1 files changed, 504 insertions, 0 deletions

diff --git a/fs/omfs/dir.c b/fs/omfs/dir.c
new file mode 100644
index 000000000000..05a5bc31e4bd
--- /dev/null
+++ b/fs/omfs/dir.c
@@ -0,0 +1,504 @@
+/*
+ * 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,
+};