Initial import

1 files changed, 537 insertions, 0 deletions

diff --git a/fs/ext3/dir.c b/fs/ext3/dir.c
new file mode 100644
index 000000000..17742eed2
--- /dev/null
+++ b/fs/ext3/dir.c
@@ -0,0 +1,537 @@
+/*
+ *  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/compat.h>
+#include "ext3.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_dx_readdir(struct file *, struct dir_context *);
+
+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]);
+}
+
+/**
+ * Check if the given dir-inode refers to an htree-indexed directory
+ * (or a directory which could potentially get converted to use htree
+ * indexing).
+ *
+ * Return 1 if it is a dx dir, 0 if not
+ */
+static int is_dx_dir(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+
+	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)))
+		return 1;
+
+	return 0;
+}
+
+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 = ext3_rec_len_from_disk(de->rec_len);
+
+	if (unlikely(rlen < EXT3_DIR_REC_LEN(1)))
+		error_msg = "rec_len is smaller than minimal";
+	else if (unlikely(rlen % 4 != 0))
+		error_msg = "rec_len % 4 != 0";
+	else if (unlikely(rlen < EXT3_DIR_REC_LEN(de->name_len)))
+		error_msg = "rec_len is too small for name_len";
+	else if (unlikely((((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)))
+		error_msg = "directory entry across blocks";
+	else if (unlikely(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 (unlikely(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 *file, struct dir_context *ctx)
+{
+	unsigned long offset;
+	int i;
+	struct ext3_dir_entry_2 *de;
+	int err;
+	struct inode *inode = file_inode(file);
+	struct super_block *sb = inode->i_sb;
+	int dir_has_error = 0;
+
+	if (is_dx_dir(inode)) {
+		err = ext3_dx_readdir(file, ctx);
+		if (err != ERR_BAD_DX_DIR)
+			return err;
+		/*
+		 * We don't set the inode dirty flag since it's not
+		 * critical that it get flushed back to the disk.
+		 */
+		EXT3_I(inode)->i_flags &= ~EXT3_INDEX_FL;
+	}
+	offset = ctx->pos & (sb->s_blocksize - 1);
+
+	while (ctx->pos < inode->i_size) {
+		unsigned long blk = ctx->pos >> EXT3_BLOCK_SIZE_BITS(sb);
+		struct buffer_head map_bh;
+		struct buffer_head *bh = NULL;
+
+		map_bh.b_state = 0;
+		err = ext3_get_blocks_handle(NULL, inode, blk, 1, &map_bh, 0);
+		if (err > 0) {
+			pgoff_t index = map_bh.b_blocknr >>
+					(PAGE_CACHE_SHIFT - inode->i_blkbits);
+			if (!ra_has_index(&file->f_ra, index))
+				page_cache_sync_readahead(
+					sb->s_bdev->bd_inode->i_mapping,
+					&file->f_ra, file,
+					index, 1);
+			file->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
+			bh = ext3_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) {
+			if (!dir_has_error) {
+				ext3_error(sb, __func__, "directory #%lu "
+					"contains a hole at offset %lld",
+					inode->i_ino, ctx->pos);
+				dir_has_error = 1;
+			}
+			/* corrupt size?  Maybe no more blocks to read */
+			if (ctx->pos > inode->i_blocks << 9)
+				break;
+			ctx->pos += sb->s_blocksize - offset;
+			continue;
+		}
+
+		/* 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 (offset && file->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 (ext3_rec_len_from_disk(de->rec_len) <
+						EXT3_DIR_REC_LEN(1))
+					break;
+				i += ext3_rec_len_from_disk(de->rec_len);
+			}
+			offset = i;
+			ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
+				| offset;
+			file->f_version = inode->i_version;
+		}
+
+		while (ctx->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 to the
+                                   next block. */
+				ctx->pos = (ctx->pos |
+						(sb->s_blocksize - 1)) + 1;
+				break;
+			}
+			offset += ext3_rec_len_from_disk(de->rec_len);
+			if (le32_to_cpu(de->inode)) {
+				if (!dir_emit(ctx, de->name, de->name_len,
+					      le32_to_cpu(de->inode),
+					      get_dtype(sb, de->file_type))) {
+					brelse(bh);
+					return 0;
+				}
+			}
+			ctx->pos += ext3_rec_len_from_disk(de->rec_len);
+		}
+		offset = 0;
+		brelse (bh);
+		if (ctx->pos < inode->i_size)
+			if (!dir_relax(inode))
+				return 0;
+	}
+	return 0;
+}
+
+static inline int is_32bit_api(void)
+{
+#ifdef CONFIG_COMPAT
+	return is_compat_task();
+#else
+	return (BITS_PER_LONG == 32);
+#endif
+}
+
+/*
+ * These functions convert from the major/minor hash to an f_pos
+ * value for dx directories
+ *
+ * Upper layer (for example NFS) should specify FMODE_32BITHASH or
+ * FMODE_64BITHASH explicitly. On the other hand, we allow ext3 to be mounted
+ * directly on both 32-bit and 64-bit nodes, under such case, neither
+ * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
+ */
+static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return major >> 1;
+	else
+		return ((__u64)(major >> 1) << 32) | (__u64)minor;
+}
+
+static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return (pos << 1) & 0xffffffff;
+	else
+		return ((pos >> 32) << 1) & 0xffffffff;
+}
+
+static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return 0;
+	else
+		return pos & 0xffffffff;
+}
+
+/*
+ * Return 32- or 64-bit end-of-file for dx directories
+ */
+static inline loff_t ext3_get_htree_eof(struct file *filp)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return EXT3_HTREE_EOF_32BIT;
+	else
+		return EXT3_HTREE_EOF_64BIT;
+}
+
+
+/*
+ * ext3_dir_llseek() calls generic_file_llseek[_size]() to handle both
+ * non-htree and htree directories, where the "offset" is in terms
+ * of the filename hash value instead of the byte offset.
+ *
+ * Because we may return a 64-bit hash that is well beyond s_maxbytes,
+ * we need to pass the max hash as the maximum allowable offset in
+ * the htree directory case.
+ *
+ * NOTE: offsets obtained *before* ext3_set_inode_flag(dir, EXT3_INODE_INDEX)
+ *       will be invalid once the directory was converted into a dx directory
+ */
+static loff_t ext3_dir_llseek(struct file *file, loff_t offset, int whence)
+{
+	struct inode *inode = file->f_mapping->host;
+	int dx_dir = is_dx_dir(inode);
+	loff_t htree_max = ext3_get_htree_eof(file);
+
+	if (likely(dx_dir))
+		return generic_file_llseek_size(file, offset, whence,
+					        htree_max, htree_max);
+	else
+		return generic_file_llseek(file, offset, whence);
+}
+
+/*
+ * 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 fname *fname, *next;
+
+	rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
+		do {
+			struct fname *old = fname;
+			fname = fname->next;
+			kfree(old);
+		} while (fname);
+
+	*root = RB_ROOT;
+}
+
+static struct dir_private_info *ext3_htree_create_dir_info(struct file *filp,
+							   loff_t pos)
+{
+	struct dir_private_info *p;
+
+	p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
+	if (!p)
+		return NULL;
+	p->curr_hash = pos2maj_hash(filp, pos);
+	p->curr_minor_hash = pos2min_hash(filp, pos);
+	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 = 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 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 bool call_filldir(struct file *file, struct dir_context *ctx,
+			struct fname *fname)
+{
+	struct dir_private_info *info = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct super_block *sb = inode->i_sb;
+
+	if (!fname) {
+		printk("call_filldir: called with null fname?!?\n");
+		return true;
+	}
+	ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
+	while (fname) {
+		if (!dir_emit(ctx, fname->name, fname->name_len,
+				fname->inode,
+				get_dtype(sb, fname->file_type))) {
+			info->extra_fname = fname;
+			return false;
+		}
+		fname = fname->next;
+	}
+	return true;
+}
+
+static int ext3_dx_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct dir_private_info *info = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct fname *fname;
+	int	ret;
+
+	if (!info) {
+		info = ext3_htree_create_dir_info(file, ctx->pos);
+		if (!info)
+			return -ENOMEM;
+		file->private_data = info;
+	}
+
+	if (ctx->pos == ext3_get_htree_eof(file))
+		return 0;	/* EOF */
+
+	/* Some one has messed with f_pos; reset the world */
+	if (info->last_pos != ctx->pos) {
+		free_rb_tree_fname(&info->root);
+		info->curr_node = NULL;
+		info->extra_fname = NULL;
+		info->curr_hash = pos2maj_hash(file, ctx->pos);
+		info->curr_minor_hash = pos2min_hash(file, ctx->pos);
+	}
+
+	/*
+	 * If there are any leftover names on the hash collision
+	 * chain, return them first.
+	 */
+	if (info->extra_fname) {
+		if (!call_filldir(file, ctx, info->extra_fname))
+			goto finished;
+		info->extra_fname = NULL;
+		goto next_node;
+	} else 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) ||
+		    (file->f_version != inode->i_version)) {
+			info->curr_node = NULL;
+			free_rb_tree_fname(&info->root);
+			file->f_version = inode->i_version;
+			ret = ext3_htree_fill_tree(file, info->curr_hash,
+						   info->curr_minor_hash,
+						   &info->next_hash);
+			if (ret < 0)
+				return ret;
+			if (ret == 0) {
+				ctx->pos = ext3_get_htree_eof(file);
+				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(file, ctx, fname))
+			break;
+	next_node:
+		info->curr_node = rb_next(info->curr_node);
+		if (info->curr_node) {
+			fname = rb_entry(info->curr_node, struct fname,
+					 rb_hash);
+			info->curr_hash = fname->hash;
+			info->curr_minor_hash = fname->minor_hash;
+		} else {
+			if (info->next_hash == ~0) {
+				ctx->pos = ext3_get_htree_eof(file);
+				break;
+			}
+			info->curr_hash = info->next_hash;
+			info->curr_minor_hash = 0;
+		}
+	}
+finished:
+	info->last_pos = ctx->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;
+}
+
+const struct file_operations ext3_dir_operations = {
+	.llseek		= ext3_dir_llseek,
+	.read		= generic_read_dir,
+	.iterate	= ext3_readdir,
+	.unlocked_ioctl = ext3_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ext3_compat_ioctl,
+#endif
+	.fsync		= ext3_sync_file,
+	.release	= ext3_release_dir,
+};