linux/fs/coda/dir.c
Yoshihisa Abe f7cc02b871 Coda: push BKL regions into coda_upcall()
Now that shared inode state is locked using the cii->c_lock, the BKL is
only used to protect the upcall queues used to communicate with the
userspace cache manager. The remaining state is all local and we can
push the lock further down into coda_upcall().

Signed-off-by: Yoshihisa Abe <yoshiabe@cs.cmu.edu>
Signed-off-by: Jan Harkes <jaharkes@cs.cmu.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-25 08:02:40 -07:00

646 lines
16 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/slab.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/spinlock.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;
}
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:
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;
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, int 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, 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;
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);
atomic_inc(&inode->i_count);
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)
de->d_inode->i_nlink = 0;
/* 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 =
(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 || 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. */
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(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;
}