fs/coda/dir.c - kernel/msm-4.9 - Gitiles


 /*
  * 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/slab.h>
 #include <linux/file.h>
 #include <linux/stat.h>
 #include <linux/errno.h>
 #include <linux/string.h>
 #include <linux/spinlock.h>
 #include <linux/namei.h>

 #include <asm/uaccess.h>

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

 #include "coda_int.h"

 /* dir inode-ops */
 static int coda_create(struct inode *dir, struct dentry *new, umode_t 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, umode_t 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(const 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))

 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;
 	}

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

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

 exit:
 	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;

 	if (mask & MAY_NOT_BLOCK)
 		return -ECHILD;

 	mask &= MAY_READ | MAY_WRITE | MAY_EXEC;

 	if (!mask)
 		return 0;

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

 	if (coda_cache_check(inode, mask))
 		return 0;

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

 	if (!error)
 		coda_cache_enter(inode, mask);

 	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, umode_t mode, struct nameidata *nd)
 {
 	int error;
 	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_isroot(dir) && coda_iscontrol(name, length))
 		return -EPERM;

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

 	inode = coda_iget(dir->i_sb, &newfid, &attrs);
 	if (IS_ERR(inode)) {
 		error = PTR_ERR(inode);
 		goto err_out;
 	}

 	/* invalidate the directory cnode's attributes */
 	coda_dir_update_mtime(dir);
 	d_instantiate(de, inode);
 	return 0;
 err_out:
 	d_drop(de);
 	return error;
 }

 static int coda_mkdir(struct inode *dir, struct dentry *de, umode_t 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;

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

 	attrs.va_mode = mode;
 	error = venus_mkdir(dir->i_sb, coda_i2f(dir),
 			       name, len, &newfid, &attrs);
 	if (error)
 		goto err_out;

 	inode = coda_iget(dir->i_sb, &newfid, &attrs);
 	if (IS_ERR(inode)) {
 		error = PTR_ERR(inode);
 		goto err_out;
 	}

 	/* invalidate the directory cnode's attributes */
 	coda_dir_inc_nlink(dir);
 	coda_dir_update_mtime(dir);
 	d_instantiate(de, inode);
 	return 0;
 err_out:
 	d_drop(de);
 	return error;
 }

 /* 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;

 	if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
 		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);
 		return error;
 	}

 	coda_dir_update_mtime(dir_inode);
 	ihold(inode);
 	d_instantiate(de, inode);
 	inc_nlink(inode);
 	return 0;
 }


 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;

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

 	symlen = strlen(symname);
 	if (symlen > CODA_MAXPATHLEN)
 		return -ENAMETOOLONG;

 	/*
 	 * This entry is now negative. Since we do not create
 	 * an inode for the entry we have to drop it.
 	 */
 	d_drop(de);
 	error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
 			      symname, symlen);

 	/* mtime is no good anymore */
 	if (!error)
 		coda_dir_update_mtime(dir_inode);

 	return error;
 }

 /* destruction routines: unlink, rmdir */
 static int coda_unlink(struct inode *dir, struct dentry *de)
 {
         int error;
 	const char *name = de->d_name.name;
 	int len = de->d_name.len;

 	error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
 	if (error)
 		return error;

 	coda_dir_update_mtime(dir);
 	drop_nlink(de->d_inode);
 	return 0;
 }

 static int coda_rmdir(struct inode *dir, struct dentry *de)
 {
 	const char *name = de->d_name.name;
 	int len = de->d_name.len;
 	int error;

 	error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
 	if (!error) {
 		/* VFS may delete the child */
 		if (de->d_inode)
 			clear_nlink(de->d_inode);

 		/* fix the link count of the parent */
 		coda_dir_drop_nlink(dir);
 		coda_dir_update_mtime(dir);
 	}
 	return error;
 }

 /* rename */
 static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
 		       struct inode *new_dir, struct dentry *new_dentry)
 {
 	const char *old_name = old_dentry->d_name.name;
 	const char *new_name = new_dentry->d_name.name;
 	int old_length = old_dentry->d_name.len;
 	int new_length = new_dentry->d_name.len;
 	int error;

 	error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
 			     coda_i2f(new_dir), old_length, new_length,
 			     (const char *) old_name, (const char *)new_name);
 	if (!error) {
 		if (new_dentry->d_inode) {
 			if (S_ISDIR(new_dentry->d_inode->i_mode)) {
 				coda_dir_drop_nlink(old_dir);
 				coda_dir_inc_nlink(new_dir);
 			}
 			coda_dir_update_mtime(old_dir);
 			coda_dir_update_mtime(new_dir);
 			coda_flag_inode(new_dentry->d_inode, C_VATTR);
 		} else {
 			coda_flag_inode(old_dir, C_VATTR);
 			coda_flag_inode(new_dir, C_VATTR);
 		}
 	}
 	return error;
 }


 /* file operations for directories */
 static int coda_readdir(struct file *coda_file, void *buf, filldir_t filldir)
 {
 	struct coda_file_info *cfi;
 	struct file *host_file;
 	int ret;

 	cfi = CODA_FTOC(coda_file);
 	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 	host_file = cfi->cfi_container;

 	if (!host_file->f_op)
 		return -ENOTDIR;

 	if (host_file->f_op->readdir)
 	{
 		/* potemkin case: we were handed a directory inode.
 		 * We can't use vfs_readdir because we have to keep the file
 		 * position in sync between the coda_file and the host_file.
 		 * and as such we need grab the inode mutex. */
 		struct inode *host_inode = host_file->f_path.dentry->d_inode;

 		mutex_lock(&host_inode->i_mutex);
 		host_file->f_pos = coda_file->f_pos;

 		ret = -ENOENT;
 		if (!IS_DEADDIR(host_inode)) {
 			ret = host_file->f_op->readdir(host_file, buf, filldir);
 			file_accessed(host_file);
 		}

 		coda_file->f_pos = host_file->f_pos;
 		mutex_unlock(&host_inode->i_mutex);
 	}
 	else /* Venus: we must read Venus dirents from a file */
 		ret = coda_venus_readdir(coda_file, buf, filldir);

 	return ret;
 }

 static inline unsigned int CDT2DT(unsigned char cdt)
 {
 	unsigned int dt;

 	switch(cdt) {
 	case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
 	case CDT_FIFO:	  dt = DT_FIFO;    break;
 	case CDT_CHR:	  dt = DT_CHR;     break;
 	case CDT_DIR:	  dt = DT_DIR;     break;
 	case CDT_BLK:	  dt = DT_BLK;     break;
 	case CDT_REG:	  dt = DT_REG;     break;
 	case CDT_LNK:	  dt = DT_LNK;     break;
 	case CDT_SOCK:	  dt = DT_SOCK;    break;
 	case CDT_WHT:	  dt = DT_WHT;     break;
 	default:	  dt = DT_UNKNOWN; break;
 	}
 	return dt;
 }

 /* support routines */
 static int coda_venus_readdir(struct file *coda_file, void *buf,
 			      filldir_t filldir)
 {
 	int result = 0; /* # of entries returned */
 	struct coda_file_info *cfi;
 	struct coda_inode_info *cii;
 	struct file *host_file;
 	struct dentry *de;
 	struct venus_dirent *vdir;
 	unsigned long vdir_size = offsetof(struct venus_dirent, d_name);
 	unsigned int type;
 	struct qstr name;
 	ino_t ino;
 	int ret;

 	cfi = CODA_FTOC(coda_file);
 	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 	host_file = cfi->cfi_container;

 	de = coda_file->f_path.dentry;
 	cii = ITOC(de->d_inode);

 	vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
 	if (!vdir) return -ENOMEM;

 	if (coda_file->f_pos == 0) {
 		ret = filldir(buf, ".", 1, 0, de->d_inode->i_ino, DT_DIR);
 		if (ret < 0)
 			goto out;
 		result++;
 		coda_file->f_pos++;
 	}
 	if (coda_file->f_pos == 1) {
 		ret = filldir(buf, "..", 2, 1, parent_ino(de), DT_DIR);
 		if (ret < 0)
 			goto out;
 		result++;
 		coda_file->f_pos++;
 	}
 	while (1) {
 		/* read entries from the directory file */
 		ret = kernel_read(host_file, coda_file->f_pos - 2, (char *)vdir,
 				  sizeof(*vdir));
 		if (ret < 0) {
 			printk(KERN_ERR "coda readdir: read dir %s failed %d\n",
 			       coda_f2s(&cii->c_fid), ret);
 			break;
 		}
 		if (ret == 0) break; /* end of directory file reached */

 		/* catch truncated reads */
 		if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
 			printk(KERN_ERR "coda readdir: short read on %s\n",
 			       coda_f2s(&cii->c_fid));
 			ret = -EBADF;
 			break;
 		}
 		/* validate whether the directory file actually makes sense */
 		if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
 			printk(KERN_ERR "coda readdir: invalid dir %s\n",
 			       coda_f2s(&cii->c_fid));
 			ret = -EBADF;
 			break;
 		}

 		name.len = vdir->d_namlen;
 		name.name = vdir->d_name;

 		/* Make sure we skip '.' and '..', we already got those */
 		if (name.name[0] == '.' && (name.len == 1 ||
 		    (vdir->d_name[1] == '.' && name.len == 2)))
 			vdir->d_fileno = name.len = 0;

 		/* skip null entries */
 		if (vdir->d_fileno && name.len) {
 			/* try to look up this entry in the dcache, that way
 			 * userspace doesn't have to worry about breaking
 			 * getcwd by having mismatched inode numbers for
 			 * internal volume mountpoints. */
 			ino = find_inode_number(de, &name);
 			if (!ino) ino = vdir->d_fileno;

 			type = CDT2DT(vdir->d_type);
 			ret = filldir(buf, name.name, name.len,
 				      coda_file->f_pos, ino, type);
 			/* failure means no space for filling in this round */
 			if (ret < 0) break;
 			result++;
 		}
 		/* we'll always have progress because d_reclen is unsigned and
 		 * we've already established it is non-zero. */
 		coda_file->f_pos += vdir->d_reclen;
 	}
 out:
 	kfree(vdir);
 	return result ? result : ret;
 }

 /* called when a cache lookup succeeds */
 static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd)
 {
 	struct inode *inode;
 	struct coda_inode_info *cii;

 	if (nd->flags & LOOKUP_RCU)
 		return -ECHILD;

 	inode = de->d_inode;
 	if (!inode || coda_isroot(inode))
 		goto out;
 	if (is_bad_inode(inode))
 		goto bad;

 	cii = ITOC(de->d_inode);
 	if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
 		goto out;

 	shrink_dcache_parent(de);

 	/* propagate for a flush */
 	if (cii->c_flags & C_FLUSH)
 		coda_flag_inode_children(inode, C_FLUSH);

 	if (de->d_count > 1)
 		/* pretend it's valid, but don't change the flags */
 		goto out;

 	/* clear the flags. */
 	spin_lock(&cii->c_lock);
 	cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
 	spin_unlock(&cii->c_lock);
 bad:
 	return 0;
 out:
 	return 1;
 }

 /*
  * This is the callback from dput() when d_count is going to 0.
  * We use this to unhash dentries with bad inodes.
  */
 static int coda_dentry_delete(const struct dentry * dentry)
 {
 	int flags;

 	if (!dentry->d_inode)
 		return 0;

 	flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
 	if (is_bad_inode(dentry->d_inode) || flags) {
 		return 1;
 	}
 	return 0;
 }


 /*
  * This is called when we want to check if the inode has
  * changed on the server.  Coda makes this easy since the
  * cache manager Venus issues a downcall to the kernel when this
  * happens
  */
 int coda_revalidate_inode(struct dentry *dentry)
 {
 	struct coda_vattr attr;
 	int error;
 	int old_mode;
 	ino_t old_ino;
 	struct inode *inode = dentry->d_inode;
 	struct coda_inode_info *cii = ITOC(inode);

 	if (!cii->c_flags)
 		return 0;

 	if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
 		error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
 		if (error)
 			return -EIO;

 		/* this inode may be lost if:
 		   - it's ino changed
 		   - type changes must be permitted for repair and
 		   missing mount points.
 		*/
 		old_mode = inode->i_mode;
 		old_ino = inode->i_ino;
 		coda_vattr_to_iattr(inode, &attr);

 		if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
 			printk("Coda: inode %ld, fid %s changed type!\n",
 			       inode->i_ino, coda_f2s(&(cii->c_fid)));
 		}

 		/* the following can happen when a local fid is replaced
 		   with a global one, here we lose and declare the inode bad */
 		if (inode->i_ino != old_ino)
 			return -EIO;

 		coda_flag_inode_children(inode, C_FLUSH);

 		spin_lock(&cii->c_lock);
 		cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
 		spin_unlock(&cii->c_lock);
 	}
 	return 0;
 }

	/*
	* 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/slab.h>
	#include <linux/file.h>
	#include <linux/stat.h>
	#include <linux/errno.h>
	#include <linux/string.h>
	#include <linux/spinlock.h>
	#include <linux/namei.h>

	#include <asm/uaccess.h>

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

	#include "coda_int.h"

	/* dir inode-ops */
	static int coda_create(struct inode dir, struct dentry new, umode_t 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, umode_t 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(const 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))

	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;
	}

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

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

	exit:
	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;

	if (mask & MAY_NOT_BLOCK)
	return -ECHILD;

	mask &= MAY_READ \| MAY_WRITE \| MAY_EXEC;

	if (!mask)
	return 0;

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

	if (coda_cache_check(inode, mask))
	return 0;

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

	if (!error)
	coda_cache_enter(inode, mask);

	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, umode_t mode, struct nameidata *nd)
	{
	int error;
	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_isroot(dir) && coda_iscontrol(name, length))
	return -EPERM;

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

	inode = coda_iget(dir->i_sb, &newfid, &attrs);
	if (IS_ERR(inode)) {
	error = PTR_ERR(inode);
	goto err_out;
	}

	/* invalidate the directory cnode's attributes */
	coda_dir_update_mtime(dir);
	d_instantiate(de, inode);
	return 0;
	err_out:
	d_drop(de);
	return error;
	}

	static int coda_mkdir(struct inode dir, struct dentry de, umode_t 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;

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

	attrs.va_mode = mode;
	error = venus_mkdir(dir->i_sb, coda_i2f(dir),
	name, len, &newfid, &attrs);
	if (error)
	goto err_out;

	inode = coda_iget(dir->i_sb, &newfid, &attrs);
	if (IS_ERR(inode)) {
	error = PTR_ERR(inode);
	goto err_out;
	}

	/* invalidate the directory cnode's attributes */
	coda_dir_inc_nlink(dir);
	coda_dir_update_mtime(dir);
	d_instantiate(de, inode);
	return 0;
	err_out:
	d_drop(de);
	return error;
	}

	/* 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;

	if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
	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);
	return error;
	}

	coda_dir_update_mtime(dir_inode);
	ihold(inode);
	d_instantiate(de, inode);
	inc_nlink(inode);
	return 0;
	}


	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;

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

	symlen = strlen(symname);
	if (symlen > CODA_MAXPATHLEN)
	return -ENAMETOOLONG;

	/*
	* This entry is now negative. Since we do not create
	* an inode for the entry we have to drop it.
	*/
	d_drop(de);
	error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
	symname, symlen);

	/* mtime is no good anymore */
	if (!error)
	coda_dir_update_mtime(dir_inode);

	return error;
	}

	/* destruction routines: unlink, rmdir */
	static int coda_unlink(struct inode dir, struct dentry de)
	{
	int error;
	const char *name = de->d_name.name;
	int len = de->d_name.len;

	error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
	if (error)
	return error;

	coda_dir_update_mtime(dir);
	drop_nlink(de->d_inode);
	return 0;
	}

	static int coda_rmdir(struct inode dir, struct dentry de)
	{
	const char *name = de->d_name.name;
	int len = de->d_name.len;
	int error;

	error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
	if (!error) {
	/* VFS may delete the child */
	if (de->d_inode)
	clear_nlink(de->d_inode);

	/* fix the link count of the parent */
	coda_dir_drop_nlink(dir);
	coda_dir_update_mtime(dir);
	}
	return error;
	}

	/* rename */
	static int coda_rename(struct inode old_dir, struct dentry old_dentry,
	struct inode new_dir, struct dentry new_dentry)
	{
	const char *old_name = old_dentry->d_name.name;
	const char *new_name = new_dentry->d_name.name;
	int old_length = old_dentry->d_name.len;
	int new_length = new_dentry->d_name.len;
	int error;

	error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
	coda_i2f(new_dir), old_length, new_length,
	(const char ) old_name, (const char )new_name);
	if (!error) {
	if (new_dentry->d_inode) {
	if (S_ISDIR(new_dentry->d_inode->i_mode)) {
	coda_dir_drop_nlink(old_dir);
	coda_dir_inc_nlink(new_dir);
	}
	coda_dir_update_mtime(old_dir);
	coda_dir_update_mtime(new_dir);
	coda_flag_inode(new_dentry->d_inode, C_VATTR);
	} else {
	coda_flag_inode(old_dir, C_VATTR);
	coda_flag_inode(new_dir, C_VATTR);
	}
	}
	return error;
	}


	/* file operations for directories */
	static int coda_readdir(struct file coda_file, void buf, filldir_t filldir)
	{
	struct coda_file_info *cfi;
	struct file *host_file;
	int ret;

	cfi = CODA_FTOC(coda_file);
	BUG_ON(!cfi \|\| cfi->cfi_magic != CODA_MAGIC);
	host_file = cfi->cfi_container;

	if (!host_file->f_op)
	return -ENOTDIR;

	if (host_file->f_op->readdir)
	{
	/* potemkin case: we were handed a directory inode.
	* We can't use vfs_readdir because we have to keep the file
	* position in sync between the coda_file and the host_file.
	* and as such we need grab the inode mutex. */
	struct inode *host_inode = host_file->f_path.dentry->d_inode;

	mutex_lock(&host_inode->i_mutex);
	host_file->f_pos = coda_file->f_pos;

	ret = -ENOENT;
	if (!IS_DEADDIR(host_inode)) {
	ret = host_file->f_op->readdir(host_file, buf, filldir);
	file_accessed(host_file);
	}

	coda_file->f_pos = host_file->f_pos;
	mutex_unlock(&host_inode->i_mutex);
	}
	else /* Venus: we must read Venus dirents from a file */
	ret = coda_venus_readdir(coda_file, buf, filldir);

	return ret;
	}

	static inline unsigned int CDT2DT(unsigned char cdt)
	{
	unsigned int dt;

	switch(cdt) {
	case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
	case CDT_FIFO: dt = DT_FIFO; break;
	case CDT_CHR: dt = DT_CHR; break;
	case CDT_DIR: dt = DT_DIR; break;
	case CDT_BLK: dt = DT_BLK; break;
	case CDT_REG: dt = DT_REG; break;
	case CDT_LNK: dt = DT_LNK; break;
	case CDT_SOCK: dt = DT_SOCK; break;
	case CDT_WHT: dt = DT_WHT; break;
	default: dt = DT_UNKNOWN; break;
	}
	return dt;
	}

	/* support routines */
	static int coda_venus_readdir(struct file coda_file, void buf,
	filldir_t filldir)
	{
	int result = 0; /* # of entries returned */
	struct coda_file_info *cfi;
	struct coda_inode_info *cii;
	struct file *host_file;
	struct dentry *de;
	struct venus_dirent *vdir;
	unsigned long vdir_size = offsetof(struct venus_dirent, d_name);
	unsigned int type;
	struct qstr name;
	ino_t ino;
	int ret;

	cfi = CODA_FTOC(coda_file);
	BUG_ON(!cfi \|\| cfi->cfi_magic != CODA_MAGIC);
	host_file = cfi->cfi_container;

	de = coda_file->f_path.dentry;
	cii = ITOC(de->d_inode);

	vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
	if (!vdir) return -ENOMEM;

	if (coda_file->f_pos == 0) {
	ret = filldir(buf, ".", 1, 0, de->d_inode->i_ino, DT_DIR);
	if (ret < 0)
	goto out;
	result++;
	coda_file->f_pos++;
	}
	if (coda_file->f_pos == 1) {
	ret = filldir(buf, "..", 2, 1, parent_ino(de), DT_DIR);
	if (ret < 0)
	goto out;
	result++;
	coda_file->f_pos++;
	}
	while (1) {
	/* read entries from the directory file */
	ret = kernel_read(host_file, coda_file->f_pos - 2, (char *)vdir,
	sizeof(*vdir));
	if (ret < 0) {
	printk(KERN_ERR "coda readdir: read dir %s failed %d\n",
	coda_f2s(&cii->c_fid), ret);
	break;
	}
	if (ret == 0) break; /* end of directory file reached */

	/* catch truncated reads */
	if (ret < vdir_size \|\| ret < vdir_size + vdir->d_namlen) {
	printk(KERN_ERR "coda readdir: short read on %s\n",
	coda_f2s(&cii->c_fid));
	ret = -EBADF;
	break;
	}
	/* validate whether the directory file actually makes sense */
	if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
	printk(KERN_ERR "coda readdir: invalid dir %s\n",
	coda_f2s(&cii->c_fid));
	ret = -EBADF;
	break;
	}

	name.len = vdir->d_namlen;
	name.name = vdir->d_name;

	/* Make sure we skip '.' and '..', we already got those */
	if (name.name[0] == '.' && (name.len == 1 \|\|
	(vdir->d_name[1] == '.' && name.len == 2)))
	vdir->d_fileno = name.len = 0;

	/* skip null entries */
	if (vdir->d_fileno && name.len) {
	/* try to look up this entry in the dcache, that way
	* userspace doesn't have to worry about breaking
	* getcwd by having mismatched inode numbers for
	* internal volume mountpoints. */
	ino = find_inode_number(de, &name);
	if (!ino) ino = vdir->d_fileno;

	type = CDT2DT(vdir->d_type);
	ret = filldir(buf, name.name, name.len,
	coda_file->f_pos, ino, type);
	/* failure means no space for filling in this round */
	if (ret < 0) break;
	result++;
	}
	/* we'll always have progress because d_reclen is unsigned and
	* we've already established it is non-zero. */
	coda_file->f_pos += vdir->d_reclen;
	}
	out:
	kfree(vdir);
	return result ? result : ret;
	}

	/* called when a cache lookup succeeds */
	static int coda_dentry_revalidate(struct dentry de, struct nameidata nd)
	{
	struct inode *inode;
	struct coda_inode_info *cii;

	if (nd->flags & LOOKUP_RCU)
	return -ECHILD;

	inode = de->d_inode;
	if (!inode \|\| coda_isroot(inode))
	goto out;
	if (is_bad_inode(inode))
	goto bad;

	cii = ITOC(de->d_inode);
	if (!(cii->c_flags & (C_PURGE \| C_FLUSH)))
	goto out;

	shrink_dcache_parent(de);

	/* propagate for a flush */
	if (cii->c_flags & C_FLUSH)
	coda_flag_inode_children(inode, C_FLUSH);

	if (de->d_count > 1)
	/* pretend it's valid, but don't change the flags */
	goto out;

	/* clear the flags. */
	spin_lock(&cii->c_lock);
	cii->c_flags &= ~(C_VATTR \| C_PURGE \| C_FLUSH);
	spin_unlock(&cii->c_lock);
	bad:
	return 0;
	out:
	return 1;
	}

	/*
	* This is the callback from dput() when d_count is going to 0.
	* We use this to unhash dentries with bad inodes.
	*/
	static int coda_dentry_delete(const struct dentry * dentry)
	{
	int flags;

	if (!dentry->d_inode)
	return 0;

	flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE;
	if (is_bad_inode(dentry->d_inode) \|\| flags) {
	return 1;
	}
	return 0;
	}



	/*
	* This is called when we want to check if the inode has
	* changed on the server. Coda makes this easy since the
	* cache manager Venus issues a downcall to the kernel when this
	* happens
	*/
	int coda_revalidate_inode(struct dentry *dentry)
	{
	struct coda_vattr attr;
	int error;
	int old_mode;
	ino_t old_ino;
	struct inode *inode = dentry->d_inode;
	struct coda_inode_info *cii = ITOC(inode);

	if (!cii->c_flags)
	return 0;

	if (cii->c_flags & (C_VATTR \| C_PURGE \| C_FLUSH)) {
	error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
	if (error)
	return -EIO;

	/* this inode may be lost if:
	- it's ino changed
	- type changes must be permitted for repair and
	missing mount points.
	*/
	old_mode = inode->i_mode;
	old_ino = inode->i_ino;
	coda_vattr_to_iattr(inode, &attr);

	if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
	printk("Coda: inode %ld, fid %s changed type!\n",
	inode->i_ino, coda_f2s(&(cii->c_fid)));
	}

	/* the following can happen when a local fid is replaced
	with a global one, here we lose and declare the inode bad */
	if (inode->i_ino != old_ino)
	return -EIO;

	coda_flag_inode_children(inode, C_FLUSH);

	spin_lock(&cii->c_lock);
	cii->c_flags &= ~(C_VATTR \| C_PURGE \| C_FLUSH);
	spin_unlock(&cii->c_lock);
	}
	return 0;
	}