Viewing file:  dir.c (20.57 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/*
* 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/sched.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/locks.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);
static int coda_mknod(struct inode *dir, struct dentry *new, int mode, int rdev);
static struct dentry *coda_lookup(struct inode *dir, struct dentry *target);
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, int);
static int coda_dentry_delete(struct dentry *);
/* support routines */
static void coda_prepare_fakefile(struct file *coda_file,
struct dentry *open_dentry,
struct file *open_file);
static int coda_venus_readdir(struct file *filp, void *dirent,
filldir_t filldir);
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,
revalidate: coda_revalidate_inode,
setattr: coda_notify_change,
};
struct file_operations coda_dir_operations = {
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 inode *res_inode = NULL;
struct ViceFid resfid = {0,0,0};
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);
}
CDEBUG(D_INODE, "name %s, len %ld in ino %ld, fid %s\n",
name, (long)length, dir->i_ino, coda_i2s(dir));
/* control object, create inode on the fly */
if (coda_isroot(dir) && coda_iscontrol(name, length)) {
error = coda_cnode_makectl(&res_inode, dir->i_sb);
CDEBUG(D_SPECIAL,
"Lookup on CTL object; dir ino %ld, count %d\n",
dir->i_ino, atomic_read(&dir->i_count));
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);
CDEBUG(D_INODE, "dropme set for %s\n",
coda_f2s(&resfid));
dropme = 1;
}
error = coda_cnode_make(&res_inode, &resfid, dir->i_sb);
if (error) return ERR_PTR(error);
} else if (error != -ENOENT) {
CDEBUG(D_INODE, "error for %s(%*s)%d\n",
coda_i2s(dir), (int)length, name, error);
return ERR_PTR(error);
}
CDEBUG(D_INODE, "lookup: %s is (%s), type %d result %d, dropme %d\n",
name, coda_f2s(&resfid), type, error, dropme);
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);
}
return NULL;
}
int coda_permission(struct inode *inode, int mask)
{
int error;
coda_vfs_stat.permission++;
if ( mask == 0 )
return 0;
if ( coda_access_cache ) {
coda_permission_stat.count++;
if ( coda_cache_check(inode, mask) ) {
coda_permission_stat.hit_count++;
return 0;
}
}
CDEBUG(D_INODE, "mask is %o\n", mask);
error = venus_access(inode->i_sb, coda_i2f(inode), mask);
CDEBUG(D_INODE, "fid: %s, ino: %ld (mask: %o) error: %d\n",
coda_i2s(inode), inode->i_ino, mask, error);
if (!error)
coda_cache_enter(inode, mask);
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)
{
int error=0;
const char *name=de->d_name.name;
int length=de->d_name.len;
struct inode *inode = NULL;
struct ViceFid newfid;
struct coda_vattr attrs;
coda_vfs_stat.create++;
CDEBUG(D_INODE, "name: %s, length %d, mode %o\n", name, length, mode);
if (coda_isroot(dir) && coda_iscontrol(name, length))
return -EPERM;
error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
0, mode, 0, &newfid, &attrs);
if ( error ) {
CDEBUG(D_INODE, "create: %s, result %d\n",
coda_f2s(&newfid), error);
d_drop(de);
return error;
}
inode = coda_iget(dir->i_sb, &newfid, &attrs);
if ( IS_ERR(inode) ) {
d_drop(de);
return PTR_ERR(inode);
}
/* invalidate the directory cnode's attributes */
coda_dir_changed(dir, 0);
d_instantiate(de, inode);
return 0;
}
static int coda_mknod(struct inode *dir, struct dentry *de, int mode, int rdev)
{
int error=0;
const char *name=de->d_name.name;
int length=de->d_name.len;
struct inode *result = NULL;
struct ViceFid newfid;
struct coda_vattr attrs;
if ( coda_hasmknod == 0 )
return -EIO;
coda_vfs_stat.create++;
CDEBUG(D_INODE, "name: %s, length %d, mode %o, rdev %x\n",
name, length, mode, rdev);
if (coda_isroot(dir) && coda_iscontrol(name, length))
return -EPERM;
error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
0, mode, rdev, &newfid, &attrs);
if ( error ) {
CDEBUG(D_INODE, "mknod: %s, result %d\n",
coda_f2s(&newfid), error);
d_drop(de);
return error;
}
error = coda_cnode_make(&result, &newfid, dir->i_sb);
if ( error ) {
d_drop(de);
result = NULL;
return error;
}
/* invalidate the directory cnode's attributes */
coda_dir_changed(dir, 0);
d_instantiate(de, result);
return 0;
}
static int coda_mkdir(struct inode *dir, struct dentry *de, int mode)
{
struct inode *inode;
struct coda_vattr attr;
const char *name = de->d_name.name;
int len = de->d_name.len;
int error;
struct ViceFid newfid;
coda_vfs_stat.mkdir++;
if (coda_isroot(dir) && coda_iscontrol(name, len))
return -EPERM;
CDEBUG(D_INODE, "mkdir %s (len %d) in %s, mode %o.\n",
name, len, coda_i2s(dir), mode);
attr.va_mode = mode;
error = venus_mkdir(dir->i_sb, coda_i2f(dir),
name, len, &newfid, &attr);
if ( error ) {
CDEBUG(D_INODE, "mkdir error: %s result %d\n",
coda_f2s(&newfid), error);
d_drop(de);
return error;
}
CDEBUG(D_INODE, "mkdir: new dir has fid %s.\n",
coda_f2s(&newfid));
error = coda_cnode_make(&inode, &newfid, dir->i_sb);
if ( error ) {
d_drop(de);
return error;
}
/* invalidate the directory cnode's attributes */
coda_dir_changed(dir, 1);
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;
coda_vfs_stat.link++;
if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
return -EPERM;
CDEBUG(D_INODE, "old: fid: %s\n", coda_i2s(inode));
CDEBUG(D_INODE, "directory: %s\n", coda_i2s(dir_inode));
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:
CDEBUG(D_INODE, "link result %d\n",error);
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;
coda_vfs_stat.symlink++;
if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
return -EPERM;
symlen = strlen(symname);
if ( symlen > CODA_MAXPATHLEN )
return -ENAMETOOLONG;
CDEBUG(D_INODE, "symname: %s, length: %d\n", symname, symlen);
/*
* 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);
CDEBUG(D_INODE, "in symlink result %d\n",error);
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;
coda_vfs_stat.unlink++;
CDEBUG(D_INODE, " %s in %s, dirino %ld\n", name ,
coda_i2s(dir), dir->i_ino);
error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
if ( error ) {
CDEBUG(D_INODE, "upc returned error %d\n", error);
return error;
}
coda_dir_changed(dir, 0);
de->d_inode->i_nlink--;
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;
coda_vfs_stat.rmdir++;
if (!d_unhashed(de))
return -EBUSY;
error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
if ( error ) {
CDEBUG(D_INODE, "upc returned error %d\n", error);
return error;
}
coda_dir_changed(dir, -1);
de->d_inode->i_nlink--;
d_delete(de);
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;
coda_vfs_stat.rename++;
CDEBUG(D_INODE, "old: %s, (%d length), new: %s"
"(%d length). old:d_count: %d, new:d_count: %d\n",
old_name, old_length, new_name, new_length,
atomic_read(&old_dentry->d_count), atomic_read(&new_dentry->d_count));
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);
}
}
CDEBUG(D_INODE, "result %d\n", error);
return error;
}
/* file operations for directories */
int coda_readdir(struct file *file, void *dirent, filldir_t filldir)
{
int result = 0;
struct dentry *cdentry;
struct inode *cinode, *inode = file->f_dentry->d_inode;
struct file *cfile, fakefile;
struct coda_inode_info *cii = ITOC(inode);
coda_vfs_stat.readdir++;
cfile = cii->c_container;
if (!cfile) BUG();
cinode = cii->c_container->f_dentry->d_inode;
if ( S_ISREG(cinode->i_mode) ) {
/* Venus: we must read Venus dirents from the file */
cdentry = cii->c_container->f_dentry;
coda_prepare_fakefile(file, cdentry, &fakefile);
result = coda_venus_readdir(&fakefile, dirent, filldir);
file->f_pos = fakefile.f_pos;
file->f_version = fakefile.f_version;
} else {
/* potemkin case: we are handed a directory inode */
result = vfs_readdir(file, filldir, dirent);
}
UPDATE_ATIME(inode);
return result;
}
/* support routines */
/* instantiate a fake file to pass to coda_venus_readdir */
static void coda_prepare_fakefile(struct file *coda_file,
struct dentry *cont_dentry,
struct file *fake_file)
{
fake_file->f_dentry = cont_dentry;
fake_file->f_pos = coda_file->f_pos;
fake_file->f_version = coda_file->f_version;
fake_file->f_op = cont_dentry->d_inode->i_fop;
fake_file->f_flags = coda_file->f_flags;
return ;
}
/*
* this structure is manipulated by filldir in vfs layer.
* the count holds the remaining amount of space in the getdents buffer,
* beyond the current_dir pointer.
*
* What structure is this comment referring to?? -JH
*/
/* should be big enough to hold any single directory entry */
#define DIR_BUFSIZE 2048
static int coda_venus_readdir(struct file *filp, void *getdent,
filldir_t filldir)
{
int bufsize;
int offset = filp->f_pos; /* offset in the directory file */
int count = 0;
int pos = 0; /* offset in the block we read */
int result = 0; /* either an error or # of entries returned */
int errfill;
char *buff = NULL;
struct venus_dirent *vdirent;
int string_offset = (int) (&((struct venus_dirent *)(0))->d_name);
int i;
CODA_ALLOC(buff, char *, DIR_BUFSIZE);
if ( !buff ) {
printk("coda_venus_readdir: out of memory.\n");
return -ENOMEM;
}
/* we use this routine to read the file into our buffer */
bufsize = kernel_read(filp, filp->f_pos, buff, DIR_BUFSIZE);
if ( bufsize < 0) {
printk("coda_venus_readdir: cannot read directory %d.\n",
bufsize);
result = bufsize;
goto exit;
}
if ( bufsize == 0) {
result = 0;
goto exit;
}
/* Parse and write into user space. Filldir tells us when done! */
CDEBUG(D_FILE, "buffsize: %d offset %d, count %d.\n",
bufsize, offset, count);
i = 0;
result = 0;
while ( pos + string_offset < bufsize && i < 1024) {
vdirent = (struct venus_dirent *) (buff + pos);
/* test if the name is fully in the buffer */
if ( pos + string_offset + (int) vdirent->d_namlen >= bufsize ){
if ( result == 0 )
printk("CODA: Invalid directory cfino: %ld\n",
filp->f_dentry->d_inode->i_ino);
break;
}
/* now we are certain that we can read the entry from buff */
/* if we don't have a null entry, copy it */
if ( vdirent->d_fileno && vdirent->d_reclen ) {
int namlen = vdirent->d_namlen;
off_t offs = filp->f_pos;
ino_t ino = vdirent->d_fileno;
char *name = vdirent->d_name;
errfill = filldir(getdent, name, namlen,
offs, ino, DT_UNKNOWN);
CDEBUG(D_FILE, "entry %d: ino %ld, namlen %d, reclen %d, type %d, pos %d, string_offs %d, name %*s, offset %d, result: %d, errfill: %d.\n", i,vdirent->d_fileno, vdirent->d_namlen, vdirent->d_reclen, vdirent->d_type, pos, string_offset, vdirent->d_namlen, vdirent->d_name, (u_int) offs, result, errfill);
/* errfill means no space for filling in this round */
if ( errfill < 0 ) {
result = 0;
break;
}
/* adjust count */
result++;
}
/* next one */
filp->f_pos += vdirent->d_reclen;
if ( filp->f_pos > filp->f_dentry->d_inode->i_size )
break;
if ( !vdirent->d_reclen ) {
printk("CODA: Invalid directory, cfino: %ld\n",
filp->f_dentry->d_inode->i_ino);
result = -EINVAL;
break;
}
pos += (unsigned int) vdirent->d_reclen;
i++;
}
if ( i >= 1024 ) {
printk("Repeating too much in readdir %ld\n",
filp->f_dentry->d_inode->i_ino);
result = -EINVAL;
}
exit:
CODA_FREE(buff, DIR_BUFSIZE);
return result;
}
/* called when a cache lookup succeeds */
static int coda_dentry_revalidate(struct dentry *de, int flags)
{
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 */
CDEBUG(D_DOWNCALL, "BOOM for: ino %ld, %s\n",
de->d_inode->i_ino, coda_f2s(&cii->c_fid));
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) {
CDEBUG(D_DOWNCALL, "bad inode, unhashing %s/%s, %ld\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
dentry->d_inode->i_ino);
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);
CDEBUG(D_INODE, "revalidating: %*s/%*s\n",
dentry->d_name.len, dentry->d_name.name,
dentry->d_parent->d_name.len, dentry->d_parent->d_name.name);
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_inode;
/* 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_inode;
if ( cii->c_flags )
coda_flag_inode_children(inode, C_FLUSH);
cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
}
ok:
unlock_kernel();
return 0;
return_bad_inode:
inode->i_mapping = &inode->i_data;
if (cii->c_container) {
fput(cii->c_container);
cii->c_container = NULL;
}
make_bad_inode(inode);
unlock_kernel();
return -EIO;
}
|