btrfs-progs: Introduce warning and error for common use
Current code use fprintf(stderr, "...") to output warnning and
error information.
The error message have different style, as:
# grep fprintf *.c
fprintf(stderr, "Open ctree failed\n");
fprintf(stderr, "%s: open ctree failed\n", __func__);
fprintf(stderr, "ERROR: cannot open ctree\n");
...
And sometimes, we forgot add tailed '\n', or use printf instead,
as in current code:
printf("warning, device %llu is missing\n",
This patch introduce warning() and error() as common function,
to make:
1: Each warning and error information have same format
2: Easy to search/change all error message
3: Easy to modify function's internal for debug or other requirement,
for example:
print function/linenumber in error()
dumpstack in error()
add some trace for some style of message
add support for -v, -vv, ...
support for locales
custom output functions
support some special device/tty
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
[print newline after the message]
Signed-off-by: David Sterba <dsterba@suse.com>