emo/busybox
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

mount: support the sizelimit and offset option for loop devices

Browse Source 
Starting with linux kernel v5.4 squashfs has a more strict parameter
checking implemented. Unlike util-linux mount, busybox never supported
the sizelimit option but simply forwards it to the kernel.
Since v5.4 mounting will fail with

    squashfs: Unknown parameter 'sizelimit'

Support the sizelimit parameter by setting it in the LOOP_SET_STATUS64
structure before handing it to the kernel.

While at it also add support for the offset option, which currently will
always be set to 0.

function                                             old     new   delta
cut_out_ull_opt                                        -     167    +167
singlemount                                         1230    1266     +36
set_loop                                             834     862     +28
losetup_main                                         479     483      +4
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 3/0 up/down: 235/0)             Total: 235 bytes

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Steffen Trumtrar
2020-07-29 10:43:53 +02:00
committed by Denys Vlasenko
parent abefc3c276
commit 6561e07460
4 changed files with 67 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
include/libbb.h
View File

@@ -1515,7 +1515,8 @@ int del_loop(const char *device) FAST_FUNC;
* malloc and return it in *devname.
* return value is the opened fd to the loop device, or < on error
*/
int set_loop(char **devname, const char *file, unsigned long long offset, unsigned flags) FAST_FUNC;
int set_loop(char **devname, const char *file, unsigned long long offset,
unsigned long long sizelimit, 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