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shmem_parse_one(): switch to use of fs_parse()
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This thing will eventually become our ->parse_param(), while
shmem_parse_options() - ->parse_monolithic().  At that point
shmem_parse_options() will start calling vfs_parse_fs_string(),
rather than calling shmem_parse_one() directly.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro committed Sep 13, 2019
1 parent e04dc42 commit 626c392
Showing 1 changed file with 116 additions and 67 deletions.
183 changes: 116 additions & 67 deletions mm/shmem.c
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@
#include <linux/khugepaged.h>
#include <linux/hugetlb.h>
#include <linux/frontswap.h>
#include <linux/fs_parser.h>

#include <asm/tlbflush.h> /* for arch/microblaze update_mmu_cache() */

Expand Down Expand Up @@ -3363,90 +3364,129 @@ static const struct export_operations shmem_export_ops = {
.fh_to_dentry = shmem_fh_to_dentry,
};

static int shmem_parse_one(struct shmem_options *ctx, char *opt, char *value)
enum shmem_param {
Opt_gid,
Opt_huge,
Opt_mode,
Opt_mpol,
Opt_nr_blocks,
Opt_nr_inodes,
Opt_size,
Opt_uid,
};

static const struct fs_parameter_spec shmem_param_specs[] = {
fsparam_u32 ("gid", Opt_gid),
fsparam_enum ("huge", Opt_huge),
fsparam_u32oct("mode", Opt_mode),
fsparam_string("mpol", Opt_mpol),
fsparam_string("nr_blocks", Opt_nr_blocks),
fsparam_string("nr_inodes", Opt_nr_inodes),
fsparam_string("size", Opt_size),
fsparam_u32 ("uid", Opt_uid),
{}
};

static const struct fs_parameter_enum shmem_param_enums[] = {
{ Opt_huge, "never", SHMEM_HUGE_NEVER },
{ Opt_huge, "always", SHMEM_HUGE_ALWAYS },
{ Opt_huge, "within_size", SHMEM_HUGE_WITHIN_SIZE },
{ Opt_huge, "advise", SHMEM_HUGE_ADVISE },
{}
};

const struct fs_parameter_description shmem_fs_parameters = {
.name = "tmpfs",
.specs = shmem_param_specs,
.enums = shmem_param_enums,
};

static int shmem_parse_one(struct shmem_options *ctx,
struct fs_parameter *param)
{
struct fs_context *fc = NULL;
struct fs_parse_result result;
unsigned long long size;
char *rest;
uid_t uid;
gid_t gid;
int opt;

opt = fs_parse(fc, &shmem_fs_parameters, param, &result);
if (opt < 0) {
if (opt == -ENOPARAM)
return invalf(fc, "tmpfs: Unknown parameter '%s'",
param->key);
return opt;
}

if (!strcmp(opt, "size")) {
unsigned long long size;
size = memparse(value,&rest);
switch (opt) {
case Opt_size:
size = memparse(param->string, &rest);
if (*rest == '%') {
size <<= PAGE_SHIFT;
size *= totalram_pages();
do_div(size, 100);
rest++;
}
if (*rest)
goto bad_val;
goto bad_value;
ctx->blocks = DIV_ROUND_UP(size, PAGE_SIZE);
ctx->seen |= SHMEM_SEEN_BLOCKS;
} else if (!strcmp(opt, "nr_blocks")) {
ctx->blocks = memparse(value, &rest);
break;
case Opt_nr_blocks:
ctx->blocks = memparse(param->string, &rest);
if (*rest)
goto bad_val;
goto bad_value;
ctx->seen |= SHMEM_SEEN_BLOCKS;
} else if (!strcmp(opt, "nr_inodes")) {
ctx->inodes = memparse(value, &rest);
break;
case Opt_nr_inodes:
ctx->inodes = memparse(param->string, &rest);
if (*rest)
goto bad_val;
goto bad_value;
ctx->seen |= SHMEM_SEEN_INODES;
} else if (!strcmp(opt, "mode")) {
ctx->mode = simple_strtoul(value, &rest, 8) & 07777;
if (*rest)
goto bad_val;
} else if (!strcmp(opt, "uid")) {
uid = simple_strtoul(value, &rest, 0);
if (*rest)
goto bad_val;
ctx->uid = make_kuid(current_user_ns(), uid);
break;
case Opt_mode:
ctx->mode = result.uint_32 & 07777;
break;
case Opt_uid:
ctx->uid = make_kuid(current_user_ns(), result.uint_32);
if (!uid_valid(ctx->uid))
goto bad_val;
} else if (!strcmp(opt, "gid")) {
gid = simple_strtoul(value, &rest, 0);
if (*rest)
goto bad_val;
ctx->gid = make_kgid(current_user_ns(), gid);
goto bad_value;
break;
case Opt_gid:
ctx->gid = make_kgid(current_user_ns(), result.uint_32);
if (!gid_valid(ctx->gid))
goto bad_val;
#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
} else if (!strcmp(opt, "huge")) {
int huge;
huge = shmem_parse_huge(value);
if (huge < 0)
goto bad_val;
if (!has_transparent_hugepage() &&
huge != SHMEM_HUGE_NEVER)
goto bad_val;
ctx->huge = huge;
goto bad_value;
break;
case Opt_huge:
ctx->huge = result.uint_32;
if (ctx->huge != SHMEM_HUGE_NEVER &&
!(IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE) &&
has_transparent_hugepage()))
goto unsupported_parameter;
ctx->seen |= SHMEM_SEEN_HUGE;
#endif
#ifdef CONFIG_NUMA
} else if (!strcmp(opt, "mpol")) {
mpol_put(ctx->mpol);
ctx->mpol = NULL;
if (mpol_parse_str(value, &ctx->mpol))
goto bad_val;
#endif
} else {
pr_err("tmpfs: Bad mount option %s\n", opt);
return -EINVAL;
break;
case Opt_mpol:
if (IS_ENABLED(CONFIG_NUMA)) {
mpol_put(ctx->mpol);
ctx->mpol = NULL;
if (mpol_parse_str(param->string, &ctx->mpol))
goto bad_value;
break;
}
goto unsupported_parameter;
}
return 0;

bad_val:
pr_err("tmpfs: Bad value '%s' for mount option '%s'\n",
value, opt);
return -EINVAL;
unsupported_parameter:
return invalf(fc, "tmpfs: Unsupported parameter '%s'", param->key);
bad_value:
return invalf(fc, "tmpfs: Bad value for '%s'", param->key);
}

static int shmem_parse_options(char *options, struct shmem_options *ctx)
{
char *this_char, *value;

while (options != NULL) {
this_char = options;
char *this_char = options;
for (;;) {
/*
* NUL-terminate this option: unfortunately,
Expand All @@ -3462,17 +3502,26 @@ static int shmem_parse_options(char *options, struct shmem_options *ctx)
break;
}
}
if (!*this_char)
continue;
if ((value = strchr(this_char,'=')) != NULL) {
*value++ = 0;
} else {
pr_err("tmpfs: No value for mount option '%s'\n",
this_char);
goto error;
if (*this_char) {
char *value = strchr(this_char,'=');
struct fs_parameter param = {
.key = this_char,
.type = fs_value_is_string,
};
int err;

if (value) {
*value++ = '\0';
param.size = strlen(value);
param.string = kstrdup(value, GFP_KERNEL);
if (!param.string)
goto error;
}
err = shmem_parse_one(ctx, &param);
kfree(param.string);
if (err)
goto error;
}
if (shmem_parse_one(ctx, this_char, value) < 0)
goto error;
}
return 0;

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