/* * linux/fs/hfs/mdb.c * * Copyright (C) 1995-1997 Paul H. Hargrove * (C) 2003 Ardis Technologies <roman@ardistech.com> * This file may be distributed under the terms of the GNU General Public License. * * This file contains functions for reading/writing the MDB. */ #include <linux/cdrom.h> #include <linux/genhd.h> #include <linux/nls.h> #include <linux/slab.h> #include "hfs_fs.h" #include "btree.h" /*================ File-local data types ================*/ /* * The HFS Master Directory Block (MDB). * * Also known as the Volume Information Block (VIB), this structure is * the HFS equivalent of a superblock. * * Reference: _Inside Macintosh: Files_ pages 2-59 through 2-62 * * modified for HFS Extended */ static int hfs_get_last_session(struct super_block *sb, sector_t *start, sector_t *size) { struct cdrom_multisession ms_info; struct cdrom_tocentry te; int res; /* default values */ *start = 0; *size = i_size_read(sb->s_bdev->bd_inode) >> 9; if (HFS_SB(sb)->session >= 0) { te.cdte_track = HFS_SB(sb)->session; te.cdte_format = CDROM_LBA; res = ioctl_by_bdev(sb->s_bdev, CDROMREADTOCENTRY, (unsigned long)&te); if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) { *start = (sector_t)te.cdte_addr.lba << 2; return 0; } pr_err("invalid session number or type of track\n"); return -EINVAL; } ms_info.addr_format = CDROM_LBA; res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION, (unsigned long)&ms_info); if (!res && ms_info.xa_flag) *start = (sector_t)ms_info.addr.lba << 2; return 0; } /* * hfs_mdb_get() * * Build the in-core MDB for a filesystem, including * the B-trees and the volume bitmap. */ int hfs_mdb_get(struct super_block *sb) { struct buffer_head *bh; struct hfs_mdb *mdb, *mdb2; unsigned int block; char *ptr; int off2, len, size, sect; sector_t part_start, part_size; loff_t off; __be16 attrib; /* set the device driver to 512-byte blocks */ size = sb_min_blocksize(sb, HFS_SECTOR_SIZE); if (!size) return -EINVAL; if (hfs_get_last_session(sb, &part_start, &part_size)) return -EINVAL; while (1) { /* See if this is an HFS filesystem */ bh = sb_bread512(sb, part_start + HFS_MDB_BLK, mdb); if (!bh) goto out; if (mdb->drSigWord == cpu_to_be16(HFS_SUPER_MAGIC)) break; brelse(bh); /* check for a partition block * (should do this only for cdrom/loop though) */ if (hfs_part_find(sb, &part_start, &part_size)) goto out; } HFS_SB(sb)->alloc_blksz = size = be32_to_cpu(mdb->drAlBlkSiz); if (!size || (size & (HFS_SECTOR_SIZE - 1))) { pr_err("bad allocation block size %d\n", size); goto out_bh; } size = min(HFS_SB(sb)->alloc_blksz, (u32)PAGE_SIZE); /* size must be a multiple of 512 */ while (size & (size - 1)) size -= HFS_SECTOR_SIZE; sect = be16_to_cpu(mdb->drAlBlSt) + part_start; /* align block size to first sector */ while (sect & ((size - 1) >> HFS_SECTOR_SIZE_BITS)) size >>= 1; /* align block size to weird alloc size */ while (HFS_SB(sb)->alloc_blksz & (size - 1)) size >>= 1; brelse(bh); if (!sb_set_blocksize(sb, size)) { pr_err("unable to set blocksize to %u\n", size); goto out; } bh = sb_bread512(sb, part_start + HFS_MDB_BLK, mdb); if (!bh) goto out; if (mdb->drSigWord != cpu_to_be16(HFS_SUPER_MAGIC)) goto out_bh; HFS_SB(sb)->mdb_bh = bh; HFS_SB(sb)->mdb = mdb; /* These parameters are read from the MDB, and never written */ HFS_SB(sb)->part_start = part_start; HFS_SB(sb)->fs_ablocks = be16_to_cpu(mdb->drNmAlBlks); HFS_SB(sb)->fs_div = HFS_SB(sb)->alloc_blksz >> sb->s_blocksize_bits; HFS_SB(sb)->clumpablks = be32_to_cpu(mdb->drClpSiz) / HFS_SB(sb)->alloc_blksz; if (!HFS_SB(sb)->clumpablks) HFS_SB(sb)->clumpablks = 1; HFS_SB(sb)->fs_start = (be16_to_cpu(mdb->drAlBlSt) + part_start) >> (sb->s_blocksize_bits - HFS_SECTOR_SIZE_BITS); /* These parameters are read from and written to the MDB */ HFS_SB(sb)->free_ablocks = be16_to_cpu(mdb->drFreeBks); HFS_SB(sb)->next_id = be32_to_cpu(mdb->drNxtCNID); HFS_SB(sb)->root_files = be16_to_cpu(mdb->drNmFls); HFS_SB(sb)->root_dirs = be16_to_cpu(mdb->drNmRtDirs); HFS_SB(sb)->file_count = be32_to_cpu(mdb->drFilCnt); HFS_SB(sb)->folder_count = be32_to_cpu(mdb->drDirCnt); /* TRY to get the alternate (backup) MDB. */ sect = part_start + part_size - 2; bh = sb_bread512(sb, sect, mdb2); if (bh) { if (mdb2->drSigWord == cpu_to_be16(HFS_SUPER_MAGIC)) { HFS_SB(sb)->alt_mdb_bh = bh; HFS_SB(sb)->alt_mdb = mdb2; } else brelse(bh); } if (!HFS_SB(sb)->alt_mdb) { pr_warn("unable to locate alternate MDB\n"); pr_warn("continuing without an alternate MDB\n"); } HFS_SB(sb)->bitmap = kmalloc(8192, GFP_KERNEL); if (!HFS_SB(sb)->bitmap) goto out; /* read in the bitmap */ block = be16_to_cpu(mdb->drVBMSt) + part_start; off = (loff_t)block << HFS_SECTOR_SIZE_BITS; size = (HFS_SB(sb)->fs_ablocks + 8) / 8; ptr = (u8 *)HFS_SB(sb)->bitmap; while (size) { bh = sb_bread(sb, off >> sb->s_blocksize_bits); if (!bh) { pr_err("unable to read volume bitmap\n"); goto out; } off2 = off & (sb->s_blocksize - 1); len = min((int)sb->s_blocksize - off2, size); memcpy(ptr, bh->b_data + off2, len); brelse(bh); ptr += len; off += len; size -= len; } HFS_SB(sb)->ext_tree = hfs_btree_open(sb, HFS_EXT_CNID, hfs_ext_keycmp); if (!HFS_SB(sb)->ext_tree) { pr_err("unable to open extent tree\n"); goto out; } HFS_SB(sb)->cat_tree = hfs_btree_open(sb, HFS_CAT_CNID, hfs_cat_keycmp); if (!HFS_SB(sb)->cat_tree) { pr_err("unable to open catalog tree\n"); goto out; } attrib = mdb->drAtrb; if (!(attrib & cpu_to_be16(HFS_SB_ATTRIB_UNMNT))) { pr_warn("filesystem was not cleanly unmounted, running fsck.hfs is recommended. mounting read-only.\n"); sb->s_flags |= SB_RDONLY; } if ((attrib & cpu_to_be16(HFS_SB_ATTRIB_SLOCK))) { pr_warn("filesystem is marked locked, mounting read-only.\n"); sb->s_flags |= SB_RDONLY; } if (!sb_rdonly(sb)) { /* Mark the volume uncleanly unmounted in case we crash */ attrib &= cpu_to_be16(~HFS_SB_ATTRIB_UNMNT); attrib |= cpu_to_be16(HFS_SB_ATTRIB_INCNSTNT); mdb->drAtrb = attrib; be32_add_cpu(&mdb->drWrCnt, 1); mdb->drLsMod = hfs_mtime(); mark_buffer_dirty(HFS_SB(sb)->mdb_bh); sync_dirty_buffer(HFS_SB(sb)->mdb_bh); } return 0; out_bh: brelse(bh); out: hfs_mdb_put(sb); return -EIO; } /* * hfs_mdb_commit() * * Description: * This updates the MDB on disk. * It does not check, if the superblock has been modified, or * if the filesystem has been mounted read-only. It is mainly * called by hfs_sync_fs() and flush_mdb(). * Input Variable(s): * struct hfs_mdb *mdb: Pointer to the hfs MDB * int backup; * Output Variable(s): * NONE * Returns: * void * Preconditions: * 'mdb' points to a "valid" (struct hfs_mdb). * Postconditions: * The HFS MDB and on disk will be updated, by copying the possibly * modified fields from the in memory MDB (in native byte order) to * the disk block buffer. * If 'backup' is non-zero then the alternate MDB is also written * and the function doesn't return until it is actually on disk. */ void hfs_mdb_commit(struct super_block *sb) { struct hfs_mdb *mdb = HFS_SB(sb)->mdb; if (sb_rdonly(sb)) return; lock_buffer(HFS_SB(sb)->mdb_bh); if (test_and_clear_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags)) { /* These parameters may have been modified, so write them back */ mdb->drLsMod = hfs_mtime(); mdb->drFreeBks = cpu_to_be16(HFS_SB(sb)->free_ablocks); mdb->drNxtCNID = cpu_to_be32(HFS_SB(sb)->next_id); mdb->drNmFls = cpu_to_be16(HFS_SB(sb)->root_files); mdb->drNmRtDirs = cpu_to_be16(HFS_SB(sb)->root_dirs); mdb->drFilCnt = cpu_to_be32(HFS_SB(sb)->file_count); mdb->drDirCnt = cpu_to_be32(HFS_SB(sb)->folder_count); /* write MDB to disk */ mark_buffer_dirty(HFS_SB(sb)->mdb_bh); } /* write the backup MDB, not returning until it is written. * we only do this when either the catalog or extents overflow * files grow. */ if (test_and_clear_bit(HFS_FLG_ALT_MDB_DIRTY, &HFS_SB(sb)->flags) && HFS_SB(sb)->alt_mdb) { hfs_inode_write_fork(HFS_SB(sb)->ext_tree->inode, mdb->drXTExtRec, &mdb->drXTFlSize, NULL); hfs_inode_write_fork(HFS_SB(sb)->cat_tree->inode, mdb->drCTExtRec, &mdb->drCTFlSize, NULL); lock_buffer(HFS_SB(sb)->alt_mdb_bh); memcpy(HFS_SB(sb)->alt_mdb, HFS_SB(sb)->mdb, HFS_SECTOR_SIZE); HFS_SB(sb)->alt_mdb->drAtrb |= cpu_to_be16(HFS_SB_ATTRIB_UNMNT); HFS_SB(sb)->alt_mdb->drAtrb &= cpu_to_be16(~HFS_SB_ATTRIB_INCNSTNT); unlock_buffer(HFS_SB(sb)->alt_mdb_bh); mark_buffer_dirty(HFS_SB(sb)->alt_mdb_bh); sync_dirty_buffer(HFS_SB(sb)->alt_mdb_bh); } if (test_and_clear_bit(HFS_FLG_BITMAP_DIRTY, &HFS_SB(sb)->flags)) { struct buffer_head *bh; sector_t block; char *ptr; int off, size, len; block = be16_to_cpu(HFS_SB(sb)->mdb->drVBMSt) + HFS_SB(sb)->part_start; off = (block << HFS_SECTOR_SIZE_BITS) & (sb->s_blocksize - 1); block >>= sb->s_blocksize_bits - HFS_SECTOR_SIZE_BITS; size = (HFS_SB(sb)->fs_ablocks + 7) / 8; ptr = (u8 *)HFS_SB(sb)->bitmap; while (size) { bh = sb_bread(sb, block); if (!bh) { pr_err("unable to read volume bitmap\n"); break; } len = min((int)sb->s_blocksize - off, size); lock_buffer(bh); memcpy(bh->b_data + off, ptr, len); unlock_buffer(bh); mark_buffer_dirty(bh); brelse(bh); block++; off = 0; ptr += len; size -= len; } } unlock_buffer(HFS_SB(sb)->mdb_bh); } void hfs_mdb_close(struct super_block *sb) { /* update volume attributes */ if (sb_rdonly(sb)) return; HFS_SB(sb)->mdb->drAtrb |= cpu_to_be16(HFS_SB_ATTRIB_UNMNT); HFS_SB(sb)->mdb->drAtrb &= cpu_to_be16(~HFS_SB_ATTRIB_INCNSTNT); mark_buffer_dirty(HFS_SB(sb)->mdb_bh); } /* * hfs_mdb_put() * * Release the resources associated with the in-core MDB. */ void hfs_mdb_put(struct super_block *sb) { if (!HFS_SB(sb)) return; /* free the B-trees */ hfs_btree_close(HFS_SB(sb)->ext_tree); hfs_btree_close(HFS_SB(sb)->cat_tree); /* free the buffers holding the primary and alternate MDBs */ brelse(HFS_SB(sb)->mdb_bh); brelse(HFS_SB(sb)->alt_mdb_bh); unload_nls(HFS_SB(sb)->nls_io); unload_nls(HFS_SB(sb)->nls_disk); kfree(HFS_SB(sb)->bitmap); kfree(HFS_SB(sb)); sb->s_fs_info = NULL; }