/*
* A check for whether or not the parent directory has changed.
* In the case it has, we assume that the dentries are untrustworthy
* and may need to be looked up again.
*/
static inline int nfs_check_verifier(struct inode *dir, struct dentry *dentry)
{
if (IS_ROOT(dentry))
return 1;
if ((NFS_FLAGS(dir) & NFS_INO_INVALID_ATTR) != 0
|| nfs_attribute_timeout(dir))
return 0;
return nfs_verify_change_attribute(dir, (unsigned long)dentry->d_fsdata);
}
/* Now we cache directories properly, by stuffing the dirent
* data directly in the page cache.
*
* Inode invalidation due to refresh etc. takes care of
* _everything_, no sloppy entry flushing logic, no extraneous
* copying, network direct to page cache, the way it was meant
* to be.
*
* NOTE: Dirent information verification is done always by the
* page-in of the RPC reply, nowhere else, this simplies
* things substantially.
*/
static
int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page)
{
struct file *file = desc->file;
struct inode *inode = file->f_dentry->d_inode;
struct rpc_cred *cred = nfs_file_cred(file);
unsigned long timestamp;
int error;
dfprintk(VFS, "NFS: nfs_readdir_filler() reading cookie %Lu into page %lu.\n", (long long)desc->entry->cookie, page->index);
again:
timestamp = jiffies;
error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, desc->entry->cookie, page,
NFS_SERVER(inode)->dtsize, desc->plus);
if (error < 0) {
/* We requested READDIRPLUS, but the server doesn't grok it */
if (error == -ENOTSUPP && desc->plus) {
NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS;
NFS_FLAGS(inode) &= ~NFS_INO_ADVISE_RDPLUS;
desc->plus = 0;
goto again;
}
goto error;
}
SetPageUptodate(page);
NFS_FLAGS(inode) |= NFS_INO_INVALID_ATIME;
/* Ensure consistent page alignment of the data.
* Note: assumes we have exclusive access to this mapping either
* throught inode->i_sem or some other mechanism.
*/
if (page->index == 0) {
invalidate_inode_pages(inode->i_mapping);
NFS_I(inode)->readdir_timestamp = timestamp;
}
unlock_page(page);
return 0;
error:
SetPageError(page);
unlock_page(page);
nfs_zap_caches(inode);
desc->error = error;
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;
}
/*
* If we cannot find a cookie in our cache, we suspect that this is
* because it points to a deleted file, so we ask the server to return
* whatever it thinks is the next entry. We then feed this to filldir.
* If all goes well, we should then be able to find our way round the
* cache on the next call to readdir_search_pagecache();
*
* NOTE: we cannot add the anonymous page to the pagecache because
* the data it contains might not be page aligned. Besides,
* we should already have a complete representation of the
* directory in the page cache by the time we get here.
*/
static inline
int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent,
filldir_t filldir)
{
struct file *file = desc->file;
struct inode *inode = file->f_dentry->d_inode;
struct rpc_cred *cred = nfs_file_cred(file);
struct page *page = NULL;
int status;
dfprintk(VFS, "NFS: uncached_readdir() searching for cookie %Lu\n", (long long)desc->target);
page = alloc_page(GFP_HIGHUSER);
if (!page) {
status = -ENOMEM;
goto out;
}
desc->error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, desc->target,
page,
NFS_SERVER(inode)->dtsize,
desc->plus);
NFS_FLAGS(inode) |= NFS_INO_INVALID_ATIME;
desc->page = page;
desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */
if (desc->error >= 0) {
if ((status = dir_decode(desc)) == 0)
desc->entry->prev_cookie = desc->target;
} else
status = -EIO;
if (status < 0)
goto out_release;
status = nfs_do_filldir(desc, dirent, filldir);
/* Reset read descriptor so it searches the page cache from
* the start upon the next call to readdir_search_pagecache() */
desc->page_index = 0;
desc->entry->cookie = desc->entry->prev_cookie = 0;
desc->entry->eof = 0;
out:
dfprintk(VFS, "NFS: uncached_readdir() returns %d\n", status);
return status;
out_release:
dir_page_release(desc);
goto out;
}
/* Now we cache directories properly, by stuffing the dirent
* data directly in the page cache.
*
* Inode invalidation due to refresh etc. takes care of
* _everything_, no sloppy entry flushing logic, no extraneous
* copying, network direct to page cache, the way it was meant
* to be.
*
* NOTE: Dirent information verification is done always by the
* page-in of the RPC reply, nowhere else, this simplies
* things substantially.
*/
static
int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page)
{
struct file *file = desc->file;
struct inode *inode = file->f_dentry->d_inode;
struct rpc_cred *cred = nfs_file_cred(file);
void *buffer = kmap(page);
int error;
dfprintk(VFS, "NFS: nfs_readdir_filler() reading cookie %Lu into page %lu.\n", (long long)desc->entry->cookie, page->index);
again:
error = NFS_PROTO(inode)->readdir(inode, cred, desc->entry->cookie, buffer,
NFS_SERVER(inode)->dtsize, desc->plus);
/* We requested READDIRPLUS, but the server doesn't grok it */
if (desc->plus && error == -ENOTSUPP) {
NFS_FLAGS(inode) &= ~NFS_INO_ADVISE_RDPLUS;
desc->plus = 0;
goto again;
}
if (error < 0)
goto error;
SetPageUptodate(page);
kunmap(page);
/* Ensure consistent page alignment of the data.
* Note: assumes we have exclusive access to this mapping either
* throught inode->i_sem or some other mechanism.
*/
if (page->index == 0)
invalidate_inode_pages(inode);
UnlockPage(page);
return 0;
error:
SetPageError(page);
kunmap(page);
UnlockPage(page);
invalidate_inode_pages(inode);
desc->error = error;
return -EIO;
}
/*
* The "read_inode" function doesn't actually do anything:
* the real data is filled in later in nfs_fhget. Here we
* just mark the cache times invalid, and zero out i_mode
* (the latter makes "nfs_refresh_inode" do the right thing
* wrt pipe inodes)
*/
static void
nfs_read_inode(struct inode * inode)
{
inode->i_blksize = inode->i_sb->s_blocksize;
inode->i_mode = 0;
inode->i_rdev = 0;
/* We can't support UPDATE_ATIME(), since the server will reset it */
inode->i_flags |= S_NOATIME;
NFS_FILEID(inode) = 0;
NFS_FSID(inode) = 0;
NFS_FLAGS(inode) = 0;
INIT_LIST_HEAD(&inode->u.nfs_i.read);
INIT_LIST_HEAD(&inode->u.nfs_i.dirty);
INIT_LIST_HEAD(&inode->u.nfs_i.commit);
INIT_LIST_HEAD(&inode->u.nfs_i.writeback);
inode->u.nfs_i.nread = 0;
inode->u.nfs_i.ndirty = 0;
inode->u.nfs_i.ncommit = 0;
inode->u.nfs_i.npages = 0;
NFS_CACHEINV(inode);
NFS_ATTRTIMEO(inode) = NFS_MINATTRTIMEO(inode);
NFS_ATTRTIMEO_UPDATE(inode) = jiffies;
}
/* 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;
}
int
nfs_permission(struct inode *inode, int mask, struct nameidata *nd)
{
struct nfs_access_cache *cache = &NFS_I(inode)->cache_access;
struct rpc_cred *cred;
int mode = inode->i_mode;
int res;
if (mask == 0)
return 0;
if (mask & MAY_WRITE) {
/*
*
* Nobody gets write access to a read-only fs.
*
*/
if (IS_RDONLY(inode) &&
(S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
return -EROFS;
/*
*
* Nobody gets write access to an immutable file.
*
*/
if (IS_IMMUTABLE(inode))
return -EACCES;
}
/* Are we checking permissions on anything other than lookup/execute? */
if ((mask & MAY_EXEC) == 0) {
/* We only need to check permissions on file open() and access() */
if (!nd || !(nd->flags & (LOOKUP_OPEN|LOOKUP_ACCESS)))
return 0;
/* NFSv4 has atomic_open... */
if (NFS_PROTO(inode)->version > 3 && (nd->flags & LOOKUP_OPEN))
return 0;
}
lock_kernel();
if (!NFS_PROTO(inode)->access)
goto out_notsup;
cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0);
if (cache->cred == cred
&& time_before(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode))
&& !(NFS_FLAGS(inode) & NFS_INO_INVALID_ATTR)) {
if (!(res = cache->err)) {
/* Is the mask a subset of an accepted mask? */
if ((cache->mask & mask) == mask)
goto out;
} else {
/* ...or is it a superset of a rejected mask? */
if ((cache->mask & mask) == cache->mask)
goto out;
}
}
res = NFS_PROTO(inode)->access(inode, cred, mask);
if (!res || res == -EACCES)
goto add_cache;
out:
put_rpccred(cred);
unlock_kernel();
return res;
out_notsup:
nfs_revalidate_inode(NFS_SERVER(inode), inode);
res = vfs_permission(inode, mask);
unlock_kernel();
return res;
add_cache:
cache->jiffies = jiffies;
if (cache->cred)
put_rpccred(cache->cred);
cache->cred = cred;
cache->mask = mask;
cache->err = res;
unlock_kernel();
return res;
}
