#include <linux/string.h>
#include <linux/mount.h>
#include <linux/ramfs.h>
+#include <linux/parser.h>
#include <linux/sched.h>
#include <linux/magic.h>
#include <linux/pstore.h>
struct pstore_private {
u64 id;
int (*erase)(u64);
+ ssize_t size;
+ char data[];
};
-#define pstore_get_inode ramfs_get_inode
+static int pstore_file_open(struct inode *inode, struct file *file)
+{
+ file->private_data = inode->i_private;
+ return 0;
+}
+
+static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
+ size_t count, loff_t *ppos)
+{
+ struct pstore_private *ps = file->private_data;
+
+ return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
+}
+
+static const struct file_operations pstore_file_operations = {
+ .open = pstore_file_open,
+ .read = pstore_file_read,
+ .llseek = default_llseek,
+};
/*
* When a file is unlinked from our file system we call the
struct pstore_private *p = dentry->d_inode->i_private;
p->erase(p->id);
- kfree(p);
return simple_unlink(dir, dentry);
}
+static void pstore_evict_inode(struct inode *inode)
+{
+ end_writeback(inode);
+ kfree(inode->i_private);
+}
+
static const struct inode_operations pstore_dir_inode_operations = {
.lookup = simple_lookup,
.unlink = pstore_unlink,
};
+static struct inode *pstore_get_inode(struct super_block *sb,
+ const struct inode *dir, int mode, dev_t dev)
+{
+ struct inode *inode = new_inode(sb);
+
+ if (inode) {
+ inode->i_ino = get_next_ino();
+ inode->i_uid = inode->i_gid = 0;
+ inode->i_mode = mode;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ switch (mode & S_IFMT) {
+ case S_IFREG:
+ inode->i_fop = &pstore_file_operations;
+ break;
+ case S_IFDIR:
+ inode->i_op = &pstore_dir_inode_operations;
+ inode->i_fop = &simple_dir_operations;
+ inc_nlink(inode);
+ break;
+ }
+ }
+ return inode;
+}
+
+enum {
+ Opt_kmsg_bytes, Opt_err
+};
+
+static const match_table_t tokens = {
+ {Opt_kmsg_bytes, "kmsg_bytes=%u"},
+ {Opt_err, NULL}
+};
+
+static void parse_options(char *options)
+{
+ char *p;
+ substring_t args[MAX_OPT_ARGS];
+ int option;
+
+ if (!options)
+ return;
+
+ while ((p = strsep(&options, ",")) != NULL) {
+ int token;
+
+ if (!*p)
+ continue;
+
+ token = match_token(p, tokens, args);
+ switch (token) {
+ case Opt_kmsg_bytes:
+ if (!match_int(&args[0], &option))
+ pstore_set_kmsg_bytes(option);
+ break;
+ }
+ }
+}
+
+static int pstore_remount(struct super_block *sb, int *flags, char *data)
+{
+ parse_options(data);
+
+ return 0;
+}
+
static const struct super_operations pstore_ops = {
.statfs = simple_statfs,
.drop_inode = generic_delete_inode,
+ .evict_inode = pstore_evict_inode,
+ .remount_fs = pstore_remount,
.show_options = generic_show_options,
};
static struct super_block *pstore_sb;
-static struct vfsmount *pstore_mnt;
int pstore_is_mounted(void)
{
- return pstore_mnt != NULL;
-}
-
-/*
- * Set up a file structure as if we had opened this file and
- * write our data to it.
- */
-static int pstore_writefile(struct inode *inode, struct dentry *dentry,
- char *data, size_t size)
-{
- struct file f;
- ssize_t n;
- mm_segment_t old_fs = get_fs();
-
- memset(&f, '0', sizeof f);
- f.f_mapping = inode->i_mapping;
- f.f_path.dentry = dentry;
- f.f_path.mnt = pstore_mnt;
- f.f_pos = 0;
- f.f_op = inode->i_fop;
- set_fs(KERNEL_DS);
- n = do_sync_write(&f, data, size, &f.f_pos);
- set_fs(old_fs);
-
- fsnotify_modify(&f);
-
- return n == size;
+ return pstore_sb != NULL;
}
/*
inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG | 0444, 0);
if (!inode)
goto fail;
- inode->i_uid = inode->i_gid = 0;
- private = kmalloc(sizeof *private, GFP_KERNEL);
+ private = kmalloc(sizeof *private + size, GFP_KERNEL);
if (!private)
goto fail_alloc;
private->id = id;
if (IS_ERR(dentry))
goto fail_lockedalloc;
- d_add(dentry, inode);
-
- mutex_unlock(&root->d_inode->i_mutex);
-
- if (!pstore_writefile(inode, dentry, data, size))
- goto fail_write;
+ memcpy(private->data, data, size);
+ inode->i_size = private->size = size;
inode->i_private = private;
if (time.tv_sec)
inode->i_mtime = inode->i_ctime = time;
- return 0;
+ d_add(dentry, inode);
-fail_write:
- kfree(private);
- inode->i_nlink--;
- mutex_lock(&root->d_inode->i_mutex);
- d_delete(dentry);
- dput(dentry);
mutex_unlock(&root->d_inode->i_mutex);
- goto fail;
+
+ return 0;
fail_lockedalloc:
mutex_unlock(&root->d_inode->i_mutex);
sb->s_op = &pstore_ops;
sb->s_time_gran = 1;
+ parse_options(data);
+
inode = pstore_get_inode(sb, NULL, S_IFDIR | 0755, 0);
if (!inode) {
err = -ENOMEM;
return err;
}
-static int pstore_get_sb(struct file_system_type *fs_type,
- int flags, const char *dev_name, void *data, struct vfsmount *mnt)
+static struct dentry *pstore_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
{
- struct dentry *root;
-
- root = mount_nodev(fs_type, flags, data, pstore_fill_super);
- if (IS_ERR(root))
- return -ENOMEM;
-
- mnt->mnt_root = root;
- mnt->mnt_sb = root->d_sb;
- pstore_mnt = mnt;
-
- return 0;
+ return mount_single(fs_type, flags, data, pstore_fill_super);
}
static void pstore_kill_sb(struct super_block *sb)
{
kill_litter_super(sb);
pstore_sb = NULL;
- pstore_mnt = NULL;
}
static struct file_system_type pstore_fs_type = {
.name = "pstore",
- .get_sb = pstore_get_sb,
+ .mount = pstore_mount,
.kill_sb = pstore_kill_sb,
};
static int __init init_pstore_fs(void)
{
- int rc = 0;
- struct kobject *pstorefs_kobj;
-
- pstorefs_kobj = kobject_create_and_add("pstore", fs_kobj);
- if (!pstorefs_kobj) {
- rc = -ENOMEM;
- goto done;
- }
-
- rc = sysfs_create_file(pstorefs_kobj, &pstore_kmsg_bytes_attr.attr);
- if (rc)
- goto done1;
-
- rc = register_filesystem(&pstore_fs_type);
- if (rc == 0)
- goto done;
-
- sysfs_remove_file(pstorefs_kobj, &pstore_kmsg_bytes_attr.attr);
-done1:
- kobject_put(pstorefs_kobj);
-done:
- return rc;
+ return register_filesystem(&pstore_fs_type);
}
module_init(init_pstore_fs)
projects / linux.git / blobdiff