fs/sysv/super.c: add support for non-PDP11 v7 filesystems
This adds byte order autodetection (of PDP-11 and LE filesystems). No attempt is made to detect big-endian filesystems -- were there any? Tested with PDP-11 v7 filesystems and PC-IX maintenance floppy. [akpm@linux-foundation.org: coding-style fixes] [AV: parser.h inclusion was a rudiment of discarded stuff] Signed-off-by: Lubomir Rintel <lkundrak@v3.sk> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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1 changed files with 50 additions and 24 deletions
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@ -434,12 +434,46 @@ Ebadsize:
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goto failed;
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}
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static int v7_sanity_check(struct super_block *sb, struct buffer_head *bh)
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{
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struct v7_super_block *v7sb;
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struct sysv_inode *v7i;
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struct buffer_head *bh2;
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struct sysv_sb_info *sbi;
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sbi = sb->s_fs_info;
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/* plausibility check on superblock */
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v7sb = (struct v7_super_block *) bh->b_data;
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if (fs16_to_cpu(sbi, v7sb->s_nfree) > V7_NICFREE ||
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fs16_to_cpu(sbi, v7sb->s_ninode) > V7_NICINOD ||
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fs32_to_cpu(sbi, v7sb->s_fsize) > V7_MAXSIZE)
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return 0;
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/* plausibility check on root inode: it is a directory,
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with a nonzero size that is a multiple of 16 */
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bh2 = sb_bread(sb, 2);
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if (bh2 == NULL)
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return 0;
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v7i = (struct sysv_inode *)(bh2->b_data + 64);
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if ((fs16_to_cpu(sbi, v7i->i_mode) & ~0777) != S_IFDIR ||
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(fs32_to_cpu(sbi, v7i->i_size) == 0) ||
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(fs32_to_cpu(sbi, v7i->i_size) & 017) ||
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(fs32_to_cpu(sbi, v7i->i_size) > V7_NFILES *
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sizeof(struct sysv_dir_entry))) {
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brelse(bh2);
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return 0;
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}
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brelse(bh2);
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return 1;
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}
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static int v7_fill_super(struct super_block *sb, void *data, int silent)
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{
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struct sysv_sb_info *sbi;
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struct buffer_head *bh, *bh2 = NULL;
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struct v7_super_block *v7sb;
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struct sysv_inode *v7i;
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struct buffer_head *bh;
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if (440 != sizeof (struct v7_super_block))
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panic("V7 FS: bad super-block size");
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@ -453,7 +487,6 @@ static int v7_fill_super(struct super_block *sb, void *data, int silent)
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sbi->s_sb = sb;
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sbi->s_block_base = 0;
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sbi->s_type = FSTYPE_V7;
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sbi->s_bytesex = BYTESEX_PDP;
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sb->s_fs_info = sbi;
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sb_set_blocksize(sb, 512);
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@ -465,34 +498,27 @@ static int v7_fill_super(struct super_block *sb, void *data, int silent)
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goto failed;
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}
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/* plausibility check on superblock */
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v7sb = (struct v7_super_block *) bh->b_data;
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if (fs16_to_cpu(sbi, v7sb->s_nfree) > V7_NICFREE ||
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fs16_to_cpu(sbi, v7sb->s_ninode) > V7_NICINOD ||
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fs32_to_cpu(sbi, v7sb->s_fsize) > V7_MAXSIZE)
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goto failed;
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/* Try PDP-11 UNIX */
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sbi->s_bytesex = BYTESEX_PDP;
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if (v7_sanity_check(sb, bh))
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goto detected;
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/* plausibility check on root inode: it is a directory,
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with a nonzero size that is a multiple of 16 */
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if ((bh2 = sb_bread(sb, 2)) == NULL)
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goto failed;
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v7i = (struct sysv_inode *)(bh2->b_data + 64);
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if ((fs16_to_cpu(sbi, v7i->i_mode) & ~0777) != S_IFDIR ||
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(fs32_to_cpu(sbi, v7i->i_size) == 0) ||
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(fs32_to_cpu(sbi, v7i->i_size) & 017) ||
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(fs32_to_cpu(sbi, v7i->i_size) > V7_NFILES *
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sizeof (struct sysv_dir_entry)))
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goto failed;
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brelse(bh2);
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bh2 = NULL;
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/* Try PC/IX, v7/x86 */
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sbi->s_bytesex = BYTESEX_LE;
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if (v7_sanity_check(sb, bh))
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goto detected;
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goto failed;
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detected:
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sbi->s_bh1 = bh;
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sbi->s_bh2 = bh;
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if (complete_read_super(sb, silent, 1))
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return 0;
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failed:
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brelse(bh2);
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printk(KERN_ERR "VFS: could not find a valid V7 on %s.\n",
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sb->s_id);
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brelse(bh);
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kfree(sbi);
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return -EINVAL;
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