[PATCH/RFC] minix filesystem update to V3 for 2.6 kernels

From: Daniel Aragonés
Date: Wed Jan 25 2006 - 11:55:35 EST

Hi Andrew,

After 2 revisions incorporating the suggestions made from Pekka, here I attach as a text file "v3_2dot6_diff.txt" my patch for minix-fs version 3 support.

I first posted it in comp.os.minix in January 11. I have no received feedback at all. Can we trust the saying "no news, good news"?...

The modifications I have made to the preexistent code have been four:

1.- The layout of the superblock variables is different in version V3. Suggested by Pekka, the structure minix3_super_block has been introduced.

2.- Disable writings to "s_state" because it has been droped out from the superblock, and its former address is now used by another parameter.

3.- Change the references to the constant "BLOCK_SIZE" to the variables "s_blocksize" or "b_size", so allowing for multiple block sizes.

4.- Introduce the new structure "minix3_dir_entry" to employ 60 characters long names in the new directory entries of 64 bytes.

Signed-off-by: Daniel Aragones <danarag@xxxxxxxxx>



diff -ur orig.linux-2.6.15.1/fs/minix/bitmap.c updated.linux-2.6.15.1/fs/minix/bitmap.c
--- orig.linux-2.6.15.1/fs/minix/bitmap.c 2006-01-15 07:16:02.000000000 +0100
+++ updated.linux-2.6.15.1/fs/minix/bitmap.c 2006-01-25 16:41:32.000000000 +0100
@@ -26,14 +26,14 @@
for (i=0; i<numblocks-1; i++) {
if (!(bh=map[i]))
return(0);
- for (j=0; j<BLOCK_SIZE; j++)
+ for (j=0; j<bh->b_size; j++)
sum += nibblemap[bh->b_data[j] & 0xf]
+ nibblemap[(bh->b_data[j]>>4) & 0xf];
}

if (numblocks==0 || !(bh=map[numblocks-1]))
return(0);
- i = ((numbits-(numblocks-1)*BLOCK_SIZE*8)/16)*2;
+ i = ((numbits-(numblocks-1)*bh->b_size*8)/16)*2;
for (j=0; j<i; j++) {
sum += nibblemap[bh->b_data[j] & 0xf]
+ nibblemap[(bh->b_data[j]>>4) & 0xf];
@@ -113,6 +113,7 @@
int block;
struct minix_sb_info *sbi = minix_sb(sb);
struct minix_inode *p;
+ int minix_inodes_per_block = BLOCK_SIZE/sizeof(struct minix_inode);

if (!ino || ino > sbi->s_ninodes) {
printk("Bad inode number on dev %s: %ld is out of range\n",
@@ -121,14 +122,14 @@
}
ino--;
block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +
- ino / MINIX_INODES_PER_BLOCK;
+ ino / minix_inodes_per_block;
*bh = sb_bread(sb, block);
if (!*bh) {
printk("unable to read i-node block\n");
return NULL;
}
p = (void *)(*bh)->b_data;
- return p + ino % MINIX_INODES_PER_BLOCK;
+ return p + ino % minix_inodes_per_block;
}

struct minix2_inode *
@@ -137,6 +138,7 @@
int block;
struct minix_sb_info *sbi = minix_sb(sb);
struct minix2_inode *p;
+ int minix2_inodes_per_block = sb->s_blocksize/sizeof(struct minix2_inode);

*bh = NULL;
if (!ino || ino > sbi->s_ninodes) {
@@ -145,15 +147,15 @@
return NULL;
}
ino--;
- block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +
- ino / MINIX2_INODES_PER_BLOCK;
+ block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +
+ ino / minix2_inodes_per_block;
*bh = sb_bread(sb, block);
if (!*bh) {
printk("unable to read i-node block\n");
return NULL;
}
p = (void *)(*bh)->b_data;
- return p + ino % MINIX2_INODES_PER_BLOCK;
+ return p + ino % minix2_inodes_per_block;
}

/* Clear the link count and mode of a deleted inode on disk. */
diff -ur orig.linux-2.6.15.1/fs/minix/dir.c updated.linux-2.6.15.1/fs/minix/dir.c
--- orig.linux-2.6.15.1/fs/minix/dir.c 2006-01-15 07:16:02.000000000 +0100
+++ updated.linux-2.6.15.1/fs/minix/dir.c 2006-01-25 16:41:32.000000000 +0100
@@ -4,12 +4,15 @@
* Copyright (C) 1991, 1992 Linus Torvalds
*
* minix directory handling functions
+ *
+ * Updated to filesystem version 3 by Daniel Aragones
*/

#include "minix.h"
#include <linux/highmem.h>
#include <linux/smp_lock.h>

+typedef struct minix3_dir_entry minix3_dirent;
typedef struct minix_dir_entry minix_dirent;

static int minix_readdir(struct file *, void *, filldir_t);
@@ -90,6 +93,8 @@
unsigned long npages = dir_pages(inode);
struct minix_sb_info *sbi = minix_sb(sb);
unsigned chunk_size = sbi->s_dirsize;
+ char *namx;
+ __u32 inodx;

lock_kernel();

@@ -107,15 +112,23 @@
p = kaddr+offset;
limit = kaddr + minix_last_byte(inode, n) - chunk_size;
for ( ; p <= limit ; p = minix_next_entry(p, sbi)) {
+ minix3_dirent *de3 = (minix3_dirent *)p;
minix_dirent *de = (minix_dirent *)p;
- if (de->inode) {
+ if (sbi->s_version == MINIX_V3) {
+ namx = de3->name;
+ inodx = de3->inode;
+ } else {
+ namx = de->name;
+ inodx = de->inode;
+ }
+ if (inodx) {
int over;
- unsigned l = strnlen(de->name,sbi->s_namelen);

+ unsigned l = strnlen(namx,sbi->s_namelen);
offset = p - kaddr;
- over = filldir(dirent, de->name, l,
- (n<<PAGE_CACHE_SHIFT) | offset,
- de->inode, DT_UNKNOWN);
+ over = filldir(dirent, namx, l,
+ (n<<PAGE_CACHE_SHIFT) | offset,
+ inodx, DT_UNKNOWN);
if (over) {
dir_put_page(page);
goto done;
@@ -157,9 +170,12 @@
unsigned long n;
unsigned long npages = dir_pages(dir);
struct page *page = NULL;
+ struct minix3_dir_entry *de3;
struct minix_dir_entry *de;

*res_page = NULL;
+ char *namx;
+ __u32 inodx;

for (n = 0; n < npages; n++) {
char *kaddr;
@@ -168,12 +184,22 @@
continue;

kaddr = (char*)page_address(page);
+ de3 = (struct minix3_dir_entry *) kaddr;
de = (struct minix_dir_entry *) kaddr;
kaddr += minix_last_byte(dir, n) - sbi->s_dirsize;
- for ( ; (char *) de <= kaddr ; de = minix_next_entry(de,sbi)) {
- if (!de->inode)
+ for ( ; (char *) de <= kaddr ;
+ de3 = minix_next_entry(de3,sbi),
+ de = minix_next_entry(de,sbi)) {
+ if (sbi->s_version == MINIX_V3) {
+ namx = de3->name;
+ inodx = de3->inode;
+ } else {
+ namx = de->name;
+ inodx = de->inode;
+ }
+ if (!inodx)
continue;
- if (namecompare(namelen,sbi->s_namelen,name,de->name))
+ if (namecompare(namelen,sbi->s_namelen,name,namx))
goto found;
}
dir_put_page(page);
@@ -193,12 +219,15 @@
struct super_block * sb = dir->i_sb;
struct minix_sb_info * sbi = minix_sb(sb);
struct page *page = NULL;
+ struct minix3_dir_entry * de3;
struct minix_dir_entry * de;
unsigned long npages = dir_pages(dir);
unsigned long n;
char *kaddr;
unsigned from, to;
int err;
+ char *namx = NULL;
+ __u32 inodx;

/*
* We take care of directory expansion in the same loop
@@ -215,19 +244,33 @@
lock_page(page);
kaddr = (char*)page_address(page);
dir_end = kaddr + minix_last_byte(dir, n);
+ de3 = (minix3_dirent *)kaddr;
de = (minix_dirent *)kaddr;
kaddr += PAGE_CACHE_SIZE - sbi->s_dirsize;
while ((char *)de <= kaddr) {
+ if (sbi->s_version == MINIX_V3) {
+ namx = de3->name;
+ inodx = de3->inode;
+ } else {
+ namx = de->name;
+ inodx = de->inode;
+ }
if ((char *)de == dir_end) {
/* We hit i_size */
- de->inode = 0;
+ if (sbi->s_version == MINIX_V3) {
+ de3->inode = 0;
+ } else {
+ de->inode = 0;
+ }
goto got_it;
}
- if (!de->inode)
+ if (!inodx)
goto got_it;
err = -EEXIST;
- if (namecompare(namelen,sbi->s_namelen,name,de->name))
+
+ if (namecompare(namelen,sbi->s_namelen,name,namx))
goto out_unlock;
+ de3 = minix_next_entry(de3, sbi);
de = minix_next_entry(de, sbi);
}
unlock_page(page);
@@ -242,9 +285,14 @@
err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
if (err)
goto out_unlock;
- memcpy (de->name, name, namelen);
- memset (de->name + namelen, 0, sbi->s_dirsize - namelen - 2);
- de->inode = inode->i_ino;
+ memcpy (namx, name, namelen);
+ if (sbi->s_version == MINIX_V3) {
+ memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
+ de3->inode = inode->i_ino;
+ } else {
+ memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
+ de->inode = inode->i_ino;
+ }
err = dir_commit_chunk(page, from, to);
dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(dir);
@@ -286,6 +334,7 @@
struct page *page = grab_cache_page(mapping, 0);
struct minix_sb_info * sbi = minix_sb(inode->i_sb);
struct minix_dir_entry * de;
+ struct minix3_dir_entry * de3;
char *kaddr;
int err;

@@ -301,11 +350,21 @@
memset(kaddr, 0, PAGE_CACHE_SIZE);

de = (struct minix_dir_entry *)kaddr;
+ de3 = (struct minix3_dir_entry *)kaddr;
de->inode = inode->i_ino;
- strcpy(de->name,".");
+ de3->inode = inode->i_ino;
+ if (sbi->s_version == MINIX_V3)
+ strcpy(de3->name,".");
+ else
+ strcpy(de->name,".");
de = minix_next_entry(de, sbi);
+ de3 = minix_next_entry(de3, sbi);
de->inode = dir->i_ino;
- strcpy(de->name,"..");
+ de3->inode = dir->i_ino;
+ if (sbi->s_version == MINIX_V3)
+ strcpy(de3->name,"..");
+ else
+ strcpy(de->name,"..");
kunmap_atomic(kaddr, KM_USER0);

err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
@@ -322,9 +381,12 @@
struct page *page = NULL;
unsigned long i, npages = dir_pages(inode);
struct minix_sb_info *sbi = minix_sb(inode->i_sb);
+ char *namx;
+ __u32 inodx;

for (i = 0; i < npages; i++) {
char *kaddr;
+ minix3_dirent * de3 = NULL;
minix_dirent * de;
page = dir_get_page(inode, i);

@@ -332,20 +394,29 @@
continue;

kaddr = (char *)page_address(page);
+ if (sbi->s_version == MINIX_V3)
+ de3 = (minix3_dirent *)kaddr;
de = (minix_dirent *)kaddr;
kaddr += minix_last_byte(inode, i) - sbi->s_dirsize;

+ if (sbi->s_version == MINIX_V3) {
+ namx = de3->name;
+ inodx = de3->inode;
+ } else {
+ namx = de->name;
+ inodx = de->inode;
+ }
while ((char *)de <= kaddr) {
- if (de->inode != 0) {
+ if (inodx != 0) {
/* check for . and .. */
- if (de->name[0] != '.')
+ if (namx[0] != '.')
goto not_empty;
- if (!de->name[1]) {
- if (de->inode != inode->i_ino)
+ if (!namx[1]) {
+ if (inodx != inode->i_ino)
goto not_empty;
- } else if (de->name[1] != '.')
+ } else if (namx[1] != '.')
goto not_empty;
- else if (de->name[2])
+ else if (namx[2])
goto not_empty;
}
de = minix_next_entry(de, sbi);
diff -ur orig.linux-2.6.15.1/fs/minix/inode.c updated.linux-2.6.15.1/fs/minix/inode.c
--- orig.linux-2.6.15.1/fs/minix/inode.c 2006-01-15 07:16:02.000000000 +0100
+++ updated.linux-2.6.15.1/fs/minix/inode.c 2006-01-25 16:41:32.000000000 +0100
@@ -7,6 +7,7 @@
* Minix V2 fs support.
*
* Modified for 680x0 by Andreas Schwab
+ * Updated to filesystem version 3 by Daniel Aragones
*/

#include <linux/module.h>
@@ -36,7 +37,8 @@
struct minix_sb_info *sbi = minix_sb(sb);

if (!(sb->s_flags & MS_RDONLY)) {
- sbi->s_ms->s_state = sbi->s_mount_state;
+ if (sbi->s_version != MINIX_V3) /* s_state is now out from V3 sb */
+ sbi->s_ms->s_state = sbi->s_mount_state;
mark_buffer_dirty(sbi->s_sbh);
}
for (i = 0; i < sbi->s_imap_blocks; i++)
@@ -117,21 +119,23 @@
!(sbi->s_mount_state & MINIX_VALID_FS))
return 0;
/* Mounting a rw partition read-only. */
- ms->s_state = sbi->s_mount_state;
+ if (sbi->s_version != MINIX_V3)
+ ms->s_state = sbi->s_mount_state;
mark_buffer_dirty(sbi->s_sbh);
} else {
/* Mount a partition which is read-only, read-write. */
sbi->s_mount_state = ms->s_state;
- ms->s_state &= ~MINIX_VALID_FS;
+ if (sbi->s_version != MINIX_V3)
+ ms->s_state &= ~MINIX_VALID_FS;
mark_buffer_dirty(sbi->s_sbh);

- if (!(sbi->s_mount_state & MINIX_VALID_FS))
- printk ("MINIX-fs warning: remounting unchecked fs, "
- "running fsck is recommended.\n");
- else if ((sbi->s_mount_state & MINIX_ERROR_FS))
- printk ("MINIX-fs warning: remounting fs with errors, "
- "running fsck is recommended.\n");
- }
+ if (!(sbi->s_mount_state & MINIX_VALID_FS) && (sbi->s_version != MINIX_V3))
+ printk ("MINIX-fs warning: remounting unchecked Minix filesystem V%i, "
+ "running fsck is recommended.\n", sbi->s_version);
+ else if ((sbi->s_mount_state & MINIX_ERROR_FS) && (sbi->s_version != MINIX_V3))
+ printk ("MINIX-fs warning: remounting Minix filesystem V%i with errors, "
+ "running fsck is recommended.\n", sbi->s_version);
+ }
return 0;
}

@@ -140,6 +144,7 @@
struct buffer_head *bh;
struct buffer_head **map;
struct minix_super_block *ms;
+ struct minix3_super_block *m3s = NULL;
int i, block;
struct inode *root_inode;
struct minix_sb_info *sbi;
@@ -197,7 +202,21 @@
sbi->s_dirsize = 32;
sbi->s_namelen = 30;
sbi->s_link_max = MINIX2_LINK_MAX;
- } else
+ } else if ( *(__u16 *)(bh->b_data + 24) == MINIX3_SUPER_MAGIC) {
+ m3s = (struct minix3_super_block *) bh->b_data;
+ s->s_magic = m3s->s_magic;
+ sbi->s_imap_blocks = m3s->s_imap_blocks;
+ sbi->s_zmap_blocks = m3s->s_zmap_blocks;
+ sbi->s_firstdatazone = m3s->s_firstdatazone;
+ sbi->s_log_zone_size = m3s->s_log_zone_size;
+ sbi->s_max_size = m3s->s_max_size;
+ sbi->s_nzones = m3s->s_zones;
+ sbi->s_dirsize = 64;
+ sbi->s_namelen = 60;
+ sbi->s_version = MINIX_V3;
+ sbi->s_link_max = MINIX2_LINK_MAX;
+ sb_set_blocksize(s, m3s->s_blocksize);
+ } else
goto out_no_fs;

/*
@@ -240,15 +259,16 @@
s->s_root->d_op = &minix_dentry_operations;

if (!(s->s_flags & MS_RDONLY)) {
- ms->s_state &= ~MINIX_VALID_FS;
+ if(sbi->s_version != MINIX_V3) /* s_state is now out from V3 sb */
+ ms->s_state &= ~MINIX_VALID_FS;
mark_buffer_dirty(bh);
}
- if (!(sbi->s_mount_state & MINIX_VALID_FS))
- printk ("MINIX-fs: mounting unchecked file system, "
- "running fsck is recommended.\n");
- else if (sbi->s_mount_state & MINIX_ERROR_FS)
- printk ("MINIX-fs: mounting file system with errors, "
- "running fsck is recommended.\n");
+ if (!(sbi->s_mount_state & MINIX_VALID_FS) && (sbi->s_version != MINIX_V3))
+ printk ("MINIX-fs: mounting unchecked Minix filesystem V%i, "
+ "running fsck is recommended.\n", sbi->s_version);
+ else if ((sbi->s_mount_state & MINIX_ERROR_FS) && (sbi->s_version != MINIX_V3))
+ printk ("MINIX-fs: mounting Minix filesystem V%i with errors, "
+ "running fsck is recommended.\n", sbi->s_version);
return 0;

out_iput:
@@ -277,8 +297,8 @@

out_no_fs:
if (!silent)
- printk("VFS: Can't find a Minix or Minix V2 filesystem on device "
- "%s.\n", s->s_id);
+ printk("VFS: Can't find a Minix filesystem V1 | V2 | V3 on device "
+ "%s.\n", s->s_id);
out_release:
brelse(bh);
goto out;
@@ -536,12 +556,14 @@

int minix_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
{
+ struct inode * dir = dentry->d_parent->d_inode;
+ struct super_block * sb = dir->i_sb;
generic_fillattr(dentry->d_inode, stat);
if (INODE_VERSION(dentry->d_inode) == MINIX_V1)
stat->blocks = (BLOCK_SIZE / 512) * V1_minix_blocks(stat->size);
else
- stat->blocks = (BLOCK_SIZE / 512) * V2_minix_blocks(stat->size);
- stat->blksize = BLOCK_SIZE;
+ stat->blocks = (sb->s_blocksize / 512) * V2_minix_blocks(stat->size);
+ stat->blksize = sb->s_blocksize;
return 0;
}

diff -ur orig.linux-2.6.15.1/fs/minix/itree_common.c updated.linux-2.6.15.1/fs/minix/itree_common.c
--- orig.linux-2.6.15.1/fs/minix/itree_common.c 2006-01-15 07:16:02.000000000 +0100
+++ updated.linux-2.6.15.1/fs/minix/itree_common.c 2006-01-25 16:41:32.000000000 +0100
@@ -23,7 +23,7 @@

static inline block_t *block_end(struct buffer_head *bh)
{
- return (block_t *)((char*)bh->b_data + BLOCK_SIZE);
+ return (block_t *)((char*)bh->b_data + bh->b_size);
}

static inline Indirect *get_branch(struct inode *inode,
@@ -85,7 +85,7 @@
branch[n].key = cpu_to_block(nr);
bh = sb_getblk(inode->i_sb, parent);
lock_buffer(bh);
- memset(bh->b_data, 0, BLOCK_SIZE);
+ memset(bh->b_data, 0, bh->b_size);
branch[n].bh = bh;
branch[n].p = (block_t*) bh->b_data + offsets[n];
*branch[n].p = branch[n].key;
@@ -292,6 +292,7 @@

static inline void truncate (struct inode * inode)
{
+ struct super_block * sb = inode->i_sb;
block_t *idata = i_data(inode);
int offsets[DEPTH];
Indirect chain[DEPTH];
@@ -301,7 +302,7 @@
int first_whole;
long iblock;

- iblock = (inode->i_size + BLOCK_SIZE-1) >> 10;
+ iblock = (inode->i_size + sb->s_blocksize -1) >> 10;
block_truncate_page(inode->i_mapping, inode->i_size, get_block);

n = block_to_path(inode, iblock, offsets);
diff -ur orig.linux-2.6.15.1/fs/minix/minix.h updated.linux-2.6.15.1/fs/minix/minix.h
--- orig.linux-2.6.15.1/fs/minix/minix.h 2006-01-15 07:16:02.000000000 +0100
+++ updated.linux-2.6.15.1/fs/minix/minix.h 2006-01-25 16:41:32.000000000 +0100
@@ -12,6 +12,7 @@

#define MINIX_V1 0x0001 /* original minix fs */
#define MINIX_V2 0x0002 /* minix V2 fs */
+#define MINIX_V3 0x0003 /* minix V3 fs */

/*
* minix fs inode data in memory
diff -ur orig.linux-2.6.15.1/include/linux/minix_fs.h updated.linux-2.6.15.1/include/linux/minix_fs.h
--- orig.linux-2.6.15.1/include/linux/minix_fs.h 2006-01-15 07:16:02.000000000 +0100
+++ updated.linux-2.6.15.1/include/linux/minix_fs.h 2006-01-25 16:41:32.000000000 +0100
@@ -23,12 +23,10 @@
#define MINIX_SUPER_MAGIC2 0x138F /* minix fs, 30 char names */
#define MINIX2_SUPER_MAGIC 0x2468 /* minix V2 fs */
#define MINIX2_SUPER_MAGIC2 0x2478 /* minix V2 fs, 30 char names */
+#define MINIX3_SUPER_MAGIC 0x4d5a /* minix V3 fs */
#define MINIX_VALID_FS 0x0001 /* Clean fs. */
#define MINIX_ERROR_FS 0x0002 /* fs has errors. */

-#define MINIX_INODES_PER_BLOCK ((BLOCK_SIZE)/(sizeof (struct minix_inode)))
-#define MINIX2_INODES_PER_BLOCK ((BLOCK_SIZE)/(sizeof (struct minix2_inode)))
-
/*
* This is the original minix inode layout on disk.
* Note the 8-bit gid and atime and ctime.
@@ -77,9 +75,33 @@
__u32 s_zones;
};

+/*
+ * V3 minix super-block data on disk
+ */
+struct minix3_super_block {
+ __u16 s_ninodes;
+ __u16 s_nzones;
+ __u16 s_pad0;
+ __u16 s_imap_blocks;
+ __u16 s_zmap_blocks;
+ __u16 s_firstdatazone;
+ __u16 s_log_zone_size;
+ __u16 s_pad1;
+ __u32 s_max_size;
+ __u32 s_zones;
+ __u16 s_magic;
+ __u16 s_pad2;
+ __u16 s_blocksize;
+ __u8 s_disk_version;
+};
+
struct minix_dir_entry {
__u16 inode;
char name[0];
};

+struct minix3_dir_entry {
+ __u32 inode;
+ char name[0];
+};
#endif