diff options
Diffstat (limited to 'fs/hfs/mdb.c')
| -rw-r--r-- | fs/hfs/mdb.c | 372 |
1 files changed, 372 insertions, 0 deletions
diff --git a/fs/hfs/mdb.c b/fs/hfs/mdb.c new file mode 100644 index 000000000..cdf0edeeb --- /dev/null +++ b/fs/hfs/mdb.c @@ -0,0 +1,372 @@ +/* + * 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_device_info *cdi = disk_to_cdi(sb->s_bdev->bd_disk); + + /* default values */ + *start = 0; + *size = i_size_read(sb->s_bdev->bd_inode) >> 9; + + if (HFS_SB(sb)->session >= 0) { + struct cdrom_tocentry te; + + if (!cdi) + return -EINVAL; + + te.cdte_track = HFS_SB(sb)->session; + te.cdte_format = CDROM_LBA; + if (cdrom_read_tocentry(cdi, &te) || + (te.cdte_ctrl & CDROM_DATA_TRACK) != 4) { + pr_err("invalid session number or type of track\n"); + return -EINVAL; + } + + *start = (sector_t)te.cdte_addr.lba << 2; + } else if (cdi) { + struct cdrom_multisession ms_info; + + ms_info.addr_format = CDROM_LBA; + if (cdrom_multisession(cdi, &ms_info) == 0 && 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; +} |