dir.c

Linux Kernel 2.6.9 for OMAP1710

/*
 * Directory operations for Coda filesystem
 * Original version: (C) 1996 P. Braam and M. Callahan
 * Rewritten for Linux 2.1. (C) 1997 Carnegie Mellon University
 * 
 * Carnegie Mellon encourages users to contribute improvements to
 * the Coda project. Contact Peter Braam ([e-mail]).
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/smp_lock.h>

#include <asm/uaccess.h>

#include <linux/coda.h>
#include <linux/coda_linux.h>
#include <linux/coda_psdev.h>
#include <linux/coda_fs_i.h>
#include <linux/coda_cache.h>
#include <linux/coda_proc.h>

/* dir inode-ops */
static int coda_create(struct inode *dir, struct dentry *new, int mode, struct nameidata *nd);
static int coda_mknod(struct inode *dir, struct dentry *new, int mode, dev_t rdev);
static struct dentry *coda_lookup(struct inode *dir, struct dentry *target, struct nameidata *nd);
static int coda_link(struct dentry *old_dentry, struct inode *dir_inode, 
		     struct dentry *entry);
static int coda_unlink(struct inode *dir_inode, struct dentry *entry);
static int coda_symlink(struct inode *dir_inode, struct dentry *entry,
			const char *symname);
static int coda_mkdir(struct inode *dir_inode, struct dentry *entry, int mode);
static int coda_rmdir(struct inode *dir_inode, struct dentry *entry);
static int coda_rename(struct inode *old_inode, struct dentry *old_dentry, 
                       struct inode *new_inode, struct dentry *new_dentry);

/* dir file-ops */
static int coda_readdir(struct file *file, void *dirent, filldir_t filldir);

/* dentry ops */
static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd);
static int coda_dentry_delete(struct dentry *);

/* support routines */
static int coda_venus_readdir(struct file *filp, filldir_t filldir,
			      void *dirent, struct dentry *dir);
int coda_fsync(struct file *, struct dentry *dentry, int datasync);

int coda_hasmknod;

struct dentry_operations coda_dentry_operations =
{
	.d_revalidate	= coda_dentry_revalidate,
	.d_delete	= coda_dentry_delete,
};

struct inode_operations coda_dir_inode_operations =
{
	.create		= coda_create,
	.lookup		= coda_lookup,
	.link		= coda_link,
	.unlink		= coda_unlink,
	.symlink	= coda_symlink,
	.mkdir		= coda_mkdir,
	.rmdir		= coda_rmdir,
	.mknod		= coda_mknod,
	.rename		= coda_rename,
	.permission	= coda_permission,
	.getattr	= coda_getattr,
	.setattr	= coda_setattr,
};

struct file_operations coda_dir_operations = {
	.llseek		= generic_file_llseek,
	.read		= generic_read_dir,
	.readdir	= coda_readdir,
	.open		= coda_open,
	.flush		= coda_flush,
	.release	= coda_release,
	.fsync		= coda_fsync,
};


/* inode operations for directories */
/* access routines: lookup, readlink, permission */
static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, struct nameidata *nd)
{
	struct inode *res_inode = NULL;
	struct CodaFid resfid = { { 0, } };
	int dropme = 0; /* to indicate entry should not be cached */
	int type = 0;
	int error = 0;
	const char *name = entry->d_name.name;
	size_t length = entry->d_name.len;
	
	if ( length > CODA_MAXNAMLEN ) {
	        printk("name too long: lookup, %s (%*s)\n", 
		       coda_i2s(dir), (int)length, name);
		return ERR_PTR(-ENAMETOOLONG);
	}

	lock_kernel();
        /* control object, create inode on the fly */
        if (coda_isroot(dir) && coda_iscontrol(name, length)) {
	        error = coda_cnode_makectl(&res_inode, dir->i_sb);
		dropme = 1;
                goto exit;
        }

	error = venus_lookup(dir->i_sb, coda_i2f(dir), 
			     (const char *)name, length, &type, &resfid);

	res_inode = NULL;
	if (!error) {
		if (type & CODA_NOCACHE) {
			type &= (~CODA_NOCACHE);
			dropme = 1;
		}

	    	error = coda_cnode_make(&res_inode, &resfid, dir->i_sb);
		if (error) {
			unlock_kernel();
			return ERR_PTR(error);
		}
	} else if (error != -ENOENT) {
		unlock_kernel();
		return ERR_PTR(error);
	}

exit:
	entry->d_time = 0;
	entry->d_op = &coda_dentry_operations;
	d_add(entry, res_inode);
	if ( dropme ) {
		d_drop(entry);
		coda_flag_inode(res_inode, C_VATTR);
	}
	unlock_kernel();
        return NULL;
}


int coda_permission(struct inode *inode, int mask, struct nameidata *nd)
{
        int error = 0;
 
	if (!mask)
		return 0; 

	lock_kernel();

	coda_vfs_stat.permission++;

	if (coda_cache_check(inode, mask))
		goto out; 

        error = venus_access(inode->i_sb, coda_i2f(inode), mask);
    
	if (!error)
		coda_cache_enter(inode, mask);

 out:
	unlock_kernel();

        return error; 
}


static inline void coda_dir_changed(struct inode *dir, int link)
{
#ifdef REQUERY_VENUS_FOR_MTIME
	/* invalidate the directory cnode's attributes so we refetch the
	 * attributes from venus next time the inode is referenced */
	coda_flag_inode(dir, C_VATTR);
#else
	/* optimistically we can also act as if our nose bleeds. The
         * granularity of the mtime is coarse anyways so we might actually be
         * right most of the time. Note: we only do this for directories. */
	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
#endif
	if (link)
		dir->i_nlink += link;
}

/* creation routines: create, mknod, mkdir, link, symlink */
static int coda_create(struct inode *dir, struct dentry *de, int mode, struct nameidata *nd)
{
        int error=0;
	const char *name=de->d_name.name;
	int length=de->d_name.len;
	struct inode *inode;
	struct CodaFid newfid;
	struct coda_vattr attrs;

	lock_kernel();
	coda_vfs_stat.create++;

	if (coda_isroot(dir) && coda_iscontrol(name, length)) {
		unlock_kernel();
		return -EPERM;
	}

	error = venus_create(dir->i_sb, coda_i2f(dir), name, length, 
				0, mode, 0, &newfid, &attrs);

        if ( error ) {
		unlock_kernel();
		d_drop(de);
		return error;
	}

	inode = coda_iget(dir->i_sb, &newfid, &attrs);
	if ( IS_ERR(inode) ) {
		unlock_kernel();
		d_drop(de);
		return PTR_ERR(inode);
	}

	/* invalidate the directory cnode's attributes */
	coda_dir_changed(dir, 0);
	unlock_kernel();
	d_instantiate(de, inode);
        return 0;
}

static int coda_mknod(struct inode *dir, struct dentry *de, int mode, dev_t rdev)
{
        int error=0;
	const char *name=de->d_name.name;
	int length=de->d_name.len;
	struct inode *inode;
	struct CodaFid newfid;
	struct coda_vattr attrs;

	if ( coda_hasmknod == 0 )
		return -EIO;

	if (!old_valid_dev(rdev))
		return -EINVAL;

	lock_kernel();
	coda_vfs_stat.create++;

	if (coda_isroot(dir) && coda_iscontrol(name, length)) {
		unlock_kernel();
		return -EPERM;
	}

	error = venus_create(dir->i_sb, coda_i2f(dir), name, length, 
				0, mode, rdev, &newfid, &attrs);

        if ( error ) {
		unlock_kernel();
		d_drop(de);
		return error;
	}

	inode = coda_iget(dir->i_sb, &newfid, &attrs);
	if ( IS_ERR(inode) ) {
		unlock_kernel();
		d_drop(de);
		return PTR_ERR(inode);
	}

	/* invalidate the directory cnode's attributes */
	coda_dir_changed(dir, 0);
	unlock_kernel();
	d_instantiate(de, inode);
        return 0;
}			     

static int coda_mkdir(struct inode *dir, struct dentry *de, int mode)
{
	struct inode *inode;
	struct coda_vattr attrs;
	const char *name = de->d_name.name;
	int len = de->d_name.len;
	int error;
	struct CodaFid newfid;

	lock_kernel();
	coda_vfs_stat.mkdir++;

	if (coda_isroot(dir) && coda_iscontrol(name, len)) {
		unlock_kernel();
		return -EPERM;
	}

	attrs.va_mode = mode;
	error = venus_mkdir(dir->i_sb, coda_i2f(dir), 
			       name, len, &newfid, &attrs);
        
        if ( error ) {
		unlock_kernel();
		d_drop(de);
		return error;
        }
         
	inode = coda_iget(dir->i_sb, &newfid, &attrs);
	if ( IS_ERR(inode) ) {
		unlock_kernel();
		d_drop(de);
		return PTR_ERR(inode);
	}
	
	/* invalidate the directory cnode's attributes */
	coda_dir_changed(dir, 1);
	unlock_kernel();
	d_instantiate(de, inode);
        return 0;
}

/* try to make de an entry in dir_inodde linked to source_de */ 
static int coda_link(struct dentry *source_de, struct inode *dir_inode, 
	  struct dentry *de)
{
	struct inode *inode = source_de->d_inode;
        const char * name = de->d_name.name;
	int len = de->d_name.len;
	int error;

	lock_kernel();
	coda_vfs_stat.link++;

	if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
		unlock_kernel();
		return -EPERM;
	}

	error = venus_link(dir_inode->i_sb, coda_i2f(inode),
			   coda_i2f(dir_inode), (const char *)name, len);

	if (error) { 
		d_drop(de);
		goto out;
	}

	coda_dir_changed(dir_inode, 0);
	atomic_inc(&inode->i_count);
	d_instantiate(de, inode);
	inode->i_nlink++;
        
out:
	unlock_kernel();
	return(error);
}


static int coda_symlink(struct inode *dir_inode, struct dentry *de,
			const char *symname)
{
        const char *name = de->d_name.name;
	int len = de->d_name.len;
	int symlen;
        int error=0;
        
	lock_kernel();
	coda_vfs_stat.symlink++;

	if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
		unlock_kernel();
		return -EPERM;
	}

	symlen = strlen(symname);
	if ( symlen > CODA_MAXPATHLEN ) {
		unlock_kernel();