static struct dentry *minix_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
{
struct inode * inode = NULL;
ino_t ino;
if (dentry->d_name.len > minix_sb(dir->i_sb)->s_namelen)
return ERR_PTR(-ENAMETOOLONG);
ino = minix_inode_by_name(dentry);
if (ino)
inode = minix_iget(dir->i_sb, ino);
return d_splice_alias(inode, dentry);
}
static struct dentry *minix_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
{
struct inode * inode = NULL;
ino_t ino;
if (dentry->d_name.len > minix_sb(dir->i_sb)->s_namelen)
return ERR_PTR(-ENAMETOOLONG);
ino = minix_inode_by_name(dentry);
if (ino) {
inode = minix_iget(dir->i_sb, ino);
if (IS_ERR(inode))
return ERR_CAST(inode);
}
d_add(dentry, inode);
return NULL;
}
static int minix_fill_super(struct super_block *s, void *data, int silent)
{
struct buffer_head *bh;
struct buffer_head **map;
struct minix_super_block *ms;
struct minix3_super_block *m3s = NULL;
unsigned long i, block;
struct inode *root_inode;
struct minix_sb_info *sbi;
int ret = -EINVAL;
sbi = kzalloc(sizeof(struct minix_sb_info), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
s->s_fs_info = sbi;
BUILD_BUG_ON(32 != sizeof (struct minix_inode));
BUILD_BUG_ON(64 != sizeof(struct minix2_inode));
if (!sb_set_blocksize(s, BLOCK_SIZE))
goto out_bad_hblock;
if (!(bh = sb_bread(s, 1)))
goto out_bad_sb;
ms = (struct minix_super_block *) bh->b_data;
sbi->s_ms = ms;
sbi->s_sbh = bh;
sbi->s_mount_state = ms->s_state;
sbi->s_ninodes = ms->s_ninodes;
sbi->s_nzones = ms->s_nzones;
sbi->s_imap_blocks = ms->s_imap_blocks;
sbi->s_zmap_blocks = ms->s_zmap_blocks;
sbi->s_firstdatazone = ms->s_firstdatazone;
sbi->s_log_zone_size = ms->s_log_zone_size;
sbi->s_max_size = ms->s_max_size;
s->s_magic = ms->s_magic;
if (s->s_magic == MINIX_SUPER_MAGIC) {
sbi->s_version = MINIX_V1;
sbi->s_dirsize = 16;
sbi->s_namelen = 14;
s->s_max_links = MINIX_LINK_MAX;
} else if (s->s_magic == MINIX_SUPER_MAGIC2) {
sbi->s_version = MINIX_V1;
sbi->s_dirsize = 32;
sbi->s_namelen = 30;
s->s_max_links = MINIX_LINK_MAX;
} else if (s->s_magic == MINIX2_SUPER_MAGIC) {
sbi->s_version = MINIX_V2;
sbi->s_nzones = ms->s_zones;
sbi->s_dirsize = 16;
sbi->s_namelen = 14;
s->s_max_links = MINIX2_LINK_MAX;
} else if (s->s_magic == MINIX2_SUPER_MAGIC2) {
sbi->s_version = MINIX_V2;
sbi->s_nzones = ms->s_zones;
sbi->s_dirsize = 32;
sbi->s_namelen = 30;
s->s_max_links = MINIX2_LINK_MAX;
} 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_ninodes = m3s->s_ninodes;
sbi->s_nzones = m3s->s_zones;
sbi->s_dirsize = 64;
sbi->s_namelen = 60;
sbi->s_version = MINIX_V3;
sbi->s_mount_state = MINIX_VALID_FS;
sb_set_blocksize(s, m3s->s_blocksize);
s->s_max_links = MINIX2_LINK_MAX;
} else
goto out_no_fs;
/*
* Allocate the buffer map to keep the superblock small.
*/
if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0)
goto out_illegal_sb;
i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh);
map = kzalloc(i, GFP_KERNEL);
if (!map)
goto out_no_map;
sbi->s_imap = &map[0];
sbi->s_zmap = &map[sbi->s_imap_blocks];
block=2;
for (i=0 ; i < sbi->s_imap_blocks ; i++) {
if (!(sbi->s_imap[i]=sb_bread(s, block)))
goto out_no_bitmap;
block++;
}
for (i=0 ; i < sbi->s_zmap_blocks ; i++) {
if (!(sbi->s_zmap[i]=sb_bread(s, block)))
goto out_no_bitmap;
block++;
}
minix_set_bit(0,sbi->s_imap[0]->b_data);
minix_set_bit(0,sbi->s_zmap[0]->b_data);
/* Apparently minix can create filesystems that allocate more blocks for
* the bitmaps than needed. We simply ignore that, but verify it didn't
* create one with not enough blocks and bail out if so.
*/
block = minix_blocks_needed(sbi->s_ninodes, s->s_blocksize);
if (sbi->s_imap_blocks < block) {
printk("MINIX-fs: file system does not have enough "
"imap blocks allocated. Refusing to mount\n");
goto out_no_bitmap;
}
block = minix_blocks_needed(
(sbi->s_nzones - (sbi->s_firstdatazone + 1)),
s->s_blocksize);
if (sbi->s_zmap_blocks < block) {
printk("MINIX-fs: file system does not have enough "
"zmap blocks allocated. Refusing to mount.\n");
goto out_no_bitmap;
}
/* set up enough so that it can read an inode */
s->s_op = &minix_sops;
root_inode = minix_iget(s, MINIX_ROOT_INO);
if (IS_ERR(root_inode)) {
ret = PTR_ERR(root_inode);
goto out_no_root;
}
ret = -ENOMEM;
s->s_root = d_make_root(root_inode);
if (!s->s_root)
goto out_no_root;
if (!(s->s_flags & MS_RDONLY)) {
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");
return 0;
out_no_root:
if (!silent)
printk("MINIX-fs: get root inode failed\n");
goto out_freemap;
out_no_bitmap:
printk("MINIX-fs: bad superblock or unable to read bitmaps\n");
out_freemap:
for (i = 0; i < sbi->s_imap_blocks; i++)
brelse(sbi->s_imap[i]);
for (i = 0; i < sbi->s_zmap_blocks; i++)
brelse(sbi->s_zmap[i]);
kfree(sbi->s_imap);
goto out_release;
out_no_map:
ret = -ENOMEM;
if (!silent)
printk("MINIX-fs: can't allocate map\n");
goto out_release;
out_illegal_sb:
if (!silent)
printk("MINIX-fs: bad superblock\n");
goto out_release;
out_no_fs:
if (!silent)
printk("VFS: Can't find a Minix filesystem V1 | V2 | V3 "
"on device %s.\n", s->s_id);
out_release:
brelse(bh);
goto out;
out_bad_hblock:
printk("MINIX-fs: blocksize too small for device\n");
goto out;
out_bad_sb:
printk("MINIX-fs: unable to read superblock\n");
out:
s->s_fs_info = NULL;
kfree(sbi);
return ret;
}
/**ltl
功能:从设备中读取超级块。
参数:
返回值:
说明:
*/
static int minix_fill_super(struct super_block *s, void *data, int silent)
{
struct buffer_head *bh;
struct buffer_head **map;
struct minix_super_block *ms;
struct minix3_super_block *m3s = NULL;
unsigned long i, block;
struct inode *root_inode;
struct minix_sb_info *sbi;
int ret = -EINVAL;
//分配内存超级块描述符
sbi = kzalloc(sizeof(struct minix_sb_info), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
s->s_fs_info = sbi;
BUILD_BUG_ON(32 != sizeof (struct minix_inode));
BUILD_BUG_ON(64 != sizeof(struct minix2_inode));
if (!sb_set_blocksize(s, BLOCK_SIZE))
goto out_bad_hblock;
//读取超级块信息。(同步操作)
if (!(bh = sb_bread(s, 1)))
goto out_bad_sb;
ms = (struct minix_super_block *) bh->b_data;
//磁盘超级块描述符
sbi->s_ms = ms;
sbi->s_sbh = bh;
sbi->s_mount_state = ms->s_state;
sbi->s_ninodes = ms->s_ninodes;
sbi->s_nzones = ms->s_nzones;
sbi->s_imap_blocks = ms->s_imap_blocks;
sbi->s_zmap_blocks = ms->s_zmap_blocks;
sbi->s_firstdatazone = ms->s_firstdatazone;
sbi->s_log_zone_size = ms->s_log_zone_size;
sbi->s_max_size = ms->s_max_size;
s->s_magic = ms->s_magic;
if (s->s_magic == MINIX_SUPER_MAGIC) {
sbi->s_version = MINIX_V1;
sbi->s_dirsize = 16;
sbi->s_namelen = 14;
sbi->s_link_max = MINIX_LINK_MAX;
} else if (s->s_magic == MINIX_SUPER_MAGIC2) {
sbi->s_version = MINIX_V1;
sbi->s_dirsize = 32;
sbi->s_namelen = 30;
sbi->s_link_max = MINIX_LINK_MAX;
} else if (s->s_magic == MINIX2_SUPER_MAGIC) {
sbi->s_version = MINIX_V2;
sbi->s_nzones = ms->s_zones;
sbi->s_dirsize = 16;
sbi->s_namelen = 14;
sbi->s_link_max = MINIX2_LINK_MAX;
} else if (s->s_magic == MINIX2_SUPER_MAGIC2) {
sbi->s_version = MINIX_V2;
sbi->s_nzones = ms->s_zones;
sbi->s_dirsize = 32;
sbi->s_namelen = 30;//文件名长度
sbi->s_link_max = MINIX2_LINK_MAX;
} 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_ninodes = m3s->s_ninodes;
sbi->s_nzones = m3s->s_zones;
sbi->s_dirsize = 64;
sbi->s_namelen = 60;//文件名长度
sbi->s_version = MINIX_V3;
sbi->s_link_max = MINIX2_LINK_MAX;
sbi->s_mount_state = MINIX_VALID_FS;
sb_set_blocksize(s, m3s->s_blocksize);
} else
goto out_no_fs;
/*
* Allocate the buffer map to keep the superblock small.
*/
if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0)
goto out_illegal_sb;
i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh);
map = kzalloc(i, GFP_KERNEL);
if (!map)
goto out_no_map;
sbi->s_imap = &map[0];
sbi->s_zmap = &map[sbi->s_imap_blocks];
//从第二块起读取imap和zmap数据值。
block=2;
for (i=0 ; i < sbi->s_imap_blocks ; i++) {
if (!(sbi->s_imap[i]=sb_bread(s, block)))//读取i节点位图
goto out_no_bitmap;
block++;
}
for (i=0 ; i < sbi->s_zmap_blocks ; i++) {
if (!(sbi->s_zmap[i]=sb_bread(s, block)))//读取逻辑块位图
goto out_no_bitmap;
block++;
}
minix_set_bit(0,sbi->s_imap[0]->b_data);
minix_set_bit(0,sbi->s_zmap[0]->b_data);
/* set up enough so that it can read an inode */
s->s_op = &minix_sops;
root_inode = minix_iget(s, MINIX_ROOT_INO);
if (IS_ERR(root_inode)) {
ret = PTR_ERR(root_inode);
goto out_no_root;
}
ret = -ENOMEM;
//分配根dentry(VFS提供了用于分配根dentry的专门函数)
s->s_root = d_alloc_root(root_inode);
if (!s->s_root)
goto out_iput;
if (!(s->s_flags & MS_RDONLY)) {
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");
return 0;
out_iput:
iput(root_inode);
goto out_freemap;
out_no_root:
if (!silent)
printk("MINIX-fs: get root inode failed\n");
goto out_freemap;
out_no_bitmap:
printk("MINIX-fs: bad superblock or unable to read bitmaps\n");
out_freemap:
for (i = 0; i < sbi->s_imap_blocks; i++)
brelse(sbi->s_imap[i]);
for (i = 0; i < sbi->s_zmap_blocks; i++)
brelse(sbi->s_zmap[i]);
kfree(sbi->s_imap);
goto out_release;
out_no_map:
ret = -ENOMEM;
if (!silent)
printk("MINIX-fs: can't allocate map\n");
goto out_release;
out_illegal_sb:
if (!silent)
printk("MINIX-fs: bad superblock\n");
goto out_release;
out_no_fs:
if (!silent)
printk("VFS: Can't find a Minix filesystem V1 | V2 | V3 "
"on device %s.\n", s->s_id);
out_release:
brelse(bh);
goto out;
out_bad_hblock:
printk("MINIX-fs: blocksize too small for device\n");
goto out;
out_bad_sb:
printk("MINIX-fs: unable to read superblock\n");
out:
s->s_fs_info = NULL;
kfree(sbi);
return ret;
}
