From e1b42f456fad6e797eaf795ed2e400c4e47d5eb4 Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Tue, 29 Apr 2014 19:03:15 +0200 Subject: block/bochs: Fix error handling for seek_to_sector() Currently, seek_to_sector() returns -1 both for errors and unallocated sectors, resulting in silent errors. As 0 is an invalid offset of data clusters (bitmap_offset is greater than 0 because s->data_offset is greater than 0), just return 0 for unallocated sectors and -errno in case of error. This should then be propagated by bochs_read(), the sole user of seek_to_sector(). That function also has a case of "return -1 in case of error", which is fixed by this patch as well. bochs_read() is called by bochs_co_read() which passes the return value through, therefore it is indeed correct for bochs_read() to return -errno. Signed-off-by: Max Reitz Signed-off-by: Kevin Wolf --- block/bochs.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) (limited to 'block') diff --git a/block/bochs.c b/block/bochs.c index eacf956..eba23df 100644 --- a/block/bochs.c +++ b/block/bochs.c @@ -187,13 +187,14 @@ static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num) uint64_t offset = sector_num * 512; uint64_t extent_index, extent_offset, bitmap_offset; char bitmap_entry; + int ret; // seek to sector extent_index = offset / s->extent_size; extent_offset = (offset % s->extent_size) / 512; if (s->catalog_bitmap[extent_index] == 0xffffffff) { - return -1; /* not allocated */ + return 0; /* not allocated */ } bitmap_offset = s->data_offset + @@ -201,13 +202,14 @@ static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num) (s->extent_blocks + s->bitmap_blocks)); /* read in bitmap for current extent */ - if (bdrv_pread(bs->file, bitmap_offset + (extent_offset / 8), - &bitmap_entry, 1) != 1) { - return -1; + ret = bdrv_pread(bs->file, bitmap_offset + (extent_offset / 8), + &bitmap_entry, 1); + if (ret < 0) { + return ret; } if (!((bitmap_entry >> (extent_offset % 8)) & 1)) { - return -1; /* not allocated */ + return 0; /* not allocated */ } return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset)); @@ -220,13 +222,16 @@ static int bochs_read(BlockDriverState *bs, int64_t sector_num, while (nb_sectors > 0) { int64_t block_offset = seek_to_sector(bs, sector_num); - if (block_offset >= 0) { + if (block_offset < 0) { + return block_offset; + } else if (block_offset > 0) { ret = bdrv_pread(bs->file, block_offset, buf, 512); - if (ret != 512) { - return -1; + if (ret < 0) { + return ret; } - } else + } else { memset(buf, 0, 512); + } nb_sectors--; sector_num++; buf += 512; -- cgit v1.1