/* * 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/time.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 <linux/net.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 (!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; } /* * 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_u.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_MAXNAMELEN && (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_u.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_path.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); unlock_page(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); }