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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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parent
610626af30
commit
537a1d4bb0
2 changed files with 15 additions and 2 deletions
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@ -361,7 +361,12 @@ static int raw_pread(BlockDriverState *bs, int64_t offset,
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static int raw_read(BlockDriverState *bs, int64_t sector_num,
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uint8_t *buf, int nb_sectors)
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{
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return raw_pread(bs, sector_num * 512, buf, (uint64_t)nb_sectors * 512);
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int ret;
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ret = raw_pread(bs, sector_num * 512, buf, nb_sectors * 512);
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if (ret == (nb_sectors * 512))
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ret = 0;
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return ret;
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}
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/*
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@ -445,7 +450,11 @@ static int raw_pwrite(BlockDriverState *bs, int64_t offset,
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static int raw_write(BlockDriverState *bs, int64_t sector_num,
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const uint8_t *buf, int nb_sectors)
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{
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return raw_pwrite(bs, sector_num * 512, buf, (uint64_t)nb_sectors * 512);
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int ret;
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ret = raw_pwrite(bs, sector_num * 512, buf, nb_sectors * 512);
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if (ret == (nb_sectors * 512))
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ret = 0;
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return ret;
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}
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#ifdef CONFIG_AIO
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@ -145,6 +145,8 @@ static int raw_read(BlockDriverState *bs, int64_t sector_num,
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#endif
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return ret_count;
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}
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if (ret_count == count)
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ret_count = 0;
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return ret_count;
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}
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@ -171,6 +173,8 @@ static int raw_write(BlockDriverState *bs, int64_t sector_num,
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#endif
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return ret_count;
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}
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if (ret_count == count)
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ret_count = 0;
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return ret_count;
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}
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