--- /dev/null
+/*
+ * linux/fs/hfsplus/wrapper.c
+ *
+ * Copyright (C) 2001
+ * Brad Boyer (flar@allandria.com)
+ * (C) 2003 Ardis Technologies <roman@ardistech.com>
+ *
+ * Handling of HFS wrappers around HFS+ volumes
+ */
+
+#include <linux/fs.h>
+#include <linux/blkdev.h>
+#include <linux/cdrom.h>
+#include <linux/genhd.h>
+#include <asm/unaligned.h>
+
+#include "hfsplus_fs.h"
+#include "hfsplus_raw.h"
+
+struct hfsplus_wd {
+ u32 ablk_size;
+ u16 ablk_start;
+ u16 embed_start;
+ u16 embed_count;
+};
+
+/**
+ * hfsplus_submit_bio - Perform block I/O
+ * @sb: super block of volume for I/O
+ * @sector: block to read or write, for blocks of HFSPLUS_SECTOR_SIZE bytes
+ * @buf: buffer for I/O
+ * @data: output pointer for location of requested data
+ * @rw: direction of I/O
+ *
+ * The unit of I/O is hfsplus_min_io_size(sb), which may be bigger than
+ * HFSPLUS_SECTOR_SIZE, and @buf must be sized accordingly. On reads
+ * @data will return a pointer to the start of the requested sector,
+ * which may not be the same location as @buf.
+ *
+ * If @sector is not aligned to the bdev logical block size it will
+ * be rounded down. For writes this means that @buf should contain data
+ * that starts at the rounded-down address. As long as the data was
+ * read using hfsplus_submit_bio() and the same buffer is used things
+ * will work correctly.
+ */
+int hfsplus_submit_bio(struct super_block *sb, sector_t sector,
+ void *buf, void **data, int rw)
+{
+ struct bio *bio;
+ int ret = 0;
+ u64 io_size;
+ loff_t start;
+ int offset;
+
+ /*
+ * Align sector to hardware sector size and find offset. We
+ * assume that io_size is a power of two, which _should_
+ * be true.
+ */
+ io_size = hfsplus_min_io_size(sb);
+ start = (loff_t)sector << HFSPLUS_SECTOR_SHIFT;
+ offset = start & (io_size - 1);
+ sector &= ~((io_size >> HFSPLUS_SECTOR_SHIFT) - 1);
+
+ bio = bio_alloc(GFP_NOIO, 1);
+ bio->bi_iter.bi_sector = sector;
+ bio->bi_bdev = sb->s_bdev;
+
+ if (!(rw & WRITE) && data)
+ *data = (u8 *)buf + offset;
+
+ while (io_size > 0) {
+ unsigned int page_offset = offset_in_page(buf);
+ unsigned int len = min_t(unsigned int, PAGE_SIZE - page_offset,
+ io_size);
+
+ ret = bio_add_page(bio, virt_to_page(buf), len, page_offset);
+ if (ret != len) {
+ ret = -EIO;
+ goto out;
+ }
+ io_size -= len;
+ buf = (u8 *)buf + len;
+ }
+
+ ret = submit_bio_wait(rw, bio);
+out:
+ bio_put(bio);
+ return ret < 0 ? ret : 0;
+}
+
+static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd)
+{
+ u32 extent;
+ u16 attrib;
+ __be16 sig;
+
+ sig = *(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG);
+ if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) &&
+ sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX))
+ return 0;
+
+ attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB));
+ if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) ||
+ !(attrib & HFSP_WRAP_ATTRIB_SPARED))
+ return 0;
+
+ wd->ablk_size =
+ be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE));
+ if (wd->ablk_size < HFSPLUS_SECTOR_SIZE)
+ return 0;
+ if (wd->ablk_size % HFSPLUS_SECTOR_SIZE)
+ return 0;
+ wd->ablk_start =
+ be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART));
+
+ extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT);
+ wd->embed_start = (extent >> 16) & 0xFFFF;
+ wd->embed_count = extent & 0xFFFF;
+
+ return 1;
+}
+
+static int hfsplus_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 (HFSPLUS_SB(sb)->session >= 0) {
+ te.cdte_track = HFSPLUS_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;
+}
+
+/* Find the volume header and fill in some minimum bits in superblock */
+/* Takes in super block, returns true if good data read */
+int hfsplus_read_wrapper(struct super_block *sb)
+{
+ struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+ struct hfsplus_wd wd;
+ sector_t part_start, part_size;
+ u32 blocksize;
+ int error = 0;
+
+ error = -EINVAL;
+ blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE);
+ if (!blocksize)
+ goto out;
+
+ if (hfsplus_get_last_session(sb, &part_start, &part_size))
+ goto out;
+
+ error = -ENOMEM;
+ sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
+ if (!sbi->s_vhdr_buf)
+ goto out;
+ sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
+ if (!sbi->s_backup_vhdr_buf)
+ goto out_free_vhdr;
+
+reread:
+ error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR,
+ sbi->s_vhdr_buf, (void **)&sbi->s_vhdr,
+ READ);
+ if (error)
+ goto out_free_backup_vhdr;
+
+ error = -EINVAL;
+ switch (sbi->s_vhdr->signature) {
+ case cpu_to_be16(HFSPLUS_VOLHEAD_SIGX):
+ set_bit(HFSPLUS_SB_HFSX, &sbi->flags);
+ /*FALLTHRU*/
+ case cpu_to_be16(HFSPLUS_VOLHEAD_SIG):
+ break;
+ case cpu_to_be16(HFSP_WRAP_MAGIC):
+ if (!hfsplus_read_mdb(sbi->s_vhdr, &wd))
+ goto out_free_backup_vhdr;
+ wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT;
+ part_start += (sector_t)wd.ablk_start +
+ (sector_t)wd.embed_start * wd.ablk_size;
+ part_size = (sector_t)wd.embed_count * wd.ablk_size;
+ goto reread;
+ default:
+ /*
+ * Check for a partition block.
+ *
+ * (should do this only for cdrom/loop though)
+ */
+ if (hfs_part_find(sb, &part_start, &part_size))
+ goto out_free_backup_vhdr;
+ goto reread;
+ }
+
+ error = hfsplus_submit_bio(sb, part_start + part_size - 2,
+ sbi->s_backup_vhdr_buf,
+ (void **)&sbi->s_backup_vhdr, READ);
+ if (error)
+ goto out_free_backup_vhdr;
+
+ error = -EINVAL;
+ if (sbi->s_backup_vhdr->signature != sbi->s_vhdr->signature) {
+ pr_warn("invalid secondary volume header\n");
+ goto out_free_backup_vhdr;
+ }
+
+ blocksize = be32_to_cpu(sbi->s_vhdr->blocksize);
+
+ /*
+ * Block size must be at least as large as a sector and a multiple of 2.
+ */
+ if (blocksize < HFSPLUS_SECTOR_SIZE || ((blocksize - 1) & blocksize))
+ goto out_free_backup_vhdr;
+ sbi->alloc_blksz = blocksize;
+ sbi->alloc_blksz_shift = ilog2(blocksize);
+ blocksize = min_t(u32, sbi->alloc_blksz, PAGE_SIZE);
+
+ /*
+ * Align block size to block offset.
+ */
+ while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1))
+ blocksize >>= 1;
+
+ if (sb_set_blocksize(sb, blocksize) != blocksize) {
+ pr_err("unable to set blocksize to %u!\n", blocksize);
+ goto out_free_backup_vhdr;
+ }
+
+ sbi->blockoffset =
+ part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT);
+ sbi->part_start = part_start;
+ sbi->sect_count = part_size;
+ sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
+ return 0;
+
+out_free_backup_vhdr:
+ kfree(sbi->s_backup_vhdr_buf);
+out_free_vhdr:
+ kfree(sbi->s_vhdr_buf);
+out:
+ return error;
+}
Code Review / kvmfornfv.git / blobdiff