mirror of https://gitee.com/openkylin/linux.git
fs/adfs: super: extract filesystem block probe
Separate the filesystem block probing from the superblock filling so we can support other ADFS filesystem formats, such as the single-zone E and E+ floppy image formats which do not have a boot block. Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Russell King
Al Viro
parent
ccbc80a89d
commit
e3858e125b
149
fs/adfs/super.c
149
fs/adfs/super.c
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@ -277,13 +277,80 @@ static const struct super_operations adfs_sops = {
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.show_options = adfs_show_options,
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};
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static int adfs_probe(struct super_block *sb, unsigned int offset, int silent,
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int (*validate)(struct super_block *sb,
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struct buffer_head *bh,
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struct adfs_discrecord **bhp))
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{
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struct adfs_sb_info *asb = ADFS_SB(sb);
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struct adfs_discrecord *dr;
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struct buffer_head *bh;
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unsigned int blocksize = BLOCK_SIZE;
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int ret, try;
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for (try = 0; try < 2; try++) {
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/* try to set the requested block size */
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if (sb->s_blocksize != blocksize &&
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!sb_set_blocksize(sb, blocksize)) {
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if (!silent)
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adfs_msg(sb, KERN_ERR,
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"error: unsupported blocksize");
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return -EINVAL;
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}
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/* read the buffer */
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bh = sb_bread(sb, offset >> sb->s_blocksize_bits);
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if (!bh) {
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adfs_msg(sb, KERN_ERR,
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"error: unable to read block %u, try %d",
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offset >> sb->s_blocksize_bits, try);
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return -EIO;
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}
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/* validate it */
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ret = validate(sb, bh, &dr);
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if (ret) {
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brelse(bh);
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return ret;
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}
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/* does the block size match the filesystem block size? */
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blocksize = 1 << dr->log2secsize;
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if (sb->s_blocksize == blocksize) {
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asb->s_map = adfs_read_map(sb, dr);
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brelse(bh);
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return PTR_ERR_OR_ZERO(asb->s_map);
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}
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brelse(bh);
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}
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return -EIO;
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}
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static int adfs_validate_bblk(struct super_block *sb, struct buffer_head *bh,
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struct adfs_discrecord **drp)
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{
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struct adfs_discrecord *dr;
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unsigned char *b_data;
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b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
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if (adfs_checkbblk(b_data))
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return -EILSEQ;
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/* Do some sanity checks on the ADFS disc record */
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dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
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if (adfs_checkdiscrecord(dr))
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return -EILSEQ;
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*drp = dr;
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return 0;
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}
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static int adfs_fill_super(struct super_block *sb, void *data, int silent)
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{
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struct adfs_discrecord *dr;
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struct buffer_head *bh;
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struct object_info root_obj;
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unsigned char *b_data;
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unsigned int blocksize;
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struct adfs_sb_info *asb;
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struct inode *root;
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int ret = -EINVAL;
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@ -308,72 +375,19 @@ static int adfs_fill_super(struct super_block *sb, void *data, int silent)
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if (parse_options(sb, asb, data))
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goto error;
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sb_set_blocksize(sb, BLOCK_SIZE);
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if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
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adfs_msg(sb, KERN_ERR, "error: unable to read superblock");
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ret = -EIO;
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goto error;
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}
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b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
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if (adfs_checkbblk(b_data)) {
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ret = -EINVAL;
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goto error_badfs;
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}
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dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
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/*
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* Do some sanity checks on the ADFS disc record
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*/
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if (adfs_checkdiscrecord(dr)) {
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ret = -EINVAL;
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goto error_badfs;
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}
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blocksize = 1 << dr->log2secsize;
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brelse(bh);
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if (sb_set_blocksize(sb, blocksize)) {
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bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
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if (!bh) {
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adfs_msg(sb, KERN_ERR,
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"error: couldn't read superblock on 2nd try.");
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ret = -EIO;
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goto error;
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}
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b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
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if (adfs_checkbblk(b_data)) {
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adfs_msg(sb, KERN_ERR,
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"error: disc record mismatch, very weird!");
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ret = -EINVAL;
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goto error_free_bh;
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}
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dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
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} else {
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/* Try to probe the filesystem boot block */
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ret = adfs_probe(sb, ADFS_DISCRECORD, silent, adfs_validate_bblk);
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if (ret == -EILSEQ) {
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if (!silent)
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adfs_msg(sb, KERN_ERR,
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"error: unsupported blocksize");
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"error: can't find an ADFS filesystem on dev %s.",
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sb->s_id);
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ret = -EINVAL;
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}
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if (ret)
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goto error;
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}
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/*
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* blocksize on this device should now be set to the ADFS log2secsize
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*/
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asb->s_map = adfs_read_map(sb, dr);
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if (IS_ERR(asb->s_map)) {
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ret = PTR_ERR(asb->s_map);
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goto error_free_bh;
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}
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brelse(bh);
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/*
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* set up enough so that we can read an inode
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*/
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/* set up enough so that we can read an inode */
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sb->s_op = &adfs_sops;
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dr = adfs_map_discrecord(asb->s_map);
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@ -417,13 +431,6 @@ static int adfs_fill_super(struct super_block *sb, void *data, int silent)
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}
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return 0;
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error_badfs:
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if (!silent)
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adfs_msg(sb, KERN_ERR,
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"error: can't find an ADFS filesystem on dev %s.",
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sb->s_id);
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error_free_bh:
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brelse(bh);
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error:
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sb->s_fs_info = NULL;
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kfree(asb);
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