--- /dev/null
+/*
+ * 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 = sb->s_bdev->bd_inode->i_size >> 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 = (__be32 *)__get_free_pages(GFP_KERNEL, PAGE_SIZE < 8192 ? 1 : 0);
+ 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 |= MS_RDONLY;
+ }
+ if ((attrib & cpu_to_be16(HFS_SB_ATTRIB_SLOCK))) {
+ pr_warn("filesystem is marked locked, mounting read-only.\n");
+ sb->s_flags |= MS_RDONLY;
+ }
+ if (!(sb->s_flags & MS_RDONLY)) {
+ /* 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->s_flags & MS_RDONLY)
+ 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->s_flags & MS_RDONLY)
+ 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);
+
+ free_pages((unsigned long)HFS_SB(sb)->bitmap, PAGE_SIZE < 8192 ? 1 : 0);
+ kfree(HFS_SB(sb));
+ sb->s_fs_info = NULL;
+}
Code Review / kvmfornfv.git / blobdiff