| Message ID | 1418969592-21278-3-git-send-email-quwenruo@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
diff --git a/disk-io.c b/disk-io.c index 03edf8e..2bf8586 100644 --- a/disk-io.c +++ b/disk-io.c @@ -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");
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> --- disk-io.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)