btrfs-progs: Fix a clang dead-judgement warning in disk-io.c.

When compiled with clang, the following warning is outputted.

disk-io.c:1017:15: warning: comparison of unsigned expression < 0 is
always false [-Wtautological-compare]
        if (dev_size < 0)
            ~~~~~~~~ ^ ~
1 warning generated.

This is because dev_size is defined as unsigned type, but lseek() will
return singed valued.
So the judgement will always to false.

Use temporary off_t return value to solve it.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
This commit is contained in:
Qu Wenruo 2014-12-19 14:13:09 +08:00 committed by David Sterba
parent 040b3f11ba
commit e363f6ba09
1 changed files with 6 additions and 3 deletions

View File

@ -1009,13 +1009,16 @@ int btrfs_scan_fs_devices(int fd, const char *path,
{
u64 total_devs;
u64 dev_size;
off_t seek_ret;
int ret;
if (!sb_bytenr)
sb_bytenr = BTRFS_SUPER_INFO_OFFSET;
dev_size = lseek(fd, 0, SEEK_END);
if (dev_size < 0)
return (int)(dev_size);
seek_ret = lseek(fd, 0, SEEK_END);
if (seek_ret < 0)
return -errno;
dev_size = seek_ret;
lseek(fd, 0, SEEK_SET);
if (sb_bytenr > dev_size) {
fprintf(stderr, "Superblock bytenr is larger than device size\n");