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Merged
jserv merged 7 commits into from
May 7, 2026
+105 −10
Merged

added support for fs_context operations -> parse_param #85

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d122d51
fs: added support for fs_context operations -> parse_param
EricKim27 May 5, 2026
2420809
formatting correction
EricKim27 May 5, 2026
9c911de
formatting correction according to coding style tests
EricKim27 May 5, 2026
53e386f
fix: formatting correction according to the coding style failures
EricKim27 May 5, 2026
3e232e6
fix: potential memory leak fixes at fs_context_operations by adding f…
EricKim27 May 5, 2026
bce1210
coding style formatting correction accordingly to coding style checks
EricKim27 May 5, 2026
e60949b
Replaced path_put to resolve possible use-after-free
EricKim27 May 5, 2026
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21 changes: 21 additions & 0 deletions fs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@

Comment thread
cubic-dev-ai[bot] marked this conversation as resolved.
#if SIMPLEFS_AT_LEAST(6, 18, 0)
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#endif
#include <linux/fs.h>
#include <linux/kernel.h>
Expand All @@ -14,14 +15,33 @@ static int simplefs_get_tree(struct fs_context *fc)
{
return get_tree_bdev(fc, simplefs_fill_super);
}
static void simplefs_free_context(struct fs_context *fc)
{
struct simplefs_fs_context *ctx = fc->fs_private;

if (!ctx)
return;

kfree(ctx->journal_path);
kfree(ctx);
}
static const struct fs_context_operations simplefs_context_ops = {
.get_tree = simplefs_get_tree,
.parse_param = simplefs_parse_param,
.free = simplefs_free_context,
};
static int init_simplefs_context(struct fs_context *fc)
{
struct simplefs_fs_context *ctx;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
fc->fs_private = ctx;
fc->ops = &simplefs_context_ops;

return 0;
}
extern const struct fs_parameter_spec simplefs_param_specs;
#else
/* Mount a simplefs partition */
struct dentry *simplefs_mount(struct file_system_type *fs_type,
Expand Down Expand Up @@ -60,6 +80,7 @@ static struct file_system_type simplefs_file_system_type = {
.name = "simplefs",
#if SIMPLEFS_AT_LEAST(6, 18, 0)
.init_fs_context = init_simplefs_context,
.parameters = &simplefs_param_specs,
#else
.mount = simplefs_mount,
#endif
Expand Down
13 changes: 11 additions & 2 deletions simplefs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -99,15 +99,24 @@ struct simplefs_dir_block {
uint32_t nr_files;
struct simplefs_file files[SIMPLEFS_FILES_PER_BLOCK];
};

#if SIMPLEFS_AT_LEAST(6, 18, 0)
struct simplefs_fs_context {
u32 journal_dev;
char *journal_path;
};
#endif
/* superblock functions */
#if SIMPLEFS_AT_LEAST(6, 18, 0)
int simplefs_fill_super(struct super_block *sb, struct fs_context *fc);
#else
int simplefs_fill_super(struct super_block *sb, void *data, int silent);
#endif
void simplefs_kill_sb(struct super_block *sb);

#if SIMPLEFS_AT_LEAST(6, 18, 0)
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
int simplefs_parse_param(struct fs_context *fc, struct fs_parameter *param);
#endif
/* inode functions */
int simplefs_init_inode_cache(void);
void simplefs_destroy_inode_cache(void);
Expand Down
81 changes: 73 additions & 8 deletions super.c
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@
#include "simplefs.h"
#if SIMPLEFS_AT_LEAST(6, 18, 0)
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#endif
struct dentry *simplefs_mount(struct file_system_type *fs_type,
int flags,
Expand Down Expand Up @@ -449,6 +450,39 @@ static const match_table_t tokens = {
{SIMPLEFS_OPT_JOURNAL_DEV, "journal_dev=%u"},
{SIMPLEFS_OPT_JOURNAL_PATH, "journal_path=%s"},
};
#if SIMPLEFS_AT_LEAST(6, 18, 0)
const struct fs_parameter_spec simplefs_param_specs[] = {
fsparam_u32("journal_dev", SIMPLEFS_OPT_JOURNAL_DEV),
fsparam_string("journal_path", SIMPLEFS_OPT_JOURNAL_PATH),
{}};
int simplefs_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
struct simplefs_fs_context *ctx = fc->fs_private;
struct fs_parse_result result;
int opt;

opt = fs_parse(fc, simplefs_param_specs, param, &result);
if (opt < 0)
return opt;

switch (opt) {
case SIMPLEFS_OPT_JOURNAL_DEV:
ctx->journal_dev = result.uint_32;
break;

case SIMPLEFS_OPT_JOURNAL_PATH: {
kfree(ctx->journal_path);
ctx->journal_path = kstrdup(param->string, GFP_KERNEL);
if (!ctx->journal_path)
return -ENOMEM;
break;
default:
return -EINVAL;
}
}
return 0;
}
#else
static int simplefs_parse_options(struct super_block *sb, char *options)
{
substring_t args[MAX_OPT_ARGS];
Expand Down Expand Up @@ -496,12 +530,9 @@ static int simplefs_parse_options(struct super_block *sb, char *options)
kfree(journal_path);
return ret;
}

journal_inode = path.dentry->d_inode;

path_put(&path);
kfree(journal_path);

journal_inode = path.dentry->d_inode;
if (S_ISBLK(journal_inode->i_mode)) {
unsigned long journal_devnum =
new_encode_dev(journal_inode->i_rdev);
Expand All @@ -513,14 +544,15 @@ static int simplefs_parse_options(struct super_block *sb, char *options)
return ret;
}
}
path_put(&path);
break;
}
}
}

return 0;
}

#endif
static struct super_operations simplefs_super_ops = {
.put_super = simplefs_put_super,
.alloc_inode = simplefs_alloc_inode,
Expand All @@ -534,6 +566,7 @@ static struct super_operations simplefs_super_ops = {
#if SIMPLEFS_AT_LEAST(6, 18, 0)
int simplefs_fill_super(struct super_block *sb, struct fs_context *fc)
{
struct simplefs_fs_context *ctx = fc->fs_private;
#else
int simplefs_fill_super(struct super_block *sb, void *data, int silent)
{
Expand Down Expand Up @@ -651,9 +684,41 @@ inode_init_owner(root_inode, NULL, root_inode->i_mode);
ret = -ENOMEM;
goto iput;
}
/* Since parse_options is not available at fill_super stage at kernels
* v6.18+, it is disabled for now. */
#if SIMPLEFS_LESS_EQUAL(6, 17, 0)

#if SIMPLEFS_AT_LEAST(6, 18, 0)
if (ctx->journal_dev) {
ret = simplefs_load_journal(sb, ctx->journal_dev);
if (ret) {
pr_err(
"simplefs_parse_options: simplefs_load_journal failed with "
"%d\n",
ret);
return ret;
}
}
if (ctx->journal_path) {
struct path path;
struct inode *inode;
ret = kern_path(ctx->journal_path, LOOKUP_FOLLOW, &path);
if (ret) {
pr_err("simplefs_parse_options: kern_path failed with error %d\n",
ret);
return ret;
}
inode = d_inode(path.dentry);
path_put(&path);
Comment thread
cubic-dev-ai[bot] marked this conversation as resolved.
if (S_ISBLK(inode->i_mode)) {
unsigned long journal_devnum = new_encode_dev(inode->i_rdev);
if ((ret = simplefs_load_journal(sb, journal_devnum))) {
pr_err(
"simplefs_parse_options: simplefs_load_journal failed "
"with %d\n",
ret);
return ret;
}
}
Comment thread
cubic-dev-ai[bot] marked this conversation as resolved.
}
#else
ret = simplefs_parse_options(sb, data);
if (ret) {
pr_err("simplefs_fill_super: Failed to parse options, error code: %d\n",
Expand Down
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