block/Kconfig


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#
# Block layer core configuration
#
menuconfig BLOCK
       bool "Enable the block layer" if EMBEDDED
       default y
       help
	 Provide block layer support for the kernel.

	 Disable this option to remove the block layer support from the
	 kernel. This may be useful for embedded devices.

	 If this option is disabled:

	   - block device files will become unusable
	   - some filesystems (such as ext3) will become unavailable.

	 Also, SCSI character devices and USB storage will be disabled since
	 they make use of various block layer definitions and facilities.

	 Say Y here unless you know you really don't want to mount disks and
	 suchlike.

if BLOCK

config LBD
	bool "Support for large block devices and files"
	depends on !64BIT
	default y
	help
	  Enable block devices or files of size 2TB and larger.

	  This option is required to support the full capacity of large
	  (2TB+) block devices, including RAID, disk, Network Block Device,
	  Logical Volume Manager (LVM) and loopback.
	
	  This option also enables support for single files larger than
	  2TB.

	  The ext4 filesystem requires that this feature be enabled in
	  order to support filesystems that have the huge_file feature
	  enabled.  Otherwise, it will refuse to mount in the read-write
	  mode any filesystems that use the huge_file feature, which is
	  enabled by default by mke2fs.ext4.

	  The GFS2 filesystem also requires this feature.

	  If unsure, say Y.

config BLK_DEV_BSG
	bool "Block layer SG support v4 (EXPERIMENTAL)"
	depends on EXPERIMENTAL
	---help---
	  Saying Y here will enable generic SG (SCSI generic) v4 support
	  for any block device.

	  Unlike SG v3 (aka block/scsi_ioctl.c drivers/scsi/sg.c), SG v4
	  can handle complicated SCSI commands: tagged variable length cdbs
	  with bidirectional data transfers and generic request/response
	  protocols (e.g. Task Management Functions and SMP in Serial
	  Attached SCSI).

	  If unsure, say N.

config BLK_DEV_INTEGRITY
	bool "Block layer data integrity support"
	---help---
	Some storage devices allow extra information to be
	stored/retrieved to help protect the data.  The block layer
	data integrity option provides hooks which can be used by
	filesystems to ensure better data integrity.

	Say yes here if you have a storage device that provides the
	T10/SCSI Data Integrity Field or the T13/ATA External Path
	Protection.  If in doubt, say N.

endif # BLOCK

config BLOCK_COMPAT
	bool
	depends on BLOCK && COMPAT
	default y

source block/Kconfig.iosched

/*
 * 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 (coda@cs.cmu.edu).
 */

#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 "coda_int.h"

/* dir inode-ops */
static int coda_create(struct inode *dir, struct dentry *new, int mode, struct nameidata *nd);
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 *buf, 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 *coda_file, void *buf,
			      filldir_t filldir);

/* same as fs/bad_inode.c */
static int coda_return_EIO(void)
{
	return -EIO;
}
#define CODA_EIO_ERROR ((void *) (coda_return_EIO))

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

const 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_EIO_ERROR,
	.rename		= coda_rename,
	.permission	= coda_permission,
	.getattr	= coda_getattr,
	.setattr	= coda_setattr,
};

const struct file_operations coda_dir_operations = {
	.llseek		= generic_file_llseek,
	.read		= generic_read_dir,
	.readdir	= coda_readdir,
	.open		= coda_open,
	.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 *inode = NULL;
	struct CodaFid resfid = { { 0, } };
	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(KERN_ERR "name too long: lookup, %s (%*s)\n",
		       coda_i2s(dir), (int)length, name);
		return ERR_PTR(-ENAMETOOLONG);
	}

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

	lock_kernel();

	error = venus_lookup(dir->i_sb, coda_i2f(dir), name, length,
			     &type, &resfid);
	if (!error)
		error = coda_cnode_make(&inode, &resfid, dir->i_sb);

	unlock_kernel();

	if (error && error != -ENOENT)
		return ERR_PTR(error);

exit:
	entry->d_op = &coda_dentry_operations;

	if (inode && (type & CODA_NOCACHE))
		coda_flag_inode(inode, C_VATTR | C_PURGE);

	return d_splice_alias(inode, entry);
}


int coda_permission(struct inode *inode, int mask)
{
        int error = 0;

	mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
 
	if (!mask)
		return 0; 

	if ((mask & MAY_EXEC) && !execute_ok(inode))
		return -EACCES;

	lock_kernel();

	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_update_mtime(struct inode *dir)
{
#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_SEC;
#endif
}

/* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a
 * trick to fool GNU find's optimizations. If we can't be sure of the link
 * (because of volume mount points) we set i_nlink to 1 which forces find
 * to consider every child as a possible directory. We should also never
 * see an increment or decrement for deleted directories where i_nlink == 0 */
static inline void coda_dir_inc_nlink(struct inode *dir)
{
	if (dir->i_nlink >= 2)
		inc_nlink(dir);
}

static inline void coda_dir_drop_nlink(struct inode *dir)
{
	if (dir->i_nlink > 2)
		drop_nlink(dir);
}

/* 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();

	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, &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_update_mtime(dir);
	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();

	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_inc_nlink(dir);
	coda_dir_update_mtime(dir);
	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();

	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_update_mtime(dir_inode);
	atomic_inc(&inode->i_count);
	d_instantiate(de, inode);
	inc_nlink(inode);

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();

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