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authorLubomir Rintel <lkundrak@v3.sk>2010-08-10 18:03:34 -0700
committerAl Viro <viro@zeniv.linux.org.uk>2010-08-11 00:24:18 -0400
commit6d0b5456e14ec19edae7c18de4d355c58b133bd6 (patch)
tree8bcb32b9122bd282844a6650e8e4059d8311ab41
parent496ee9b8f349a8ae2065114c414a47e89bdeb930 (diff)
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>
-rw-r--r--fs/sysv/super.c74
1 files changed, 50 insertions, 24 deletions
diff --git a/fs/sysv/super.c b/fs/sysv/super.c
index 5c0aab0b7e18..a0b0cda6927e 100644
--- a/fs/sysv/super.c
+++ b/fs/sysv/super.c
@@ -434,12 +434,46 @@ Ebadsize:
goto failed;
}
-static int v7_fill_super(struct super_block *sb, void *data, int silent)
+static int v7_sanity_check(struct super_block *sb, struct buffer_head *bh)
{
- struct sysv_sb_info *sbi;
- struct buffer_head *bh, *bh2 = NULL;
struct v7_super_block *v7sb;
struct sysv_inode *v7i;
+ struct buffer_head *bh2;
+ struct sysv_sb_info *sbi;
+
+ sbi = sb->s_fs_info;
+
+ /* plausibility check on superblock */
+ v7sb = (struct v7_super_block *) bh->b_data;
+ if (fs16_to_cpu(sbi, v7sb->s_nfree) > V7_NICFREE ||
+ fs16_to_cpu(sbi, v7sb->s_ninode) > V7_NICINOD ||
+ fs32_to_cpu(sbi, v7sb->s_fsize) > V7_MAXSIZE)
+ return 0;
+
+ /* plausibility check on root inode: it is a directory,
+ with a nonzero size that is a multiple of 16 */
+ bh2 = sb_bread(sb, 2);
+ if (bh2 == NULL)
+ return 0;
+
+ v7i = (struct sysv_inode *)(bh2->b_data + 64);
+ if ((fs16_to_cpu(sbi, v7i->i_mode) & ~0777) != S_IFDIR ||
+ (fs32_to_cpu(sbi, v7i->i_size) == 0) ||
+ (fs32_to_cpu(sbi, v7i->i_size) & 017) ||
+ (fs32_to_cpu(sbi, v7i->i_size) > V7_NFILES *
+ sizeof(struct sysv_dir_entry))) {
+ brelse(bh2);
+ return 0;
+ }
+
+ brelse(bh2);
+ return 1;
+}
+
+static int v7_fill_super(struct super_block *sb, void *data, int silent)
+{
+ struct sysv_sb_info *sbi;
+ struct buffer_head *bh;
if (440 != sizeof (struct v7_super_block))
panic("V7 FS: bad super-block size");
@@ -453,7 +487,6 @@ static int v7_fill_super(struct super_block *sb, void *data, int silent)
sbi->s_sb = sb;
sbi->s_block_base = 0;
sbi->s_type = FSTYPE_V7;
- sbi->s_bytesex = BYTESEX_PDP;
sb->s_fs_info = sbi;
sb_set_blocksize(sb, 512);
@@ -465,34 +498,27 @@ static int v7_fill_super(struct super_block *sb, void *data, int silent)
goto failed;
}
- /* plausibility check on superblock */
- v7sb = (struct v7_super_block *) bh->b_data;
- if (fs16_to_cpu(sbi, v7sb->s_nfree) > V7_NICFREE ||
- fs16_to_cpu(sbi, v7sb->s_ninode) > V7_NICINOD ||
- fs32_to_cpu(sbi, v7sb->s_fsize) > V7_MAXSIZE)
- goto failed;
+ /* Try PDP-11 UNIX */
+ sbi->s_bytesex = BYTESEX_PDP;
+ if (v7_sanity_check(sb, bh))
+ goto detected;
- /* plausibility check on root inode: it is a directory,
- with a nonzero size that is a multiple of 16 */
- if ((bh2 = sb_bread(sb, 2)) == NULL)
- goto failed;
- v7i = (struct sysv_inode *)(bh2->b_data + 64);
- if ((fs16_to_cpu(sbi, v7i->i_mode) & ~0777) != S_IFDIR ||
- (fs32_to_cpu(sbi, v7i->i_size) == 0) ||
- (fs32_to_cpu(sbi, v7i->i_size) & 017) ||
- (fs32_to_cpu(sbi, v7i->i_size) > V7_NFILES *
- sizeof (struct sysv_dir_entry)))
- goto failed;
- brelse(bh2);
- bh2 = NULL;
+ /* Try PC/IX, v7/x86 */
+ sbi->s_bytesex = BYTESEX_LE;
+ if (v7_sanity_check(sb, bh))
+ goto detected;
+ goto failed;
+
+detected:
sbi->s_bh1 = bh;
sbi->s_bh2 = bh;
if (complete_read_super(sb, silent, 1))
return 0;
failed:
- brelse(bh2);
+ printk(KERN_ERR "VFS: could not find a valid V7 on %s.\n",
+ sb->s_id);
brelse(bh);
kfree(sbi);
return -EINVAL;