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/*
* cache.c
*
* Copyright (C) 1997 by Bill Hawes
*
* Routines to support directory cacheing using the page cache.
* This cache code is almost directly taken from ncpfs.
*
* Please add a note about your changes to smbfs in the ChangeLog file.
*/
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/dirent.h>
#include <linux/smb_fs.h>
#include <linux/pagemap.h>
#include <asm/page.h>
#include "smb_debug.h"
#include "proto.h"
/*
* Force the next attempt to use the cache to be a timeout.
* If we can't find the page that's fine, it will cause a refresh.
*/
void
smb_invalid_dir_cache(struct inode * dir)
{
struct smb_sb_info *server = server_from_inode(dir);
union smb_dir_cache *cache = NULL;
struct page *page = NULL;
page = grab_cache_page(&dir->i_data, 0);
if (!page)
goto out;
if (!Page_Uptodate(page))
goto out_unlock;
cache = kmap(page);
cache->head.time = jiffies - SMB_MAX_AGE(server);
kunmap(page);
SetPageUptodate(page);
out_unlock:
UnlockPage(page);
page_cache_release(page);
out:
return;
}
/*
* Mark all dentries for 'parent' as invalid, forcing them to be re-read
*/
void
smb_invalidate_dircache_entries(struct dentry *parent)
{
struct smb_sb_info *server = server_from_dentry(parent);
struct list_head *next;
struct dentry *dentry;
spin_lock(&dcache_lock);
next = parent->d_subdirs.next;
while (next != &parent->d_subdirs) {
dentry = list_entry(next, struct dentry, d_child);
dentry->d_fsdata = NULL;
smb_age_dentry(server, dentry);
next = next->next;
}
spin_unlock(&dcache_lock);
}
/*
* dget, but require that fpos and parent matches what the dentry contains.
* dentry is not known to be a valid pointer at entry.
*/
struct dentry *
smb_dget_fpos(struct dentry *dentry, struct dentry *parent, unsigned long fpos)
{
struct dentry *dent = dentry;
struct list_head *next;
if (d_validate(dent, parent)) {
if (dent->d_name.len <= SMB_MAXPATHLEN &&
(unsigned long)dent->d_fsdata == fpos) {
if (!dent->d_inode) {
dput(dent);
dent = NULL;
}
return dent;
}
dput(dent);
}
/* If a pointer is invalid, we search the dentry. */
spin_lock(&dcache_lock);
next = parent->d_subdirs.next;
while (next != &parent->d_subdirs) {
dent = list_entry(next, struct dentry, d_child);
if ((unsigned long)dent->d_fsdata == fpos) {
if (dent->d_inode)
dget_locked(dent);
else
dent = NULL;
goto out_unlock;
}
next = next->next;
}
dent = NULL;
out_unlock:
spin_unlock(&dcache_lock);
return dent;
}
/*
* Create dentry/inode for this file and add it to the dircache.
*/
int
smb_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
struct smb_cache_control *ctrl, struct qstr *qname,
struct smb_fattr *entry)
{
struct dentry *newdent, *dentry = filp->f_dentry;
struct inode *newino, *inode = dentry->d_inode;
struct smb_cache_control ctl = *ctrl;
int valid = 0;
int hashed = 0;
ino_t ino = 0;
qname->hash = full_name_hash(qname->name, qname->len);
if (dentry->d_op && dentry->d_op->d_hash)
if (dentry->d_op->d_hash(dentry, qname) != 0)
goto end_advance;
newdent = d_lookup(dentry, qname);
if (!newdent) {
newdent = d_alloc(dentry, qname);
if (!newdent)
goto end_advance;
} else {
hashed = 1;
memcpy((char *) newdent->d_name.name, qname->name,
newdent->d_name.len);
}
if (!newdent->d_inode) {
smb_renew_times(newdent);
entry->f_ino = iunique(inode->i_sb, 2);
newino = smb_iget(inode->i_sb, entry);
if (newino) {
smb_new_dentry(newdent);
d_instantiate(newdent, newino);
if (!hashed)
d_rehash(newdent);
}
} else
smb_set_inode_attr(newdent->d_inode, entry);
if (newdent->d_inode) {
ino = newdent->d_inode->i_ino;
newdent->d_fsdata = (void *) ctl.fpos;
smb_new_dentry(newdent);
}
if (ctl.idx >= SMB_DIRCACHE_SIZE) {
if (ctl.page) {
kunmap(ctl.page);
SetPageUptodate(ctl.page);
UnlockPage(ctl.page);
page_cache_release(ctl.page);
}
ctl.cache = NULL;
ctl.idx -= SMB_DIRCACHE_SIZE;
ctl.ofs += 1;
ctl.page = grab_cache_page(&inode->i_data, ctl.ofs);
if (ctl.page)
ctl.cache = kmap(ctl.page);
}
if (ctl.cache) {
ctl.cache->dentry[ctl.idx] = newdent;
valid = 1;
}
dput(newdent);
end_advance:
if (!valid)
ctl.valid = 0;
if (!ctl.filled && (ctl.fpos == filp->f_pos)) {
if (!ino)
ino = find_inode_number(dentry, qname);
if (!ino)
ino = iunique(inode->i_sb, 2);
ctl.filled = filldir(dirent, qname->name, qname->len,
filp->f_pos, ino, DT_UNKNOWN);
if (!ctl.filled)
filp->f_pos += 1;
}
ctl.fpos += 1;
ctl.idx += 1;
*ctrl = ctl;
return (ctl.valid || !ctl.filled);
}
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