + + /* none feature bit used now */ + ACOW_FEATURE_MASK = 0, + + ACOW_MAGIC = 'A' | 'C' << 8 | 'O' << 16 | 'W' << 24, + ACOW_CACHE_SIZE = 16, + DEFAULT_HEADER_SIZE = 4096, + MIN_CLUSTER_BITS = 9, + MAX_CLUSTER_BITS = 21, +}; + +typedef struct AddCowHeader { + uint32_t magic; + + uint32_t backing_offset; + uint32_t backing_size; + uint32_t image_offset; + uint32_t image_size; + + uint32_t cluster_bits; + uint64_t features; + uint64_t compat_features; + uint32_t header_size; + + char backing_fmt[16]; + char image_fmt[16]; +} QEMU_PACKED AddCowHeader; + +typedef struct BDRVAddCowState { + BlockDriverState *image_hd; + CoMutex lock; + int cluster_size; + int cluster_sectors; + BlockCache *bitmap_cache; + uint64_t bitmap_size; + AddCowHeader header; + char backing_fmt[16]; + char image_fmt[16]; +} BDRVAddCowState; + +/* Convert sector_num to offset in bitmap */ +static inline int64_t offset_in_bitmap(int64_t sector_num, + int64_t cluster_sectors) +{ + int64_t cluster_num = sector_num / cluster_sectors; + return cluster_num / 8; +} + +static inline bool is_cluster_head(int64_t sector_num, + int64_t cluster_sectors) +{ + return sector_num % cluster_sectors == 0; +} + +static inline bool is_cluster_tail(int64_t sector_num, + int64_t cluster_sectors) +{ + return (sector_num + 1) % cluster_sectors == 0; +} + +static void add_cow_header_le_to_cpu(const AddCowHeader *le, AddCowHeader *cpu) +{ + cpu->magic = le32_to_cpu(le->magic); + + cpu->backing_offset = le32_to_cpu(le->backing_offset); + cpu->backing_size = le32_to_cpu(le->backing_size); + cpu->image_offset = le32_to_cpu(le->image_offset); + cpu->image_size = le32_to_cpu(le->image_size); + + cpu->cluster_bits = le32_to_cpu(le->cluster_bits); + cpu->features = le64_to_cpu(le->features); + cpu->compat_features = le64_to_cpu(le->compat_features); + cpu->header_size = le32_to_cpu(le->header_size); + + memcpy(cpu->backing_fmt, le->backing_fmt, sizeof(cpu->backing_fmt)); + memcpy(cpu->image_fmt, le->image_fmt, sizeof(cpu->image_fmt)); +} + +static void add_cow_header_cpu_to_le(const AddCowHeader *cpu, AddCowHeader *le) +{ + le->magic = cpu_to_le32(cpu->magic); + + le->backing_offset = cpu_to_le32(cpu->backing_offset); + le->backing_size = cpu_to_le32(cpu->backing_size); + le->image_offset = cpu_to_le32(cpu->image_offset); + le->image_size = cpu_to_le32(cpu->image_size); + + le->cluster_bits = cpu_to_le32(cpu->cluster_bits); + le->features = cpu_to_le64(cpu->features); + le->compat_features = cpu_to_le64(cpu->compat_features); + le->header_size = cpu_to_le32(cpu->header_size); + memcpy(le->backing_fmt, cpu->backing_fmt, sizeof(le->backing_fmt)); + memcpy(le->image_fmt, cpu->image_fmt, sizeof(le->image_fmt)); +} + +static int add_cow_probe(const uint8_t *buf, int buf_size, const char *filename) +{ + const AddCowHeader *header = (const AddCowHeader *)buf; + + if (buf_size < sizeof(*header)) { + return 0; + } + if (le32_to_cpu(header->magic) == ACOW_MAGIC) { + return 100; + } + return 0; +} + +static int add_cow_create(const char *filename, QemuOpts *opts) +{ + AddCowHeader header = { + .magic = ACOW_MAGIC, + .features = 0, + .compat_features = 0, + }; + AddCowHeader le_header; + int64_t image_len = 0; + const char *backing_filename = NULL, *backing_fmt = NULL; + const char *image_filename = NULL, *image_format = NULL; + size_t cluster_size = ACOW_CLUSTER_SIZE; + BlockDriverState *bs, *backing_bs; + BlockDriver *drv = bdrv_find_format("add-cow"); + int ret; + + image_len = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); + backing_filename = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); + backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); + image_filename = qemu_opt_get(opts, BLOCK_OPT_IMAGE_FILE); + image_format = qemu_opt_get(opts, BLOCK_OPT_IMAGE_FMT); + cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, + ACOW_CLUSTER_SIZE); + + header.cluster_bits = ffs(cluster_size) - 1; + if (header.cluster_bits < MIN_CLUSTER_BITS || + header.cluster_bits > MAX_CLUSTER_BITS || + (1 << header.cluster_bits) != cluster_size) { + error_report( + "Cluster size must be a power of two between %d and %dk", + 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); + return -EINVAL; + } + + header.header_size = MAX(cluster_size, DEFAULT_HEADER_SIZE); + if (backing_filename) { + header.backing_offset = sizeof(header); + header.backing_size = strlen(backing_filename); + + if (!backing_fmt) { + backing_bs = bdrv_new("image"); + ret = bdrv_open(backing_bs, backing_filename, NULL, + BDRV_O_RDWR | BDRV_O_CACHE_WB, NULL); + if (ret < 0) { + return ret; + } + backing_fmt = bdrv_get_format_name(backing_bs); + bdrv_delete(backing_bs); + } + } else { + header.compat_features |= ACOW_F_ALL_ALLOCATED; + } + + if (image_filename) { + header.image_offset = sizeof(header) + header.backing_size; + header.image_size = strlen(image_filename); + } else { + error_report("Error: image_file should be given."); + return -EINVAL; + } + + if (backing_filename && !strcmp(backing_filename, image_filename)) { + error_report("Error: Trying to create an image with the " + "same backing file name as the image file name"); + return -EINVAL; + } + + if (!strcmp(filename, image_filename)) { + error_report("Error: Trying to create an image with the " + "same filename as the image file name"); + return -EINVAL; + } + + if (header.image_offset + header.image_size > header.header_size) { + error_report("image_file name or backing_file name too long."); + return -ENOSPC; + } + + ret = bdrv_file_open(&bs, image_filename, NULL, 0); + if (ret < 0) { + return ret; + } + bdrv_close(bs); + + ret = bdrv_create_file(filename, NULL); + if (ret < 0) { + return ret; + } + + ret = bdrv_file_open(&bs, filename, NULL, BDRV_O_RDWR); + if (ret < 0) { + return ret; + } + snprintf(header.backing_fmt, sizeof(header.backing_fmt), "%s", + backing_fmt ? backing_fmt : ""); + snprintf(header.image_fmt, sizeof(header.image_fmt), "%s", + image_format ? image_format : "raw"); + add_cow_header_cpu_to_le(&header, &le_header); + ret = bdrv_pwrite(bs, 0, &le_header, sizeof(le_header)); + if (ret < 0) { + bdrv_delete(bs); + return ret; + } + + ret = bdrv_pwrite(bs, header.image_offset, image_filename, + header.image_size); + if (ret < 0) { + bdrv_delete(bs); + return ret; + } + + if (backing_filename) { + ret = bdrv_pwrite(bs, header.backing_offset, backing_filename, + header.backing_size); + if (ret < 0) { + bdrv_delete(bs); + return ret; + } + } + bdrv_close(bs); + + ret = bdrv_open(bs, filename, NULL, BDRV_O_RDWR | BDRV_O_NO_FLUSH, drv); + if (ret < 0) { + bdrv_delete(bs); + return ret; + } + + ret = bdrv_truncate(bs, image_len); + bdrv_delete(bs); + return ret; +} + +static int add_cow_open(BlockDriverState *bs, QDict *options, int flags) +{ + char image_filename[PATH_MAX]; + char tmp_name[PATH_MAX]; + int ret; + int sector_per_byte; + BDRVAddCowState *s = bs->opaque; + AddCowHeader le_header; + char backing_filename[PATH_MAX]; + + ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header)); + if (ret < 0) { + goto fail; + } + + add_cow_header_le_to_cpu(&le_header, &s->header); + + if (s->header.magic != ACOW_MAGIC) { + ret = -EINVAL; + goto fail; + } + + if (s->header.features & ~ACOW_FEATURE_MASK) { + char buf[64]; + snprintf(buf, sizeof(buf), "Feature Flags: %" PRIx64, + s->header.features & ~ACOW_FEATURE_MASK); + qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, + bs->device_name, "add-cow", buf); + return -ENOTSUP; + } + + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { + snprintf(bs->backing_format, sizeof(bs->backing_format), + "%s", s->header.backing_fmt); + } + + if (s->header.cluster_bits < MIN_CLUSTER_BITS || + s->header.cluster_bits > MAX_CLUSTER_BITS) { + ret = -EINVAL; + goto fail; + } + + s->cluster_size = 1 << s->header.cluster_bits; + if (s->header.header_size != MAX(s->cluster_size, DEFAULT_HEADER_SIZE)) { + char buf[64]; + snprintf(buf, sizeof(buf), "Header size: %d", + s->header.header_size); + qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, + bs->device_name, "add-cow", buf); + return -ENOTSUP; + } + + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { + ret = bdrv_read_string(bs->file, s->header.backing_offset, + s->header.backing_size, + bs->backing_file, + sizeof(bs->backing_file)); + if (ret < 0) { + goto fail; + } + } + + ret = bdrv_read_string(bs->file, s->header.image_offset, + s->header.image_size, tmp_name, + sizeof(tmp_name)); + if (ret < 0) { + goto fail; + } + + if (path_has_protocol(tmp_name)) { + pstrcpy(image_filename, sizeof(image_filename), tmp_name); + } else { + path_combine(image_filename, sizeof(image_filename), + bs->filename, tmp_name); + } + bdrv_get_full_backing_filename(bs, backing_filename, + sizeof(backing_filename)); + if (!strcmp(backing_filename, image_filename)) { + error_report("Error: backing file and image file are same: %s\n", + backing_filename); + ret = EINVAL; + goto fail; + } + s->image_hd = bdrv_new(""); + ret = bdrv_open(s->image_hd, image_filename, NULL, flags, + bdrv_find_format(s->header.image_fmt)); + if (ret < 0) { + bdrv_delete(s->image_hd); + goto fail; + } + + bs->total_sectors = bdrv_getlength(s->image_hd) / BDRV_SECTOR_SIZE; + s->cluster_sectors = s->cluster_size / BDRV_SECTOR_SIZE; + sector_per_byte = s->cluster_sectors * 8; + s->bitmap_size = + (bs->total_sectors + sector_per_byte - 1) / sector_per_byte; + s->bitmap_cache = block_cache_create(bs, ACOW_CACHE_SIZE, + s->cluster_size, + BLOCK_TABLE_BITMAP); + qemu_co_mutex_init(&s->lock); + return 0; +fail: + return ret; +} + +static void add_cow_close(BlockDriverState *bs) +{ + BDRVAddCowState *s = bs->opaque; + if (s->bitmap_cache) { + block_cache_destroy(bs, s->bitmap_cache); + } + bdrv_delete(s->image_hd); +} + +static bool is_allocated(BlockDriverState *bs, int64_t sector_num) +{ + BDRVAddCowState *s = bs->opaque; + int64_t cluster_num = sector_num / s->cluster_sectors; + uint8_t *table = NULL; + bool val = false; + int ret; + + uint64_t offset = s->header.header_size + + (offset_in_bitmap(sector_num, s->cluster_sectors) + & (~(s->cluster_size - 1))); + ret = block_cache_get(bs, s->bitmap_cache, offset, (void **)&table); + if (ret < 0) { + return ret; + } + + val = table[cluster_num / 8 % s->cluster_size] & (1 << (cluster_num % 8)); + ret = block_cache_put(bs, s->bitmap_cache, (void **)&table); + if (ret < 0) { + return ret; + } + return val; +} + +static coroutine_fn int add_cow_is_allocated(BlockDriverState *bs, + int64_t sector_num, int nb_sectors, int *num_same) +{ + BDRVAddCowState *s = bs->opaque; + int changed; + + if (nb_sectors == 0) { + *num_same = 0; + return 0; + } + + if (s->header.compat_features & ACOW_F_ALL_ALLOCATED) { + *num_same = nb_sectors; + return 1; + } + changed = is_allocated(bs, sector_num); + + for (*num_same = 1; *num_same < nb_sectors; (*num_same)++) { + if (is_allocated(bs, sector_num + *num_same) != changed) { + break; + } + } + return changed; +} + +static int add_cow_backing_read(BlockDriverState *bs, QEMUIOVector *qiov, + int64_t sector_num, int nb_sectors) +{ + int n1; + if ((sector_num + nb_sectors) <= bs->total_sectors) { + return nb_sectors; + } + if (sector_num >= bs->total_sectors) { + n1 = 0; + } else { + n1 = bs->total_sectors - sector_num; + } + + qemu_iovec_memset(qiov, BDRV_SECTOR_SIZE * n1, + 0, BDRV_SECTOR_SIZE * (nb_sectors - n1)); + + return n1; +} + +static coroutine_fn int add_cow_co_readv(BlockDriverState *bs, + int64_t sector_num, + int remaining_sectors, + QEMUIOVector *qiov) +{ + BDRVAddCowState *s = bs->opaque; + int cur_nr_sectors; + uint64_t bytes_done = 0; + QEMUIOVector hd_qiov; + int n1, ret = 0; + + qemu_iovec_init(&hd_qiov, qiov->niov); + qemu_co_mutex_lock(&s->lock); + while (remaining_sectors != 0) { + cur_nr_sectors = remaining_sectors; + if (add_cow_is_allocated(bs, sector_num, cur_nr_sectors, + &cur_nr_sectors)) { + qemu_iovec_reset(&hd_qiov); + qemu_iovec_concat(&hd_qiov, qiov, bytes_done, + cur_nr_sectors * BDRV_SECTOR_SIZE); + qemu_co_mutex_unlock(&s->lock); + ret = bdrv_co_readv(s->image_hd, sector_num, + cur_nr_sectors, &hd_qiov); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + goto fail; + } + } else { + if (bs->backing_hd) { + qemu_iovec_reset(&hd_qiov); + qemu_iovec_concat(&hd_qiov, qiov, bytes_done, + cur_nr_sectors * BDRV_SECTOR_SIZE); + n1 = add_cow_backing_read(bs->backing_hd, &hd_qiov, + sector_num, cur_nr_sectors); + if (n1 > 0) { + qemu_co_mutex_unlock(&s->lock); + ret = bdrv_co_readv(bs->backing_hd, sector_num, + cur_nr_sectors, &hd_qiov); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + goto fail; + } + } + } else { + qemu_iovec_memset(&hd_qiov, 0, 0, + BDRV_SECTOR_SIZE * cur_nr_sectors); + } + } + remaining_sectors -= cur_nr_sectors; + sector_num += cur_nr_sectors; + bytes_done += cur_nr_sectors * BDRV_SECTOR_SIZE; + } +fail: + qemu_co_mutex_unlock(&s->lock); + qemu_iovec_destroy(&hd_qiov); + return ret; +} + +static int coroutine_fn copy_sectors(BlockDriverState *bs, + int n_start, int n_end) +{ + BDRVAddCowState *s = bs->opaque; + QEMUIOVector qiov; + struct iovec iov; + int n, ret; + + n = n_end - n_start; + if (n <= 0) { + return 0; + } + + iov.iov_len = n * BDRV_SECTOR_SIZE; + iov.iov_base = qemu_blockalign(bs, iov.iov_len); + + qemu_iovec_init_external(&qiov, &iov, 1); + + ret = bdrv_co_readv(bs->backing_hd, n_start, n, &qiov); + if (ret < 0) { + goto out; + } + ret = bdrv_co_writev(s->image_hd, n_start, n, &qiov); + if (ret < 0) { + goto out; + } + + ret = 0; +out: + qemu_vfree(iov.iov_base); + return ret; +} + +static coroutine_fn int add_cow_co_writev(BlockDriverState *bs, + int64_t sector_num, + int remaining_sectors, + QEMUIOVector *qiov) +{ + BDRVAddCowState *s = bs->opaque; + int ret = 0, i; + QEMUIOVector hd_qiov; + uint8_t *table; + uint64_t offset; + int mask = s->cluster_sectors - 1; + int cluster_mask = s->cluster_size - 1; + + qemu_co_mutex_lock(&s->lock); + qemu_iovec_init(&hd_qiov, qiov->niov); + ret = bdrv_co_writev(s->image_hd, sector_num, + remaining_sectors, qiov); + + if (ret < 0) { + goto fail; + } + if ((s->header.compat_features & ACOW_F_ALL_ALLOCATED) == 0) { + /* Copy content of unmodified sectors */ + if (!is_cluster_head(sector_num, s->cluster_sectors) + && !is_allocated(bs, sector_num)) { + ret = copy_sectors(bs, sector_num & ~mask, sector_num); + if (ret < 0) { + goto fail; + } + } + + if (!is_cluster_tail(sector_num + remaining_sectors - 1, + s->cluster_sectors) + && !is_allocated(bs, sector_num + remaining_sectors - 1)) { + ret = copy_sectors(bs, sector_num + remaining_sectors, + ((sector_num + remaining_sectors) | mask) + 1); + if (ret < 0) { + goto fail; + } + } + + for (i = sector_num / s->cluster_sectors; + i <= (sector_num + remaining_sectors - 1) / s->cluster_sectors; + i++) { + offset = s->header.header_size + + (offset_in_bitmap(i * s->cluster_sectors, + s->cluster_sectors) & (~cluster_mask)); + ret = block_cache_get(bs, s->bitmap_cache, offset, (void **)&table); + if (ret < 0) { + goto fail; + } + if ((table[i / 8] & (1 << (i % 8))) == 0) { + table[i / 8] |= (1 << (i % 8)); + block_cache_entry_mark_dirty(s->bitmap_cache, table); + } + + ret = block_cache_put(bs, s->bitmap_cache, (void **) &table); + if (ret < 0) { + goto fail; + } + } + } + ret = 0; +fail: + qemu_co_mutex_unlock(&s->lock); + qemu_iovec_destroy(&hd_qiov); + return ret; +} + +static int bdrv_add_cow_truncate(BlockDriverState *bs, int64_t size) +{ + BDRVAddCowState *s = bs->opaque; + int sector_per_byte = s->cluster_sectors * 8; + int ret; + int64_t bitmap_size = + (size / BDRV_SECTOR_SIZE + sector_per_byte - 1) / sector_per_byte; + bitmap_size = (bitmap_size + s->cluster_size - 1) + & (~(s->cluster_size - 1)); + + ret = bdrv_truncate(bs->file, s->header.header_size + bitmap_size); + if (ret < 0) { + return ret; + } + + ret = bdrv_truncate(s->image_hd, size); + if (ret < 0) { + return ret; + } + return 0; +} + +static int add_cow_reopen_prepare(BDRVReopenState *state, + BlockReopenQueue *queue, Error **errp) +{ + BDRVAddCowState *s; + int ret = -1; + + assert(state != NULL); + assert(state->bs != NULL); + + if (queue == NULL) { + error_set(errp, ERROR_CLASS_GENERIC_ERROR, + "No reopen queue for add-cow"); + goto exit; + } + + s = state->bs->opaque; + + assert(s != NULL); + + + bdrv_reopen_queue(queue, s->image_hd, state->flags); + ret = 0; + +exit: + return ret; +} + + +static coroutine_fn int add_cow_co_flush(BlockDriverState *bs) +{ + BDRVAddCowState *s = bs->opaque; + int ret; + + qemu_co_mutex_lock(&s->lock); + if (s->bitmap_cache) { + ret = block_cache_flush(bs, s->bitmap_cache); + if (ret < 0) { + return ret; + } + } + ret = bdrv_flush(s->image_hd); + qemu_co_mutex_unlock(&s->lock); + return ret; +} + +static int add_cow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) +{ + BDRVAddCowState *s = bs->opaque; + bdi->cluster_size = s->cluster_size; + return 0; +} + +static QemuOptsList add_cow_create_opts = { + .name = "add-cow-create-opts", + .head = QTAILQ_HEAD_INITIALIZER(add_cow_create_opts.head), + .desc = { + { + .name = BLOCK_OPT_SIZE, + .type = QEMU_OPT_SIZE, + .help = "Virtual disk size" + }, + { + .name = BLOCK_OPT_BACKING_FILE, + .type = QEMU_OPT_STRING, + .help = "File name of a base image" + }, + { + .name = BLOCK_OPT_BACKING_FMT, + .type = QEMU_OPT_STRING, + .help = "Image format of the base image" + }, + { + .name = BLOCK_OPT_IMAGE_FILE, + .type = QEMU_OPT_STRING, + .help = "File name of a image file" + }, + { + .name = BLOCK_OPT_IMAGE_FMT, + .type = QEMU_OPT_STRING, + .help = "Image format of the image file" + }, + { + .name = BLOCK_OPT_CLUSTER_SIZE, + .type = QEMU_OPT_SIZE, + .help = "add-cow cluster size", + .def_value_str = stringify(ACOW_CLUSTER_SIZE) + }, + { /* end of list */ } + } +}; + +static BlockDriver bdrv_add_cow = { + .format_name = "add-cow", + .instance_size = sizeof(BDRVAddCowState), + .bdrv_probe = add_cow_probe, + .bdrv_open = add_cow_open, + .bdrv_close = add_cow_close, + .bdrv_create = add_cow_create, + .bdrv_co_readv = add_cow_co_readv, + .bdrv_co_writev = add_cow_co_writev, + .bdrv_truncate = bdrv_add_cow_truncate, + .bdrv_co_is_allocated = add_cow_is_allocated, + .bdrv_reopen_prepare = add_cow_reopen_prepare, + .bdrv_get_info = add_cow_get_info, + + .bdrv_create_opts = &add_cow_create_opts, + .bdrv_co_flush_to_os = add_cow_co_flush, +}; + +static void bdrv_add_cow_init(void) +{ + bdrv_register(&bdrv_add_cow); +} + +block_init(bdrv_add_cow_init); diff --git a/block/block-cache.c b/block/block-cache.c index 3544691..4824632 100644 --- a/block/block-cache.c +++ b/block/block-cache.c @@ -130,7 +130,7 @@ static int block_cache_entry_flush(BlockDriverState *bs, BlockCache *c, int i) } else if (c->table_type == BLOCK_TABLE_L2) { BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); } else if (c->table_type == BLOCK_TABLE_BITMAP) { - BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE); + BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); } ret = bdrv_pwrite(bs->file, c->entries[i].offset, @@ -265,7 +265,7 @@ static int block_cache_do_get(BlockDriverState *bs, BlockCache *c, if (c->table_type == BLOCK_TABLE_L2) { BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); } else if (c->table_type == BLOCK_TABLE_BITMAP) { - BLKDBG_EVENT(bs->file, BLKDBG_COW_READ); + BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); } ret = bdrv_pread(bs->file, offset, c->entries[i].table, diff --git a/block/qcow2.h b/block/qcow2.h index e7f6aec..a4e514b 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -98,6 +98,9 @@ typedef struct QCowSnapshot { uint64_t vm_clock_nsec; } QCowSnapshot; +struct BlockCache; +typedef struct BlockCache BlockCache; + typedef struct Qcow2UnknownHeaderExtension { uint32_t magic; uint32_t len; @@ -389,7 +392,4 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name); void qcow2_free_snapshots(BlockDriverState *bs); int qcow2_read_snapshots(BlockDriverState *bs); -/* qcow2-cache.c functions */ - - #endif diff --git a/include/block/block_int.h b/include/block/block_int.h index a44a9ac..b9eb9b8 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -57,6 +57,8 @@ #define BLOCK_OPT_COMPAT_LEVEL "compat" #define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts" #define BLOCK_OPT_ADAPTER_TYPE "adapter_type" +#define BLOCK_OPT_IMAGE_FILE "image_file" +#define BLOCK_OPT_IMAGE_FMT "image_fmt" typedef struct BdrvTrackedRequest BdrvTrackedRequest;
add-cow file format core code. It use block-cache.c as cache code. It lacks of snapshot_blkdev support. Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com> --- v17-v18: 1) use error_report, not fprintf. 2) remove version field from header. 3) header_size is MAX(cluster_size, 4096). 4) introduce s->cluster_sectors. 5) use BLKDBG_L2_LOAD/UPDATE. v16->v17: 1) Use stringify. v15->v16: 1) Judge if opts is null in add_cow_create function. block/Makefile.objs | 1 + block/add-cow.c | 741 ++++++++++++++++++++++++++++++++++++++++++++++ block/block-cache.c | 4 +- block/qcow2.h | 6 +- include/block/block_int.h | 2 + 5 files changed, 749 insertions(+), 5 deletions(-) create mode 100644 block/add-cow.c