Commit a7a8f4a1 authored by Martin Kaistra's avatar Martin Kaistra Committed by Richard Weinberger
Browse files

ubifs: add option to specify version for new file systems 



Instead of creating ubifs file systems with UBIFS_FORMAT_VERSION
by default, add a module parameter ubifs.default_version to allow
the user to specify the desired version. Valid values are 4 to
UBIFS_FORMAT_VERSION (currently 5).

This way, one can for example create a file system with version 4
on kernel 4.19 which can still be mounted rw when downgrading to
kernel 4.9.

Signed-off-by: default avatarMartin Kaistra <martin.kaistra@linutronix.de>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent 92ed3019

fs/ubifs/sb.c

+3 −2
Original line number Diff line number Diff line
@@ -174,6 +174,7 @@ static int create_default_filesystem(struct ubifs_info *c) 
	tmp64 = (long long)max_buds * c->leb_size;

	if (big_lpt)

		sup_flags |= UBIFS_FLG_BIGLPT;

	if (ubifs_default_version > 4)

		sup_flags |= UBIFS_FLG_DOUBLE_HASH;



	if (ubifs_authenticated(c)) {
@@ -200,7 +201,7 @@ static int create_default_filesystem(struct ubifs_info *c) 
	sup->jhead_cnt     = cpu_to_le32(DEFAULT_JHEADS_CNT);

	sup->fanout        = cpu_to_le32(DEFAULT_FANOUT);

	sup->lsave_cnt     = cpu_to_le32(c->lsave_cnt);

	sup->fmt_version   = cpu_to_le32(UBIFS_FORMAT_VERSION);

	sup->fmt_version   = cpu_to_le32(ubifs_default_version);

	sup->time_gran     = cpu_to_le32(DEFAULT_TIME_GRAN);

	if (c->mount_opts.override_compr)

		sup->default_compr = cpu_to_le16(c->mount_opts.compr_type);

fs/ubifs/super.c

+18 −0
Original line number Diff line number Diff line
@@ -26,6 +26,24 @@ 
#include <linux/writeback.h>

#include "ubifs.h"



static int ubifs_default_version_set(const char *val, const struct kernel_param *kp)

{

	int n = 0, ret;



	ret = kstrtoint(val, 10, &n);

	if (ret != 0 || n < 4 || n > UBIFS_FORMAT_VERSION)

		return -EINVAL;

	return param_set_int(val, kp);

}



static const struct kernel_param_ops ubifs_default_version_ops = {

	.set = ubifs_default_version_set,

	.get = param_get_int,

};



int ubifs_default_version = UBIFS_FORMAT_VERSION;

module_param_cb(default_version, &ubifs_default_version_ops, &ubifs_default_version, 0600);



/*

 * Maximum amount of memory we may 'kmalloc()' without worrying that we are

 * allocating too much.

fs/ubifs/ubifs.h

+1 −0
Original line number Diff line number Diff line
@@ -1504,6 +1504,7 @@ extern const struct file_operations ubifs_dir_operations; 
extern const struct inode_operations ubifs_dir_inode_operations;

extern const struct inode_operations ubifs_symlink_inode_operations;

extern struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];

extern int ubifs_default_version;



/* auth.c */

static inline int ubifs_authenticated(const struct ubifs_info *c)