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589 lines
14 KiB
C
589 lines
14 KiB
C
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/*
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* Directory operations for Coda filesystem
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* Original version: (C) 1996 P. Braam and M. Callahan
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* Rewritten for Linux 2.1. (C) 1997 Carnegie Mellon University
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*
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* Carnegie Mellon encourages users to contribute improvements to
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* the Coda project. Contact Peter Braam (coda@cs.cmu.edu).
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/time.h>
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <linux/file.h>
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#include <linux/stat.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/spinlock.h>
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#include <linux/namei.h>
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#include <linux/uaccess.h>
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#include <linux/coda.h>
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#include <linux/coda_psdev.h>
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#include "coda_linux.h"
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#include "coda_cache.h"
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#include "coda_int.h"
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/* same as fs/bad_inode.c */
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static int coda_return_EIO(void)
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{
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return -EIO;
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}
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#define CODA_EIO_ERROR ((void *) (coda_return_EIO))
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/* inode operations for directories */
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/* access routines: lookup, readlink, permission */
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static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, unsigned int flags)
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{
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struct super_block *sb = dir->i_sb;
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const char *name = entry->d_name.name;
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size_t length = entry->d_name.len;
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struct inode *inode;
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int type = 0;
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if (length > CODA_MAXNAMLEN) {
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pr_err("name too long: lookup, %s (%*s)\n",
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coda_i2s(dir), (int)length, name);
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return ERR_PTR(-ENAMETOOLONG);
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}
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/* control object, create inode on the fly */
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if (is_root_inode(dir) && coda_iscontrol(name, length)) {
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inode = coda_cnode_makectl(sb);
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type = CODA_NOCACHE;
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} else {
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struct CodaFid fid = { { 0, } };
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int error = venus_lookup(sb, coda_i2f(dir), name, length,
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&type, &fid);
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inode = !error ? coda_cnode_make(&fid, sb) : ERR_PTR(error);
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}
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if (!IS_ERR(inode) && (type & CODA_NOCACHE))
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coda_flag_inode(inode, C_VATTR | C_PURGE);
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if (inode == ERR_PTR(-ENOENT))
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inode = NULL;
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return d_splice_alias(inode, entry);
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}
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int coda_permission(struct inode *inode, int mask)
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{
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int error;
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if (mask & MAY_NOT_BLOCK)
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return -ECHILD;
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mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
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if (!mask)
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return 0;
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if ((mask & MAY_EXEC) && !execute_ok(inode))
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return -EACCES;
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if (coda_cache_check(inode, mask))
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return 0;
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error = venus_access(inode->i_sb, coda_i2f(inode), mask);
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if (!error)
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coda_cache_enter(inode, mask);
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return error;
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}
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static inline void coda_dir_update_mtime(struct inode *dir)
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{
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#ifdef REQUERY_VENUS_FOR_MTIME
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/* invalidate the directory cnode's attributes so we refetch the
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* attributes from venus next time the inode is referenced */
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coda_flag_inode(dir, C_VATTR);
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#else
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/* optimistically we can also act as if our nose bleeds. The
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* granularity of the mtime is coarse anyways so we might actually be
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* right most of the time. Note: we only do this for directories. */
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dir->i_mtime = dir->i_ctime = current_time(dir);
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#endif
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}
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/* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a
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* trick to fool GNU find's optimizations. If we can't be sure of the link
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* (because of volume mount points) we set i_nlink to 1 which forces find
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* to consider every child as a possible directory. We should also never
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* see an increment or decrement for deleted directories where i_nlink == 0 */
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static inline void coda_dir_inc_nlink(struct inode *dir)
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{
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if (dir->i_nlink >= 2)
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inc_nlink(dir);
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}
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static inline void coda_dir_drop_nlink(struct inode *dir)
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{
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if (dir->i_nlink > 2)
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drop_nlink(dir);
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}
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/* creation routines: create, mknod, mkdir, link, symlink */
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static int coda_create(struct inode *dir, struct dentry *de, umode_t mode, bool excl)
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{
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int error;
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const char *name=de->d_name.name;
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int length=de->d_name.len;
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struct inode *inode;
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struct CodaFid newfid;
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struct coda_vattr attrs;
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if (is_root_inode(dir) && coda_iscontrol(name, length))
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return -EPERM;
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error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
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0, mode, &newfid, &attrs);
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if (error)
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goto err_out;
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inode = coda_iget(dir->i_sb, &newfid, &attrs);
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if (IS_ERR(inode)) {
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error = PTR_ERR(inode);
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goto err_out;
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}
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/* invalidate the directory cnode's attributes */
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coda_dir_update_mtime(dir);
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d_instantiate(de, inode);
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return 0;
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err_out:
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d_drop(de);
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return error;
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}
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static int coda_mkdir(struct inode *dir, struct dentry *de, umode_t mode)
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{
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struct inode *inode;
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struct coda_vattr attrs;
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const char *name = de->d_name.name;
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int len = de->d_name.len;
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int error;
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struct CodaFid newfid;
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if (is_root_inode(dir) && coda_iscontrol(name, len))
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return -EPERM;
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attrs.va_mode = mode;
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error = venus_mkdir(dir->i_sb, coda_i2f(dir),
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name, len, &newfid, &attrs);
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if (error)
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goto err_out;
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inode = coda_iget(dir->i_sb, &newfid, &attrs);
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if (IS_ERR(inode)) {
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error = PTR_ERR(inode);
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goto err_out;
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}
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/* invalidate the directory cnode's attributes */
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coda_dir_inc_nlink(dir);
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coda_dir_update_mtime(dir);
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d_instantiate(de, inode);
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return 0;
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err_out:
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d_drop(de);
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return error;
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}
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/* try to make de an entry in dir_inodde linked to source_de */
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static int coda_link(struct dentry *source_de, struct inode *dir_inode,
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struct dentry *de)
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{
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struct inode *inode = d_inode(source_de);
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const char * name = de->d_name.name;
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int len = de->d_name.len;
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int error;
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if (is_root_inode(dir_inode) && coda_iscontrol(name, len))
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return -EPERM;
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error = venus_link(dir_inode->i_sb, coda_i2f(inode),
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coda_i2f(dir_inode), (const char *)name, len);
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if (error) {
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d_drop(de);
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return error;
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}
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coda_dir_update_mtime(dir_inode);
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ihold(inode);
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d_instantiate(de, inode);
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inc_nlink(inode);
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return 0;
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}
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static int coda_symlink(struct inode *dir_inode, struct dentry *de,
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const char *symname)
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{
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const char *name = de->d_name.name;
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int len = de->d_name.len;
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int symlen;
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int error;
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if (is_root_inode(dir_inode) && coda_iscontrol(name, len))
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return -EPERM;
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symlen = strlen(symname);
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if (symlen > CODA_MAXPATHLEN)
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return -ENAMETOOLONG;
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/*
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* This entry is now negative. Since we do not create
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* an inode for the entry we have to drop it.
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*/
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d_drop(de);
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error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
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symname, symlen);
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/* mtime is no good anymore */
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if (!error)
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coda_dir_update_mtime(dir_inode);
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return error;
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}
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/* destruction routines: unlink, rmdir */
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static int coda_unlink(struct inode *dir, struct dentry *de)
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{
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int error;
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const char *name = de->d_name.name;
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int len = de->d_name.len;
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error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
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if (error)
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return error;
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coda_dir_update_mtime(dir);
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drop_nlink(d_inode(de));
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return 0;
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}
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static int coda_rmdir(struct inode *dir, struct dentry *de)
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{
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const char *name = de->d_name.name;
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int len = de->d_name.len;
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int error;
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error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
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if (!error) {
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/* VFS may delete the child */
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if (d_really_is_positive(de))
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clear_nlink(d_inode(de));
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/* fix the link count of the parent */
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coda_dir_drop_nlink(dir);
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coda_dir_update_mtime(dir);
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}
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return error;
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}
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/* rename */
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static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
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struct inode *new_dir, struct dentry *new_dentry,
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unsigned int flags)
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{
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const char *old_name = old_dentry->d_name.name;
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const char *new_name = new_dentry->d_name.name;
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int old_length = old_dentry->d_name.len;
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int new_length = new_dentry->d_name.len;
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int error;
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if (flags)
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return -EINVAL;
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error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
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coda_i2f(new_dir), old_length, new_length,
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(const char *) old_name, (const char *)new_name);
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if (!error) {
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if (d_really_is_positive(new_dentry)) {
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if (d_is_dir(new_dentry)) {
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coda_dir_drop_nlink(old_dir);
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coda_dir_inc_nlink(new_dir);
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}
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coda_dir_update_mtime(old_dir);
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coda_dir_update_mtime(new_dir);
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coda_flag_inode(d_inode(new_dentry), C_VATTR);
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} else {
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coda_flag_inode(old_dir, C_VATTR);
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coda_flag_inode(new_dir, C_VATTR);
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}
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}
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return error;
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}
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static inline unsigned int CDT2DT(unsigned char cdt)
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{
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unsigned int dt;
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switch(cdt) {
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case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
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case CDT_FIFO: dt = DT_FIFO; break;
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case CDT_CHR: dt = DT_CHR; break;
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case CDT_DIR: dt = DT_DIR; break;
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case CDT_BLK: dt = DT_BLK; break;
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case CDT_REG: dt = DT_REG; break;
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case CDT_LNK: dt = DT_LNK; break;
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case CDT_SOCK: dt = DT_SOCK; break;
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case CDT_WHT: dt = DT_WHT; break;
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default: dt = DT_UNKNOWN; break;
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}
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return dt;
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}
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/* support routines */
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static int coda_venus_readdir(struct file *coda_file, struct dir_context *ctx)
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{
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struct coda_file_info *cfi;
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struct coda_inode_info *cii;
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struct file *host_file;
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struct venus_dirent *vdir;
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unsigned long vdir_size = offsetof(struct venus_dirent, d_name);
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unsigned int type;
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struct qstr name;
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ino_t ino;
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int ret;
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cfi = CODA_FTOC(coda_file);
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BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
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host_file = cfi->cfi_container;
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cii = ITOC(file_inode(coda_file));
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vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
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if (!vdir) return -ENOMEM;
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if (!dir_emit_dots(coda_file, ctx))
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goto out;
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while (1) {
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/* read entries from the directory file */
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ret = kernel_read(host_file, ctx->pos - 2, (char *)vdir,
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sizeof(*vdir));
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if (ret < 0) {
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pr_err("%s: read dir %s failed %d\n",
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__func__, coda_f2s(&cii->c_fid), ret);
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break;
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}
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if (ret == 0) break; /* end of directory file reached */
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/* catch truncated reads */
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if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
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pr_err("%s: short read on %s\n",
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__func__, coda_f2s(&cii->c_fid));
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ret = -EBADF;
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break;
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}
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/* validate whether the directory file actually makes sense */
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if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
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pr_err("%s: invalid dir %s\n",
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__func__, coda_f2s(&cii->c_fid));
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ret = -EBADF;
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break;
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}
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name.len = vdir->d_namlen;
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name.name = vdir->d_name;
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/* Make sure we skip '.' and '..', we already got those */
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if (name.name[0] == '.' && (name.len == 1 ||
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(name.name[1] == '.' && name.len == 2)))
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vdir->d_fileno = name.len = 0;
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/* skip null entries */
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if (vdir->d_fileno && name.len) {
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ino = vdir->d_fileno;
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type = CDT2DT(vdir->d_type);
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if (!dir_emit(ctx, name.name, name.len, ino, type))
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break;
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}
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/* we'll always have progress because d_reclen is unsigned and
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* we've already established it is non-zero. */
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ctx->pos += vdir->d_reclen;
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}
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out:
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kfree(vdir);
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return 0;
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}
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/* file operations for directories */
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static int coda_readdir(struct file *coda_file, struct dir_context *ctx)
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{
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struct coda_file_info *cfi;
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struct file *host_file;
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int ret;
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cfi = CODA_FTOC(coda_file);
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BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
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host_file = cfi->cfi_container;
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if (host_file->f_op->iterate || host_file->f_op->iterate_shared) {
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struct inode *host_inode = file_inode(host_file);
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ret = -ENOENT;
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if (!IS_DEADDIR(host_inode)) {
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if (host_file->f_op->iterate_shared) {
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inode_lock_shared(host_inode);
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ret = host_file->f_op->iterate_shared(host_file, ctx);
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file_accessed(host_file);
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inode_unlock_shared(host_inode);
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} else {
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inode_lock(host_inode);
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ret = host_file->f_op->iterate(host_file, ctx);
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file_accessed(host_file);
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inode_unlock(host_inode);
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}
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}
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return ret;
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}
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/* Venus: we must read Venus dirents from a file */
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return coda_venus_readdir(coda_file, ctx);
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}
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/* called when a cache lookup succeeds */
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static int coda_dentry_revalidate(struct dentry *de, unsigned int flags)
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{
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struct inode *inode;
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struct coda_inode_info *cii;
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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inode = d_inode(de);
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if (!inode || is_root_inode(inode))
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goto out;
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if (is_bad_inode(inode))
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goto bad;
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cii = ITOC(d_inode(de));
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if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
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goto out;
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shrink_dcache_parent(de);
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/* propagate for a flush */
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if (cii->c_flags & C_FLUSH)
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coda_flag_inode_children(inode, C_FLUSH);
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if (d_count(de) > 1)
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/* pretend it's valid, but don't change the flags */
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goto out;
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/* clear the flags. */
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spin_lock(&cii->c_lock);
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cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
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spin_unlock(&cii->c_lock);
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bad:
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return 0;
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out:
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return 1;
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}
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/*
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* This is the callback from dput() when d_count is going to 0.
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* We use this to unhash dentries with bad inodes.
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*/
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static int coda_dentry_delete(const struct dentry * dentry)
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{
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int flags;
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if (d_really_is_negative(dentry))
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return 0;
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flags = (ITOC(d_inode(dentry))->c_flags) & C_PURGE;
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if (is_bad_inode(d_inode(dentry)) || flags) {
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return 1;
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}
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return 0;
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}
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|
|
|
|
|
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/*
|
|
* 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 inode *inode)
|
|
{
|
|
struct coda_vattr attr;
|
|
int error;
|
|
int old_mode;
|
|
ino_t old_ino;
|
|
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)) {
|
|
pr_warn("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;
|
|
}
|
|
|
|
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,
|
|
.iterate = coda_readdir,
|
|
.open = coda_open,
|
|
.release = coda_release,
|
|
.fsync = coda_fsync,
|
|
};
|