/*
* 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 (!PageUptodate(page))
goto out_unlock;
cache = kmap(page);
cache->head.time = jiffies - SMB_MAX_AGE(server);
kunmap(page);
SetPageUptodate(page);
out_unlock:
unlock_page(page);
page_cache_release(page);
out:
return;
}
/*
* This is the callback when the dcache has a lookup hit.
*/
static int
smb_lookup_validate(struct dentry * dentry, struct nameidata *nd)
{
struct smb_sb_info *server = server_from_dentry(dentry);
struct inode * inode = dentry->d_inode;
unsigned long age = jiffies - dentry->d_time;
int valid;
/*
* The default validation is based on dentry age:
* we believe in dentries for a few seconds. (But each
* successful server lookup renews the timestamp.)
*/
valid = (age <= SMB_MAX_AGE(server));
#ifdef SMBFS_DEBUG_VERBOSE
if (!valid)
VERBOSE("%s/%s not valid, age=%lu\n",
DENTRY_PATH(dentry), age);
#endif
if (inode) {
lock_kernel();
if (is_bad_inode(inode)) {
PARANOIA("%s/%s has dud inode\n", DENTRY_PATH(dentry));
valid = 0;
} else if (!valid)
valid = (smb_revalidate_inode(dentry) == 0);
unlock_kernel();
} else {
/*
* What should we do for negative dentries?
*/
}
return valid;
}
/*
* This is called when we want to check whether the inode
* has changed on the server. If it has changed, we must
* invalidate our local caches.
*/
int
smb_revalidate_inode(struct dentry *dentry)
{
struct smb_sb_info *s = server_from_dentry(dentry);
struct inode *inode = dentry->d_inode;
int error = 0;
DEBUG1("smb_revalidate_inode\n");
lock_kernel();
/*
* Check whether we've recently refreshed the inode.
*/
if (time_before(jiffies, SMB_I(inode)->oldmtime + SMB_MAX_AGE(s))) {
VERBOSE("up-to-date, ino=%ld, jiffies=%lu, oldtime=%lu\n",
inode->i_ino, jiffies, SMB_I(inode)->oldmtime);
goto out;
}
error = smb_refresh_inode(dentry);
out:
unlock_kernel();
return error;
}
/*
* Read a directory, using filldir to fill the dirent memory.
* smb_proc_readdir does the actual reading from the smb server.
*
* The cache code is almost directly taken from ncpfs
*/
static int
smb_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
struct dentry *dentry = filp->f_path.dentry;
struct inode *dir = dentry->d_inode;
struct smb_sb_info *server = server_from_dentry(dentry);
union smb_dir_cache *cache = NULL;
struct smb_cache_control ctl;
struct page *page = NULL;
int result;
ctl.page = NULL;
ctl.cache = NULL;
VERBOSE("reading %s/%s, f_pos=%d\n",
DENTRY_PATH(dentry), (int) filp->f_pos);
result = 0;
lock_kernel();
switch ((unsigned int) filp->f_pos) {
case 0:
if (filldir(dirent, ".", 1, 0, dir->i_ino, DT_DIR) < 0)
goto out;
filp->f_pos = 1;
/* fallthrough */
case 1:
if (filldir(dirent, "..", 2, 1, parent_ino(dentry), DT_DIR) < 0)
goto out;
filp->f_pos = 2;
}
/*
* Make sure our inode is up-to-date.
*/
result = smb_revalidate_inode(dentry);
if (result)
goto out;
page = grab_cache_page(&dir->i_data, 0);
if (!page)
goto read_really;
ctl.cache = cache = kmap(page);
ctl.head = cache->head;
if (!PageUptodate(page) || !ctl.head.eof) {
VERBOSE("%s/%s, page uptodate=%d, eof=%d\n",
DENTRY_PATH(dentry), PageUptodate(page),ctl.head.eof);
goto init_cache;
}
if (filp->f_pos == 2) {
if (jiffies - ctl.head.time >= SMB_MAX_AGE(server))
goto init_cache;
/*
* N.B. ncpfs checks mtime of dentry too here, we don't.
* 1. common smb servers do not update mtime on dir changes
* 2. it requires an extra smb request
* (revalidate has the same timeout as ctl.head.time)
*
* Instead smbfs invalidates its own cache on local changes
* and remote changes are not seen until timeout.
*/
}
if (filp->f_pos > ctl.head.end)
goto finished;
ctl.fpos = filp->f_pos + (SMB_DIRCACHE_START - 2);
ctl.ofs = ctl.fpos / SMB_DIRCACHE_SIZE;
ctl.idx = ctl.fpos % SMB_DIRCACHE_SIZE;
for (;;) {
if (ctl.ofs != 0) {
ctl.page = find_lock_page(&dir->i_data, ctl.ofs);
if (!ctl.page)
goto invalid_cache;
ctl.cache = kmap(ctl.page);
if (!PageUptodate(ctl.page))
goto invalid_cache;
}
while (ctl.idx < SMB_DIRCACHE_SIZE) {
struct dentry *dent;
int res;
dent = smb_dget_fpos(ctl.cache->dentry[ctl.idx],
dentry, filp->f_pos);
if (!dent)
goto invalid_cache;
res = filldir(dirent, dent->d_name.name,
dent->d_name.len, filp->f_pos,
dent->d_inode->i_ino, DT_UNKNOWN);
dput(dent);
if (res)
goto finished;
filp->f_pos += 1;
ctl.idx += 1;
if (filp->f_pos > ctl.head.end)
goto finished;
}
if (ctl.page) {
kunmap(ctl.page);
SetPageUptodate(ctl.page);
unlock_page(ctl.page);
page_cache_release(ctl.page);
ctl.page = NULL;
}
ctl.idx = 0;
ctl.ofs += 1;
}
invalid_cache:
if (ctl.page) {
kunmap(ctl.page);
unlock_page(ctl.page);
page_cache_release(ctl.page);
ctl.page = NULL;
}
ctl.cache = cache;
init_cache:
smb_invalidate_dircache_entries(dentry);
ctl.head.time = jiffies;
ctl.head.eof = 0;
ctl.fpos = 2;
ctl.ofs = 0;
ctl.idx = SMB_DIRCACHE_START;
ctl.filled = 0;
ctl.valid = 1;
read_really:
result = server->ops->readdir(filp, dirent, filldir, &ctl);
if (result == -ERESTARTSYS && page)
ClearPageUptodate(page);
if (ctl.idx == -1)
goto invalid_cache; /* retry */
ctl.head.end = ctl.fpos - 1;
ctl.head.eof = ctl.valid;
finished:
if (page) {
cache->head = ctl.head;
kunmap(page);
if (result != -ERESTARTSYS)
SetPageUptodate(page);
unlock_page(page);
page_cache_release(page);
}
if (ctl.page) {
kunmap(ctl.page);
SetPageUptodate(ctl.page);
unlock_page(ctl.page);
page_cache_release(ctl.page);
}
out:
unlock_kernel();
return result;
}