Commit 537a1d4bb02b7c5d21c8f3c853f7c7ae3782bc3f
1 parent
610626af
Fix regression introduced by r6824
The changes introduced by r6824 broke a subtle, and admittedly obscure, aspect
of the block API. While bdrv_{pread,pwrite} return the number of bytes read
or written upon success, bdrv_{read,write} returns a zero upon success.
When using bdrv_pread for bdrv_read, special care must be taken to handle this
case.
This fixes certain guest images (notably linux-0.2 provided on the qemu
website).
Reported-by: malc <av1474@comtv.ru>
Reported-by: Herve Poussineau <hpoussin@reactos.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6828 c046a42c-6fe2-441c-8c8c-71466251a162
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2 changed files
with
15 additions
and
2 deletions
block-raw-posix.c
| @@ -361,7 +361,12 @@ static int raw_pread(BlockDriverState *bs, int64_t offset, | @@ -361,7 +361,12 @@ static int raw_pread(BlockDriverState *bs, int64_t offset, | ||
| 361 | static int raw_read(BlockDriverState *bs, int64_t sector_num, | 361 | static int raw_read(BlockDriverState *bs, int64_t sector_num, |
| 362 | uint8_t *buf, int nb_sectors) | 362 | uint8_t *buf, int nb_sectors) |
| 363 | { | 363 | { |
| 364 | - return raw_pread(bs, sector_num * 512, buf, (uint64_t)nb_sectors * 512); | 364 | + int ret; |
| 365 | + | ||
| 366 | + ret = raw_pread(bs, sector_num * 512, buf, nb_sectors * 512); | ||
| 367 | + if (ret == (nb_sectors * 512)) | ||
| 368 | + ret = 0; | ||
| 369 | + return ret; | ||
| 365 | } | 370 | } |
| 366 | 371 | ||
| 367 | /* | 372 | /* |
| @@ -445,7 +450,11 @@ static int raw_pwrite(BlockDriverState *bs, int64_t offset, | @@ -445,7 +450,11 @@ static int raw_pwrite(BlockDriverState *bs, int64_t offset, | ||
| 445 | static int raw_write(BlockDriverState *bs, int64_t sector_num, | 450 | static int raw_write(BlockDriverState *bs, int64_t sector_num, |
| 446 | const uint8_t *buf, int nb_sectors) | 451 | const uint8_t *buf, int nb_sectors) |
| 447 | { | 452 | { |
| 448 | - return raw_pwrite(bs, sector_num * 512, buf, (uint64_t)nb_sectors * 512); | 453 | + int ret; |
| 454 | + ret = raw_pwrite(bs, sector_num * 512, buf, nb_sectors * 512); | ||
| 455 | + if (ret == (nb_sectors * 512)) | ||
| 456 | + ret = 0; | ||
| 457 | + return ret; | ||
| 449 | } | 458 | } |
| 450 | 459 | ||
| 451 | #ifdef CONFIG_AIO | 460 | #ifdef CONFIG_AIO |
block-raw-win32.c
| @@ -145,6 +145,8 @@ static int raw_read(BlockDriverState *bs, int64_t sector_num, | @@ -145,6 +145,8 @@ static int raw_read(BlockDriverState *bs, int64_t sector_num, | ||
| 145 | #endif | 145 | #endif |
| 146 | return ret_count; | 146 | return ret_count; |
| 147 | } | 147 | } |
| 148 | + if (ret_count == count) | ||
| 149 | + ret_count = 0; | ||
| 148 | return ret_count; | 150 | return ret_count; |
| 149 | } | 151 | } |
| 150 | 152 | ||
| @@ -171,6 +173,8 @@ static int raw_write(BlockDriverState *bs, int64_t sector_num, | @@ -171,6 +173,8 @@ static int raw_write(BlockDriverState *bs, int64_t sector_num, | ||
| 171 | #endif | 173 | #endif |
| 172 | return ret_count; | 174 | return ret_count; |
| 173 | } | 175 | } |
| 176 | + if (ret_count == count) | ||
| 177 | + ret_count = 0; | ||
| 174 | return ret_count; | 178 | return ret_count; |
| 175 | } | 179 | } |
| 176 | 180 |