diff options
Diffstat (limited to 'fs/ext3/namei.c')
| -rw-r--r-- | fs/ext3/namei.c | 2378 |
1 files changed, 2378 insertions, 0 deletions
diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c new file mode 100644 index 00000000000..79742d824a0 --- /dev/null +++ b/fs/ext3/namei.c @@ -0,0 +1,2378 @@ +/* + * linux/fs/ext3/namei.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/namei.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * Big-endian to little-endian byte-swapping/bitmaps by + * David S. Miller (davem@caip.rutgers.edu), 1995 + * Directory entry file type support and forward compatibility hooks + * for B-tree directories by Theodore Ts'o (tytso@mit.edu), 1998 + * Hash Tree Directory indexing (c) + * Daniel Phillips, 2001 + * Hash Tree Directory indexing porting + * Christopher Li, 2002 + * Hash Tree Directory indexing cleanup + * Theodore Ts'o, 2002 + */ + +#include <linux/fs.h> +#include <linux/pagemap.h> +#include <linux/jbd.h> +#include <linux/time.h> +#include <linux/ext3_fs.h> +#include <linux/ext3_jbd.h> +#include <linux/fcntl.h> +#include <linux/stat.h> +#include <linux/string.h> +#include <linux/quotaops.h> +#include <linux/buffer_head.h> +#include <linux/smp_lock.h> +#include "xattr.h" +#include "acl.h" + +/* + * define how far ahead to read directories while searching them. + */ +#define NAMEI_RA_CHUNKS 2 +#define NAMEI_RA_BLOCKS 4 +#define NAMEI_RA_SIZE (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS) +#define NAMEI_RA_INDEX(c,b) (((c) * NAMEI_RA_BLOCKS) + (b)) + +static struct buffer_head *ext3_append(handle_t *handle, + struct inode *inode, + u32 *block, int *err) +{ + struct buffer_head *bh; + + *block = inode->i_size >> inode->i_sb->s_blocksize_bits; + + if ((bh = ext3_bread(handle, inode, *block, 1, err))) { + inode->i_size += inode->i_sb->s_blocksize; + EXT3_I(inode)->i_disksize = inode->i_size; + ext3_journal_get_write_access(handle,bh); + } + return bh; +} + +#ifndef assert +#define assert(test) J_ASSERT(test) +#endif + +#ifndef swap +#define swap(x, y) do { typeof(x) z = x; x = y; y = z; } while (0) +#endif + +#ifdef DX_DEBUG +#define dxtrace(command) command +#else +#define dxtrace(command) +#endif + +struct fake_dirent +{ + __le32 inode; + __le16 rec_len; + u8 name_len; + u8 file_type; +}; + +struct dx_countlimit +{ + __le16 limit; + __le16 count; +}; + +struct dx_entry +{ + __le32 hash; + __le32 block; +}; + +/* + * dx_root_info is laid out so that if it should somehow get overlaid by a + * dirent the two low bits of the hash version will be zero. Therefore, the + * hash version mod 4 should never be 0. Sincerely, the paranoia department. + */ + +struct dx_root +{ + struct fake_dirent dot; + char dot_name[4]; + struct fake_dirent dotdot; + char dotdot_name[4]; + struct dx_root_info + { + __le32 reserved_zero; + u8 hash_version; + u8 info_length; /* 8 */ + u8 indirect_levels; + u8 unused_flags; + } + info; + struct dx_entry entries[0]; +}; + +struct dx_node +{ + struct fake_dirent fake; + struct dx_entry entries[0]; +}; + + +struct dx_frame +{ + struct buffer_head *bh; + struct dx_entry *entries; + struct dx_entry *at; +}; + +struct dx_map_entry +{ + u32 hash; + u32 offs; +}; + +#ifdef CONFIG_EXT3_INDEX +static inline unsigned dx_get_block (struct dx_entry *entry); +static void dx_set_block (struct dx_entry *entry, unsigned value); +static inline unsigned dx_get_hash (struct dx_entry *entry); +static void dx_set_hash (struct dx_entry *entry, unsigned value); +static unsigned dx_get_count (struct dx_entry *entries); +static unsigned dx_get_limit (struct dx_entry *entries); +static void dx_set_count (struct dx_entry *entries, unsigned value); +static void dx_set_limit (struct dx_entry *entries, unsigned value); +static unsigned dx_root_limit (struct inode *dir, unsigned infosize); +static unsigned dx_node_limit (struct inode *dir); +static struct dx_frame *dx_probe(struct dentry *dentry, + struct inode *dir, + struct dx_hash_info *hinfo, + struct dx_frame *frame, + int *err); +static void dx_release (struct dx_frame *frames); +static int dx_make_map (struct ext3_dir_entry_2 *de, int size, + struct dx_hash_info *hinfo, struct dx_map_entry map[]); +static void dx_sort_map(struct dx_map_entry *map, unsigned count); +static struct ext3_dir_entry_2 *dx_move_dirents (char *from, char *to, + struct dx_map_entry *offsets, int count); +static struct ext3_dir_entry_2* dx_pack_dirents (char *base, int size); +static void dx_insert_block (struct dx_frame *frame, u32 hash, u32 block); +static int ext3_htree_next_block(struct inode *dir, __u32 hash, + struct dx_frame *frame, + struct dx_frame *frames, + __u32 *start_hash); +static struct buffer_head * ext3_dx_find_entry(struct dentry *dentry, + struct ext3_dir_entry_2 **res_dir, int *err); +static int ext3_dx_add_entry(handle_t *handle, struct dentry *dentry, + struct inode *inode); + +/* + * Future: use high four bits of block for coalesce-on-delete flags + * Mask them off for now. + */ + +static inline unsigned dx_get_block (struct dx_entry *entry) +{ + return le32_to_cpu(entry->block) & 0x00ffffff; +} + +static inline void dx_set_block (struct dx_entry *entry, unsigned value) +{ + entry->block = cpu_to_le32(value); +} + +static inline unsigned dx_get_hash (struct dx_entry *entry) +{ + return le32_to_cpu(entry->hash); +} + +static inline void dx_set_hash (struct dx_entry *entry, unsigned value) +{ + entry->hash = cpu_to_le32(value); +} + +static inline unsigned dx_get_count (struct dx_entry *entries) +{ + return le16_to_cpu(((struct dx_countlimit *) entries)->count); +} + +static inline unsigned dx_get_limit (struct dx_entry *entries) +{ + return le16_to_cpu(((struct dx_countlimit *) entries)->limit); +} + +static inline void dx_set_count (struct dx_entry *entries, unsigned value) +{ + ((struct dx_countlimit *) entries)->count = cpu_to_le16(value); +} + +static inline void dx_set_limit (struct dx_entry *entries, unsigned value) +{ + ((struct dx_countlimit *) entries)->limit = cpu_to_le16(value); +} + +static inline unsigned dx_root_limit (struct inode *dir, unsigned infosize) +{ + unsigned entry_space = dir->i_sb->s_blocksize - EXT3_DIR_REC_LEN(1) - + EXT3_DIR_REC_LEN(2) - infosize; + return 0? 20: entry_space / sizeof(struct dx_entry); +} + +static inline unsigned dx_node_limit (struct inode *dir) +{ + unsigned entry_space = dir->i_sb->s_blocksize - EXT3_DIR_REC_LEN(0); + return 0? 22: entry_space / sizeof(struct dx_entry); +} + +/* + * Debug + */ +#ifdef DX_DEBUG +static void dx_show_index (char * label, struct dx_entry *entries) +{ + int i, n = dx_get_count (entries); + printk("%s index ", label); + for (i = 0; i < n; i++) + { + printk("%x->%u ", i? dx_get_hash(entries + i): 0, dx_get_block(entries + i)); + } + printk("\n"); +} + +struct stats +{ + unsigned names; + unsigned space; + unsigned bcount; +}; + +static struct stats dx_show_leaf(struct dx_hash_info *hinfo, struct ext3_dir_entry_2 *de, + int size, int show_names) +{ + unsigned names = 0, space = 0; + char *base = (char *) de; + struct dx_hash_info h = *hinfo; + + printk("names: "); + while ((char *) de < base + size) + { + if (de->inode) + { + if (show_names) + { + int len = de->name_len; + char *name = de->name; + while (len--) printk("%c", *name++); + ext3fs_dirhash(de->name, de->name_len, &h); + printk(":%x.%u ", h.hash, + ((char *) de - base)); + } + space += EXT3_DIR_REC_LEN(de->name_len); + names++; + } + de = (struct ext3_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len)); + } + printk("(%i)\n", names); + return (struct stats) { names, space, 1 }; +} + +struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir, + struct dx_entry *entries, int levels) +{ + unsigned blocksize = dir->i_sb->s_blocksize; + unsigned count = dx_get_count (entries), names = 0, space = 0, i; + unsigned bcount = 0; + struct buffer_head *bh; + int err; + printk("%i indexed blocks...\n", count); + for (i = 0; i < count; i++, entries++) + { + u32 block = dx_get_block(entries), hash = i? dx_get_hash(entries): 0; + u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash; + struct stats stats; + printk("%s%3u:%03u hash %8x/%8x ",levels?"":" ", i, block, hash, range); + if (!(bh = ext3_bread (NULL,dir, block, 0,&err))) continue; + stats = levels? + dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1): + dx_show_leaf(hinfo, (struct ext3_dir_entry_2 *) bh->b_data, blocksize, 0); + names += stats.names; + space += stats.space; + bcount += stats.bcount; + brelse (bh); + } + if (bcount) + printk("%snames %u, fullness %u (%u%%)\n", levels?"":" ", + names, space/bcount,(space/bcount)*100/blocksize); + return (struct stats) { names, space, bcount}; +} +#endif /* DX_DEBUG */ + +/* + * Probe for a directory leaf block to search. + * + * dx_probe can return ERR_BAD_DX_DIR, which means there was a format + * error in the directory index, and the caller should fall back to + * searching the directory normally. The callers of dx_probe **MUST** + * check for this error code, and make sure it never gets reflected + * back to userspace. + */ +static struct dx_frame * +dx_probe(struct dentry *dentry, struct inode *dir, + struct dx_hash_info *hinfo, struct dx_frame *frame_in, int *err) +{ + unsigned count, indirect; + struct dx_entry *at, *entries, *p, *q, *m; + struct dx_root *root; + struct buffer_head *bh; + struct dx_frame *frame = frame_in; + u32 hash; + + frame->bh = NULL; + if (dentry) + dir = dentry->d_parent->d_inode; + if (!(bh = ext3_bread (NULL,dir, 0, 0, err))) + goto fail; + root = (struct dx_root *) bh->b_data; + if (root->info.hash_version != DX_HASH_TEA && + root->info.hash_version != DX_HASH_HALF_MD4 && + root->info.hash_version != DX_HASH_LEGACY) { + ext3_warning(dir->i_sb, __FUNCTION__, + "Unrecognised inode hash code %d", + root->info.hash_version); + brelse(bh); + *err = ERR_BAD_DX_DIR; + goto fail; + } + hinfo->hash_version = root->info.hash_version; + hinfo->seed = EXT3_SB(dir->i_sb)->s_hash_seed; + if (dentry) + ext3fs_dirhash(dentry->d_name.name, dentry->d_name.len, hinfo); + hash = hinfo->hash; + + if (root->info.unused_flags & 1) { + ext3_warning(dir->i_sb, __FUNCTION__, + "Unimplemented inode hash flags: %#06x", + root->info.unused_flags); + brelse(bh); + *err = ERR_BAD_DX_DIR; + goto fail; + } + + if ((indirect = root->info.indirect_levels) > 1) { + ext3_warning(dir->i_sb, __FUNCTION__, + "Unimplemented inode hash depth: %#06x", + root->info.indirect_levels); + brelse(bh); + *err = ERR_BAD_DX_DIR; + goto fail; + } + + entries = (struct dx_entry *) (((char *)&root->info) + + root->info.info_length); + assert(dx_get_limit(entries) == dx_root_limit(dir, + root->info.info_length)); + dxtrace (printk("Look up %x", hash)); + while (1) + { + count = dx_get_count(entries); + assert (count && count <= dx_get_limit(entries)); + p = entries + 1; + q = entries + count - 1; + while (p <= q) + { + m = p + (q - p)/2; + dxtrace(printk(".")); + if (dx_get_hash(m) > hash) + q = m - 1; + else + p = m + 1; + } + + if (0) // linear search cross check + { + unsigned n = count - 1; + at = entries; + while (n--) + { + dxtrace(printk(",")); + if (dx_get_hash(++at) > hash) + { + at--; + break; + } + } + assert (at == p - 1); + } + + at = p - 1; + dxtrace(printk(" %x->%u\n", at == entries? 0: dx_get_hash(at), dx_get_block(at))); + frame->bh = bh; + frame->entries = entries; + frame->at = at; + if (!indirect--) return frame; + if (!(bh = ext3_bread (NULL,dir, dx_get_block(at), 0, err))) + goto fail2; + at = entries = ((struct dx_node *) bh->b_data)->entries; + assert (dx_get_limit(entries) == dx_node_limit (dir)); + frame++; + } +fail2: + while (frame >= frame_in) { + brelse(frame->bh); + frame--; + } +fail: + return NULL; +} + +static void dx_release (struct dx_frame *frames) +{ + if (frames[0].bh == NULL) + return; + + if (((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels) + brelse(frames[1].bh); + brelse(frames[0].bh); +} + +/* + * This function increments the frame pointer to search the next leaf + * block, and reads in the necessary intervening nodes if the search + * should be necessary. Whether or not the search is necessary is + * controlled by the hash parameter. If the hash value is even, then + * the search is only continued if the next block starts with that + * hash value. This is used if we are searching for a specific file. + * + * If the hash value is HASH_NB_ALWAYS, then always go to the next block. + * + * This function returns 1 if the caller should continue to search, + * or 0 if it should not. If there is an error reading one of the + * index blocks, it will a negative error code. + * + * If start_hash is non-null, it will be filled in with the starting + * hash of the next page. + */ +static int ext3_htree_next_block(struct inode *dir, __u32 hash, + struct dx_frame *frame, + struct dx_frame *frames, + __u32 *start_hash) +{ + struct dx_frame *p; + struct buffer_head *bh; + int err, num_frames = 0; + __u32 bhash; + + p = frame; + /* + * Find the next leaf page by incrementing the frame pointer. + * If we run out of entries in the interior node, loop around and + * increment pointer in the parent node. When we break out of + * this loop, num_frames indicates the number of interior + * nodes need to be read. + */ + while (1) { + if (++(p->at) < p->entries + dx_get_count(p->entries)) + break; + if (p == frames) + return 0; + num_frames++; + p--; + } + + /* + * If the hash is 1, then continue only if the next page has a + * continuation hash of any value. This is used for readdir + * handling. Otherwise, check to see if the hash matches the + * desired contiuation hash. If it doesn't, return since + * there's no point to read in the successive index pages. + */ + bhash = dx_get_hash(p->at); + if (start_hash) + *start_hash = bhash; + if ((hash & 1) == 0) { + if ((bhash & ~1) != hash) + return 0; + } + /* + * If the hash is HASH_NB_ALWAYS, we always go to the next + * block so no check is necessary + */ + while (num_frames--) { + if (!(bh = ext3_bread(NULL, dir, dx_get_block(p->at), + 0, &err))) + return err; /* Failure */ + p++; + brelse (p->bh); + p->bh = bh; + p->at = p->entries = ((struct dx_node *) bh->b_data)->entries; + } + return 1; +} + + +/* + * p is at least 6 bytes before the end of page + */ +static inline struct ext3_dir_entry_2 *ext3_next_entry(struct ext3_dir_entry_2 *p) +{ + return (struct ext3_dir_entry_2 *)((char*)p + le16_to_cpu(p->rec_len)); +} + +/* + * This function fills a red-black tree with information from a + * directory block. It returns the number directory entries loaded + * into the tree. If there is an error it is returned in err. + */ +static int htree_dirblock_to_tree(struct file *dir_file, + struct inode *dir, int block, + struct dx_hash_info *hinfo, + __u32 start_hash, __u32 start_minor_hash) +{ + struct buffer_head *bh; + struct ext3_dir_entry_2 *de, *top; + int err, count = 0; + + dxtrace(printk("In htree dirblock_to_tree: block %d\n", block)); + if (!(bh = ext3_bread (NULL, dir, block, 0, &err))) + return err; + + de = (struct ext3_dir_entry_2 *) bh->b_data; + top = (struct ext3_dir_entry_2 *) ((char *) de + + dir->i_sb->s_blocksize - + EXT3_DIR_REC_LEN(0)); + for (; de < top; de = ext3_next_entry(de)) { + ext3fs_dirhash(de->name, de->name_len, hinfo); + if ((hinfo->hash < start_hash) || + ((hinfo->hash == start_hash) && + (hinfo->minor_hash < start_minor_hash))) + continue; + if (de->inode == 0) + continue; + if ((err = ext3_htree_store_dirent(dir_file, + hinfo->hash, hinfo->minor_hash, de)) != 0) { + brelse(bh); + return err; + } + count++; + } + brelse(bh); + return count; +} + + +/* + * This function fills a red-black tree with information from a + * directory. We start scanning the directory in hash order, starting + * at start_hash and start_minor_hash. + * + * This function returns the number of entries inserted into the tree, + * or a negative error code. + */ +int ext3_htree_fill_tree(struct file *dir_file, __u32 start_hash, + __u32 start_minor_hash, __u32 *next_hash) +{ + struct dx_hash_info hinfo; + struct ext3_dir_entry_2 *de; + struct dx_frame frames[2], *frame; + struct inode *dir; + int block, err; + int count = 0; + int ret; + __u32 hashval; + + dxtrace(printk("In htree_fill_tree, start hash: %x:%x\n", start_hash, + start_minor_hash)); + dir = dir_file->f_dentry->d_inode; + if (!(EXT3_I(dir)->i_flags & EXT3_INDEX_FL)) { + hinfo.hash_version = EXT3_SB(dir->i_sb)->s_def_hash_version; + hinfo.seed = EXT3_SB(dir->i_sb)->s_hash_seed; + count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo, + start_hash, start_minor_hash); + *next_hash = ~0; + return count; + } + hinfo.hash = start_hash; + hinfo.minor_hash = 0; + frame = dx_probe(NULL, dir_file->f_dentry->d_inode, &hinfo, frames, &err); + if (!frame) + return err; + + /* Add '.' and '..' from the htree header */ + if (!start_hash && !start_minor_hash) { + de = (struct ext3_dir_entry_2 *) frames[0].bh->b_data; + if ((err = ext3_htree_store_dirent(dir_file, 0, 0, de)) != 0) + goto errout; + count++; + } + if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) { + de = (struct ext3_dir_entry_2 *) frames[0].bh->b_data; + de = ext3_next_entry(de); + if ((err = ext3_htree_store_dirent(dir_file, 2, 0, de)) != 0) + goto errout; + count++; + } + + while (1) { + block = dx_get_block(frame->at); + ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo, + start_hash, start_minor_hash); + if (ret < 0) { + err = ret; + goto errout; + } + count += ret; + hashval = ~0; + ret = ext3_htree_next_block(dir, HASH_NB_ALWAYS, + frame, frames, &hashval); + *next_hash = hashval; + if (ret < 0) { + err = ret; + goto errout; + } + /* + * Stop if: (a) there are no more entries, or + * (b) we have inserted at least one entry and the + * next hash value is not a continuation + */ + if ((ret == 0) || + (count && ((hashval & 1) == 0))) + break; + } + dx_release(frames); + dxtrace(printk("Fill tree: returned %d entries, next hash: %x\n", + count, *next_hash)); + return count; +errout: + dx_release(frames); + return (err); +} + + +/* + * Directory block splitting, compacting + */ + +static int dx_make_map (struct ext3_dir_entry_2 *de, int size, + struct dx_hash_info *hinfo, struct dx_map_entry *map_tail) +{ + int count = 0; + char *base = (char *) de; + struct dx_hash_info h = *hinfo; + + while ((char *) de < base + size) + { + if (de->name_len && de->inode) { + ext3fs_dirhash(de->name, de->name_len, &h); + map_tail--; + map_tail->hash = h.hash; + map_tail->offs = (u32) ((char *) de - base); + count++; + cond_resched(); + } + /* XXX: do we need to check rec_len == 0 case? -Chris */ + de = (struct ext3_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len)); + } + return count; +} + +static void dx_sort_map (struct dx_map_entry *map, unsigned count) +{ + struct dx_map_entry *p, *q, *top = map + count - 1; + int more; + /* Combsort until bubble sort doesn't suck */ + while (count > 2) + { + count = count*10/13; + if (count - 9 < 2) /* 9, 10 -> 11 */ + count = 11; + for (p = top, q = p - count; q >= map; p--, q--) + if (p->hash < q->hash) + swap(*p, *q); + } + /* Garden variety bubble sort */ + do { + more = 0; + q = top; + while (q-- > map) + { + if (q[1].hash >= q[0].hash) + continue; + swap(*(q+1), *q); + more = 1; + } + } while(more); +} + +static void dx_insert_block(struct dx_frame *frame, u32 hash, u32 block) +{ + struct dx_entry *entries = frame->entries; + struct dx_entry *old = frame->at, *new = old + 1; + int count = dx_get_count(entries); + + assert(count < dx_get_limit(entries)); + assert(old < entries + count); + memmove(new + 1, new, (char *)(entries + count) - (char *)(new)); + dx_set_hash(new, hash); + dx_set_block(new, block); + dx_set_count(entries, count + 1); +} +#endif + + +static void ext3_update_dx_flag(struct inode *inode) +{ + if (!EXT3_HAS_COMPAT_FEATURE(inode->i_sb, + EXT3_FEATURE_COMPAT_DIR_INDEX)) + EXT3_I(inode)->i_flags &= ~EXT3_INDEX_FL; +} + +/* + * NOTE! unlike strncmp, ext3_match returns 1 for success, 0 for failure. + * + * `len <= EXT3_NAME_LEN' is guaranteed by caller. + * `de != NULL' is guaranteed by caller. + */ +static inline int ext3_match (int len, const char * const name, + struct ext3_dir_entry_2 * de) +{ + if (len != de->name_len) + return 0; + if (!de->inode) + return 0; + return !memcmp(name, de->name, len); +} + +/* + * Returns 0 if not found, -1 on failure, and 1 on success + */ +static inline int search_dirblock(struct buffer_head * bh, + struct inode *dir, + struct dentry *dentry, + unsigned long offset, + struct ext3_dir_entry_2 ** res_dir) +{ + struct ext3_dir_entry_2 * de; + char * dlimit; + int de_len; + const char *name = dentry->d_name.name; + int namelen = dentry->d_name.len; + + de = (struct ext3_dir_entry_2 *) bh->b_data; + dlimit = bh->b_data + dir->i_sb->s_blocksize; + while ((char *) de < dlimit) { + /* this code is executed quadratically often */ + /* do minimal checking `by hand' */ + + if ((char *) de + namelen <= dlimit && + ext3_match (namelen, name, de)) { + /* found a match - just to be sure, do a full check */ + if (!ext3_check_dir_entry("ext3_find_entry", + dir, de, bh, offset)) + return -1; + *res_dir = de; + return 1; + } + /* prevent looping on a bad block */ + de_len = le16_to_cpu(de->rec_len); + if (de_len <= 0) + return -1; + offset += de_len; + de = (struct ext3_dir_entry_2 *) ((char *) de + de_len); + } + return 0; +} + + +/* + * ext3_find_entry() + * + * finds an entry in the specified directory with the wanted name. It + * returns the cache buffer in which the entry was found, and the entry + * itself (as a parameter - res_dir). It does NOT read the inode of the + * entry - you'll have to do that yourself if you want to. + * + * The returned buffer_head has ->b_count elevated. The caller is expected + * to brelse() it when appropriate. + */ +static struct buffer_head * ext3_find_entry (struct dentry *dentry, + struct ext3_dir_entry_2 ** res_dir) +{ + struct super_block * sb; + struct buffer_head * bh_use[NAMEI_RA_SIZE]; + struct buffer_head * bh, *ret = NULL; + unsigned long start, block, b; + int ra_max = 0; /* Number of bh's in the readahead + buffer, bh_use[] */ + int ra_ptr = 0; /* Current index into readahead + buffer */ + int num = 0; + int nblocks, i, err; + struct inode *dir = dentry->d_parent->d_inode; + int namelen; + const u8 *name; + unsigned blocksize; + + *res_dir = NULL; + sb = dir->i_sb; + blocksize = sb->s_blocksize; + namelen = dentry->d_name.len; + name = dentry->d_name.name; + if (namelen > EXT3_NAME_LEN) + return NULL; +#ifdef CONFIG_EXT3_INDEX + if (is_dx(dir)) { + bh = ext3_dx_find_entry(dentry, res_dir, &err); + /* + * On success, or if the error was file not found, + * return. Otherwise, fall back to doing a search the + * old fashioned way. + */ + if (bh || (err != ERR_BAD_DX_DIR)) + return bh; + dxtrace(printk("ext3_find_entry: dx failed, falling back\n")); + } +#endif + nblocks = dir->i_size >> EXT3_BLOCK_SIZE_BITS(sb); + start = EXT3_I(dir)->i_dir_start_lookup; + if (start >= nblocks) + start = 0; + block = start; +restart: + do { + /* + * We deal with the read-ahead logic here. + */ + if (ra_ptr >= ra_max) { + /* Refill the readahead buffer */ + ra_ptr = 0; + b = block; + for (ra_max = 0; ra_max < NAMEI_RA_SIZE; ra_max++) { + /* + * Terminate if we reach the end of the + * directory and must wrap, or if our + * search has finished at this block. + */ + if (b >= nblocks || (num && block == start)) { + bh_use[ra_max] = NULL; + break; + } + num++; + bh = ext3_getblk(NULL, dir, b++, 0, &err); + bh_use[ra_max] = bh; + if (bh) + ll_rw_block(READ, 1, &bh); + } + } + if ((bh = bh_use[ra_ptr++]) == NULL) + goto next; + wait_on_buffer(bh); + if (!buffer_uptodate(bh)) { + /* read error, skip block & hope for the best */ + ext3_error(sb, __FUNCTION__, "reading directory #%lu " + "offset %lu", dir->i_ino, block); + brelse(bh); + goto next; + } + i = search_dirblock(bh, dir, dentry, + block << EXT3_BLOCK_SIZE_BITS(sb), res_dir); + if (i == 1) { + EXT3_I(dir)->i_dir_start_lookup = block; + ret = bh; + goto cleanup_and_exit; + } else { + brelse(bh); + if (i < 0) + goto cleanup_and_exit; + } + next: + if (++block >= nblocks) + block = 0; + } while (block != start); + + /* + * If the directory has grown while we were searching, then + * search the last part of the directory before giving up. + */ + block = nblocks; + nblocks = dir->i_size >> EXT3_BLOCK_SIZE_BITS(sb); + if (block < nblocks) { + start = 0; + goto restart; + } + +cleanup_and_exit: + /* Clean up the read-ahead blocks */ + for (; ra_ptr < ra_max; ra_ptr++) + brelse (bh_use[ra_ptr]); + return ret; +} + +#ifdef CONFIG_EXT3_INDEX +static struct buffer_head * ext3_dx_find_entry(struct dentry *dentry, + struct ext3_dir_entry_2 **res_dir, int *err) +{ + struct super_block * sb; + struct dx_hash_info hinfo; + u32 hash; + struct dx_frame frames[2], *frame; + struct ext3_dir_entry_2 *de, *top; + struct buffer_head *bh; + unsigned long block; + int retval; + int namelen = dentry->d_name.len; + const u8 *name = dentry->d_name.name; + struct inode *dir = dentry->d_parent->d_inode; + + sb = dir->i_sb; + if (!(frame = dx_probe(dentry, NULL, &hinfo, frames, err))) + return NULL; + hash = hinfo.hash; + do { + block = dx_get_block(frame->at); + if (!(bh = ext3_bread (NULL,dir, block, 0, err))) + goto errout; + de = (struct ext3_dir_entry_2 *) bh->b_data; + top = (struct ext3_dir_entry_2 *) ((char *) de + sb->s_blocksize - + EXT3_DIR_REC_LEN(0)); + for (; de < top; de = ext3_next_entry(de)) + if (ext3_match (namelen, name, de)) { + if (!ext3_check_dir_entry("ext3_find_entry", + dir, de, bh, + (block<<EXT3_BLOCK_SIZE_BITS(sb)) + +((char *)de - bh->b_data))) { + brelse (bh); + goto errout; + } + *res_dir = de; + dx_release (frames); + return bh; + } + brelse (bh); + /* Check to see if we should continue to search */ + retval = ext3_htree_next_block(dir, hash, frame, + frames, NULL); + if (retval < 0) { + ext3_warning(sb, __FUNCTION__, + "error reading index page in directory #%lu", + dir->i_ino); + *err = retval; + goto errout; + } + } while (retval == 1); + + *err = -ENOENT; +errout: + dxtrace(printk("%s not found\n", name)); + dx_release (frames); + return NULL; +} +#endif + +static struct dentry *ext3_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd) +{ + struct inode * inode; + struct ext3_dir_entry_2 * de; + struct buffer_head * bh; + + if (dentry->d_name.len > EXT3_NAME_LEN) + return ERR_PTR(-ENAMETOOLONG); + + bh = ext3_find_entry(dentry, &de); + inode = NULL; + if (bh) { + unsigned long ino = le32_to_cpu(de->inode); + brelse (bh); + inode = iget(dir->i_sb, ino); + + if (!inode) + return ERR_PTR(-EACCES); + } + if (inode) + return d_splice_alias(inode, dentry); + d_add(dentry, inode); + return NULL; +} + + +struct dentry *ext3_get_parent(struct dentry *child) +{ + unsigned long ino; + struct dentry *parent; + struct inode *inode; + struct dentry dotdot; + struct ext3_dir_entry_2 * de; + struct buffer_head *bh; + + dotdot.d_name.name = ".."; + dotdot.d_name.len = 2; + dotdot.d_parent = child; /* confusing, isn't it! */ + + bh = ext3_find_entry(&dotdot, &de); + inode = NULL; + if (!bh) + return ERR_PTR(-ENOENT); + ino = le32_to_cpu(de->inode); + brelse(bh); + inode = iget(child->d_inode->i_sb, ino); + + if (!inode) + return ERR_PTR(-EACCES); + + parent = d_alloc_anon(inode); + if (!parent) { + iput(inode); + parent = ERR_PTR(-ENOMEM); + } + return parent; +} + +#define S_SHIFT 12 +static unsigned char ext3_type_by_mode[S_IFMT >> S_SHIFT] = { + [S_IFREG >> S_SHIFT] = EXT3_FT_REG_FILE, + [S_IFDIR >> S_SHIFT] = EXT3_FT_DIR, + [S_IFCHR >> S_SHIFT] = EXT3_FT_CHRDEV, + [S_IFBLK >> S_SHIFT] = EXT3_FT_BLKDEV, + [S_IFIFO >> S_SHIFT] = EXT3_FT_FIFO, + [S_IFSOCK >> S_SHIFT] = EXT3_FT_SOCK, + [S_IFLNK >> S_SHIFT] = EXT3_FT_SYMLINK, +}; + +static inline void ext3_set_de_type(struct super_block *sb, + struct ext3_dir_entry_2 *de, + umode_t mode) { + if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_FILETYPE)) + de->file_type = ext3_type_by_mode[(mode & S_IFMT)>>S_SHIFT]; +} + +#ifdef CONFIG_EXT3_INDEX +static struct ext3_dir_entry_2 * +dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count) +{ + unsigned rec_len = 0; + + while (count--) { + struct ext3_dir_entry_2 *de = (struct ext3_dir_entry_2 *) (from + map->offs); + rec_len = EXT3_DIR_REC_LEN(de->name_len); + memcpy (to, de, rec_len); + ((struct ext3_dir_entry_2 *) to)->rec_len = + cpu_to_le16(rec_len); + de->inode = 0; + map++; + to += rec_len; + } + return (struct ext3_dir_entry_2 *) (to - rec_len); +} + +static struct ext3_dir_entry_2* dx_pack_dirents(char *base, int size) +{ + struct ext3_dir_entry_2 *next, *to, *prev, *de = (struct ext3_dir_entry_2 *) base; + unsigned rec_len = 0; + + prev = to = de; + while ((char*)de < base + size) { + next = (struct ext3_dir_entry_2 *) ((char *) de + + le16_to_cpu(de->rec_len)); + if (de->inode && de->name_len) { + rec_len = EXT3_DIR_REC_LEN(de->name_len); + if (de > to) + memmove(to, de, rec_len); + to->rec_len = cpu_to_le16(rec_len); + prev = to; + to = (struct ext3_dir_entry_2 *) (((char *) to) + rec_len); + } + de = next; + } + return prev; +} + +static struct ext3_dir_entry_2 *do_split(handle_t *handle, struct inode *dir, + struct buffer_head **bh,struct dx_frame *frame, + struct dx_hash_info *hinfo, int *error) +{ + unsigned blocksize = dir->i_sb->s_blocksize; + unsigned count, continued; + struct buffer_head *bh2; + u32 newblock; + u32 hash2; + struct dx_map_entry *map; + char *data1 = (*bh)->b_data, *data2; + unsigned split; + struct ext3_dir_entry_2 *de = NULL, *de2; + int err; + + bh2 = ext3_append (handle, dir, &newblock, error); + if (!(bh2)) { + brelse(*bh); + *bh = NULL; + goto errout; + } + + BUFFER_TRACE(*bh, "get_write_access"); + err = ext3_journal_get_write_access(handle, *bh); + if (err) { + journal_error: + brelse(*bh); + brelse(bh2); + *bh = NULL; + ext3_std_error(dir->i_sb, err); + goto errout; + } + BUFFER_TRACE(frame->bh, "get_write_access"); + err = ext3_journal_get_write_access(handle, frame->bh); + if (err) + goto journal_error; + + data2 = bh2->b_data; + + /* create map in the end of data2 block */ + map = (struct dx_map_entry *) (data2 + blocksize); + count = dx_make_map ((struct ext3_dir_entry_2 *) data1, + blocksize, hinfo, map); + map -= count; + split = count/2; // need to adjust to actual middle + dx_sort_map (map, count); + hash2 = map[split].hash; + continued = hash2 == map[split - 1].hash; + dxtrace(printk("Split block %i at %x, %i/%i\n", + dx_get_block(frame->at), hash2, split, count-split)); + + /* Fancy dance to stay within two buffers */ + de2 = dx_move_dirents(data1, data2, map + split, count - split); + de = dx_pack_dirents(data1,blocksize); + de->rec_len = cpu_to_le16(data1 + blocksize - (char *) de); + de2->rec_len = cpu_to_le16(data2 + blocksize - (char *) de2); + dxtrace(dx_show_leaf (hinfo, (struct ext3_dir_entry_2 *) data1, blocksize, 1)); + dxtrace(dx_show_leaf (hinfo, (struct ext3_dir_entry_2 *) data2, blocksize, 1)); + + /* Which block gets the new entry? */ + if (hinfo->hash >= hash2) + { + swap(*bh, bh2); + de = de2; + } + dx_insert_block (frame, hash2 + continued, newblock); + err = ext3_journal_dirty_metadata (handle, bh2); + if (err) + goto journal_error; + err = ext3_journal_dirty_metadata (handle, frame->bh); + if (err) + goto journal_error; + brelse (bh2); + dxtrace(dx_show_index ("frame", frame->entries)); +errout: + return de; +} +#endif + + +/* + * Add a new entry into a directory (leaf) block. If de is non-NULL, + * it points to a directory entry which is guaranteed to be large + * enough for new directory entry. If de is NULL, then + * add_dirent_to_buf will attempt search the directory block for + * space. It will return -ENOSPC if no space is available, and -EIO + * and -EEXIST if directory entry already exists. + * + * NOTE! bh is NOT released in the cas |