gwj / at91sam9263 · Commits

Commit 537a1d4bb02b7c5d21c8f3c853f7c7ae3782bc3f

Authored by aliguori
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
Inline Side-by-side
Showing 2 changed files with 15 additions and 2 deletions
block-raw-posix.c
  View file @537a1d4
... ... @@ -361,7 +361,12 @@ static int raw_pread(BlockDriverState *bs, int64_t offset,
361 361 static int raw_read(BlockDriverState *bs, int64_t sector_num,
362 362 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,
445 450 static int raw_write(BlockDriverState *bs, int64_t sector_num,
446 451 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  
451 460 #ifdef CONFIG_AIO
... ...
block-raw-win32.c
  View file @537a1d4
... ... @@ -145,6 +145,8 @@ static int raw_read(BlockDriverState *bs, int64_t sector_num,
145 145 #endif
146 146 return ret_count;
147 147 }
  148 + if (ret_count == count)
  149 + ret_count = 0;
148 150 return ret_count;
149 151 }
150 152  
... ... @@ -171,6 +173,8 @@ static int raw_write(BlockDriverState *bs, int64_t sector_num,
171 173 #endif
172 174 return ret_count;
173 175 }
  176 + if (ret_count == count)
  177 + ret_count = 0;
174 178 return ret_count;
175 179 }
176 180  
... ...