// SPDX-License-Identifier: GPL-2.0-only /* * This file is part of UBIFS. * * Copyright (C) 2006-2008 Nokia Corporation. * * Authors: Artem Bityutskiy (Битюцкий Артём) * Adrian Hunter */ /* * This file implements UBIFS initialization and VFS superblock operations. Some * initialization stuff which is rather large and complex is placed at * corresponding subsystems, but most of it is here. */ #include <linux/init.h> #include <linux/slab.h> #include <linux/module.h> #include <linux/ctype.h> #include <linux/kthread.h> #include <linux/parser.h> #include <linux/seq_file.h> #include <linux/mount.h> #include <linux/math64.h> #include <linux/writeback.h> #include "ubifs.h" static int ubifs_default_version_set(const char *val, const struct kernel_param *kp) { … } static const struct kernel_param_ops ubifs_default_version_ops = …; int ubifs_default_version = …; module_param_cb(…); /* * Maximum amount of memory we may 'kmalloc()' without worrying that we are * allocating too much. */ #define UBIFS_KMALLOC_OK … /* Slab cache for UBIFS inodes */ static struct kmem_cache *ubifs_inode_slab; /* UBIFS TNC shrinker description */ static struct shrinker *ubifs_shrinker_info; /** * validate_inode - validate inode. * @c: UBIFS file-system description object * @inode: the inode to validate * * This is a helper function for 'ubifs_iget()' which validates various fields * of a newly built inode to make sure they contain sane values and prevent * possible vulnerabilities. Returns zero if the inode is all right and * a non-zero error code if not. */ static int validate_inode(struct ubifs_info *c, const struct inode *inode) { … } struct inode *ubifs_iget(struct super_block *sb, unsigned long inum) { … } static struct inode *ubifs_alloc_inode(struct super_block *sb) { struct ubifs_inode *ui; ui = alloc_inode_sb(sb, ubifs_inode_slab, GFP_NOFS); if (!ui) return NULL; memset((void *)ui + sizeof(struct inode), 0, sizeof(struct ubifs_inode) - sizeof(struct inode)); mutex_init(&ui->ui_mutex); init_rwsem(&ui->xattr_sem); spin_lock_init(&ui->ui_lock); return &ui->vfs_inode; }; static void ubifs_free_inode(struct inode *inode) { … } /* * Note, Linux write-back code calls this without 'i_mutex'. */ static int ubifs_write_inode(struct inode *inode, struct writeback_control *wbc) { … } static int ubifs_drop_inode(struct inode *inode) { … } static void ubifs_evict_inode(struct inode *inode) { … } static void ubifs_dirty_inode(struct inode *inode, int flags) { … } static int ubifs_statfs(struct dentry *dentry, struct kstatfs *buf) { … } static int ubifs_show_options(struct seq_file *s, struct dentry *root) { … } static int ubifs_sync_fs(struct super_block *sb, int wait) { … } /** * init_constants_early - initialize UBIFS constants. * @c: UBIFS file-system description object * * This function initialize UBIFS constants which do not need the superblock to * be read. It also checks that the UBI volume satisfies basic UBIFS * requirements. Returns zero in case of success and a negative error code in * case of failure. */ static int init_constants_early(struct ubifs_info *c) { … } /** * bud_wbuf_callback - bud LEB write-buffer synchronization call-back. * @c: UBIFS file-system description object * @lnum: LEB the write-buffer was synchronized to * @free: how many free bytes left in this LEB * @pad: how many bytes were padded * * This is a callback function which is called by the I/O unit when the * write-buffer is synchronized. We need this to correctly maintain space * accounting in bud logical eraseblocks. This function returns zero in case of * success and a negative error code in case of failure. * * This function actually belongs to the journal, but we keep it here because * we want to keep it static. */ static int bud_wbuf_callback(struct ubifs_info *c, int lnum, int free, int pad) { … } /* * init_constants_sb - initialize UBIFS constants. * @c: UBIFS file-system description object * * This is a helper function which initializes various UBIFS constants after * the superblock has been read. It also checks various UBIFS parameters and * makes sure they are all right. Returns zero in case of success and a * negative error code in case of failure. */ static int init_constants_sb(struct ubifs_info *c) { … } /* * init_constants_master - initialize UBIFS constants. * @c: UBIFS file-system description object * * This is a helper function which initializes various UBIFS constants after * the master node has been read. It also checks various UBIFS parameters and * makes sure they are all right. */ static void init_constants_master(struct ubifs_info *c) { … } /** * take_gc_lnum - reserve GC LEB. * @c: UBIFS file-system description object * * This function ensures that the LEB reserved for garbage collection is marked * as "taken" in lprops. We also have to set free space to LEB size and dirty * space to zero, because lprops may contain out-of-date information if the * file-system was un-mounted before it has been committed. This function * returns zero in case of success and a negative error code in case of * failure. */ static int take_gc_lnum(struct ubifs_info *c) { … } /** * alloc_wbufs - allocate write-buffers. * @c: UBIFS file-system description object * * This helper function allocates and initializes UBIFS write-buffers. Returns * zero in case of success and %-ENOMEM in case of failure. */ static int alloc_wbufs(struct ubifs_info *c) { … } /** * free_wbufs - free write-buffers. * @c: UBIFS file-system description object */ static void free_wbufs(struct ubifs_info *c) { … } /** * free_orphans - free orphans. * @c: UBIFS file-system description object */ static void free_orphans(struct ubifs_info *c) { … } /** * free_buds - free per-bud objects. * @c: UBIFS file-system description object */ static void free_buds(struct ubifs_info *c) { … } /** * check_volume_empty - check if the UBI volume is empty. * @c: UBIFS file-system description object * * This function checks if the UBIFS volume is empty by looking if its LEBs are * mapped or not. The result of checking is stored in the @c->empty variable. * Returns zero in case of success and a negative error code in case of * failure. */ static int check_volume_empty(struct ubifs_info *c) { … } /* * UBIFS mount options. * * Opt_fast_unmount: do not run a journal commit before un-mounting * Opt_norm_unmount: run a journal commit before un-mounting * Opt_bulk_read: enable bulk-reads * Opt_no_bulk_read: disable bulk-reads * Opt_chk_data_crc: check CRCs when reading data nodes * Opt_no_chk_data_crc: do not check CRCs when reading data nodes * Opt_override_compr: override default compressor * Opt_assert: set ubifs_assert() action * Opt_auth_key: The key name used for authentication * Opt_auth_hash_name: The hash type used for authentication * Opt_err: just end of array marker */ enum { … }; static const match_table_t tokens = …; /** * parse_standard_option - parse a standard mount option. * @option: the option to parse * * Normally, standard mount options like "sync" are passed to file-systems as * flags. However, when a "rootflags=" kernel boot parameter is used, they may * be present in the options string. This function tries to deal with this * situation and parse standard options. Returns 0 if the option was not * recognized, and the corresponding integer flag if it was. * * UBIFS is only interested in the "sync" option, so do not check for anything * else. */ static int parse_standard_option(const char *option) { … } /** * ubifs_parse_options - parse mount parameters. * @c: UBIFS file-system description object * @options: parameters to parse * @is_remount: non-zero if this is FS re-mount * * This function parses UBIFS mount options and returns zero in case success * and a negative error code in case of failure. */ static int ubifs_parse_options(struct ubifs_info *c, char *options, int is_remount) { … } /* * ubifs_release_options - release mount parameters which have been dumped. * @c: UBIFS file-system description object */ static void ubifs_release_options(struct ubifs_info *c) { … } /** * destroy_journal - destroy journal data structures. * @c: UBIFS file-system description object * * This function destroys journal data structures including those that may have * been created by recovery functions. */ static void destroy_journal(struct ubifs_info *c) { … } /** * bu_init - initialize bulk-read information. * @c: UBIFS file-system description object */ static void bu_init(struct ubifs_info *c) { … } /** * check_free_space - check if there is enough free space to mount. * @c: UBIFS file-system description object * * This function makes sure UBIFS has enough free space to be mounted in * read/write mode. UBIFS must always have some free space to allow deletions. */ static int check_free_space(struct ubifs_info *c) { … } /** * mount_ubifs - mount UBIFS file-system. * @c: UBIFS file-system description object * * This function mounts UBIFS file system. Returns zero in case of success and * a negative error code in case of failure. */ static int mount_ubifs(struct ubifs_info *c) { … } /** * ubifs_umount - un-mount UBIFS file-system. * @c: UBIFS file-system description object * * Note, this function is called to free allocated resourced when un-mounting, * as well as free resources when an error occurred while we were half way * through mounting (error path cleanup function). So it has to make sure the * resource was actually allocated before freeing it. */ static void ubifs_umount(struct ubifs_info *c) { … } /** * ubifs_remount_rw - re-mount in read-write mode. * @c: UBIFS file-system description object * * UBIFS avoids allocating many unnecessary resources when mounted in read-only * mode. This function allocates the needed resources and re-mounts UBIFS in * read-write mode. */ static int ubifs_remount_rw(struct ubifs_info *c) { … } /** * ubifs_remount_ro - re-mount in read-only mode. * @c: UBIFS file-system description object * * We assume VFS has stopped writing. Possibly the background thread could be * running a commit, however kthread_stop will wait in that case. */ static void ubifs_remount_ro(struct ubifs_info *c) { … } static void ubifs_put_super(struct super_block *sb) { … } static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data) { … } const struct super_operations ubifs_super_operations = …; /** * open_ubi - parse UBI device name string and open the UBI device. * @name: UBI volume name * @mode: UBI volume open mode * * The primary method of mounting UBIFS is by specifying the UBI volume * character device node path. However, UBIFS may also be mounted without any * character device node using one of the following methods: * * o ubiX_Y - mount UBI device number X, volume Y; * o ubiY - mount UBI device number 0, volume Y; * o ubiX:NAME - mount UBI device X, volume with name NAME; * o ubi:NAME - mount UBI device 0, volume with name NAME. * * Alternative '!' separator may be used instead of ':' (because some shells * like busybox may interpret ':' as an NFS host name separator). This function * returns UBI volume description object in case of success and a negative * error code in case of failure. */ static struct ubi_volume_desc *open_ubi(const char *name, int mode) { … } static struct ubifs_info *alloc_ubifs_info(struct ubi_volume_desc *ubi) { … } static int ubifs_fill_super(struct super_block *sb, void *data, int silent) { … } static int sb_test(struct super_block *sb, void *data) { … } static int sb_set(struct super_block *sb, void *data) { … } static struct dentry *ubifs_mount(struct file_system_type *fs_type, int flags, const char *name, void *data) { … } static void kill_ubifs_super(struct super_block *s) { … } static struct file_system_type ubifs_fs_type = …; MODULE_ALIAS_FS(…) …; /* * Inode slab cache constructor. */ static void inode_slab_ctor(void *obj) { … } static int __init ubifs_init(void) { … } /* late_initcall to let compressors initialize first */ late_initcall(ubifs_init); static void __exit ubifs_exit(void) { … } module_exit(ubifs_exit); MODULE_LICENSE(…) …; MODULE_VERSION(…); MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …;
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