From ab518eea9c41235a3fcde80f3ea99669eaade621 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Thu, 16 Mar 2017 16:49:37 +0100 Subject: mount: create loop devices with LO_FLAGS_AUTOCLEAR flag The "autolooped" mount (mount [-oloop] IMAGE /DIR/DIR) always creates AUTOCLEARed loopdevs, so that umounting drops them (and this does not require any code in the umount userspace). This happens since circa linux-2.6.25: commit 96c5865559cee0f9cbc5173f3c949f6ce3525581 Date: Wed Feb 6 01:36:27 2008 -0800 Subject: Allow auto-destruction of loop devices IOW: in this case, umount does not have to use -d to drop the loopdev. The explicit loop mount (mount /dev/loopN /DIR/DIR) does not do this. In this case, umount without -d should not drop loopdev. Unfortunately, bbox umount currently always implies -d, this probably needs fixing. function old new delta set_loop 537 597 +60 singlemount 1101 1138 +37 losetup_main 419 432 +13 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 3/0 up/down: 110/0) Total: 110 bytes Signed-off-by: Denys Vlasenko --- include/libbb.h | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'include/libbb.h') diff --git a/include/libbb.h b/include/libbb.h index b054e0559..e97efcb6e 100644 --- a/include/libbb.h +++ b/include/libbb.h @@ -1329,10 +1329,15 @@ extern int get_linux_version_code(void) FAST_FUNC; extern char *query_loop(const char *device) FAST_FUNC; extern int del_loop(const char *device) FAST_FUNC; -/* If *devname is not NULL, use that name, otherwise try to find free one, +/* + * If *devname is not NULL, use that name, otherwise try to find free one, * malloc and return it in *devname. - * return value: 1: read-only loopdev was setup, 0: rw, < 0: error */ -extern int set_loop(char **devname, const char *file, unsigned long long offset, int ro) FAST_FUNC; + * return value is the opened fd to the loop device, or < on error + */ +extern int set_loop(char **devname, const char *file, unsigned long long offset, unsigned flags) FAST_FUNC; +/* These constants match linux/loop.h (without BB_ prefix): */ +#define BB_LO_FLAGS_READ_ONLY 1 +#define BB_LO_FLAGS_AUTOCLEAR 4 /* Like bb_ask below, but asks on stdin with no timeout. */ char *bb_ask_stdin(const char * prompt) FAST_FUNC; -- cgit v1.2.3