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linux-next/fs/coda/dir.c
Arjan van de Ven 754661f143 [PATCH] mark struct inode_operations const 1
Many struct inode_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:46 -08:00

706 lines
17 KiB
C

/*
* 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 <linux/coda_proc.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 *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);
/* 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,
.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_SEC;
#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, &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);
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();
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();
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_changed(dir_inode, 0);
unlock_kernel();
return error;
}
/* destruction routines: unlink, rmdir */
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();
coda_vfs_stat.unlink++;
error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
if ( error ) {
unlock_kernel();
return error;
}
coda_dir_changed(dir, 0);
drop_nlink(de->d_inode);
unlock_kernel();
return 0;
}
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();
coda_vfs_stat.rmdir++;
if (!d_unhashed(de)) {
unlock_kernel();
return -EBUSY;
}
error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
if ( error ) {
unlock_kernel();
return error;
}
coda_dir_changed(dir, -1);
drop_nlink(de->d_inode);
d_delete(de);
unlock_kernel();
return 0;
}
/* 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 link_adjust = 0;
int error;
lock_kernel();
coda_vfs_stat.rename++;
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) )
link_adjust = 1;
coda_dir_changed(old_dir, -link_adjust);
coda_dir_changed(new_dir, link_adjust);
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 */
int coda_readdir(struct file *coda_file, void *dirent, filldir_t filldir)
{
struct dentry *coda_dentry = coda_file->f_path.dentry;
struct coda_file_info *cfi;
struct file *host_file;
struct inode *host_inode;
int ret;
cfi = CODA_FTOC(coda_file);
BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
host_file = cfi->cfi_container;
coda_vfs_stat.readdir++;
host_inode = host_file->f_path.dentry->d_inode;
mutex_lock(&host_inode->i_mutex);
host_file->f_pos = coda_file->f_pos;
if (!host_file->f_op->readdir) {
/* Venus: we must read Venus dirents from the file */
ret = coda_venus_readdir(host_file, filldir, dirent, coda_dentry);
} else {
/* potemkin case: we were handed a directory inode. */
/* Yuk, we can't call vfs_readdir because we are already
* holding the inode semaphore. */
ret = -ENOTDIR;
if (!host_file->f_op || !host_file->f_op->readdir)
goto out;
ret = -ENOENT;
if (!IS_DEADDIR(host_inode)) {
ret = host_file->f_op->readdir(host_file, filldir, dirent);
file_accessed(host_file);
}
}
out:
coda_file->f_pos = host_file->f_pos;
mutex_unlock(&host_inode->i_mutex);
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 *filp, filldir_t filldir,
void *dirent, struct dentry *dir)
{
int result = 0; /* # of entries returned */
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, i;
vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
if (!vdir) return -ENOMEM;
i = filp->f_pos;
switch(i) {
case 0:
ret = filldir(dirent, ".", 1, 0, dir->d_inode->i_ino, DT_DIR);
if (ret < 0) break;
result++;
filp->f_pos++;
/* fallthrough */
case 1:
ret = filldir(dirent, "..", 2, 1, dir->d_parent->d_inode->i_ino, DT_DIR);
if (ret < 0) break;
result++;
filp->f_pos++;
/* fallthrough */
default:
while (1) {
/* read entries from the directory file */
ret = kernel_read(filp, filp->f_pos - 2, (char *)vdir,
sizeof(*vdir));
if (ret < 0) {
printk("coda_venus_readdir: read dir failed %d\n", 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("coda_venus_readdir: short read: %ld\n",
filp->f_path.dentry->d_inode->i_ino);
ret = -EBADF;
break;
}
/* validate whether the directory file actually makes sense */
if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
printk("coda_venus_readdir: Invalid dir: %ld\n",
filp->f_path.dentry->d_inode->i_ino);
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(dir, &name);
if (!ino) ino = vdir->d_fileno;
type = CDT2DT(vdir->d_type);
ret = filldir(dirent, name.name, name.len, filp->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. */
filp->f_pos += vdir->d_reclen;
}
}
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;
}