/*
* Find the given page, and call find_dirent() in order to try to
* return the next entry.
*/
static inline
int find_dirent_page(nfs_readdir_descriptor_t *desc)
{
struct inode *inode = desc->file->f_dentry->d_inode;
struct page *page;
int status;
dfprintk(VFS, "NFS: find_dirent_page() searching directory page %ld\n", desc->page_index);
desc->plus = NFS_USE_READDIRPLUS(inode);
page = read_cache_page(&inode->i_data, desc->page_index,
(filler_t *)nfs_readdir_filler, desc);
if (IS_ERR(page)) {
status = PTR_ERR(page);
goto out;
}
if (!Page_Uptodate(page))
goto read_error;
/* NOTE: Someone else may have changed the READDIRPLUS flag */
desc->page = page;
desc->ptr = kmap(page);
status = find_dirent(desc, page);
if (status < 0)
dir_page_release(desc);
out:
dfprintk(VFS, "NFS: find_dirent_page() returns %d\n", status);
return status;
read_error:
page_cache_release(page);
return -EIO;
}
/*
* Use the cached Readdirplus results in order to avoid a LOOKUP call
* whenever we believe that the parent directory has not changed.
*
* We assume that any file creation/rename changes the directory mtime.
* As this results in a page cache invalidation whenever it occurs,
* we don't require any other tests for cache coherency.
*/
static
int nfs_cached_lookup(struct inode *dir, struct dentry *dentry,
struct nfs_fh *fh, struct nfs_fattr *fattr)
{
nfs_readdir_descriptor_t desc;
struct nfs_server *server;
struct nfs_entry entry;
struct page *page;
unsigned long timestamp;
int res;
if (!NFS_USE_READDIRPLUS(dir))
return -ENOENT;
server = NFS_SERVER(dir);
/* Don't use readdirplus unless the cache is stable */
if ((server->flags & NFS_MOUNT_NOAC) != 0
|| nfs_caches_unstable(dir)
|| nfs_attribute_timeout(dir))
return -ENOENT;
if ((NFS_FLAGS(dir) & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA)) != 0)
return -ENOENT;
timestamp = NFS_I(dir)->readdir_timestamp;
entry.fh = fh;
entry.fattr = fattr;
desc.decode = NFS_PROTO(dir)->decode_dirent;
desc.entry = &entry;
desc.page_index = 0;
desc.plus = 1;
for(;(page = find_get_page(dir->i_mapping, desc.page_index)); desc.page_index++) {
res = -EIO;
if (PageUptodate(page)) {
void * kaddr = kmap_atomic(page, KM_USER0);
desc.ptr = kaddr;
res = find_dirent_name(&desc, page, dentry);
kunmap_atomic(kaddr, KM_USER0);
}
page_cache_release(page);
if (res == 0)
goto out_found;
if (res != -EAGAIN)
break;
}
return -ENOENT;
out_found:
fattr->timestamp = timestamp;
return 0;
}
/* The file offset position is now represented as a true offset into the
* page cache as is the case in most of the other filesystems.
*/
static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
struct dentry *dentry = filp->f_dentry;
struct inode *inode = dentry->d_inode;
nfs_readdir_descriptor_t my_desc,
*desc = &my_desc;
struct nfs_entry my_entry;
struct nfs_fh fh;
struct nfs_fattr fattr;
long res;
lock_kernel();
res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
if (res < 0) {
unlock_kernel();
return res;
}
/*
* filp->f_pos points to the file offset in the page cache.
* but if the cache has meanwhile been zapped, we need to
* read from the last dirent to revalidate f_pos
* itself.
*/
memset(desc, 0, sizeof(*desc));
desc->file = filp;
desc->target = filp->f_pos;
desc->decode = NFS_PROTO(inode)->decode_dirent;
desc->plus = NFS_USE_READDIRPLUS(inode);
my_entry.cookie = my_entry.prev_cookie = 0;
my_entry.eof = 0;
my_entry.fh = &fh;
my_entry.fattr = &fattr;
desc->entry = &my_entry;
while(!desc->entry->eof) {
res = readdir_search_pagecache(desc);
if (res == -EBADCOOKIE) {
/* This means either end of directory */
if (desc->entry->cookie != desc->target) {
/* Or that the server has 'lost' a cookie */
res = uncached_readdir(desc, dirent, filldir);
if (res >= 0)
continue;
}
res = 0;
break;
}
if (res == -ETOOSMALL && desc->plus) {
NFS_FLAGS(inode) &= ~NFS_INO_ADVISE_RDPLUS;
nfs_zap_caches(inode);
desc->plus = 0;
desc->entry->eof = 0;
continue;
}
if (res < 0)
break;
res = nfs_do_filldir(desc, dirent, filldir);
if (res < 0) {
res = 0;
break;
}
}
unlock_kernel();
if (desc->error < 0)
return desc->error;
if (res < 0)
return res;
return 0;
}
