diff options
Diffstat (limited to 'fs/sdcardfs/main.c')
| -rw-r--r-- | fs/sdcardfs/main.c | 486 |
1 files changed, 486 insertions, 0 deletions
diff --git a/fs/sdcardfs/main.c b/fs/sdcardfs/main.c new file mode 100644 index 000000000000..dd4b87c7cb1d --- /dev/null +++ b/fs/sdcardfs/main.c @@ -0,0 +1,486 @@ +/* + * fs/sdcardfs/main.c + * + * Copyright (c) 2013 Samsung Electronics Co. Ltd + * Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun, + * Sunghwan Yun, Sungjong Seo + * + * This program has been developed as a stackable file system based on + * the WrapFS which written by + * + * Copyright (c) 1998-2011 Erez Zadok + * Copyright (c) 2009 Shrikar Archak + * Copyright (c) 2003-2011 Stony Brook University + * Copyright (c) 2003-2011 The Research Foundation of SUNY + * + * This file is dual licensed. It may be redistributed and/or modified + * under the terms of the Apache 2.0 License OR version 2 of the GNU + * General Public License. + */ + +#include "sdcardfs.h" +#include <linux/module.h> +#include <linux/types.h> +#include <linux/parser.h> + +enum { + Opt_fsuid, + Opt_fsgid, + Opt_gid, + Opt_debug, + Opt_mask, + Opt_multiuser, + Opt_userid, + Opt_reserved_mb, + Opt_err, +}; + +static const match_table_t sdcardfs_tokens = { + {Opt_fsuid, "fsuid=%u"}, + {Opt_fsgid, "fsgid=%u"}, + {Opt_gid, "gid=%u"}, + {Opt_debug, "debug"}, + {Opt_mask, "mask=%u"}, + {Opt_userid, "userid=%d"}, + {Opt_multiuser, "multiuser"}, + {Opt_reserved_mb, "reserved_mb=%u"}, + {Opt_err, NULL} +}; + +static int parse_options(struct super_block *sb, char *options, int silent, + int *debug, struct sdcardfs_vfsmount_options *vfsopts, + struct sdcardfs_mount_options *opts) +{ + char *p; + substring_t args[MAX_OPT_ARGS]; + int option; + + /* by default, we use AID_MEDIA_RW as uid, gid */ + opts->fs_low_uid = AID_MEDIA_RW; + opts->fs_low_gid = AID_MEDIA_RW; + vfsopts->mask = 0; + opts->multiuser = false; + opts->fs_user_id = 0; + vfsopts->gid = 0; + /* by default, 0MB is reserved */ + opts->reserved_mb = 0; + + *debug = 0; + + if (!options) + return 0; + + while ((p = strsep(&options, ",")) != NULL) { + int token; + + if (!*p) + continue; + + token = match_token(p, sdcardfs_tokens, args); + + switch (token) { + case Opt_debug: + *debug = 1; + break; + case Opt_fsuid: + if (match_int(&args[0], &option)) + return 0; + opts->fs_low_uid = option; + break; + case Opt_fsgid: + if (match_int(&args[0], &option)) + return 0; + opts->fs_low_gid = option; + break; + case Opt_gid: + if (match_int(&args[0], &option)) + return 0; + vfsopts->gid = option; + break; + case Opt_userid: + if (match_int(&args[0], &option)) + return 0; + opts->fs_user_id = option; + break; + case Opt_mask: + if (match_int(&args[0], &option)) + return 0; + vfsopts->mask = option; + break; + case Opt_multiuser: + opts->multiuser = true; + break; + case Opt_reserved_mb: + if (match_int(&args[0], &option)) + return 0; + opts->reserved_mb = option; + break; + /* unknown option */ + default: + if (!silent) + pr_err("Unrecognized mount option \"%s\" or missing value", p); + return -EINVAL; + } + } + + if (*debug) { + pr_info("sdcardfs : options - debug:%d\n", *debug); + pr_info("sdcardfs : options - uid:%d\n", + opts->fs_low_uid); + pr_info("sdcardfs : options - gid:%d\n", + opts->fs_low_gid); + } + + return 0; +} + +int parse_options_remount(struct super_block *sb, char *options, int silent, + struct sdcardfs_vfsmount_options *vfsopts) +{ + char *p; + substring_t args[MAX_OPT_ARGS]; + int option; + int debug; + + if (!options) + return 0; + + while ((p = strsep(&options, ",")) != NULL) { + int token; + + if (!*p) + continue; + + token = match_token(p, sdcardfs_tokens, args); + + switch (token) { + case Opt_debug: + debug = 1; + break; + case Opt_gid: + if (match_int(&args[0], &option)) + return 0; + vfsopts->gid = option; + + break; + case Opt_mask: + if (match_int(&args[0], &option)) + return 0; + vfsopts->mask = option; + break; + case Opt_multiuser: + case Opt_userid: + case Opt_fsuid: + case Opt_fsgid: + case Opt_reserved_mb: + pr_warn("Option \"%s\" can't be changed during remount\n", p); + break; + /* unknown option */ + default: + if (!silent) + pr_err("Unrecognized mount option \"%s\" or missing value", p); + return -EINVAL; + } + } + + if (debug) { + pr_info("sdcardfs : options - debug:%d\n", debug); + pr_info("sdcardfs : options - gid:%d\n", vfsopts->gid); + pr_info("sdcardfs : options - mask:%d\n", vfsopts->mask); + } + + return 0; +} + +#if 0 +/* + * our custom d_alloc_root work-alike + * + * we can't use d_alloc_root if we want to use our own interpose function + * unchanged, so we simply call our own "fake" d_alloc_root + */ +static struct dentry *sdcardfs_d_alloc_root(struct super_block *sb) +{ + struct dentry *ret = NULL; + + if (sb) { + static const struct qstr name = { + .name = "/", + .len = 1 + }; + + ret = d_alloc(NULL, &name); + if (ret) { + d_set_d_op(ret, &sdcardfs_ci_dops); + ret->d_sb = sb; + ret->d_parent = ret; + } + } + return ret; +} +#endif + +DEFINE_MUTEX(sdcardfs_super_list_lock); +EXPORT_SYMBOL_GPL(sdcardfs_super_list_lock); +LIST_HEAD(sdcardfs_super_list); +EXPORT_SYMBOL_GPL(sdcardfs_super_list); + +/* + * There is no need to lock the sdcardfs_super_info's rwsem as there is no + * way anyone can have a reference to the superblock at this point in time. + */ +static int sdcardfs_read_super(struct vfsmount *mnt, struct super_block *sb, + const char *dev_name, void *raw_data, int silent) +{ + int err = 0; + int debug; + struct super_block *lower_sb; + struct path lower_path; + struct sdcardfs_sb_info *sb_info; + struct sdcardfs_vfsmount_options *mnt_opt = mnt->data; + struct inode *inode; + + pr_info("sdcardfs version 2.0\n"); + + if (!dev_name) { + pr_err("sdcardfs: read_super: missing dev_name argument\n"); + err = -EINVAL; + goto out; + } + + pr_info("sdcardfs: dev_name -> %s\n", dev_name); + pr_info("sdcardfs: options -> %s\n", (char *)raw_data); + pr_info("sdcardfs: mnt -> %p\n", mnt); + + /* parse lower path */ + err = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, + &lower_path); + if (err) { + pr_err("sdcardfs: error accessing lower directory '%s'\n", dev_name); + goto out; + } + + /* allocate superblock private data */ + sb->s_fs_info = kzalloc(sizeof(struct sdcardfs_sb_info), GFP_KERNEL); + if (!SDCARDFS_SB(sb)) { + pr_crit("sdcardfs: read_super: out of memory\n"); + err = -ENOMEM; + goto out_free; + } + + sb_info = sb->s_fs_info; + /* parse options */ + err = parse_options(sb, raw_data, silent, &debug, mnt_opt, &sb_info->options); + if (err) { + pr_err("sdcardfs: invalid options\n"); + goto out_freesbi; + } + + /* set the lower superblock field of upper superblock */ + lower_sb = lower_path.dentry->d_sb; + atomic_inc(&lower_sb->s_active); + sdcardfs_set_lower_super(sb, lower_sb); + + /* inherit maxbytes from lower file system */ + sb->s_maxbytes = lower_sb->s_maxbytes; + + /* + * Our c/m/atime granularity is 1 ns because we may stack on file + * systems whose granularity is as good. + */ + sb->s_time_gran = 1; + + sb->s_magic = SDCARDFS_SUPER_MAGIC; + sb->s_op = &sdcardfs_sops; + + /* get a new inode and allocate our root dentry */ + inode = sdcardfs_iget(sb, lower_path.dentry->d_inode, 0); + if (IS_ERR(inode)) { + err = PTR_ERR(inode); + goto out_sput; + } + sb->s_root = d_make_root(inode); + if (!sb->s_root) { + err = -ENOMEM; + goto out_iput; + } + d_set_d_op(sb->s_root, &sdcardfs_ci_dops); + + /* link the upper and lower dentries */ + sb->s_root->d_fsdata = NULL; + err = new_dentry_private_data(sb->s_root); + if (err) + goto out_freeroot; + + /* set the lower dentries for s_root */ + sdcardfs_set_lower_path(sb->s_root, &lower_path); + + /* + * No need to call interpose because we already have a positive + * dentry, which was instantiated by d_make_root. Just need to + * d_rehash it. + */ + d_rehash(sb->s_root); + + /* setup permission policy */ + sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL); + mutex_lock(&sdcardfs_super_list_lock); + if (sb_info->options.multiuser) { + setup_derived_state(sb->s_root->d_inode, PERM_PRE_ROOT, + sb_info->options.fs_user_id, AID_ROOT, + false, SDCARDFS_I(sb->s_root->d_inode)->data); + snprintf(sb_info->obbpath_s, PATH_MAX, "%s/obb", dev_name); + } else { + setup_derived_state(sb->s_root->d_inode, PERM_ROOT, + sb_info->options.fs_user_id, AID_ROOT, + false, SDCARDFS_I(sb->s_root->d_inode)->data); + snprintf(sb_info->obbpath_s, PATH_MAX, "%s/Android/obb", dev_name); + } + fixup_tmp_permissions(sb->s_root->d_inode); + sb_info->sb = sb; + list_add(&sb_info->list, &sdcardfs_super_list); + mutex_unlock(&sdcardfs_super_list_lock); + + if (!silent) + pr_info("sdcardfs: mounted on top of %s type %s\n", + dev_name, lower_sb->s_type->name); + goto out; /* all is well */ + + /* no longer needed: free_dentry_private_data(sb->s_root); */ +out_freeroot: + dput(sb->s_root); +out_iput: + iput(inode); +out_sput: + /* drop refs we took earlier */ + atomic_dec(&lower_sb->s_active); +out_freesbi: + kfree(SDCARDFS_SB(sb)); + sb->s_fs_info = NULL; +out_free: + path_put(&lower_path); + +out: + return err; +} + +/* A feature which supports mount_nodev() with options */ +static struct dentry *mount_nodev_with_options(struct vfsmount *mnt, + struct file_system_type *fs_type, int flags, + const char *dev_name, void *data, + int (*fill_super)(struct vfsmount *, struct super_block *, + const char *, void *, int)) + +{ + int error; + struct super_block *s = sget(fs_type, NULL, set_anon_super, flags, NULL); + + if (IS_ERR(s)) + return ERR_CAST(s); + + s->s_flags = flags; + + error = fill_super(mnt, s, dev_name, data, flags & MS_SILENT ? 1 : 0); + if (error) { + deactivate_locked_super(s); + return ERR_PTR(error); + } + s->s_flags |= MS_ACTIVE; + return dget(s->s_root); +} + +static struct dentry *sdcardfs_mount(struct vfsmount *mnt, + struct file_system_type *fs_type, int flags, + const char *dev_name, void *raw_data) +{ + /* + * dev_name is a lower_path_name, + * raw_data is a option string. + */ + return mount_nodev_with_options(mnt, fs_type, flags, dev_name, + raw_data, sdcardfs_read_super); +} + +static struct dentry *sdcardfs_mount_wrn(struct file_system_type *fs_type, + int flags, const char *dev_name, void *raw_data) +{ + WARN(1, "sdcardfs does not support mount. Use mount2.\n"); + return ERR_PTR(-EINVAL); +} + +void *sdcardfs_alloc_mnt_data(void) +{ + return kmalloc(sizeof(struct sdcardfs_vfsmount_options), GFP_KERNEL); +} + +void sdcardfs_kill_sb(struct super_block *sb) +{ + struct sdcardfs_sb_info *sbi; + + if (sb->s_magic == SDCARDFS_SUPER_MAGIC) { + sbi = SDCARDFS_SB(sb); + mutex_lock(&sdcardfs_super_list_lock); + list_del(&sbi->list); + mutex_unlock(&sdcardfs_super_list_lock); + } + generic_shutdown_super(sb); +} + +static struct file_system_type sdcardfs_fs_type = { + .owner = THIS_MODULE, + .name = SDCARDFS_NAME, + .mount = sdcardfs_mount_wrn, + .mount2 = sdcardfs_mount, + .alloc_mnt_data = sdcardfs_alloc_mnt_data, + .kill_sb = sdcardfs_kill_sb, + .fs_flags = 0, +}; +MODULE_ALIAS_FS(SDCARDFS_NAME); + +static int __init init_sdcardfs_fs(void) +{ + int err; + + pr_info("Registering sdcardfs " SDCARDFS_VERSION "\n"); + + err = sdcardfs_init_inode_cache(); + if (err) + goto out; + err = sdcardfs_init_dentry_cache(); + if (err) + goto out; + err = packagelist_init(); + if (err) + goto out; + err = register_filesystem(&sdcardfs_fs_type); +out: + if (err) { + sdcardfs_destroy_inode_cache(); + sdcardfs_destroy_dentry_cache(); + packagelist_exit(); + } + return err; +} + +static void __exit exit_sdcardfs_fs(void) +{ + sdcardfs_destroy_inode_cache(); + sdcardfs_destroy_dentry_cache(); + packagelist_exit(); + unregister_filesystem(&sdcardfs_fs_type); + pr_info("Completed sdcardfs module unload\n"); +} + +/* Original wrapfs authors */ +MODULE_AUTHOR("Erez Zadok, Filesystems and Storage Lab, Stony Brook University (http://www.fsl.cs.sunysb.edu/)"); + +/* Original sdcardfs authors */ +MODULE_AUTHOR("Woojoong Lee, Daeho Jeong, Kitae Lee, Yeongjin Gil System Memory Lab., Samsung Electronics"); + +/* Current maintainer */ +MODULE_AUTHOR("Daniel Rosenberg, Google"); +MODULE_DESCRIPTION("Sdcardfs " SDCARDFS_VERSION); +MODULE_LICENSE("GPL"); + +module_init(init_sdcardfs_fs); +module_exit(exit_sdcardfs_fs); |