linux/fs/qnx4/inode.c

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/*
* QNX4 file system, Linux implementation.
*
* Version : 0.2.1
*
* Using parts of the xiafs filesystem.
*
* History :
*
* 01-06-1998 by Richard Frowijn : first release.
* 20-06-1998 by Frank Denis : Linux 2.1.99+ support, boot signature, misc.
* 30-06-1998 by Frank Denis : first step to write inodes.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/highuid.h>
#include <linux/smp_lock.h>
#include <linux/pagemap.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/statfs.h>
#include "qnx4.h"
#define QNX4_VERSION 4
#define QNX4_BMNAME ".bitmap"
static const struct super_operations qnx4_sops;
static void qnx4_put_super(struct super_block *sb);
static struct inode *qnx4_alloc_inode(struct super_block *sb);
static void qnx4_destroy_inode(struct inode *inode);
static int qnx4_remount(struct super_block *sb, int *flags, char *data);
static int qnx4_statfs(struct dentry *, struct kstatfs *);
static const struct super_operations qnx4_sops =
{
.alloc_inode = qnx4_alloc_inode,
.destroy_inode = qnx4_destroy_inode,
.put_super = qnx4_put_super,
.statfs = qnx4_statfs,
.remount_fs = qnx4_remount,
};
static int qnx4_remount(struct super_block *sb, int *flags, char *data)
{
struct qnx4_sb_info *qs;
qs = qnx4_sb(sb);
qs->Version = QNX4_VERSION;
*flags |= MS_RDONLY;
return 0;
}
static struct buffer_head *qnx4_getblk(struct inode *inode, int nr,
int create)
{
struct buffer_head *result = NULL;
if ( nr >= 0 )
nr = qnx4_block_map( inode, nr );
if (nr) {
result = sb_getblk(inode->i_sb, nr);
return result;
}
return NULL;
}
struct buffer_head *qnx4_bread(struct inode *inode, int block, int create)
{
struct buffer_head *bh;
bh = qnx4_getblk(inode, block, create);
if (!bh || buffer_uptodate(bh)) {
return bh;
}
ll_rw_block(READ, 1, &bh);
wait_on_buffer(bh);
if (buffer_uptodate(bh)) {
return bh;
}
brelse(bh);
return NULL;
}
static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
{
unsigned long phys;
QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
phys = qnx4_block_map( inode, iblock );
if ( phys ) {
// logical block is before EOF
map_bh(bh, inode->i_sb, phys);
}
return 0;
}
unsigned long qnx4_block_map( struct inode *inode, long iblock )
{
int ix;
long offset, i_xblk;
unsigned long block = 0;
struct buffer_head *bh = NULL;
struct qnx4_xblk *xblk = NULL;
struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
if ( iblock < le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size) ) {
// iblock is in the first extent. This is easy.
block = le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_blk) + iblock - 1;
} else {
// iblock is beyond first extent. We have to follow the extent chain.
i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
offset = iblock - le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size);
ix = 0;
while ( --nxtnt > 0 ) {
if ( ix == 0 ) {
// read next xtnt block.
bh = sb_bread(inode->i_sb, i_xblk - 1);
if ( !bh ) {
QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
return -EIO;
}
xblk = (struct qnx4_xblk*)bh->b_data;
if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
return -EIO;
}
}
if ( offset < le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size) ) {
// got it!
block = le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_blk) + offset - 1;
break;
}
offset -= le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size);
if ( ++ix >= xblk->xblk_num_xtnts ) {
i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
ix = 0;
brelse( bh );
bh = NULL;
}
}
if ( bh )
brelse( bh );
}
QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
return block;
}
static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *sb = dentry->d_sb;
u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
lock_kernel();
buf->f_type = sb->s_magic;
buf->f_bsize = sb->s_blocksize;
buf->f_blocks = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
buf->f_bfree = qnx4_count_free_blocks(sb);
buf->f_bavail = buf->f_bfree;
buf->f_namelen = QNX4_NAME_MAX;
buf->f_fsid.val[0] = (u32)id;
buf->f_fsid.val[1] = (u32)(id >> 32);
unlock_kernel();
return 0;
}
/*
* Check the root directory of the filesystem to make sure
* it really _is_ a qnx4 filesystem, and to check the size
* of the directory entry.
*/
static const char *qnx4_checkroot(struct super_block *sb)
{
struct buffer_head *bh;
struct qnx4_inode_entry *rootdir;
int rd, rl;
int i, j;
int found = 0;
if (*(qnx4_sb(sb)->sb->RootDir.di_fname) != '/') {
return "no qnx4 filesystem (no root dir).";
} else {
QNX4DEBUG((KERN_NOTICE "QNX4 filesystem found on dev %s.\n", sb->s_id));
rd = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_blk) - 1;
rl = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_size);
for (j = 0; j < rl; j++) {
bh = sb_bread(sb, rd + j); /* root dir, first block */
if (bh == NULL) {
return "unable to read root entry.";
}
for (i = 0; i < QNX4_INODES_PER_BLOCK; i++) {
rootdir = (struct qnx4_inode_entry *) (bh->b_data + i * QNX4_DIR_ENTRY_SIZE);
if (rootdir->di_fname != NULL) {
QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
if (!strcmp(rootdir->di_fname,
QNX4_BMNAME)) {
found = 1;
qnx4_sb(sb)->BitMap = kmalloc( sizeof( struct qnx4_inode_entry ), GFP_KERNEL );
if (!qnx4_sb(sb)->BitMap) {
brelse (bh);
return "not enough memory for bitmap inode";
}
memcpy( qnx4_sb(sb)->BitMap, rootdir, sizeof( struct qnx4_inode_entry ) ); /* keep bitmap inode known */
break;
}
}
}
brelse(bh);
if (found != 0) {
break;
}
}
if (found == 0) {
return "bitmap file not found.";
}
}
return NULL;
}
static int qnx4_fill_super(struct super_block *s, void *data, int silent)
{
struct buffer_head *bh;
struct inode *root;
const char *errmsg;
struct qnx4_sb_info *qs;
int ret = -EINVAL;
qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
if (!qs)
return -ENOMEM;
s->s_fs_info = qs;
sb_set_blocksize(s, QNX4_BLOCK_SIZE);
/* Check the superblock signature. Since the qnx4 code is
dangerous, we should leave as quickly as possible
if we don't belong here... */
bh = sb_bread(s, 1);
if (!bh) {
printk(KERN_ERR "qnx4: unable to read the superblock\n");
goto outnobh;
}
if ( le32_to_cpup((__le32*) bh->b_data) != QNX4_SUPER_MAGIC ) {
if (!silent)
printk(KERN_ERR "qnx4: wrong fsid in superblock.\n");
goto out;
}
s->s_op = &qnx4_sops;
s->s_magic = QNX4_SUPER_MAGIC;
s->s_flags |= MS_RDONLY; /* Yup, read-only yet */
qnx4_sb(s)->sb_buf = bh;
qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;
/* check before allocating dentries, inodes, .. */
errmsg = qnx4_checkroot(s);
if (errmsg != NULL) {
if (!silent)
printk(KERN_ERR "qnx4: %s\n", errmsg);
goto out;
}
/* does root not have inode number QNX4_ROOT_INO ?? */
root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
if (IS_ERR(root)) {
printk(KERN_ERR "qnx4: get inode failed\n");
ret = PTR_ERR(root);
goto out;
}
ret = -ENOMEM;
s->s_root = d_alloc_root(root);
if (s->s_root == NULL)
goto outi;
brelse(bh);
return 0;
outi:
iput(root);
out:
brelse(bh);
outnobh:
kfree(qs);
s->s_fs_info = NULL;
return ret;
}
static void qnx4_put_super(struct super_block *sb)
{
struct qnx4_sb_info *qs = qnx4_sb(sb);
kfree( qs->BitMap );
kfree( qs );
sb->s_fs_info = NULL;
return;
}
static int qnx4_writepage(struct page *page, struct writeback_control *wbc)
{
return block_write_full_page(page,qnx4_get_block, wbc);
}
static int qnx4_readpage(struct file *file, struct page *page)
{
return block_read_full_page(page,qnx4_get_block);
}
static int qnx4_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
struct qnx4_inode_info *qnx4_inode = qnx4_i(mapping->host);
*pagep = NULL;
return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
qnx4_get_block,
&qnx4_inode->mmu_private);
}
static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
{
return generic_block_bmap(mapping,block,qnx4_get_block);
}
static const struct address_space_operations qnx4_aops = {
.readpage = qnx4_readpage,
.writepage = qnx4_writepage,
.sync_page = block_sync_page,
.write_begin = qnx4_write_begin,
.write_end = generic_write_end,
.bmap = qnx4_bmap
};
struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
{
struct buffer_head *bh;
struct qnx4_inode_entry *raw_inode;
int block;
struct qnx4_inode_entry *qnx4_inode;
struct inode *inode;
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
if (!(inode->i_state & I_NEW))
return inode;
qnx4_inode = qnx4_raw_inode(inode);
inode->i_mode = 0;
QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
if (!ino) {
printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
"out of range\n",
sb->s_id, ino);
iget_failed(inode);
return ERR_PTR(-EIO);
}
block = ino / QNX4_INODES_PER_BLOCK;
if (!(bh = sb_bread(sb, block))) {
printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
"%s\n", sb->s_id);
iget_failed(inode);
return ERR_PTR(-EIO);
}
raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
(ino % QNX4_INODES_PER_BLOCK);
inode->i_mode = le16_to_cpu(raw_inode->di_mode);
inode->i_uid = (uid_t)le16_to_cpu(raw_inode->di_uid);
inode->i_gid = (gid_t)le16_to_cpu(raw_inode->di_gid);
inode->i_nlink = le16_to_cpu(raw_inode->di_nlink);
inode->i_size = le32_to_cpu(raw_inode->di_size);
inode->i_mtime.tv_sec = le32_to_cpu(raw_inode->di_mtime);
inode->i_mtime.tv_nsec = 0;
inode->i_atime.tv_sec = le32_to_cpu(raw_inode->di_atime);
inode->i_atime.tv_nsec = 0;
inode->i_ctime.tv_sec = le32_to_cpu(raw_inode->di_ctime);
inode->i_ctime.tv_nsec = 0;
inode->i_blocks = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
if (S_ISREG(inode->i_mode)) {
inode->i_fop = &generic_ro_fops;
inode->i_mapping->a_ops = &qnx4_aops;
qnx4_i(inode)->mmu_private = inode->i_size;
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op = &qnx4_dir_inode_operations;
inode->i_fop = &qnx4_dir_operations;
} else if (S_ISLNK(inode->i_mode)) {
inode->i_op = &page_symlink_inode_operations;
inode->i_mapping->a_ops = &qnx4_aops;
qnx4_i(inode)->mmu_private = inode->i_size;
} else {
printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
ino, sb->s_id);
iget_failed(inode);
brelse(bh);
return ERR_PTR(-EIO);
}
brelse(bh);
unlock_new_inode(inode);
return inode;
}
static struct kmem_cache *qnx4_inode_cachep;
static struct inode *qnx4_alloc_inode(struct super_block *sb)
{
struct qnx4_inode_info *ei;
ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
if (!ei)
return NULL;
return &ei->vfs_inode;
}
static void qnx4_destroy_inode(struct inode *inode)
{
kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
}
static void init_once(void *foo)
{
struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
inode_init_once(&ei->vfs_inode);
}
static int init_inodecache(void)
{
qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
sizeof(struct qnx4_inode_info),
0, (SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD),
init_once);
if (qnx4_inode_cachep == NULL)
return -ENOMEM;
return 0;
}
static void destroy_inodecache(void)
{
kmem_cache_destroy(qnx4_inode_cachep);
}
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 09:02:57 +00:00
static int qnx4_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 09:02:57 +00:00
return get_sb_bdev(fs_type, flags, dev_name, data, qnx4_fill_super,
mnt);
}
static struct file_system_type qnx4_fs_type = {
.owner = THIS_MODULE,
.name = "qnx4",
.get_sb = qnx4_get_sb,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
static int __init init_qnx4_fs(void)
{
int err;
err = init_inodecache();
if (err)
return err;
err = register_filesystem(&qnx4_fs_type);
if (err) {
destroy_inodecache();
return err;
}
printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
return 0;
}
static void __exit exit_qnx4_fs(void)
{
unregister_filesystem(&qnx4_fs_type);
destroy_inodecache();
}
module_init(init_qnx4_fs)
module_exit(exit_qnx4_fs)
MODULE_LICENSE("GPL");