--- /dev/null
+/*
+ * OMFS (as used by RIO Karma) directory operations.
+ * Copyright (C) 2005 Bob Copeland <me@bobcopeland.com>
+ * Released under GPL v2.
+ */
+
+#include <linux/fs.h>
+#include <linux/ctype.h>
+#include <linux/buffer_head.h>
+#include "omfs.h"
+
+static int omfs_hash(const char *name, int namelen, int mod)
+{
+ int i, hash = 0;
+ for (i = 0; i < namelen; i++)
+ hash ^= tolower(name[i]) << (i % 24);
+ return hash % mod;
+}
+
+/*
+ * Finds the bucket for a given name and reads the containing block;
+ * *ofs is set to the offset of the first list entry.
+ */
+static struct buffer_head *omfs_get_bucket(struct inode *dir,
+ const char *name, int namelen, int *ofs)
+{
+ int nbuckets = (dir->i_size - OMFS_DIR_START)/8;
+ int block = clus_to_blk(OMFS_SB(dir->i_sb), dir->i_ino);
+ int bucket = omfs_hash(name, namelen, nbuckets);
+
+ *ofs = OMFS_DIR_START + bucket * 8;
+ return sb_bread(dir->i_sb, block);
+}
+
+static struct buffer_head *omfs_scan_list(struct inode *dir, u64 block,
+ const char *name, int namelen,
+ u64 *prev_block)
+{
+ struct buffer_head *bh;
+ struct omfs_inode *oi;
+ int err = -ENOENT;
+ *prev_block = ~0;
+
+ while (block != ~0) {
+ bh = sb_bread(dir->i_sb,
+ clus_to_blk(OMFS_SB(dir->i_sb), block));
+ if (!bh) {
+ err = -EIO;
+ goto err;
+ }
+
+ oi = (struct omfs_inode *) bh->b_data;
+ if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, block)) {
+ brelse(bh);
+ goto err;
+ }
+
+ if (strncmp(oi->i_name, name, namelen) == 0)
+ return bh;
+
+ *prev_block = block;
+ block = be64_to_cpu(oi->i_sibling);
+ brelse(bh);
+ }
+err:
+ return ERR_PTR(err);
+}
+
+static struct buffer_head *omfs_find_entry(struct inode *dir,
+ const char *name, int namelen)
+{
+ struct buffer_head *bh;
+ int ofs;
+ u64 block, dummy;
+
+ bh = omfs_get_bucket(dir, name, namelen, &ofs);
+ if (!bh)
+ return ERR_PTR(-EIO);
+
+ block = be64_to_cpu(*((__be64 *) &bh->b_data[ofs]));
+ brelse(bh);
+
+ return omfs_scan_list(dir, block, name, namelen, &dummy);
+}
+
+int omfs_make_empty(struct inode *inode, struct super_block *sb)
+{
+ struct omfs_sb_info *sbi = OMFS_SB(sb);
+ int block = clus_to_blk(sbi, inode->i_ino);
+ struct buffer_head *bh;
+ struct omfs_inode *oi;
+
+ bh = sb_bread(sb, block);
+ if (!bh)
+ return -ENOMEM;
+
+ memset(bh->b_data, 0, sizeof(struct omfs_inode));
+
+ if (inode->i_mode & S_IFDIR) {
+ memset(&bh->b_data[OMFS_DIR_START], 0xff,
+ sbi->s_sys_blocksize - OMFS_DIR_START);
+ } else
+ omfs_make_empty_table(bh, OMFS_EXTENT_START);
+
+ oi = (struct omfs_inode *) bh->b_data;
+ oi->i_head.h_self = cpu_to_be64(inode->i_ino);
+ oi->i_sibling = ~0ULL;
+
+ mark_buffer_dirty(bh);
+ brelse(bh);
+ return 0;
+}
+
+static int omfs_add_link(struct dentry *dentry, struct inode *inode)
+{
+ struct inode *dir = dentry->d_parent->d_inode;
+ const char *name = dentry->d_name.name;
+ int namelen = dentry->d_name.len;
+ struct omfs_inode *oi;
+ struct buffer_head *bh;
+ u64 block;
+ __be64 *entry;
+ int ofs;
+
+ /* just prepend to head of queue in proper bucket */
+ bh = omfs_get_bucket(dir, name, namelen, &ofs);
+ if (!bh)
+ goto out;
+
+ entry = (__be64 *) &bh->b_data[ofs];
+ block = be64_to_cpu(*entry);
+ *entry = cpu_to_be64(inode->i_ino);
+ mark_buffer_dirty(bh);
+ brelse(bh);
+
+ /* now set the sibling and parent pointers on the new inode */
+ bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb), inode->i_ino));
+ if (!bh)
+ goto out;
+
+ oi = (struct omfs_inode *) bh->b_data;
+ memcpy(oi->i_name, name, namelen);
+ memset(oi->i_name + namelen, 0, OMFS_NAMELEN - namelen);
+ oi->i_sibling = cpu_to_be64(block);
+ oi->i_parent = cpu_to_be64(dir->i_ino);
+ mark_buffer_dirty(bh);
+ brelse(bh);
+
+ dir->i_ctime = CURRENT_TIME_SEC;
+
+ /* mark affected inodes dirty to rebuild checksums */
+ mark_inode_dirty(dir);
+ mark_inode_dirty(inode);
+ return 0;
+out:
+ return -ENOMEM;
+}
+
+static int omfs_delete_entry(struct dentry *dentry)
+{
+ struct inode *dir = dentry->d_parent->d_inode;
+ struct inode *dirty;
+ const char *name = dentry->d_name.name;
+ int namelen = dentry->d_name.len;
+ struct omfs_inode *oi;
+ struct buffer_head *bh, *bh2;
+ __be64 *entry, next;
+ u64 block, prev;
+ int ofs;
+ int err = -ENOMEM;
+
+ /* delete the proper node in the bucket's linked list */
+ bh = omfs_get_bucket(dir, name, namelen, &ofs);
+ if (!bh)
+ goto out;
+
+ entry = (__be64 *) &bh->b_data[ofs];
+ block = be64_to_cpu(*entry);
+
+ bh2 = omfs_scan_list(dir, block, name, namelen, &prev);
+ if (IS_ERR(bh2)) {
+ err = PTR_ERR(bh2);
+ goto out_free_bh;
+ }
+
+ oi = (struct omfs_inode *) bh2->b_data;
+ next = oi->i_sibling;
+ brelse(bh2);
+
+ if (prev != ~0) {
+ /* found in middle of list, get list ptr */
+ brelse(bh);
+ bh = sb_bread(dir->i_sb,
+ clus_to_blk(OMFS_SB(dir->i_sb), prev));
+ if (!bh)
+ goto out;
+
+ oi = (struct omfs_inode *) bh->b_data;
+ entry = &oi->i_sibling;
+ }
+
+ *entry = next;
+ mark_buffer_dirty(bh);
+
+ if (prev != ~0) {
+ dirty = omfs_iget(dir->i_sb, prev);
+ if (!IS_ERR(dirty)) {
+ mark_inode_dirty(dirty);
+ iput(dirty);
+ }
+ }
+
+ err = 0;
+out_free_bh:
+ brelse(bh);
+out:
+ return err;
+}
+
+static int omfs_dir_is_empty(struct inode *inode)
+{
+ int nbuckets = (inode->i_size - OMFS_DIR_START) / 8;
+ struct buffer_head *bh;
+ u64 *ptr;
+ int i;
+
+ bh = sb_bread(inode->i_sb, clus_to_blk(OMFS_SB(inode->i_sb),
+ inode->i_ino));
+
+ if (!bh)
+ return 0;
+
+ ptr = (u64 *) &bh->b_data[OMFS_DIR_START];
+
+ for (i = 0; i < nbuckets; i++, ptr++)
+ if (*ptr != ~0)
+ break;
+
+ brelse(bh);
+ return *ptr != ~0;
+}
+
+static int omfs_unlink(struct inode *dir, struct dentry *dentry)
+{
+ int ret;
+ struct inode *inode = dentry->d_inode;
+
+ ret = omfs_delete_entry(dentry);
+ if (ret)
+ goto end_unlink;
+
+ inode_dec_link_count(inode);
+ mark_inode_dirty(dir);
+
+end_unlink:
+ return ret;
+}
+
+static int omfs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ int err = -ENOTEMPTY;
+ struct inode *inode = dentry->d_inode;
+
+ if (omfs_dir_is_empty(inode)) {
+ err = omfs_unlink(dir, dentry);
+ if (!err)
+ inode_dec_link_count(inode);
+ }
+ return err;
+}
+
+static int omfs_add_node(struct inode *dir, struct dentry *dentry, int mode)
+{
+ int err;
+ struct inode *inode = omfs_new_inode(dir, mode);
+
+ if (IS_ERR(inode))
+ return PTR_ERR(inode);
+
+ err = omfs_make_empty(inode, dir->i_sb);
+ if (err)
+ goto out_free_inode;
+
+ err = omfs_add_link(dentry, inode);
+ if (err)
+ goto out_free_inode;
+
+ d_instantiate(dentry, inode);
+ return 0;
+
+out_free_inode:
+ iput(inode);
+ return err;
+}
+
+static int omfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+ return omfs_add_node(dir, dentry, mode | S_IFDIR);
+}
+
+static int omfs_create(struct inode *dir, struct dentry *dentry, int mode,
+ struct nameidata *nd)
+{
+ return omfs_add_node(dir, dentry, mode | S_IFREG);
+}
+
+static struct dentry *omfs_lookup(struct inode *dir, struct dentry *dentry,
+ struct nameidata *nd)
+{
+ struct buffer_head *bh;
+ struct inode *inode = NULL;
+
+ if (dentry->d_name.len > OMFS_NAMELEN)
+ return ERR_PTR(-ENAMETOOLONG);
+
+ bh = omfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
+ if (!IS_ERR(bh)) {
+ struct omfs_inode *oi = (struct omfs_inode *)bh->b_data;
+ ino_t ino = be64_to_cpu(oi->i_head.h_self);
+ brelse(bh);
+ inode = omfs_iget(dir->i_sb, ino);
+ if (IS_ERR(inode))
+ return ERR_CAST(inode);
+ }
+ d_add(dentry, inode);
+ return NULL;
+}
+
+/* sanity check block's self pointer */
+int omfs_is_bad(struct omfs_sb_info *sbi, struct omfs_header *header,
+ u64 fsblock)
+{
+ int is_bad;
+ u64 ino = be64_to_cpu(header->h_self);
+ is_bad = ((ino != fsblock) || (ino < sbi->s_root_ino) ||
+ (ino > sbi->s_num_blocks));
+
+ if (is_bad)
+ printk(KERN_WARNING "omfs: bad hash chain detected\n");
+
+ return is_bad;
+}
+
+static int omfs_fill_chain(struct file *filp, void *dirent, filldir_t filldir,
+ u64 fsblock, int hindex)
+{
+ struct inode *dir = filp->f_dentry->d_inode;
+ struct buffer_head *bh;
+ struct omfs_inode *oi;
+ u64 self;
+ int res = 0;
+ unsigned char d_type;
+
+ /* follow chain in this bucket */
+ while (fsblock != ~0) {
+ bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb),
+ fsblock));
+ if (!bh)
+ goto out;
+
+ oi = (struct omfs_inode *) bh->b_data;
+ if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, fsblock)) {
+ brelse(bh);
+ goto out;
+ }
+
+ self = fsblock;
+ fsblock = be64_to_cpu(oi->i_sibling);
+
+ /* skip visited nodes */
+ if (hindex) {
+ hindex--;
+ brelse(bh);
+ continue;
+ }
+
+ d_type = (oi->i_type == OMFS_DIR) ? DT_DIR : DT_REG;
+
+ res = filldir(dirent, oi->i_name, strnlen(oi->i_name,
+ OMFS_NAMELEN), filp->f_pos, self, d_type);
+ if (res == 0)
+ filp->f_pos++;
+ brelse(bh);
+ }
+out:
+ return res;
+}
+
+static int omfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry)
+{
+ struct inode *new_inode = new_dentry->d_inode;
+ struct inode *old_inode = old_dentry->d_inode;
+ struct buffer_head *bh;
+ int is_dir;
+ int err;
+
+ is_dir = S_ISDIR(old_inode->i_mode);
+
+ if (new_inode) {
+ /* overwriting existing file/dir */
+ err = -ENOTEMPTY;
+ if (is_dir && !omfs_dir_is_empty(new_inode))
+ goto out;
+
+ err = -ENOENT;
+ bh = omfs_find_entry(new_dir, new_dentry->d_name.name,
+ new_dentry->d_name.len);
+ if (IS_ERR(bh))
+ goto out;
+ brelse(bh);
+
+ err = omfs_unlink(new_dir, new_dentry);
+ if (err)
+ goto out;
+ }
+
+ /* since omfs locates files by name, we need to unlink _before_
+ * adding the new link or we won't find the old one */
+ inode_inc_link_count(old_inode);
+ err = omfs_unlink(old_dir, old_dentry);
+ if (err) {
+ inode_dec_link_count(old_inode);
+ goto out;
+ }
+
+ err = omfs_add_link(new_dentry, old_inode);
+ if (err)
+ goto out;
+
+ old_inode->i_ctime = CURRENT_TIME_SEC;
+out:
+ return err;
+}
+
+static int omfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
+{
+ struct inode *dir = filp->f_dentry->d_inode;
+ struct buffer_head *bh;
+ loff_t offset, res;
+ unsigned int hchain, hindex;
+ int nbuckets;
+ u64 fsblock;
+ int ret = -EINVAL;
+
+ if (filp->f_pos >> 32)
+ goto success;
+
+ switch ((unsigned long) filp->f_pos) {
+ case 0:
+ if (filldir(dirent, ".", 1, 0, dir->i_ino, DT_DIR) < 0)
+ goto success;
+ filp->f_pos++;
+ /* fall through */
+ case 1:
+ if (filldir(dirent, "..", 2, 1,
+ parent_ino(filp->f_dentry), DT_DIR) < 0)
+ goto success;
+ filp->f_pos = 1 << 20;
+ /* fall through */
+ }
+
+ nbuckets = (dir->i_size - OMFS_DIR_START) / 8;
+
+ /* high 12 bits store bucket + 1 and low 20 bits store hash index */
+ hchain = (filp->f_pos >> 20) - 1;
+ hindex = filp->f_pos & 0xfffff;
+
+ bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb), dir->i_ino));
+ if (!bh)
+ goto out;
+
+ offset = OMFS_DIR_START + hchain * 8;
+
+ for (; hchain < nbuckets; hchain++, offset += 8) {
+ fsblock = be64_to_cpu(*((__be64 *) &bh->b_data[offset]));
+
+ res = omfs_fill_chain(filp, dirent, filldir, fsblock, hindex);
+ hindex = 0;
+ if (res < 0)
+ break;
+
+ filp->f_pos = (hchain+2) << 20;
+ }
+ brelse(bh);
+success:
+ ret = 0;
+out:
+ return ret;
+}
+
+struct inode_operations omfs_dir_inops = {
+ .lookup = omfs_lookup,
+ .mkdir = omfs_mkdir,
+ .rename = omfs_rename,
+ .create = omfs_create,
+ .unlink = omfs_unlink,
+ .rmdir = omfs_rmdir,
+};
+
+struct file_operations omfs_dir_operations = {
+ .read = generic_read_dir,
+ .readdir = omfs_readdir,
+};
projects / GitHub / LineageOS / android_kernel_samsung_universal7580.git / commitdiff