Re: [PATCH 3/7] block: Make bdrv_{pread, pwrite}() return 0 on success
On Fri, May 13, 2022 at 9:22 AM Paolo Bonzini wrote: > The callers only check the return code of vhdx_log_peek_hdr, > vhdx_log_read_sectors, vhdx_log_write_sectors with ret < 0. But looking > at the callers: > > - vhdx_log_read_desc propagates ret directly from a successful > vhdx_log_read_sectors, but its callers don't care about which > nonnegative result is returned > > - vhdx_validate_log_entry might occasionally return ret directly from a > successful vhdx_log_read_desc or vhdx_log_read_sectors, but > vhdx_log_search, the caller of vhdx_validate_log_entry, also doesn't > care about which nonnegative result is returned > > - vhdx_log_flush only returns a successful return value from bdrv_flush > > - vhdx_log_write propagates ret directly from a successful > vhdx_log_write_sectors, but vhdx_log_write_and_flush only returns a > successful return value from vhdx_log_flush > > So (perhaps as a separate patch?) you can remove the three assignments > of ret. Thanks, I'll fix this. I think I'll just fold it in, but let me know if it really should be split into a separate patch. > As an aside, while reviewing I noticed this in qcow2_mark_dirty: > > ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, > incompatible_features), >&val, sizeof(val)); > if (ret < 0) { > return ret; > } > ret = bdrv_flush(bs->file->bs); > if (ret < 0) { > return ret; > } > > I'm not sure if there are other occurrencies, perhaps you can try using > Coccinelle to find them and change them to a bdrv_pwrite_sync. Looks like this is the only occurrence. I'll add a patch to convert it to bdrv_pwrite_sync(). Alberto
Re: [PATCH 3/7] block: Make bdrv_{pread, pwrite}() return 0 on success
On 5/13/22 01:38, Alberto Faria wrote: @@ -113,7 +113,7 @@ static ssize_t qcow2_crypto_hdr_read_func(QCryptoBlock *block, size_t offset, error_setg_errno(errp, -ret, "Could not read encryption header"); return -1; } -return ret; +return buflen; } @@ -174,7 +174,7 @@ static ssize_t qcow2_crypto_hdr_write_func(QCryptoBlock *block, size_t offset, error_setg_errno(errp, -ret, "Could not read encryption header"); return -1; } -return ret; +return buflen; } static QDict* As a follow-up you could change the calling convention of readfunc and writefunc in crypto/block-luks.c and crypto/block-qcow.c. More in general, crypto/block-luks.c and crypto/block-qcow.c should be annotated for coroutine_fn. Let's put it on the todo list. @@ -88,6 +88,7 @@ static int vhdx_log_peek_hdr(BlockDriverState *bs, VHDXLogEntries *log, if (ret < 0) { goto exit; } +ret = sizeof(VHDXLogEntryHeader); vhdx_log_entry_hdr_le_import(hdr); exit: The callers only check the return code of vhdx_log_peek_hdr, vhdx_log_read_sectors, vhdx_log_write_sectors with ret < 0. But looking at the callers: - vhdx_log_read_desc propagates ret directly from a successful vhdx_log_read_sectors, but its callers don't care about which nonnegative result is returned - vhdx_validate_log_entry might occasionally return ret directly from a successful vhdx_log_read_desc or vhdx_log_read_sectors, but vhdx_log_search, the caller of vhdx_validate_log_entry, also doesn't care about which nonnegative result is returned - vhdx_log_flush only returns a successful return value from bdrv_flush - vhdx_log_write propagates ret directly from a successful vhdx_log_write_sectors, but vhdx_log_write_and_flush only returns a successful return value from vhdx_log_flush So (perhaps as a separate patch?) you can remove the three assignments of ret. A possible cleanup is missing in vdi_co_pwritev: ret = bdrv_pwrite(bs->file, offset * SECTOR_SIZE, base, n_sectors * SECTOR_SIZE); } return ret < 0 ? ret : 0; ret is returned by either bdrv_pwrite or bdrv_co_writev, so it can be simplified to just "return ret". As an aside, while reviewing I noticed this in qcow2_mark_dirty: ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features), &val, sizeof(val)); if (ret < 0) { return ret; } ret = bdrv_flush(bs->file->bs); if (ret < 0) { return ret; } I'm not sure if there are other occurrencies, perhaps you can try using Coccinelle to find them and change them to a bdrv_pwrite_sync. But anyway: Reviewed-by: Paolo Bonzini Paolo
[PATCH 3/7] block: Make bdrv_{pread,pwrite}() return 0 on success
They currently return the value of their 'bytes' parameter on success. Make them return 0 instead, for consistency with other I/O functions and in preparation to implement them using generated_co_wrapper. This also makes it clear that short reads/writes are not possible. The few callers that rely on the previous behavior are adjusted accordingly by hand. Signed-off-by: Alberto Faria --- block/cloop.c| 2 +- block/crypto.c | 4 ++-- block/dmg.c | 10 +- block/io.c | 10 ++ block/qcow.c | 2 +- block/qcow2.c| 4 ++-- block/qed.c | 7 +-- block/vhdx-log.c | 3 +++ block/vmdk.c | 5 ++--- tests/unit/test-block-iothread.c | 4 ++-- 10 files changed, 21 insertions(+), 30 deletions(-) diff --git a/block/cloop.c b/block/cloop.c index 9a2334495e..40b146e714 100644 --- a/block/cloop.c +++ b/block/cloop.c @@ -222,7 +222,7 @@ static inline int cloop_read_block(BlockDriverState *bs, int block_num) ret = bdrv_pread(bs->file, s->offsets[block_num], bytes, s->compressed_block, 0); -if (ret != bytes) { +if (ret < 0) { return -1; } diff --git a/block/crypto.c b/block/crypto.c index deec7fae2f..e7f5c4e31a 100644 --- a/block/crypto.c +++ b/block/crypto.c @@ -70,7 +70,7 @@ static ssize_t block_crypto_read_func(QCryptoBlock *block, error_setg_errno(errp, -ret, "Could not read encryption header"); return ret; } -return ret; +return buflen; } static ssize_t block_crypto_write_func(QCryptoBlock *block, @@ -88,7 +88,7 @@ static ssize_t block_crypto_write_func(QCryptoBlock *block, error_setg_errno(errp, -ret, "Could not write encryption header"); return ret; } -return ret; +return buflen; } diff --git a/block/dmg.c b/block/dmg.c index 5a460c3eb1..98db18d82a 100644 --- a/block/dmg.c +++ b/block/dmg.c @@ -390,7 +390,7 @@ static int dmg_read_plist_xml(BlockDriverState *bs, DmgHeaderState *ds, buffer = g_malloc(info_length + 1); buffer[info_length] = '\0'; ret = bdrv_pread(bs->file, info_begin, info_length, buffer, 0); -if (ret != info_length) { +if (ret < 0) { ret = -EINVAL; goto fail; } @@ -611,7 +611,7 @@ static inline int dmg_read_chunk(BlockDriverState *bs, uint64_t sector_num) * inflated. */ ret = bdrv_pread(bs->file, s->offsets[chunk], s->lengths[chunk], s->compressed_chunk, 0); -if (ret != s->lengths[chunk]) { +if (ret < 0) { return -1; } @@ -637,7 +637,7 @@ static inline int dmg_read_chunk(BlockDriverState *bs, uint64_t sector_num) * inflated. */ ret = bdrv_pread(bs->file, s->offsets[chunk], s->lengths[chunk], s->compressed_chunk, 0); -if (ret != s->lengths[chunk]) { +if (ret < 0) { return -1; } @@ -658,7 +658,7 @@ static inline int dmg_read_chunk(BlockDriverState *bs, uint64_t sector_num) * inflated. */ ret = bdrv_pread(bs->file, s->offsets[chunk], s->lengths[chunk], s->compressed_chunk, 0); -if (ret != s->lengths[chunk]) { +if (ret < 0) { return -1; } @@ -674,7 +674,7 @@ static inline int dmg_read_chunk(BlockDriverState *bs, uint64_t sector_num) case UDRW: /* copy */ ret = bdrv_pread(bs->file, s->offsets[chunk], s->lengths[chunk], s->uncompressed_chunk, 0); -if (ret != s->lengths[chunk]) { +if (ret < 0) { return -1; } break; diff --git a/block/io.c b/block/io.c index 2ed963d9e0..78a289192e 100644 --- a/block/io.c +++ b/block/io.c @@ -1115,7 +1115,6 @@ int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags) int bdrv_pread(BdrvChild *child, int64_t offset, int64_t bytes, void *buf, BdrvRequestFlags flags) { -int ret; QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); IO_CODE(); @@ -1123,9 +1122,7 @@ int bdrv_pread(BdrvChild *child, int64_t offset, int64_t bytes, void *buf, return -EINVAL; } -ret = bdrv_preadv(child, offset, bytes, &qiov, flags); - -return ret < 0 ? ret : bytes; +return bdrv_preadv(child, offset, bytes, &qiov, flags); } /* Return no. of bytes on success or < 0 on error. Important errors are: @@ -1137,7 +1134,6 @@ int bdrv_pread(BdrvChild *child, int64_t offset, int64_t bytes, void *buf, int bdrv_pwrite(BdrvChild *child, int64_t offset, int64_t bytes, const void *buf, BdrvRequestFlags flags) { -int ret; QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf