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authorMax Reitz <mreitz@redhat.com>2014-04-29 19:03:15 +0200
committerKevin Wolf <kwolf@redhat.com>2014-04-30 14:46:17 +0200
commite1b42f456fad6e797eaf795ed2e400c4e47d5eb4 (patch)
treef0a4f982ce7c8c1a10165b42e4eb25715ddf1252 /block
parentb93f995081cc32e56071fef179161d2907d0491e (diff)
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 <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block')
-rw-r--r--block/bochs.c23
1 files changed, 14 insertions, 9 deletions
diff --git a/block/bochs.c b/block/bochs.c
index eacf956e7d..eba23df335 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;