375a8ef5e
Lauri Kasanen
2010-04-14
Subject
mount: add an optional capability to create new /dev/loopN as needed
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Commit Diff GitHub →
libbb/loop.c+12 -2
| @@ -104,14 +104,24 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse | |
| /* Find a loop device. */ | |
| try = *device ? *device : dev; | |
| - | for (i = 0; rc; i++) { |
| + | for (i = 0; rc && i < 256; i++) { |
| sprintf(dev, LOOP_FORMAT, i); | |
| - | /* Ran out of block devices, return failure. */ |
| + | IF_FEATURE_MOUNT_LOOP_CREATE(errno = 0;) |
| if (stat(try, &statbuf) != 0 || !S_ISBLK(statbuf.st_mode)) { | |
| + | if (ENABLE_FEATURE_MOUNT_LOOP_CREATE |
| + | && errno == ENOENT |
| + | && try == dev |
| + | ) { |
| + | /* Node doesn't exist, try to create it. */ |
| + | if (mknod(dev, S_IFBLK|0644, makedev(7, i)) == 0) |
| + | goto try_to_open; |
| + | } |
| + | /* Ran out of block devices, return failure. */ |
| rc = -ENOENT; | |
| break; | |
| } | |
| + | try_to_open: |
| /* Open the sucker and check its loopiness. */ | |
| dfd = open(try, mode); | |
| if (dfd < 0 && errno == EROFS) { | |
scripts/defconfig+1 -0
| @@ -574,6 +574,7 @@ CONFIG_FEATURE_UMOUNT_ALL=y | |
| # Common options for mount/umount | |
| # | |
| CONFIG_FEATURE_MOUNT_LOOP=y | |
| + | # CONFIG_FEATURE_MOUNT_LOOP_CREATE is not set |
| # CONFIG_FEATURE_MTAB_SUPPORT is not set | |
| # | |
util-linux/Config.in+12 -0
| @@ -901,6 +901,18 @@ config FEATURE_MOUNT_LOOP | |
| specify an offset or cryptographic options to the loopback device. | |
| (If you don't want umount to free the loop device, use "umount -D".) | |
| + | config FEATURE_MOUNT_LOOP_CREATE |
| + | bool "Create new loopback devices if needed" |
| + | default n |
| + | depends on FEATURE_MOUNT_LOOP |
| + | help |
| + | Linux kernels >= 2.6.24 support unlimited loopback devices. They are |
| + | allocated for use when trying to use a loop device. The loop device |
| + | must however exist. |
| + | |
| + | This feature lets mount to try to create next /dev/loopN device |
| + | if it does not find a free one. |
| + | |
| config FEATURE_MTAB_SUPPORT | |
| bool "Support for the old /etc/mtab file" | |
| default n | |