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DEFINITIONS
This source file includes following definitions.
- coda_return_EIO
- coda_lookup
- coda_permission
- coda_dir_update_mtime
- coda_dir_inc_nlink
- coda_dir_drop_nlink
- coda_create
- coda_mkdir
- coda_link
- coda_symlink
- coda_unlink
- coda_rmdir
- coda_rename
- coda_readdir
- CDT2DT
- coda_venus_readdir
- coda_dentry_revalidate
- coda_dentry_delete
- coda_revalidate_inode
/*
* 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 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;
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;
}
symlen = strlen(symname);
if ( symlen > CODA_MAXPATHLEN ) {
unlock_kernel();
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);
unlock_kernel();
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;
lock_kernel();
error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
if ( error ) {
unlock_kernel();
return error;
}
coda_dir_update_mtime(dir);
drop_nlink(de->d_inode);
unlock_kernel();
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;
lock_kernel();
error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
if (!error) {
/* VFS may delete the child */
if (de->d_inode)
de->d_inode->i_nlink = 0;
/* fix the link count of the parent */
coda_dir_drop_nlink(dir);
coda_dir_update_mtime(dir);
}
unlock_kernel();
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;
lock_kernel();
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);
}
}
unlock_kernel();
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 =
(unsigned long)(&((struct venus_dirent *)0)->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, de->d_parent->d_inode->i_ino, 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 = de->d_inode;
struct coda_inode_info *cii;
if (!inode)
return 1;
lock_kernel();
if (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 (atomic_read(&de->d_count) > 1)
/* pretend it's valid, but don't change the flags */
goto out;
/* clear the flags. */
cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
bad:
unlock_kernel();
return 0;
out:
unlock_kernel();
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(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 = 0;
int old_mode;
ino_t old_ino;
struct inode *inode = dentry->d_inode;
struct coda_inode_info *cii = ITOC(inode);
lock_kernel();
if ( !cii->c_flags )
goto ok;
if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
if ( error )
goto return_bad;
/* 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)
goto return_bad;
coda_flag_inode_children(inode, C_FLUSH);
cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
}
ok:
unlock_kernel();
return 0;
return_bad:
unlock_kernel();
return -EIO;
}