+++ /dev/null
-/*
- * 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,
-};
Code Review / kvmfornfv.git / blobdiff