1 files changed, 519 insertions, 0 deletions

diff --git a/fs/ext3/dir.c b/fs/ext3/dir.c
new file mode 100644
index 000000000000..832867aef3dc
--- /dev/null
+++ b/fs/ext3/dir.c
@@ -0,0 +1,519 @@
+/*
+ *  linux/fs/ext3/dir.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/dir.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext3 directory handling functions
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ *
+ * Hash Tree Directory indexing (c) 2001  Daniel Phillips
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/jbd.h>
+#include <linux/ext3_fs.h>
+#include <linux/buffer_head.h>
+#include <linux/smp_lock.h>
+#include <linux/slab.h>
+#include <linux/rbtree.h>
+
+static unsigned char ext3_filetype_table[] = {
+        DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
+};
+
+static int ext3_readdir(struct file *, void *, filldir_t);
+static int ext3_dx_readdir(struct file * filp,
+                           void * dirent, filldir_t filldir);
+static int ext3_release_dir (struct inode * inode,
+                                struct file * filp);
+
+struct file_operations ext3_dir_operations = {
+        .llseek         = generic_file_llseek,
+        .read           = generic_read_dir,
+        .readdir        = ext3_readdir,         /* we take BKL. needed?*/
+        .ioctl          = ext3_ioctl,           /* BKL held */
+        .fsync          = ext3_sync_file,       /* BKL held */
+#ifdef CONFIG_EXT3_INDEX
+        .release        = ext3_release_dir,
+#endif
+};
+
+
+static unsigned char get_dtype(struct super_block *sb, int filetype)
+{
+        if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_FILETYPE) ||
+            (filetype >= EXT3_FT_MAX))
+                return DT_UNKNOWN;
+
+        return (ext3_filetype_table[filetype]);
+}
+                               
+
+int ext3_check_dir_entry (const char * function, struct inode * dir,
+                          struct ext3_dir_entry_2 * de,
+                          struct buffer_head * bh,
+                          unsigned long offset)
+{
+        const char * error_msg = NULL;
+        const int rlen = le16_to_cpu(de->rec_len);
+
+        if (rlen < EXT3_DIR_REC_LEN(1))
+                error_msg = "rec_len is smaller than minimal";
+        else if (rlen % 4 != 0)
+                error_msg = "rec_len % 4 != 0";
+        else if (rlen < EXT3_DIR_REC_LEN(de->name_len))
+                error_msg = "rec_len is too small for name_len";
+        else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)
+                error_msg = "directory entry across blocks";
+        else if (le32_to_cpu(de->inode) >
+                        le32_to_cpu(EXT3_SB(dir->i_sb)->s_es->s_inodes_count))
+                error_msg = "inode out of bounds";
+
+        if (error_msg != NULL)
+                ext3_error (dir->i_sb, function,
+                        "bad entry in directory #%lu: %s - "
+                        "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
+                        dir->i_ino, error_msg, offset,
+                        (unsigned long) le32_to_cpu(de->inode),
+                        rlen, de->name_len);
+        return error_msg == NULL ? 1 : 0;
+}
+
+static int ext3_readdir(struct file * filp,
+                         void * dirent, filldir_t filldir)
+{
+        int error = 0;
+        unsigned long offset, blk;
+        int i, num, stored;
+        struct buffer_head * bh, * tmp, * bha[16];
+        struct ext3_dir_entry_2 * de;
+        struct super_block * sb;
+        int err;
+        struct inode *inode = filp->f_dentry->d_inode;
+        int ret = 0;
+
+        sb = inode->i_sb;
+
+#ifdef CONFIG_EXT3_INDEX
+        if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
+                                    EXT3_FEATURE_COMPAT_DIR_INDEX) &&
+            ((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) ||
+             ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
+                err = ext3_dx_readdir(filp, dirent, filldir);
+                if (err != ERR_BAD_DX_DIR) {
+                        ret = err;
+                        goto out;
+                }
+                /*
+                 * We don't set the inode dirty flag since it's not
+                 * critical that it get flushed back to the disk.
+                 */
+                EXT3_I(filp->f_dentry->d_inode)->i_flags &= ~EXT3_INDEX_FL;
+        }
+#endif
+        stored = 0;
+        bh = NULL;
+        offset = filp->f_pos & (sb->s_blocksize - 1);
+
+        while (!error && !stored && filp->f_pos < inode->i_size) {
+                blk = (filp->f_pos) >> EXT3_BLOCK_SIZE_BITS(sb);
+                bh = ext3_bread(NULL, inode, blk, 0, &err);
+                if (!bh) {
+                        ext3_error (sb, "ext3_readdir",
+                                "directory #%lu contains a hole at offset %lu",
+                                inode->i_ino, (unsigned long)filp->f_pos);
+                        filp->f_pos += sb->s_blocksize - offset;
+                        continue;
+                }
+
+                /*
+                 * Do the readahead
+                 */
+                if (!offset) {
+                        for (i = 16 >> (EXT3_BLOCK_SIZE_BITS(sb) - 9), num = 0;
+                             i > 0; i--) {
+                                tmp = ext3_getblk (NULL, inode, ++blk, 0, &err);
+                                if (tmp && !buffer_uptodate(tmp) &&
+                                                !buffer_locked(tmp))
+                                        bha[num++] = tmp;
+                                else
+                                        brelse (tmp);
+                        }
+                        if (num) {
+                                ll_rw_block (READA, num, bha);
+                                for (i = 0; i < num; i++)
+                                        brelse (bha[i]);
+                        }
+                }
+
+revalidate:
+                /* If the dir block has changed since the last call to
+                 * readdir(2), then we might be pointing to an invalid
+                 * dirent right now.  Scan from the start of the block
+                 * to make sure. */
+                if (filp->f_version != inode->i_version) {
+                        for (i = 0; i < sb->s_blocksize && i < offset; ) {
+                                de = (struct ext3_dir_entry_2 *) 
+                                        (bh->b_data + i);
+                                /* It's too expensive to do a full
+                                 * dirent test each time round this
+                                 * loop, but we do have to test at
+                                 * least that it is non-zero.  A
+                                 * failure will be detected in the
+                                 * dirent test below. */
+                                if (le16_to_cpu(de->rec_len) <
+                                                EXT3_DIR_REC_LEN(1))
+                                        break;
+                                i += le16_to_cpu(de->rec_len);
+                        }
+                        offset = i;
+                        filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
+                                | offset;
+                        filp->f_version = inode->i_version;
+                }
+
+                while (!error && filp->f_pos < inode->i_size 
+                       && offset < sb->s_blocksize) {
+                        de = (struct ext3_dir_entry_2 *) (bh->b_data + offset);
+                        if (!ext3_check_dir_entry ("ext3_readdir", inode, de,
+                                                   bh, offset)) {
+                                /* On error, skip the f_pos to the
+                                   next block. */
+                                filp->f_pos = (filp->f_pos |
+                                                (sb->s_blocksize - 1)) + 1;
+                                brelse (bh);
+                                ret = stored;
+                                goto out;
+                        }
+                        offset += le16_to_cpu(de->rec_len);
+                        if (le32_to_cpu(de->inode)) {
+                                /* We might block in the next section
+                                 * if the data destination is
+                                 * currently swapped out.  So, use a
+                                 * version stamp to detect whether or
+                                 * not the directory has been modified
+                                 * during the copy operation.
+                                 */
+                                unsigned long version = filp->f_version;
+
+                                error = filldir(dirent, de->name,
+                                                de->name_len,
+                                                filp->f_pos,
+                                                le32_to_cpu(de->inode),
+                                                get_dtype(sb, de->file_type));
+                                if (error)
+                                        break;
+                                if (version != filp->f_version)
+                                        goto revalidate;
+                                stored ++;
+                        }
+                        filp->f_pos += le16_to_cpu(de->rec_len);
+                }
+                offset = 0;
+                brelse (bh);
+        }
+out:
+        return ret;
+}
+
+#ifdef CONFIG_EXT3_INDEX
+/*
+ * These functions convert from the major/minor hash to an f_pos
+ * value.
+ * 
+ * Currently we only use major hash numer.  This is unfortunate, but
+ * on 32-bit machines, the same VFS interface is used for lseek and
+ * llseek, so if we use the 64 bit offset, then the 32-bit versions of
+ * lseek/telldir/seekdir will blow out spectacularly, and from within
+ * the ext2 low-level routine, we don't know if we're being called by
+ * a 64-bit version of the system call or the 32-bit version of the
+ * system call.  Worse yet, NFSv2 only allows for a 32-bit readdir
+ * cookie.  Sigh.
+ */
+#define hash2pos(major, minor)  (major >> 1)
+#define pos2maj_hash(pos)       ((pos << 1) & 0xffffffff)
+#define pos2min_hash(pos)       (0)
+
+/*
+ * This structure holds the nodes of the red-black tree used to store
+ * the directory entry in hash order.
+ */
+struct fname {
+        __u32           hash;
+        __u32           minor_hash;
+        struct rb_node  rb_hash; 
+        struct fname    *next;
+        __u32           inode;
+        __u8            name_len;
+        __u8            file_type;
+        char            name[0];
+};
+
+/*
+ * This functoin implements a non-recursive way of freeing all of the
+ * nodes in the red-black tree.
+ */
+static void free_rb_tree_fname(struct rb_root *root)
+{
+        struct rb_node  *n = root->rb_node;
+        struct rb_node  *parent;
+        struct fname    *fname;
+
+        while (n) {
+                /* Do the node's children first */
+                if ((n)->rb_left) {
+                        n = n->rb_left;
+                        continue;
+                }
+                if (n->rb_right) {
+                        n = n->rb_right;
+                        continue;
+                }
+                /*
+                 * The node has no children; free it, and then zero
+                 * out parent's link to it.  Finally go to the
+                 * beginning of the loop and try to free the parent
+                 * node.
+                 */
+                parent = n->rb_parent;
+                fname = rb_entry(n, struct fname, rb_hash);
+                while (fname) {
+                        struct fname * old = fname;
+                        fname = fname->next;
+                        kfree (old);
+                }
+                if (!parent)
+                        root->rb_node = NULL;
+                else if (parent->rb_left == n)
+                        parent->rb_left = NULL;
+                else if (parent->rb_right == n)
+                        parent->rb_right = NULL;
+                n = parent;
+        }
+        root->rb_node = NULL;
+}
+
+
+static struct dir_private_info *create_dir_info(loff_t pos)
+{
+        struct dir_private_info *p;
+
+        p = kmalloc(sizeof(struct dir_private_info), GFP_KERNEL);
+        if (!p)
+                return NULL;
+        p->root.rb_node = NULL;
+        p->curr_node = NULL;
+        p->extra_fname = NULL;
+        p->last_pos = 0;
+        p->curr_hash = pos2maj_hash(pos);
+        p->curr_minor_hash = pos2min_hash(pos);
+        p->next_hash = 0;
+        return p;
+}
+
+void ext3_htree_free_dir_info(struct dir_private_info *p)
+{
+        free_rb_tree_fname(&p->root);
+        kfree(p);
+}
+
+/*
+ * Given a directory entry, enter it into the fname rb tree.
+ */
+int ext3_htree_store_dirent(struct file *dir_file, __u32 hash,
+                             __u32 minor_hash,
+                             struct ext3_dir_entry_2 *dirent)
+{
+        struct rb_node **p, *parent = NULL;
+        struct fname * fname, *new_fn;
+        struct dir_private_info *info;
+        int len;
+
+        info = (struct dir_private_info *) dir_file->private_data;
+        p = &info->root.rb_node;
+
+        /* Create and allocate the fname structure */
+        len = sizeof(struct fname) + dirent->name_len + 1;
+        new_fn = kmalloc(len, GFP_KERNEL);
+        if (!new_fn)
+                return -ENOMEM;
+        memset(new_fn, 0, len);
+        new_fn->hash = hash;
+        new_fn->minor_hash = minor_hash;
+        new_fn->inode = le32_to_cpu(dirent->inode);
+        new_fn->name_len = dirent->name_len;
+        new_fn->file_type = dirent->file_type;
+        memcpy(new_fn->name, dirent->name, dirent->name_len);
+        new_fn->name[dirent->name_len] = 0;
+
+        while (*p) {
+                parent = *p;
+                fname = rb_entry(parent, struct fname, rb_hash);
+
+                /*
+                 * If the hash and minor hash match up, then we put
+                 * them on a linked list.  This rarely happens...
+                 */
+                if ((new_fn->hash == fname->hash) &&
+                    (new_fn->minor_hash == fname->minor_hash)) {
+                        new_fn->next = fname->next;
+                        fname->next = new_fn;
+                        return 0;
+                }
+
+                if (new_fn->hash < fname->hash)
+                        p = &(*p)->rb_left;
+                else if (new_fn->hash > fname->hash)
+                        p = &(*p)->rb_right;
+                else if (new_fn->minor_hash < fname->minor_hash)
+                        p = &(*p)->rb_left;
+                else /* if (new_fn->minor_hash > fname->minor_hash) */
+                        p = &(*p)->rb_right;
+        }
+
+        rb_link_node(&new_fn->rb_hash, parent, p);
+        rb_insert_color(&new_fn->rb_hash, &info->root);
+        return 0;
+}
+
+
+
+/*
+ * This is a helper function for ext3_dx_readdir.  It calls filldir
+ * for all entres on the fname linked list.  (Normally there is only
+ * one entry on the linked list, unless there are 62 bit hash collisions.)
+ */
+static int call_filldir(struct file * filp, void * dirent,
+                        filldir_t filldir, struct fname *fname)
+{
+        struct dir_private_info *info = filp->private_data;
+        loff_t  curr_pos;
+        struct inode *inode = filp->f_dentry->d_inode;
+        struct super_block * sb;
+        int error;
+
+        sb = inode->i_sb;
+
+        if (!fname) {
+                printk("call_filldir: called with null fname?!?\n");
+                return 0;
+        }
+        curr_pos = hash2pos(fname->hash, fname->minor_hash);
+        while (fname) {
+                error = filldir(dirent, fname->name,
+                                fname->name_len, curr_pos, 
+                                fname->inode,
+                                get_dtype(sb, fname->file_type));
+                if (error) {
+                        filp->f_pos = curr_pos;
+                        info->extra_fname = fname->next;
+                        return error;
+                }
+                fname = fname->next;
+        }
+        return 0;
+}
+
+static int ext3_dx_readdir(struct file * filp,
+                         void * dirent, filldir_t filldir)
+{
+        struct dir_private_info *info = filp->private_data;
+        struct inode *inode = filp->f_dentry->d_inode;
+        struct fname *fname;
+        int     ret;
+
+        if (!info) {
+                info = create_dir_info(filp->f_pos);
+                if (!info)
+                        return -ENOMEM;
+                filp->private_data = info;
+        }
+
+        if (filp->f_pos == EXT3_HTREE_EOF)
+                return 0;       /* EOF */
+
+        /* Some one has messed with f_pos; reset the world */
+        if (info->last_pos != filp->f_pos) {
+                free_rb_tree_fname(&info->root);
+                info->curr_node = NULL;
+                info->extra_fname = NULL;
+                info->curr_hash = pos2maj_hash(filp->f_pos);
+                info->curr_minor_hash = pos2min_hash(filp->f_pos);
+        }
+
+        /*
+         * If there are any leftover names on the hash collision
+         * chain, return them first.
+         */
+        if (info->extra_fname &&
+            call_filldir(filp, dirent, filldir, info->extra_fname))
+                goto finished;
+
+        if (!info->curr_node)
+                info->curr_node = rb_first(&info->root);
+
+        while (1) {
+                /*
+                 * Fill the rbtree if we have no more entries,
+                 * or the inode has changed since we last read in the
+                 * cached entries. 
+                 */
+                if ((!info->curr_node) ||
+                    (filp->f_version != inode->i_version)) {
+                        info->curr_node = NULL;
+                        free_rb_tree_fname(&info->root);
+                        filp->f_version = inode->i_version;
+                        ret = ext3_htree_fill_tree(filp, info->curr_hash,
+                                                   info->curr_minor_hash,
+                                                   &info->next_hash);
+                        if (ret < 0)
+                                return ret;
+                        if (ret == 0) {
+                                filp->f_pos = EXT3_HTREE_EOF;
+                                break;
+                        }
+                        info->curr_node = rb_first(&info->root);
+                }
+
+                fname = rb_entry(info->curr_node, struct fname, rb_hash);
+                info->curr_hash = fname->hash;
+                info->curr_minor_hash = fname->minor_hash;
+                if (call_filldir(filp, dirent, filldir, fname))
+                        break;
+
+                info->curr_node = rb_next(info->curr_node);
+                if (!info->curr_node) {
+                        if (info->next_hash == ~0) {
+                                filp->f_pos = EXT3_HTREE_EOF;
+                                break;
+                        }
+                        info->curr_hash = info->next_hash;
+                        info->curr_minor_hash = 0;
+                }
+        }
+finished:
+        info->last_pos = filp->f_pos;
+        return 0;
+}
+
+static int ext3_release_dir (struct inode * inode, struct file * filp)
+{
+       if (filp->private_data)
+                ext3_htree_free_dir_info(filp->private_data);
+
+        return 0;
+}
+
+#endif