--- /dev/null
+/*
+ * linux/fs/ext4/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
+ *
+ * ext4 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/jbd2.h>
+#include <linux/ext4_fs.h>
+#include <linux/buffer_head.h>
+#include <linux/smp_lock.h>
+#include <linux/slab.h>
+#include <linux/rbtree.h>
+
+static unsigned char ext4_filetype_table[] = {
+ DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
+};
+
+static int ext4_readdir(struct file *, void *, filldir_t);
+static int ext4_dx_readdir(struct file * filp,
+ void * dirent, filldir_t filldir);
+static int ext4_release_dir (struct inode * inode,
+ struct file * filp);
+
+const struct file_operations ext4_dir_operations = {
+ .llseek = generic_file_llseek,
+ .read = generic_read_dir,
+ .readdir = ext4_readdir, /* we take BKL. needed?*/
+ .ioctl = ext4_ioctl, /* BKL held */
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = ext4_compat_ioctl,
+#endif
+ .fsync = ext4_sync_file, /* BKL held */
+#ifdef CONFIG_EXT4_INDEX
+ .release = ext4_release_dir,
+#endif
+};
+
+
+static unsigned char get_dtype(struct super_block *sb, int filetype)
+{
+ if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE) ||
+ (filetype >= EXT4_FT_MAX))
+ return DT_UNKNOWN;
+
+ return (ext4_filetype_table[filetype]);
+}
+
+
+int ext4_check_dir_entry (const char * function, struct inode * dir,
+ struct ext4_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 < EXT4_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 < EXT4_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(EXT4_SB(dir->i_sb)->s_es->s_inodes_count))
+ error_msg = "inode out of bounds";
+
+ if (error_msg != NULL)
+ ext4_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 ext4_readdir(struct file * filp,
+ void * dirent, filldir_t filldir)
+{
+ int error = 0;
+ unsigned long offset;
+ int i, stored;
+ struct ext4_dir_entry_2 *de;
+ struct super_block *sb;
+ int err;
+ struct inode *inode = filp->f_path.dentry->d_inode;
+ int ret = 0;
+
+ sb = inode->i_sb;
+
+#ifdef CONFIG_EXT4_INDEX
+ if (EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
+ EXT4_FEATURE_COMPAT_DIR_INDEX) &&
+ ((EXT4_I(inode)->i_flags & EXT4_INDEX_FL) ||
+ ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
+ err = ext4_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.
+ */
+ EXT4_I(filp->f_path.dentry->d_inode)->i_flags &= ~EXT4_INDEX_FL;
+ }
+#endif
+ stored = 0;
+ offset = filp->f_pos & (sb->s_blocksize - 1);
+
+ while (!error && !stored && filp->f_pos < inode->i_size) {
+ unsigned long blk = filp->f_pos >> EXT4_BLOCK_SIZE_BITS(sb);
+ struct buffer_head map_bh;
+ struct buffer_head *bh = NULL;
+
+ map_bh.b_state = 0;
+ err = ext4_get_blocks_wrap(NULL, inode, blk, 1, &map_bh, 0, 0);
+ if (err > 0) {
+ page_cache_readahead(sb->s_bdev->bd_inode->i_mapping,
+ &filp->f_ra,
+ filp,
+ map_bh.b_blocknr >>
+ (PAGE_CACHE_SHIFT - inode->i_blkbits),
+ 1);
+ bh = ext4_bread(NULL, inode, blk, 0, &err);
+ }
+
+ /*
+ * We ignore I/O errors on directories so users have a chance
+ * of recovering data when there's a bad sector
+ */
+ if (!bh) {
+ ext4_error (sb, "ext4_readdir",
+ "directory #%lu contains a hole at offset %lu",
+ inode->i_ino, (unsigned long)filp->f_pos);
+ /* corrupt size? Maybe no more blocks to read */
+ if (filp->f_pos > inode->i_blocks << 9)
+ break;
+ filp->f_pos += sb->s_blocksize - offset;
+ continue;
+ }
+
+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 ext4_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) <
+ EXT4_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 ext4_dir_entry_2 *) (bh->b_data + offset);
+ if (!ext4_check_dir_entry ("ext4_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_EXT4_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 = rb_parent(n);
+ 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 ext4_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 ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
+ __u32 minor_hash,
+ struct ext4_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 = kzalloc(len, GFP_KERNEL);
+ if (!new_fn)
+ return -ENOMEM;
+ 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 ext4_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_path.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 ext4_dx_readdir(struct file * filp,
+ void * dirent, filldir_t filldir)
+{
+ struct dir_private_info *info = filp->private_data;
+ struct inode *inode = filp->f_path.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 == EXT4_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 = ext4_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 = EXT4_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 = EXT4_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 ext4_release_dir (struct inode * inode, struct file * filp)
+{
+ if (filp->private_data)
+ ext4_htree_free_dir_info(filp->private_data);
+
+ return 0;
+}
+
+#endif
git://git.onelab.eu / linux-2.6.git / blobdiff