UBIFS: add new flash file system

This is a new flash file system. See
http://www.linux-mtd.infradead.org/doc/ubifs.html

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>

1 files changed, 1240 insertions, 0 deletions

diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
new file mode 100644
index 000000000000..e90374be7d3b
--- /dev/null
+++ b/fs/ubifs/dir.c
@@ -0,0 +1,1240 @@
+/* * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ * Copyright (C) 2006, 2007 University of Szeged, Hungary
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ *          Zoltan Sogor
+ */
+
+/*
+ * This file implements directory operations.
+ *
+ * All FS operations in this file allocate budget before writing anything to the
+ * media. If they fail to allocate it, the error is returned. The only
+ * exceptions are 'ubifs_unlink()' and 'ubifs_rmdir()' which keep working even
+ * if they unable to allocate the budget, because deletion %-ENOSPC failure is
+ * not what users are usually ready to get. UBIFS budgeting subsystem has some
+ * space reserved for these purposes.
+ *
+ * All operations in this file write all inodes which they change straight
+ * away, instead of marking them dirty. For example, 'ubifs_link()' changes
+ * @i_size of the parent inode and writes the parent inode together with the
+ * target inode. This was done to simplify file-system recovery which would
+ * otherwise be very difficult to do. The only exception is rename which marks
+ * the re-named inode dirty (because its @i_ctime is updated) but does not
+ * write it, but just marks it as dirty.
+ */
+
+#include "ubifs.h"
+
+/**
+ * inherit_flags - inherit flags of the parent inode.
+ * @dir: parent inode
+ * @mode: new inode mode flags
+ *
+ * This is a helper function for 'ubifs_new_inode()' which inherits flag of the
+ * parent directory inode @dir. UBIFS inodes inherit the following flags:
+ * o %UBIFS_COMPR_FL, which is useful to switch compression on/of on
+ *   sub-directory basis;
+ * o %UBIFS_SYNC_FL - useful for the same reasons;
+ * o %UBIFS_DIRSYNC_FL - similar, but relevant only to directories.
+ *
+ * This function returns the inherited flags.
+ */
+static int inherit_flags(const struct inode *dir, int mode)
+{
+        int flags;
+        const struct ubifs_inode *ui = ubifs_inode(dir);
+
+        if (!S_ISDIR(dir->i_mode))
+                /*
+                 * The parent is not a directory, which means that an extended
+                 * attribute inode is being created. No flags.
+                 */
+                return 0;
+
+        flags = ui->flags & (UBIFS_COMPR_FL | UBIFS_SYNC_FL | UBIFS_DIRSYNC_FL);
+        if (!S_ISDIR(mode))
+                /* The "DIRSYNC" flag only applies to directories */
+                flags &= ~UBIFS_DIRSYNC_FL;
+        return flags;
+}
+
+/**
+ * ubifs_new_inode - allocate new UBIFS inode object.
+ * @c: UBIFS file-system description object
+ * @dir: parent directory inode
+ * @mode: inode mode flags
+ *
+ * This function finds an unused inode number, allocates new inode and
+ * initializes it. Returns new inode in case of success and an error code in
+ * case of failure.
+ */
+struct inode *ubifs_new_inode(struct ubifs_info *c, const struct inode *dir,
+                              int mode)
+{
+        struct inode *inode;
+        struct ubifs_inode *ui;
+
+        inode = new_inode(c->vfs_sb);
+        ui = ubifs_inode(inode);
+        if (!inode)
+                return ERR_PTR(-ENOMEM);
+
+        /*
+         * Set 'S_NOCMTIME' to prevent VFS form updating [mc]time of inodes and
+         * marking them dirty in file write path (see 'file_update_time()').
+         * UBIFS has to fully control "clean <-> dirty" transitions of inodes
+         * to make budgeting work.
+         */
+        inode->i_flags |= (S_NOCMTIME);
+
+        inode->i_uid = current->fsuid;
+        if (dir->i_mode & S_ISGID) {
+                inode->i_gid = dir->i_gid;
+                if (S_ISDIR(mode))
+                        mode |= S_ISGID;
+        } else
+                inode->i_gid = current->fsgid;
+        inode->i_mode = mode;
+        inode->i_mtime = inode->i_atime = inode->i_ctime =
+                         ubifs_current_time(inode);
+        inode->i_mapping->nrpages = 0;
+        /* Disable readahead */
+        inode->i_mapping->backing_dev_info = &c->bdi;
+
+        switch (mode & S_IFMT) {
+        case S_IFREG:
+                inode->i_mapping->a_ops = &ubifs_file_address_operations;
+                inode->i_op = &ubifs_file_inode_operations;
+                inode->i_fop = &ubifs_file_operations;
+                break;
+        case S_IFDIR:
+                inode->i_op  = &ubifs_dir_inode_operations;
+                inode->i_fop = &ubifs_dir_operations;
+                inode->i_size = ui->ui_size = UBIFS_INO_NODE_SZ;
+                break;
+        case S_IFLNK:
+                inode->i_op = &ubifs_symlink_inode_operations;
+                break;
+        case S_IFSOCK:
+        case S_IFIFO:
+        case S_IFBLK:
+        case S_IFCHR:
+                inode->i_op  = &ubifs_file_inode_operations;
+                break;
+        default:
+                BUG();
+        }
+
+        ui->flags = inherit_flags(dir, mode);
+        ubifs_set_inode_flags(inode);
+        if (S_ISREG(mode))
+                ui->compr_type = c->default_compr;
+        else
+                ui->compr_type = UBIFS_COMPR_NONE;
+        ui->synced_i_size = 0;
+
+        spin_lock(&c->cnt_lock);
+        /* Inode number overflow is currently not supported */
+        if (c->highest_inum >= INUM_WARN_WATERMARK) {
+                if (c->highest_inum >= INUM_WATERMARK) {
+                        spin_unlock(&c->cnt_lock);
+                        ubifs_err("out of inode numbers");
+                        make_bad_inode(inode);
+                        iput(inode);
+                        return ERR_PTR(-EINVAL);
+                }
+                ubifs_warn("running out of inode numbers (current %lu, max %d)",
+                           c->highest_inum, INUM_WATERMARK);
+        }
+
+        inode->i_ino = ++c->highest_inum;
+        inode->i_generation = ++c->vfs_gen;
+        /*
+         * The creation sequence number remains with this inode for its
+         * lifetime. All nodes for this inode have a greater sequence number,
+         * and so it is possible to distinguish obsolete nodes belonging to a
+         * previous incarnation of the same inode number - for example, for the
+         * purpose of rebuilding the index.
+         */
+        ui->creat_sqnum = ++c->max_sqnum;
+        spin_unlock(&c->cnt_lock);
+        return inode;
+}
+
+#ifdef CONFIG_UBIFS_FS_DEBUG
+
+static int dbg_check_name(struct ubifs_dent_node *dent, struct qstr *nm)
+{
+        if (!(ubifs_chk_flags & UBIFS_CHK_GEN))
+                return 0;
+        if (le16_to_cpu(dent->nlen) != nm->len)
+                return -EINVAL;
+        if (memcmp(dent->name, nm->name, nm->len))
+                return -EINVAL;
+        return 0;
+}
+
+#else
+
+#define dbg_check_name(dent, nm) 0
+
+#endif
+
+static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry,
+                                   struct nameidata *nd)
+{
+        int err;
+        union ubifs_key key;
+        struct inode *inode = NULL;
+        struct ubifs_dent_node *dent;
+        struct ubifs_info *c = dir->i_sb->s_fs_info;
+
+        dbg_gen("'%.*s' in dir ino %lu",
+                dentry->d_name.len, dentry->d_name.name, dir->i_ino);
+
+        if (dentry->d_name.len > UBIFS_MAX_NLEN)
+                return ERR_PTR(-ENAMETOOLONG);
+
+        dent = kmalloc(UBIFS_MAX_DENT_NODE_SZ, GFP_NOFS);
+        if (!dent)
+                return ERR_PTR(-ENOMEM);
+
+        dent_key_init(c, &key, dir->i_ino, &dentry->d_name);
+
+        err = ubifs_tnc_lookup_nm(c, &key, dent, &dentry->d_name);
+        if (err) {
+                /*
+                 * Do not hash the direntry if parent 'i_nlink' is zero, because
+                 * this has side-effects - '->delete_inode()' call will not be
+                 * called for the parent orphan inode, because 'd_count' of its
+                 * direntry will stay 1 (it'll be negative direntry I guess)
+                 * and prevent 'iput_final()' until the dentry is destroyed due
+                 * to unmount or memory pressure.
+                 */
+                if (err == -ENOENT && dir->i_nlink != 0) {
+                        dbg_gen("not found");
+                        goto done;
+                }
+                goto out;
+        }
+
+        if (dbg_check_name(dent, &dentry->d_name)) {
+                err = -EINVAL;
+                goto out;
+        }
+
+        inode = ubifs_iget(dir->i_sb, le64_to_cpu(dent->inum));
+        if (IS_ERR(inode)) {
+                /*
+                 * This should not happen. Probably the file-system needs
+                 * checking.
+                 */
+                err = PTR_ERR(inode);
+                ubifs_err("dead directory entry '%.*s', error %d",
+                          dentry->d_name.len, dentry->d_name.name, err);
+                ubifs_ro_mode(c, err);
+                goto out;
+        }
+
+done:
+        kfree(dent);
+        /*
+         * Note, d_splice_alias() would be required instead if we supported
+         * NFS.
+         */
+        d_add(dentry, inode);
+        return NULL;
+
+out:
+        kfree(dent);
+        return ERR_PTR(err);
+}
+
+static int ubifs_create(struct inode *dir, struct dentry *dentry, int mode,
+                        struct nameidata *nd)
+{
+        struct inode *inode;
+        struct ubifs_info *c = dir->i_sb->s_fs_info;
+        int err, sz_change = CALC_DENT_SIZE(dentry->d_name.len);
+        struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
+                                        .dirtied_ino = 1 };
+        struct ubifs_inode *dir_ui = ubifs_inode(dir);
+
+        /*
+         * Budget request settings: new inode, new direntry, changing the
+         * parent directory inode.
+         */
+
+        dbg_gen("dent '%.*s', mode %#x in dir ino %lu",
+                dentry->d_name.len, dentry->d_name.name, mode, dir->i_ino);
+
+        err = ubifs_budget_space(c, &req);
+        if (err)
+                return err;
+
+        inode = ubifs_new_inode(c, dir, mode);
+        if (IS_ERR(inode)) {
+                err = PTR_ERR(inode);
+                goto out_budg;
+        }
+
+        mutex_lock(&dir_ui->ui_mutex);
+        dir->i_size += sz_change;
+        dir_ui->ui_size = dir->i_size;
+        dir->i_mtime = dir->i_ctime = inode->i_ctime;
+        err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
+        if (err)
+                goto out_cancel;
+        mutex_unlock(&dir_ui->ui_mutex);
+
+        ubifs_release_budget(c, &req);
+        insert_inode_hash(inode);
+        d_instantiate(dentry, inode);
+        return 0;
+
+out_cancel:
+        dir->i_size -= sz_change;
+        dir_ui->ui_size = dir->i_size;
+        mutex_unlock(&dir_ui->ui_mutex);
+        make_bad_inode(inode);
+        iput(inode);
+out_budg:
+        ubifs_release_budget(c, &req);
+        ubifs_err("cannot create regular file, error %d", err);
+        return err;
+}
+
+/**
+ * vfs_dent_type - get VFS directory entry type.
+ * @type: UBIFS directory entry type
+ *
+ * This function converts UBIFS directory entry type into VFS directory entry
+ * type.
+ */
+static unsigned int vfs_dent_type(uint8_t type)
+{
+        switch (type) {
+        case UBIFS_ITYPE_REG:
+                return DT_REG;
+        case UBIFS_ITYPE_DIR:
+                return DT_DIR;
+        case UBIFS_ITYPE_LNK:
+                return DT_LNK;
+        case UBIFS_ITYPE_BLK:
+                return DT_BLK;
+        case UBIFS_ITYPE_CHR:
+                return DT_CHR;
+        case UBIFS_ITYPE_FIFO:
+                return DT_FIFO;
+        case UBIFS_ITYPE_SOCK:
+                return DT_SOCK;
+        default:
+                BUG();
+        }
+        return 0;
+}
+
+/*
+ * The classical Unix view for directory is that it is a linear array of
+ * (name, inode number) entries. Linux/VFS assumes this model as well.
+ * Particularly, 'readdir()' call wants us to return a directory entry offset
+ * which later may be used to continue 'readdir()'ing the directory or to
+ * 'seek()' to that specific direntry. Obviously UBIFS does not really fit this
+ * model because directory entries are identified by keys, which may collide.
+ *
+ * UBIFS uses directory entry hash value for directory offsets, so
+ * 'seekdir()'/'telldir()' may not always work because of possible key
+ * collisions. But UBIFS guarantees that consecutive 'readdir()' calls work
+ * properly by means of saving full directory entry name in the private field
+ * of the file description object.
+ *
+ * This means that UBIFS cannot support NFS which requires full
+ * 'seekdir()'/'telldir()' support.
+ */
+static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
+{
+        int err, over = 0;
+        struct qstr nm;
+        union ubifs_key key;
+        struct ubifs_dent_node *dent;
+        struct inode *dir = file->f_path.dentry->d_inode;
+        struct ubifs_info *c = dir->i_sb->s_fs_info;
+
+        dbg_gen("dir ino %lu, f_pos %#llx", dir->i_ino, file->f_pos);
+
+        if (file->f_pos > UBIFS_S_KEY_HASH_MASK || file->f_pos == 2)
+                /*
+                 * The directory was seek'ed to a senseless position or there
+                 * are no more entries.
+                 */
+                return 0;
+
+        /* File positions 0 and 1 correspond to "." and ".." */
+        if (file->f_pos == 0) {
+                ubifs_assert(!file->private_data);
+                over = filldir(dirent, ".", 1, 0, dir->i_ino, DT_DIR);
+                if (over)
+                        return 0;
+                file->f_pos = 1;
+        }
+
+        if (file->f_pos == 1) {
+                ubifs_assert(!file->private_data);
+                over = filldir(dirent, "..", 2, 1,
+                               parent_ino(file->f_path.dentry), DT_DIR);
+                if (over)
+                        return 0;
+
+                /* Find the first entry in TNC and save it */
+                lowest_dent_key(c, &key, dir->i_ino);
+                nm.name = NULL;
+                dent = ubifs_tnc_next_ent(c, &key, &nm);
+                if (IS_ERR(dent)) {
+                        err = PTR_ERR(dent);
+                        goto out;
+                }
+
+                file->f_pos = key_hash_flash(c, &dent->key);
+                file->private_data = dent;
+        }
+
+        dent = file->private_data;
+        if (!dent) {
+                /*
+                 * The directory was seek'ed to and is now readdir'ed.
+                 * Find the entry corresponding to @file->f_pos or the
+                 * closest one.
+                 */
+                dent_key_init_hash(c, &key, dir->i_ino, file->f_pos);
+                nm.name = NULL;
+                dent = ubifs_tnc_next_ent(c, &key, &nm);
+                if (IS_ERR(dent)) {
+                        err = PTR_ERR(dent);
+                        goto out;
+                }
+                file->f_pos = key_hash_flash(c, &dent->key);
+                file->private_data = dent;
+        }
+
+        while (1) {
+                dbg_gen("feed '%s', ino %llu, new f_pos %#x",
+                        dent->name, le64_to_cpu(dent->inum),
+                        key_hash_flash(c, &dent->key));
+                ubifs_assert(dent->ch.sqnum > ubifs_inode(dir)->creat_sqnum);
+
+                nm.len = le16_to_cpu(dent->nlen);
+                over = filldir(dirent, dent->name, nm.len, file->f_pos,
+                               le64_to_cpu(dent->inum),
+                               vfs_dent_type(dent->type));
+                if (over)
+                        return 0;
+
+                /* Switch to the next entry */
+                key_read(c, &dent->key, &key);
+                nm.name = dent->name;
+                dent = ubifs_tnc_next_ent(c, &key, &nm);
+                if (IS_ERR(dent)) {
+                        err = PTR_ERR(dent);
+                        goto out;
+                }
+
+                kfree(file->private_data);
+                file->f_pos = key_hash_flash(c, &dent->key);
+                file->private_data = dent;
+                cond_resched();
+        }
+
+out:
+        if (err != -ENOENT) {
+                ubifs_err("cannot find next direntry, error %d", err);
+                return err;
+        }
+
+        kfree(file->private_data);
+        file->private_data = NULL;
+        file->f_pos = 2;
+        return 0;
+}
+
+/* If a directory is seeked, we have to free saved readdir() state */
+static loff_t ubifs_dir_llseek(struct file *file, loff_t offset, int origin)
+{
+        kfree(file->private_data);
+        file->private_data = NULL;
+        return generic_file_llseek(file, offset, origin);
+}
+
+/* Free saved readdir() state when the directory is closed */
+static int ubifs_dir_release(struct inode *dir, struct file *file)
+{
+        kfree(file->private_data);
+        file->private_data = NULL;
+        return 0;
+}
+
+/**
+ * lock_2_inodes - lock two UBIFS inodes.
+ * @inode1: first inode
+ * @inode2: second inode
+ */
+static void lock_2_inodes(struct inode *inode1, struct inode *inode2)
+{
+        if (inode1->i_ino < inode2->i_ino) {
+                mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_2);
+                mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_3);
+        } else {
+                mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_2);
+                mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_3);
+        }
+}
+
+/**
+ * unlock_2_inodes - unlock two UBIFS inodes inodes.
+ * @inode1: first inode
+ * @inode2: second inode
+ */
+static void unlock_2_inodes(struct inode *inode1, struct inode *inode2)
+{
+        mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
+        mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
+}
+
+static int ubifs_link(struct dentry *old_dentry, struct inode *dir,
+                      struct dentry *dentry)
+{
+        struct ubifs_info *c = dir->i_sb->s_fs_info;
+        struct inode *inode = old_dentry->d_inode;
+        struct ubifs_inode *ui = ubifs_inode(inode);
+        struct ubifs_inode *dir_ui = ubifs_inode(dir);
+        int err, sz_change = CALC_DENT_SIZE(dentry->d_name.len);
+        struct ubifs_budget_req req = { .new_dent = 1, .dirtied_ino = 2,
+                                        .dirtied_ino_d = ui->data_len };
+
+        /*
+         * Budget request settings: new direntry, changing the target inode,
+         * changing the parent inode.
+         */
+
+        dbg_gen("dent '%.*s' to ino %lu (nlink %d) in dir ino %lu",
+                dentry->d_name.len, dentry->d_name.name, inode->i_ino,
+                inode->i_nlink, dir->i_ino);
+        err = dbg_check_synced_i_size(inode);
+        if (err)
+                return err;
+
+        err = ubifs_budget_space(c, &req);
+        if (err)
+                return err;
+
+        lock_2_inodes(dir, inode);
+        inc_nlink(inode);
+        atomic_inc(&inode->i_count);
+        inode->i_ctime = ubifs_current_time(inode);
+        dir->i_size += sz_change;
+        dir_ui->ui_size = dir->i_size;
+        dir->i_mtime = dir->i_ctime = inode->i_ctime;
+        err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
+        if (err)
+                goto out_cancel;
+        unlock_2_inodes(dir, inode);
+
+        ubifs_release_budget(c, &req);
+        d_instantiate(dentry, inode);
+        return 0;
+
+out_cancel:
+        dir->i_size -= sz_change;
+        dir_ui->ui_size = dir->i_size;
+        drop_nlink(inode);
+        unlock_2_inodes(dir, inode);
+        ubifs_release_budget(c, &req);
+        iput(inode);
+        return err;
+}
+
+static int ubifs_unlink(struct inode *dir, struct dentry *dentry)
+{
+        struct ubifs_info *c = dir->i_sb->s_fs_info;
+        struct inode *inode = dentry->d_inode;
+        struct ubifs_inode *dir_ui = ubifs_inode(dir);
+        int sz_change = CALC_DENT_SIZE(dentry->d_name.len);
+        int err, budgeted = 1;
+        struct ubifs_budget_req req = { .mod_dent = 1, .dirtied_ino = 2 };
+
+        /*
+         * Budget request settings: deletion direntry, deletion inode (+1 for
+         * @dirtied_ino), changing the parent directory inode. If budgeting
+         * fails, go ahead anyway because we have extra space reserved for
+         * deletions.
+         */
+
+        dbg_gen("dent '%.*s' from ino %lu (nlink %d) in dir ino %lu",
+                dentry->d_name.len, dentry->d_name.name, inode->i_ino,
+                inode->i_nlink, dir->i_ino);
+        err = dbg_check_synced_i_size(inode);
+        if (err)
+                return err;
+
+        err = ubifs_budget_space(c, &req);
+        if (err) {
+                if (err != -ENOSPC)
+                        return err;
+                err = 0;
+                budgeted = 0;
+        }
+
+        lock_2_inodes(dir, inode);
+        inode->i_ctime = ubifs_current_time(dir);
+        drop_nlink(inode);
+        dir->i_size -= sz_change;
+        dir_ui->ui_size = dir->i_size;
+        dir->i_mtime = dir->i_ctime = inode->i_ctime;
+        err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 1, 0);
+        if (err)
+                goto out_cancel;
+        unlock_2_inodes(dir, inode);
+
+        if (budgeted)
+                ubifs_release_budget(c, &req);
+        else {
+                /* We've deleted something - clean the "no space" flags */
+                c->nospace = c->nospace_rp = 0;
+                smp_wmb();
+        }
+        return 0;
+
+out_cancel:
+        dir->i_size += sz_change;
+        dir_ui->ui_size = dir->i_size;
+        inc_nlink(inode);
+        unlock_2_inodes(dir, inode);
+        if (budgeted)
+                ubifs_release_budget(c, &req);
+        return err;
+}
+
+/**
+ * check_dir_empty - check if a directory is empty or not.
+ * @c: UBIFS file-system description object
+ * @dir: VFS inode object of the directory to check
+ *
+ * This function checks if directory @dir is empty. Returns zero if the
+ * directory is empty, %-ENOTEMPTY if it is not, and other negative error codes
+ * in case of of errors.
+ */
+static int check_dir_empty(struct ubifs_info *c, struct inode *dir)
+{
+        struct qstr nm = { .name = NULL };
+        struct ubifs_dent_node *dent;
+        union ubifs_key key;
+        int err;
+
+        lowest_dent_key(c, &key, dir->i_ino);
+        dent = ubifs_tnc_next_ent(c, &key, &nm);
+        if (IS_ERR(dent)) {
+                err = PTR_ERR(dent);
+                if (err == -ENOENT)
+                        err = 0;
+        } else {
+                kfree(dent);
+                err = -ENOTEMPTY;
+        }
+        return err;
+}
+
+static int ubifs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+        struct ubifs_info *c = dir->i_sb->s_fs_info;
+        struct inode *inode = dentry->d_inode;
+        int sz_change = CALC_DENT_SIZE(dentry->d_name.len);
+        int err, budgeted = 1;
+        struct ubifs_inode *dir_ui = ubifs_inode(dir);
+        struct ubifs_budget_req req = { .mod_dent = 1, .dirtied_ino = 2 };
+
+        /*
+         * Budget request settings: deletion direntry, deletion inode and
+         * changing the parent inode. If budgeting fails, go ahead anyway
+         * because we have extra space reserved for deletions.
+         */
+
+        dbg_gen("directory '%.*s', ino %lu in dir ino %lu", dentry->d_name.len,
+                dentry->d_name.name, inode->i_ino, dir->i_ino);
+
+        err = check_dir_empty(c, dentry->d_inode);
+        if (err)
+                return err;
+
+        err = ubifs_budget_space(c, &req);
+        if (err) {
+                if (err != -ENOSPC)
+                        return err;
+                budgeted = 0;
+        }
+
+        lock_2_inodes(dir, inode);
+        inode->i_ctime = ubifs_current_time(dir);
+        clear_nlink(inode);
+        drop_nlink(dir);
+        dir->i_size -= sz_change;
+        dir_ui->ui_size = dir->i_size;
+        dir->i_mtime = dir->i_ctime = inode->i_ctime;
+        err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 1, 0);
+        if (err)
+                goto out_cancel;
+        unlock_2_inodes(dir, inode);
+
+        if (budgeted)
+                ubifs_release_budget(c, &req);
+        else {
+                /* We've deleted something - clean the "no space" flags */
+                c->nospace = c->nospace_rp = 0;
+                smp_wmb();
+        }
+        return 0;
+
+out_cancel:
+        dir->i_size += sz_change;
+        dir_ui->ui_size = dir->i_size;
+        inc_nlink(dir);
+        inc_nlink(inode);
+        inc_nlink(inode);
+        unlock_2_inodes(dir, inode);
+        if (budgeted)
+                ubifs_release_budget(c, &req);
+        return err;
+}
+
+static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+        struct inode *inode;
+        struct ubifs_inode *dir_ui = ubifs_inode(dir);
+        struct ubifs_info *c = dir->i_sb->s_fs_info;
+        int err, sz_change = CALC_DENT_SIZE(dentry->d_name.len);
+        struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
+                                        .dirtied_ino_d = 1 };
+
+        /*
+         * Budget request settings: new inode, new direntry and changing parent
+         * directory inode.
+         */
+
+        dbg_gen("dent '%.*s', mode %#x in dir ino %lu",
+                dentry->d_name.len, dentry->d_name.name, mode, dir->i_ino);
+
+        err = ubifs_budget_space(c, &req);
+        if (err)
+                return err;
+
+        inode = ubifs_new_inode(c, dir, S_IFDIR | mode);
+        if (IS_ERR(inode)) {
+                err = PTR_ERR(inode);
+                goto out_budg;
+        }
+
+        mutex_lock(&dir_ui->ui_mutex);
+        insert_inode_hash(inode);
+        inc_nlink(inode);
+        inc_nlink(dir);
+        dir->i_size += sz_change;
+        dir_ui->ui_size = dir->i_size;
+        dir->i_mtime = dir->i_ctime = inode->i_ctime;
+        err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
+        if (err) {
+                ubifs_err("cannot create directory, error %d", err);
+                goto out_cancel;
+        }
+        mutex_unlock(&dir_ui->ui_mutex);
+
+        ubifs_release_budget(c, &req);
+        d_instantiate(dentry, inode);
+        return 0;
+
+out_cancel:
+        dir->i_size -= sz_change;
+        dir_ui->ui_size = dir->i_size;
+        drop_nlink(dir);
+        mutex_unlock(&dir_ui->ui_mutex);
+        make_bad_inode(inode);
+        iput(inode);
+out_budg:
+        ubifs_release_budget(c, &req);
+        return err;
+}
+
+static int ubifs_mknod(struct inode *dir, struct dentry *dentry,
+                       int mode, dev_t rdev)
+{
+        struct inode *inode;
+        struct ubifs_inode *ui;
+        struct ubifs_inode *dir_ui = ubifs_inode(dir);
+        struct ubifs_info *c = dir->i_sb->s_fs_info;
+        union ubifs_dev_desc *dev = NULL;
+        int sz_change = CALC_DENT_SIZE(dentry->d_name.len);
+        int err, devlen = 0;
+        struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
+                                        .new_ino_d = devlen, .dirtied_ino = 1 };
+
+        /*
+         * Budget request settings: new inode, new direntry and changing parent
+         * directory inode.
+         */
+
+        dbg_gen("dent '%.*s' in dir ino %lu",
+                dentry->d_name.len, dentry->d_name.name, dir->i_ino);
+
+        if (!new_valid_dev(rdev))
+                return -EINVAL;
+
+        if (S_ISBLK(mode) || S_ISCHR(mode)) {
+                dev = kmalloc(sizeof(union ubifs_dev_desc), GFP_NOFS);
+                if (!dev)
+                        return -ENOMEM;
+                devlen = ubifs_encode_dev(dev, rdev);
+        }
+
+        err = ubifs_budget_space(c, &req);
+        if (err) {
+                kfree(dev);
+                return err;
+        }
+
+        inode = ubifs_new_inode(c, dir, mode);
+        if (IS_ERR(inode)) {
+                kfree(dev);
+                err = PTR_ERR(inode);
+                goto out_budg;
+        }
+
+        init_special_inode(inode, inode->i_mode, rdev);
+        inode->i_size = ubifs_inode(inode)->ui_size = devlen;
+        ui = ubifs_inode(inode);
+        ui->data = dev;
+        ui->data_len = devlen;
+
+        mutex_lock(&dir_ui->ui_mutex);
+        dir->i_size += sz_change;
+        dir_ui->ui_size = dir->i_size;
+        dir->i_mtime = dir->i_ctime = inode->i_ctime;
+        err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
+        if (err)
+                goto out_cancel;
+        mutex_unlock(&dir_ui->ui_mutex);
+
+        ubifs_release_budget(c, &req);
+        insert_inode_hash(inode);
+        d_instantiate(dentry, inode);
+        return 0;
+
+out_cancel:
+        dir->i_size -= sz_change;
+        dir_ui->ui_size = dir->i_size;
+        mutex_unlock(&dir_ui->ui_mutex);
+        make_bad_inode(inode);
+        iput(inode);
+out_budg:
+        ubifs_release_budget(c, &req);
+        return err;
+}
+
+static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
+                         const char *symname)
+{
+        struct inode *inode;
+        struct ubifs_inode *ui;
+        struct ubifs_inode *dir_ui = ubifs_inode(dir);
+        struct ubifs_info *c = dir->i_sb->s_fs_info;
+        int err, len = strlen(symname);
+        int sz_change = CALC_DENT_SIZE(dentry->d_name.len);
+        struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
+                                        .new_ino_d = len, .dirtied_ino = 1 };
+
+        /*
+         * Budget request settings: new inode, new direntry and changing parent
+         * directory inode.
+         */
+
+        dbg_gen("dent '%.*s', target '%s' in dir ino %lu", dentry->d_name.len,
+                dentry->d_name.name, symname, dir->i_ino);
+
+        if (len > UBIFS_MAX_INO_DATA)
+                return -ENAMETOOLONG;
+
+        err = ubifs_budget_space(c, &req);
+        if (err)
+                return err;
+
+        inode = ubifs_new_inode(c, dir, S_IFLNK | S_IRWXUGO);
+        if (IS_ERR(inode)) {
+                err = PTR_ERR(inode);
+                goto out_budg;
+        }
+
+        ui = ubifs_inode(inode);
+        ui->data = kmalloc(len + 1, GFP_NOFS);
+        if (!ui->data) {
+                err = -ENOMEM;
+                goto out_inode;
+        }
+
+        memcpy(ui->data, symname, len);
+        ((char *)ui->data)[len] = '\0';
+        /*
+         * The terminating zero byte is not written to the flash media and it
+         * is put just to make later in-memory string processing simpler. Thus,
+         * data length is @len, not @len + %1.
+         */
+        ui->data_len = len;
+        inode->i_size = ubifs_inode(inode)->ui_size = len;
+
+        mutex_lock(&dir_ui->ui_mutex);
+        dir->i_size += sz_change;
+        dir_ui->ui_size = dir->i_size;
+        dir->i_mtime = dir->i_ctime = inode->i_ctime;
+        err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
+        if (err)
+                goto out_cancel;
+        mutex_unlock(&dir_ui->ui_mutex);
+
+        ubifs_release_budget(c, &req);
+        insert_inode_hash(inode);
+        d_instantiate(dentry, inode);
+        return 0;
+
+out_cancel:
+        dir->i_size -= sz_change;
+        dir_ui->ui_size = dir->i_size;
+        mutex_unlock(&dir_ui->ui_mutex);
+out_inode:
+        make_bad_inode(inode);
+        iput(inode);
+out_budg:
+        ubifs_release_budget(c, &req);
+        return err;
+}
+
+/**
+ * lock_3_inodes - lock three UBIFS inodes for rename.
+ * @inode1: first inode
+ * @inode2: second inode
+ * @inode3: third inode
+ *
+ * For 'ubifs_rename()', @inode1 may be the same as @inode2 whereas @inode3 may
+ * be null.
+ */
+static void lock_3_inodes(struct inode *inode1, struct inode *inode2,
+                          struct inode *inode3)
+{
+        struct inode *i1, *i2, *i3;
+
+        if (!inode3) {
+                if (inode1 != inode2) {
+                        lock_2_inodes(inode1, inode2);
+                        return;
+                }
+                mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_1);
+                return;
+        }
+
+        if (inode1 == inode2) {
+                lock_2_inodes(inode1, inode3);
+                return;
+        }
+
+        /* 3 different inodes */
+        if (inode1 < inode2) {
+                i3 = inode2;
+                if (inode1 < inode3) {
+                        i1 = inode1;
+                        i2 = inode3;
+                } else {
+                        i1 = inode3;
+                        i2 = inode1;
+                }
+        } else {
+                i3 = inode1;
+                if (inode2 < inode3) {
+                        i1 = inode2;
+                        i2 = inode3;
+                } else {
+                        i1 = inode3;
+                        i2 = inode2;
+                }
+        }
+        mutex_lock_nested(&ubifs_inode(i1)->ui_mutex, WB_MUTEX_1);
+        lock_2_inodes(i2, i3);
+}
+
+/**
+ * unlock_3_inodes - unlock three UBIFS inodes for rename.
+ * @inode1: first inode
+ * @inode2: second inode
+ * @inode3: third inode
+ */
+static void unlock_3_inodes(struct inode *inode1, struct inode *inode2,
+                            struct inode *inode3)
+{
+        mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
+        if (inode1 != inode2)
+                mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
+        if (inode3)
+                mutex_unlock(&ubifs_inode(inode3)->ui_mutex);
+}
+
+static int ubifs_rename(struct inode *old_dir, struct dentry *old_dentry,
+                        struct inode *new_dir, struct dentry *new_dentry)
+{
+        struct ubifs_info *c = old_dir->i_sb->s_fs_info;
+        struct inode *old_inode = old_dentry->d_inode;
+        struct inode *new_inode = new_dentry->d_inode;
+        struct ubifs_inode *old_inode_ui = ubifs_inode(old_inode);
+        int err, release, sync = 0, move = (new_dir != old_dir);
+        int is_dir = S_ISDIR(old_inode->i_mode);
+        int unlink = !!new_inode;
+        int new_sz = CALC_DENT_SIZE(new_dentry->d_name.len);
+        int old_sz = CALC_DENT_SIZE(old_dentry->d_name.len);
+        struct ubifs_budget_req req = { .new_dent = 1, .mod_dent = 1,
+                                        .dirtied_ino = 3 };
+        struct ubifs_budget_req ino_req = { .dirtied_ino = 1,
+                                .dirtied_ino_d = old_inode_ui->data_len };
+        struct timespec time;
+
+        /*
+         * Budget request settings: deletion direntry, new direntry, removing
+         * the old inode, and changing old and new parent directory inodes.
+         *
+         * However, this operation also marks the target inode as dirty and
+         * does not write it, so we allocate budget for the target inode
+         * separately.
+         */
+
+        dbg_gen("dent '%.*s' ino %lu in dir ino %lu to dent '%.*s' in "
+                "dir ino %lu", old_dentry->d_name.len, old_dentry->d_name.name,
+                old_inode->i_ino, old_dir->i_ino, new_dentry->d_name.len,
+                new_dentry->d_name.name, new_dir->i_ino);
+
+        if (unlink && is_dir) {
+                err = check_dir_empty(c, new_inode);
+                if (err)
+                        return err;
+        }
+
+        err = ubifs_budget_space(c, &req);
+        if (err)
+                return err;
+        err = ubifs_budget_space(c, &ino_req);
+        if (err) {
+                ubifs_release_budget(c, &req);
+                return err;
+        }
+
+        lock_3_inodes(old_dir, new_dir, new_inode);
+
+        /*
+         * Like most other Unix systems, set the @i_ctime for inodes on a
+         * rename.
+         */
+        time = ubifs_current_time(old_dir);
+        old_inode->i_ctime = time;
+
+        /* We must adjust parent link count when renaming directories */
+        if (is_dir) {
+                if (move) {
+                        /*
+                         * @old_dir loses a link because we are moving
+                         * @old_inode to a different directory.
+                         */
+                        drop_nlink(old_dir);
+                        /*
+                         * @new_dir only gains a link if we are not also
+                         * overwriting an existing directory.
+                         */
+                        if (!unlink)
+                                inc_nlink(new_dir);
+                } else {
+                        /*
+                         * @old_inode is not moving to a different directory,
+                         * but @old_dir still loses a link if we are
+                         * overwriting an existing directory.
+                         */
+                        if (unlink)
+                                drop_nlink(old_dir);
+                }
+        }
+
+        old_dir->i_size -= old_sz;
+        ubifs_inode(old_dir)->ui_size = old_dir->i_size;
+        old_dir->i_mtime = old_dir->i_ctime = time;
+        new_dir->i_mtime = new_dir->i_ctime = time;
+
+        /*
+         * And finally, if we unlinked a direntry which happened to have the
+         * same name as the moved direntry, we have to decrement @i_nlink of
+         * the unlinked inode and change its ctime.
+         */
+        if (unlink) {
+                /*
+                 * Directories cannot have hard-links, so if this is a
+                 * directory, decrement its @i_nlink twice because an empty
+                 * directory has @i_nlink 2.
+                 */
+                if (is_dir)
+                        drop_nlink(new_inode);
+                new_inode->i_ctime = time;
+                drop_nlink(new_inode);
+        } else {
+                new_dir->i_size += new_sz;
+                ubifs_inode(new_dir)->ui_size = new_dir->i_size;
+        }
+
+        /*
+         * Do not ask 'ubifs_jnl_rename()' to flush write-buffer if @old_inode
+         * is dirty, because this will be done later on at the end of
+         * 'ubifs_rename()'.
+         */
+        if (IS_SYNC(old_inode)) {
+                sync = IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir);
+                if (unlink && IS_SYNC(new_inode))
+                        sync = 1;
+        }
+        err = ubifs_jnl_rename(c, old_dir, old_dentry, new_dir, new_dentry,
+                               sync);
+        if (err)
+                goto out_cancel;
+
+        unlock_3_inodes(old_dir, new_dir, new_inode);
+        ubifs_release_budget(c, &req);
+
+        mutex_lock(&old_inode_ui->ui_mutex);
+        release = old_inode_ui->dirty;
+        mark_inode_dirty_sync(old_inode);
+        mutex_unlock(&old_inode_ui->ui_mutex);
+
+        if (release)
+                ubifs_release_budget(c, &ino_req);
+        if (IS_SYNC(old_inode))
+                err = old_inode->i_sb->s_op->write_inode(old_inode, 1);
+        return err;
+
+out_cancel:
+        if (unlink) {
+                if (is_dir)
+                        inc_nlink(new_inode);
+                inc_nlink(new_inode);
+        } else {
+                new_dir->i_size -= new_sz;
+                ubifs_inode(new_dir)->ui_size = new_dir->i_size;
+        }
+        old_dir->i_size += old_sz;
+        ubifs_inode(old_dir)->ui_size = old_dir->i_size;
+        if (is_dir) {
+                if (move) {
+                        inc_nlink(old_dir);
+                        if (!unlink)
+                                drop_nlink(new_dir);
+                } else {
+                        if (unlink)
+                                inc_nlink(old_dir);
+                }
+        }
+        unlock_3_inodes(old_dir, new_dir, new_inode);
+        ubifs_release_budget(c, &ino_req);
+        ubifs_release_budget(c, &req);
+        return err;
+}
+
+int ubifs_getattr(struct vfsmount *mnt, struct dentry *dentry,
+                  struct kstat *stat)
+{
+        loff_t size;
+        struct inode *inode = dentry->d_inode;
+        struct ubifs_inode *ui = ubifs_inode(inode);
+
+        mutex_lock(&ui->ui_mutex);
+        stat->dev = inode->i_sb->s_dev;
+        stat->ino = inode->i_ino;
+        stat->mode = inode->i_mode;
+        stat->nlink = inode->i_nlink;
+        stat->uid = inode->i_uid;
+        stat->gid = inode->i_gid;
+        stat->rdev = inode->i_rdev;
+        stat->atime = inode->i_atime;
+        stat->mtime = inode->i_mtime;
+        stat->ctime = inode->i_ctime;
+        stat->blksize = UBIFS_BLOCK_SIZE;
+        stat->size = ui->ui_size;
+
+        /*
+         * Unfortunately, the 'stat()' system call was designed for block
+         * device based file systems, and it is not appropriate for UBIFS,
+         * because UBIFS does not have notion of "block". For example, it is
+         * difficult to tell how many block a directory takes - it actually
+         * takes less than 300 bytes, but we have to round it to block size,
+         * which introduces large mistake. This makes utilities like 'du' to
+         * report completely senseless numbers. This is the reason why UBIFS
+         * goes the same way as JFFS2 - it reports zero blocks for everything
+         * but regular files, which makes more sense than reporting completely
+         * wrong sizes.
+         */
+        if (S_ISREG(inode->i_mode)) {
+                size = ui->xattr_size;
+                size += stat->size;
+                size = ALIGN(size, UBIFS_BLOCK_SIZE);
+                /*
+                 * Note, user-space expects 512-byte blocks count irrespectively
+                 * of what was reported in @stat->size.
+                 */
+                stat->blocks = size >> 9;
+        } else
+                stat->blocks = 0;
+        mutex_unlock(&ui->ui_mutex);
+        return 0;
+}
+
+struct inode_operations ubifs_dir_inode_operations = {
+        .lookup      = ubifs_lookup,
+        .create      = ubifs_create,
+        .link        = ubifs_link,
+        .symlink     = ubifs_symlink,
+        .unlink      = ubifs_unlink,
+        .mkdir       = ubifs_mkdir,
+        .rmdir       = ubifs_rmdir,
+        .mknod       = ubifs_mknod,
+        .rename      = ubifs_rename,
+        .setattr     = ubifs_setattr,
+        .getattr     = ubifs_getattr,
+#ifdef CONFIG_UBIFS_FS_XATTR
+        .setxattr    = ubifs_setxattr,
+        .getxattr    = ubifs_getxattr,
+        .listxattr   = ubifs_listxattr,
+        .removexattr = ubifs_removexattr,
+#endif
+};
+
+struct file_operations ubifs_dir_operations = {
+        .llseek         = ubifs_dir_llseek,
+        .release        = ubifs_dir_release,
+        .read           = generic_read_dir,
+        .readdir        = ubifs_readdir,
+        .fsync          = ubifs_fsync,
+        .unlocked_ioctl = ubifs_ioctl,
+#ifdef CONFIG_COMPAT
+        .compat_ioctl   = ubifs_compat_ioctl,
+#endif
+};