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linux-stable/fs/nfs/dir.c
Bryan Schumaker 89d77c8fa8 NFS: Convert v4 into a module 
This patch exports symbols needed by the v4 module.  In addition, I also
switch over to using IS_ENABLED() to check if CONFIG_NFS_V4 or
CONFIG_NFS_V4_MODULE are set.

The module (nfs4.ko) will be created in the same directory as nfs.ko and
will be automatically loaded the first time you try to mount over NFS v4.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-07-30 19:06:52 -04:00

2215 lines
55 KiB
C
Raw Blame History

/*
* linux/fs/nfs/dir.c
*
* Copyright (C) 1992 Rick Sladkey
*
* nfs directory handling functions
*
* 10 Apr 1996 Added silly rename for unlink --okir
* 28 Sep 1996 Improved directory cache --okir
* 23 Aug 1997 Claus Heine claus@momo.math.rwth-aachen.de
* Re-implemented silly rename for unlink, newly implemented
* silly rename for nfs_rename() following the suggestions
* of Olaf Kirch (okir) found in this file.
* Following Linus comments on my original hack, this version
* depends only on the dcache stuff and doesn't touch the inode
* layer (iput() and friends).
* 6 Jun 1999 Cache readdir lookups in the page cache. -DaveM
*/
#include <linux/module.h>
#include <linux/time.h>
#include <linux/errno.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/pagemap.h>
#include <linux/pagevec.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/sched.h>
#include <linux/kmemleak.h>
#include <linux/xattr.h>
#include "delegation.h"
#include "iostat.h"
#include "internal.h"
#include "fscache.h"
/* #define NFS_DEBUG_VERBOSE 1 */
static int nfs_opendir(struct inode *, struct file *);
static int nfs_closedir(struct inode *, struct file *);
static int nfs_readdir(struct file *, void *, filldir_t);
static int nfs_fsync_dir(struct file *, loff_t, loff_t, int);
static loff_t nfs_llseek_dir(struct file *, loff_t, int);
static void nfs_readdir_clear_array(struct page*);
const struct file_operations nfs_dir_operations = {
.llseek = nfs_llseek_dir,
.read = generic_read_dir,
.readdir = nfs_readdir,
.open = nfs_opendir,
.release = nfs_closedir,
.fsync = nfs_fsync_dir,
};
const struct address_space_operations nfs_dir_aops = {
.freepage = nfs_readdir_clear_array,
};
static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct inode *dir, struct rpc_cred *cred)
{
struct nfs_open_dir_context *ctx;
ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
if (ctx != NULL) {
ctx->duped = 0;
ctx->attr_gencount = NFS_I(dir)->attr_gencount;
ctx->dir_cookie = 0;
ctx->dup_cookie = 0;
ctx->cred = get_rpccred(cred);
return ctx;
}
return ERR_PTR(-ENOMEM);
}
static void put_nfs_open_dir_context(struct nfs_open_dir_context *ctx)
{
put_rpccred(ctx->cred);
kfree(ctx);
}
/*
* Open file
*/
static int
nfs_opendir(struct inode *inode, struct file *filp)
{
int res = 0;
struct nfs_open_dir_context *ctx;
struct rpc_cred *cred;
dfprintk(FILE, "NFS: open dir(%s/%s)\n",
filp->f_path.dentry->d_parent->d_name.name,
filp->f_path.dentry->d_name.name);
nfs_inc_stats(inode, NFSIOS_VFSOPEN);
cred = rpc_lookup_cred();
if (IS_ERR(cred))
return PTR_ERR(cred);
ctx = alloc_nfs_open_dir_context(inode, cred);
if (IS_ERR(ctx)) {
res = PTR_ERR(ctx);
goto out;
}
filp->private_data = ctx;
if (filp->f_path.dentry == filp->f_path.mnt->mnt_root) {
/* This is a mountpoint, so d_revalidate will never
* have been called, so we need to refresh the
* inode (for close-open consistency) ourselves.
*/
__nfs_revalidate_inode(NFS_SERVER(inode), inode);
}
out:
put_rpccred(cred);
return res;
}
static int
nfs_closedir(struct inode *inode, struct file *filp)
{
put_nfs_open_dir_context(filp->private_data);
return 0;
}
struct nfs_cache_array_entry {
u64 cookie;
u64 ino;
struct qstr string;
unsigned char d_type;
};
struct nfs_cache_array {
int size;
int eof_index;
u64 last_cookie;
struct nfs_cache_array_entry array[0];
};
typedef int (*decode_dirent_t)(struct xdr_stream *, struct nfs_entry *, int);
typedef struct {
struct file *file;
struct page *page;
unsigned long page_index;
u64 *dir_cookie;
u64 last_cookie;
loff_t current_index;
decode_dirent_t decode;
unsigned long timestamp;
unsigned long gencount;
unsigned int cache_entry_index;
unsigned int plus:1;
unsigned int eof:1;
} nfs_readdir_descriptor_t;
/*
* The caller is responsible for calling nfs_readdir_release_array(page)
*/
static
struct nfs_cache_array *nfs_readdir_get_array(struct page *page)
{
void *ptr;
if (page == NULL)
return ERR_PTR(-EIO);
ptr = kmap(page);
if (ptr == NULL)
return ERR_PTR(-ENOMEM);
return ptr;
}
static
void nfs_readdir_release_array(struct page *page)
{
kunmap(page);
}
/*
* we are freeing strings created by nfs_add_to_readdir_array()
*/
static
void nfs_readdir_clear_array(struct page *page)
{
struct nfs_cache_array *array;
int i;
array = kmap_atomic(page);
for (i = 0; i < array->size; i++)
kfree(array->array[i].string.name);
kunmap_atomic(array);
}
/*
* the caller is responsible for freeing qstr.name
* when called by nfs_readdir_add_to_array, the strings will be freed in
* nfs_clear_readdir_array()
*/
static
int nfs_readdir_make_qstr(struct qstr *string, const char *name, unsigned int len)
{
string->len = len;
string->name = kmemdup(name, len, GFP_KERNEL);
if (string->name == NULL)
return -ENOMEM;
/*
* Avoid a kmemleak false positive. The pointer to the name is stored
* in a page cache page which kmemleak does not scan.
*/
kmemleak_not_leak(string->name);
string->hash = full_name_hash(name, len);
return 0;
}
static
int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
{
struct nfs_cache_array *array = nfs_readdir_get_array(page);
struct nfs_cache_array_entry *cache_entry;
int ret;
if (IS_ERR(array))
return PTR_ERR(array);
cache_entry = &array->array[array->size];
/* Check that this entry lies within the page bounds */
ret = -ENOSPC;
if ((char *)&cache_entry[1] - (char *)page_address(page) > PAGE_SIZE)
goto out;
cache_entry->cookie = entry->prev_cookie;
cache_entry->ino = entry->ino;
cache_entry->d_type = entry->d_type;
ret = nfs_readdir_make_qstr(&cache_entry->string, entry->name, entry->len);
if (ret)
goto out;
array->last_cookie = entry->cookie;
array->size++;
if (entry->eof != 0)
array->eof_index = array->size;
out:
nfs_readdir_release_array(page);
return ret;
}
static
int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc)
{
loff_t diff = desc->file->f_pos - desc->current_index;
unsigned int index;
if (diff < 0)
goto out_eof;
if (diff >= array->size) {
if (array->eof_index >= 0)
goto out_eof;
return -EAGAIN;
}
index = (unsigned int)diff;
*desc->dir_cookie = array->array[index].cookie;
desc->cache_entry_index = index;
return 0;
out_eof:
desc->eof = 1;
return -EBADCOOKIE;
}
static
int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc)
{
int i;
loff_t new_pos;
int status = -EAGAIN;
for (i = 0; i < array->size; i++) {
if (array->array[i].cookie == *desc->dir_cookie) {
struct nfs_inode *nfsi = NFS_I(desc->file->f_path.dentry->d_inode);
struct nfs_open_dir_context *ctx = desc->file->private_data;
new_pos = desc->current_index + i;
if (ctx->attr_gencount != nfsi->attr_gencount
|| (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA))) {
ctx->duped = 0;
ctx->attr_gencount = nfsi->attr_gencount;
} else if (new_pos < desc->file->f_pos) {
if (ctx->duped > 0
&& ctx->dup_cookie == *desc->dir_cookie) {
if (printk_ratelimit()) {
pr_notice("NFS: directory %s/%s contains a readdir loop."
"Please contact your server vendor. "
"The file: %s has duplicate cookie %llu\n",
desc->file->f_dentry->d_parent->d_name.name,
desc->file->f_dentry->d_name.name,
array->array[i].string.name,
*desc->dir_cookie);
}
status = -ELOOP;
goto out;
}
ctx->dup_cookie = *desc->dir_cookie;
ctx->duped = -1;
}
desc->file->f_pos = new_pos;
desc->cache_entry_index = i;
return 0;
}
}
if (array->eof_index >= 0) {
status = -EBADCOOKIE;
if (*desc->dir_cookie == array->last_cookie)
desc->eof = 1;
}
out:
return status;
}
static
int nfs_readdir_search_array(nfs_readdir_descriptor_t *desc)
{
struct nfs_cache_array *array;
int status;
array = nfs_readdir_get_array(desc->page);
if (IS_ERR(array)) {
status = PTR_ERR(array);
goto out;
}
if (*desc->dir_cookie == 0)
status = nfs_readdir_search_for_pos(array, desc);
else
status = nfs_readdir_search_for_cookie(array, desc);
if (status == -EAGAIN) {
desc->last_cookie = array->last_cookie;
desc->current_index += array->size;
desc->page_index++;
}
nfs_readdir_release_array(desc->page);
out:
return status;
}
/* Fill a page with xdr information before transferring to the cache page */
static
int nfs_readdir_xdr_filler(struct page **pages, nfs_readdir_descriptor_t *desc,
struct nfs_entry *entry, struct file *file, struct inode *inode)
{
struct nfs_open_dir_context *ctx = file->private_data;
struct rpc_cred *cred = ctx->cred;
unsigned long timestamp, gencount;
int error;
again:
timestamp = jiffies;
gencount = nfs_inc_attr_generation_counter();
error = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred, entry->cookie, pages,
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;
clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
desc->plus = 0;
goto again;
}
goto error;
}
desc->timestamp = timestamp;
desc->gencount = gencount;
error:
return error;
}
static int xdr_decode(nfs_readdir_descriptor_t *desc,
struct nfs_entry *entry, struct xdr_stream *xdr)
{
int error;
error = desc->decode(xdr, entry, desc->plus);
if (error)
return error;
entry->fattr->time_start = desc->timestamp;
entry->fattr->gencount = desc->gencount;
return 0;
}
static
int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry)
{
if (dentry->d_inode == NULL)
goto different;
if (nfs_compare_fh(entry->fh, NFS_FH(dentry->d_inode)) != 0)
goto different;
return 1;
different:
return 0;
}
static
bool nfs_use_readdirplus(struct inode *dir, struct file *filp)
{
if (!nfs_server_capable(dir, NFS_CAP_READDIRPLUS))
return false;
if (test_and_clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags))
return true;
if (filp->f_pos == 0)
return true;
return false;
}
/*
* This function is called by the lookup code to request the use of
* readdirplus to accelerate any future lookups in the same
* directory.
*/
static
void nfs_advise_use_readdirplus(struct inode *dir)
{
set_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags);
}
static
void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry)
{
struct qstr filename = QSTR_INIT(entry->name, entry->len);
struct dentry *dentry;
struct dentry *alias;
struct inode *dir = parent->d_inode;
struct inode *inode;
if (filename.name[0] == '.') {
if (filename.len == 1)
return;
if (filename.len == 2 && filename.name[1] == '.')
return;
}
filename.hash = full_name_hash(filename.name, filename.len);
dentry = d_lookup(parent, &filename);
if (dentry != NULL) {
if (nfs_same_file(dentry, entry)) {
nfs_refresh_inode(dentry->d_inode, entry->fattr);
goto out;
} else {
d_drop(dentry);
dput(dentry);
}
}
dentry = d_alloc(parent, &filename);
if (dentry == NULL)
return;
inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr);
if (IS_ERR(inode))
goto out;
alias = d_materialise_unique(dentry, inode);
if (IS_ERR(alias))
goto out;
else if (alias) {
nfs_set_verifier(alias, nfs_save_change_attribute(dir));
dput(alias);
} else
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
out:
dput(dentry);
}
/* Perform conversion from xdr to cache array */
static
int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry,
struct page **xdr_pages, struct page *page, unsigned int buflen)
{
struct xdr_stream stream;
struct xdr_buf buf;
struct page *scratch;
struct nfs_cache_array *array;
unsigned int count = 0;
int status;
scratch = alloc_page(GFP_KERNEL);
if (scratch == NULL)
return -ENOMEM;
xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen);
xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
do {
status = xdr_decode(desc, entry, &stream);
if (status != 0) {
if (status == -EAGAIN)
status = 0;
break;
}
count++;
if (desc->plus != 0)
nfs_prime_dcache(desc->file->f_path.dentry, entry);
status = nfs_readdir_add_to_array(entry, page);
if (status != 0)
break;
} while (!entry->eof);
if (count == 0 || (status == -EBADCOOKIE && entry->eof != 0)) {
array = nfs_readdir_get_array(page);
if (!IS_ERR(array)) {
array->eof_index = array->size;
status = 0;
nfs_readdir_release_array(page);
} else
status = PTR_ERR(array);
}
put_page(scratch);
return status;
}
static
void nfs_readdir_free_pagearray(struct page **pages, unsigned int npages)
{
unsigned int i;
for (i = 0; i < npages; i++)
put_page(pages[i]);
}
static
void nfs_readdir_free_large_page(void *ptr, struct page **pages,
unsigned int npages)
{
nfs_readdir_free_pagearray(pages, npages);
}
/*
* nfs_readdir_large_page will allocate pages that must be freed with a call
* to nfs_readdir_free_large_page
*/
static
int nfs_readdir_large_page(struct page **pages, unsigned int npages)
{
unsigned int i;
for (i = 0; i < npages; i++) {
struct page *page = alloc_page(GFP_KERNEL);
if (page == NULL)
goto out_freepages;
pages[i] = page;
}
return 0;
out_freepages:
nfs_readdir_free_pagearray(pages, i);
return -ENOMEM;
}
static
int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, struct inode *inode)
{
struct page *pages[NFS_MAX_READDIR_PAGES];
void *pages_ptr = NULL;
struct nfs_entry entry;
struct file *file = desc->file;
struct nfs_cache_array *array;
int status = -ENOMEM;
unsigned int array_size = ARRAY_SIZE(pages);
entry.prev_cookie = 0;
entry.cookie = desc->last_cookie;
entry.eof = 0;
entry.fh = nfs_alloc_fhandle();
entry.fattr = nfs_alloc_fattr();
entry.server = NFS_SERVER(inode);
if (entry.fh == NULL || entry.fattr == NULL)
goto out;
array = nfs_readdir_get_array(page);
if (IS_ERR(array)) {
status = PTR_ERR(array);
goto out;
}
memset(array, 0, sizeof(struct nfs_cache_array));
array->eof_index = -1;
status = nfs_readdir_large_page(pages, array_size);
if (status < 0)
goto out_release_array;
do {
unsigned int pglen;
status = nfs_readdir_xdr_filler(pages, desc, &entry, file, inode);
if (status < 0)
break;
pglen = status;
status = nfs_readdir_page_filler(desc, &entry, pages, page, pglen);
if (status < 0) {
if (status == -ENOSPC)
status = 0;
break;
}
} while (array->eof_index < 0);
nfs_readdir_free_large_page(pages_ptr, pages, array_size);
out_release_array:
nfs_readdir_release_array(page);
out:
nfs_free_fattr(entry.fattr);
nfs_free_fhandle(entry.fh);
return status;
}
/*
* Now we cache directories properly, by converting xdr information
* to an array that can be used for lookups later. This results in
* fewer cache pages, since we can store more information on each page.
* We only need to convert from xdr once so future lookups are much simpler
*/
static
int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page* page)
{
struct inode *inode = desc->file->f_path.dentry->d_inode;
int ret;
ret = nfs_readdir_xdr_to_array(desc, page, inode);
if (ret < 0)
goto error;
SetPageUptodate(page);
if (invalidate_inode_pages2_range(inode->i_mapping, page->index + 1, -1) < 0) {
/* Should never happen */
nfs_zap_mapping(inode, inode->i_mapping);
}
unlock_page(page);
return 0;
error:
unlock_page(page);
return ret;
}
static
void cache_page_release(nfs_readdir_descriptor_t *desc)
{
if (!desc->page->mapping)
nfs_readdir_clear_array(desc->page);
page_cache_release(desc->page);
desc->page = NULL;
}
static
struct page *get_cache_page(nfs_readdir_descriptor_t *desc)
{
return read_cache_page(desc->file->f_path.dentry->d_inode->i_mapping,
desc->page_index, (filler_t *)nfs_readdir_filler, desc);
}
/*
* Returns 0 if desc->dir_cookie was found on page desc->page_index
*/
static
int find_cache_page(nfs_readdir_descriptor_t *desc)
{
int res;
desc->page = get_cache_page(desc);
if (IS_ERR(desc->page))
return PTR_ERR(desc->page);
res = nfs_readdir_search_array(desc);
if (res != 0)
cache_page_release(desc);
return res;
}
/* Search for desc->dir_cookie from the beginning of the page cache */
static inline
int readdir_search_pagecache(nfs_readdir_descriptor_t *desc)
{
int res;
if (desc->page_index == 0) {
desc->current_index = 0;
desc->last_cookie = 0;
}
do {
res = find_cache_page(desc);
} while (res == -EAGAIN);
return res;
}
/*
* Once we've found the start of the dirent within a page: fill 'er up...
*/
static
int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent,
filldir_t filldir)
{
struct file *file = desc->file;
int i = 0;
int res = 0;
struct nfs_cache_array *array = NULL;
struct nfs_open_dir_context *ctx = file->private_data;
array = nfs_readdir_get_array(desc->page);
if (IS_ERR(array)) {
res = PTR_ERR(array);
goto out;
}
for (i = desc->cache_entry_index; i < array->size; i++) {
struct nfs_cache_array_entry *ent;
ent = &array->array[i];
if (filldir(dirent, ent->string.name, ent->string.len,
file->f_pos, nfs_compat_user_ino64(ent->ino),
ent->d_type) < 0) {
desc->eof = 1;
break;
}
file->f_pos++;
if (i < (array->size-1))
*desc->dir_cookie = array->array[i+1].cookie;
else
*desc->dir_cookie = array->last_cookie;
if (ctx->duped != 0)
ctx->duped = 1;
}
if (array->eof_index >= 0)
desc->eof = 1;
nfs_readdir_release_array(desc->page);
out:
cache_page_release(desc);
dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n",
(unsigned long long)*desc->dir_cookie, res);
return res;
}
/*
* 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 page *page = NULL;
int status;
struct inode *inode = desc->file->f_path.dentry->d_inode;
struct nfs_open_dir_context *ctx = desc->file->private_data;
dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n",
(unsigned long long)*desc->dir_cookie);
page = alloc_page(GFP_HIGHUSER);
if (!page) {
status = -ENOMEM;
goto out;
}
desc->page_index = 0;
desc->last_cookie = *desc->dir_cookie;
desc->page = page;
ctx->duped = 0;
status = nfs_readdir_xdr_to_array(desc, page, inode);
if (status < 0)
goto out_release;
status = nfs_do_filldir(desc, dirent, filldir);
out:
dfprintk(DIRCACHE, "NFS: %s: returns %d\n",
__func__, status);
return status;
out_release:
cache_page_release(desc);
goto out;
}
/* The file offset position represents the dirent entry number. A
last cookie cache takes care of the common case of reading the
whole directory.
*/
static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;
nfs_readdir_descriptor_t my_desc,
*desc = &my_desc;
struct nfs_open_dir_context *dir_ctx = filp->private_data;
int res;
dfprintk(FILE, "NFS: readdir(%s/%s) starting at cookie %llu\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
(long long)filp->f_pos);
nfs_inc_stats(inode, NFSIOS_VFSGETDENTS);
/*
* filp->f_pos points to the dirent entry number.
* *desc->dir_cookie has the cookie for the next entry. We have
* to either find the entry with the appropriate number or
* revalidate the cookie.
*/
memset(desc, 0, sizeof(*desc));
desc->file = filp;
desc->dir_cookie = &dir_ctx->dir_cookie;
desc->decode = NFS_PROTO(inode)->decode_dirent;
desc->plus = nfs_use_readdirplus(inode, filp) ? 1 : 0;
nfs_block_sillyrename(dentry);
res = nfs_revalidate_mapping(inode, filp->f_mapping);
if (res < 0)
goto out;
do {
res = readdir_search_pagecache(desc);
if (res == -EBADCOOKIE) {
res = 0;
/* This means either end of directory */
if (*desc->dir_cookie && desc->eof == 0) {
/* Or that the server has 'lost' a cookie */
res = uncached_readdir(desc, dirent, filldir);
if (res == 0)
continue;
}
break;
}
if (res == -ETOOSMALL && desc->plus) {
clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
nfs_zap_caches(inode);
desc->page_index = 0;
desc->plus = 0;
desc->eof = 0;
continue;
}
if (res < 0)
break;
res = nfs_do_filldir(desc, dirent, filldir);
if (res < 0)
break;
} while (!desc->eof);
out:
nfs_unblock_sillyrename(dentry);
if (res > 0)
res = 0;
dfprintk(FILE, "NFS: readdir(%s/%s) returns %d\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
res);
return res;
}
static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int origin)
{
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;
struct nfs_open_dir_context *dir_ctx = filp->private_data;
dfprintk(FILE, "NFS: llseek dir(%s/%s, %lld, %d)\n",
dentry->d_parent->d_name.name,
dentry->d_name.name,
offset, origin);
mutex_lock(&inode->i_mutex);
switch (origin) {
case 1:
offset += filp->f_pos;
case 0:
if (offset >= 0)
break;
default:
offset = -EINVAL;
goto out;
}
if (offset != filp->f_pos) {
filp->f_pos = offset;
dir_ctx->dir_cookie = 0;
dir_ctx->duped = 0;
}
out:
mutex_unlock(&inode->i_mutex);
return offset;
}
/*
* All directory operations under NFS are synchronous, so fsync()
* is a dummy operation.
*/
static int nfs_fsync_dir(struct file *filp, loff_t start, loff_t end,
int datasync)
{
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;
dfprintk(FILE, "NFS: fsync dir(%s/%s) datasync %d\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
datasync);
mutex_lock(&inode->i_mutex);
nfs_inc_stats(dentry->d_inode, NFSIOS_VFSFSYNC);
mutex_unlock(&inode->i_mutex);
return 0;
}
/**
* nfs_force_lookup_revalidate - Mark the directory as having changed
* @dir - pointer to directory inode
*
* This forces the revalidation code in nfs_lookup_revalidate() to do a
* full lookup on all child dentries of 'dir' whenever a change occurs
* on the server that might have invalidated our dcache.
*
* The caller should be holding dir->i_lock
*/
void nfs_force_lookup_revalidate(struct inode *dir)
{
NFS_I(dir)->cache_change_attribute++;
}
EXPORT_SYMBOL_GPL(nfs_force_lookup_revalidate);
/*
* 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 int nfs_check_verifier(struct inode *dir, struct dentry *dentry)
{
if (IS_ROOT(dentry))
return 1;
if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
return 0;
if (!nfs_verify_change_attribute(dir, dentry->d_time))
return 0;
/* Revalidate nfsi->cache_change_attribute before we declare a match */
if (nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0)
return 0;
if (!nfs_verify_change_attribute(dir, dentry->d_time))
return 0;
return 1;
}
/*
* Use intent information to check whether or not we're going to do
* an O_EXCL create using this path component.
*/
static int nfs_is_exclusive_create(struct inode *dir, unsigned int flags)
{
if (NFS_PROTO(dir)->version == 2)
return 0;
return flags & LOOKUP_EXCL;
}
/*
* Inode and filehandle revalidation for lookups.
*
* We force revalidation in the cases where the VFS sets LOOKUP_REVAL,
* or if the intent information indicates that we're about to open this
* particular file and the "nocto" mount flag is not set.
*
*/
static inline
int nfs_lookup_verify_inode(struct inode *inode, unsigned int flags)
{
struct nfs_server *server = NFS_SERVER(inode);
if (IS_AUTOMOUNT(inode))
return 0;
/* VFS wants an on-the-wire revalidation */
if (flags & LOOKUP_REVAL)
goto out_force;
/* This is an open(2) */
if ((flags & LOOKUP_OPEN) && !(server->flags & NFS_MOUNT_NOCTO) &&
(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
goto out_force;
return 0;
out_force:
return __nfs_revalidate_inode(server, inode);
}
/*
* We judge how long we want to trust negative
* dentries by looking at the parent inode mtime.
*
* If parent mtime has changed, we revalidate, else we wait for a
* period corresponding to the parent's attribute cache timeout value.
*/
static inline
int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
/* Don't revalidate a negative dentry if we're creating a new file */
if (flags & LOOKUP_CREATE)
return 0;
if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG)
return 1;
return !nfs_check_verifier(dir, dentry);
}
/*
* This is called every time the dcache has a lookup hit,
* and we should check whether we can really trust that
* lookup.
*
* NOTE! The hit can be a negative hit too, don't assume
* we have an inode!
*
* If the parent directory is seen to have changed, we throw out the
* cached dentry and do a new lookup.
*/
static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
{
struct inode *dir;
struct inode *inode;
struct dentry *parent;
struct nfs_fh *fhandle = NULL;
struct nfs_fattr *fattr = NULL;
int error;
if (flags & LOOKUP_RCU)
return -ECHILD;
parent = dget_parent(dentry);
dir = parent->d_inode;
nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE);
inode = dentry->d_inode;
if (!inode) {
if (nfs_neg_need_reval(dir, dentry, flags))
goto out_bad;
goto out_valid_noent;
}
if (is_bad_inode(inode)) {
dfprintk(LOOKUPCACHE, "%s: %s/%s has dud inode\n",
__func__, dentry->d_parent->d_name.name,
dentry->d_name.name);
goto out_bad;
}
if (NFS_PROTO(dir)->have_delegation(inode, FMODE_READ))
goto out_set_verifier;
/* Force a full look up iff the parent directory has changed */
if (!nfs_is_exclusive_create(dir, flags) && nfs_check_verifier(dir, dentry)) {
if (nfs_lookup_verify_inode(inode, flags))
goto out_zap_parent;
goto out_valid;
}
if (NFS_STALE(inode))
goto out_bad;
error = -ENOMEM;
fhandle = nfs_alloc_fhandle();
fattr = nfs_alloc_fattr();
if (fhandle == NULL || fattr == NULL)
goto out_error;
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
if (error)
goto out_bad;
if (nfs_compare_fh(NFS_FH(inode), fhandle))
goto out_bad;
if ((error = nfs_refresh_inode(inode, fattr)) != 0)
goto out_bad;
nfs_free_fattr(fattr);
nfs_free_fhandle(fhandle);
out_set_verifier:
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
out_valid:
/* Success: notify readdir to use READDIRPLUS */
nfs_advise_use_readdirplus(dir);
out_valid_noent:
dput(parent);
dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is valid\n",
__func__, dentry->d_parent->d_name.name,
dentry->d_name.name);
return 1;
out_zap_parent:
nfs_zap_caches(dir);
out_bad:
nfs_mark_for_revalidate(dir);
if (inode && S_ISDIR(inode->i_mode)) {
/* Purge readdir caches. */
nfs_zap_caches(inode);
/* If we have submounts, don't unhash ! */
if (have_submounts(dentry))
goto out_valid;
if (dentry->d_flags & DCACHE_DISCONNECTED)
goto out_valid;
shrink_dcache_parent(dentry);
}
d_drop(dentry);
nfs_free_fattr(fattr);
nfs_free_fhandle(fhandle);
dput(parent);
dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is invalid\n",
__func__, dentry->d_parent->d_name.name,
dentry->d_name.name);
return 0;
out_error:
nfs_free_fattr(fattr);
nfs_free_fhandle(fhandle);
dput(parent);
dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) lookup returned error %d\n",
__func__, dentry->d_parent->d_name.name,
dentry->d_name.name, error);
return error;
}
/*
* This is called from dput() when d_count is going to 0.
*/
static int nfs_dentry_delete(const struct dentry *dentry)
{
dfprintk(VFS, "NFS: dentry_delete(%s/%s, %x)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
dentry->d_flags);
/* Unhash any dentry with a stale inode */
if (dentry->d_inode != NULL && NFS_STALE(dentry->d_inode))
return 1;
if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
/* Unhash it, so that ->d_iput() would be called */
return 1;
}
if (!(dentry->d_sb->s_flags & MS_ACTIVE)) {
/* Unhash it, so that ancestors of killed async unlink
* files will be cleaned up during umount */
return 1;
}
return 0;
}
static void nfs_drop_nlink(struct inode *inode)
{
spin_lock(&inode->i_lock);
if (inode->i_nlink > 0)
drop_nlink(inode);
spin_unlock(&inode->i_lock);
}
/*
* Called when the dentry loses inode.
* We use it to clean up silly-renamed files.
*/
static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode)
{
if (S_ISDIR(inode->i_mode))
/* drop any readdir cache as it could easily be old */
NFS_I(inode)->cache_validity |= NFS_INO_INVALID_DATA;
if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
drop_nlink(inode);
nfs_complete_unlink(dentry, inode);
}
iput(inode);
}
static void nfs_d_release(struct dentry *dentry)
{
/* free cached devname value, if it survived that far */
if (unlikely(dentry->d_fsdata)) {
if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
WARN_ON(1);
else
kfree(dentry->d_fsdata);
}
}
const struct dentry_operations nfs_dentry_operations = {
.d_revalidate = nfs_lookup_revalidate,
.d_delete = nfs_dentry_delete,
.d_iput = nfs_dentry_iput,
.d_automount = nfs_d_automount,
.d_release = nfs_d_release,
};
EXPORT_SYMBOL_GPL(nfs_dentry_operations);
struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
{
struct dentry *res;
struct dentry *parent;
struct inode *inode = NULL;
struct nfs_fh *fhandle = NULL;
struct nfs_fattr *fattr = NULL;
int error;
dfprintk(VFS, "NFS: lookup(%s/%s)\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
nfs_inc_stats(dir, NFSIOS_VFSLOOKUP);
res = ERR_PTR(-ENAMETOOLONG);
if (dentry->d_name.len > NFS_SERVER(dir)->namelen)
goto out;
/*
* If we're doing an exclusive create, optimize away the lookup
* but don't hash the dentry.
*/
if (nfs_is_exclusive_create(dir, flags)) {
d_instantiate(dentry, NULL);
res = NULL;
goto out;
}
res = ERR_PTR(-ENOMEM);
fhandle = nfs_alloc_fhandle();
fattr = nfs_alloc_fattr();
if (fhandle == NULL || fattr == NULL)
goto out;
parent = dentry->d_parent;
/* Protect against concurrent sillydeletes */
nfs_block_sillyrename(parent);
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
if (error == -ENOENT)
goto no_entry;
if (error < 0) {
res = ERR_PTR(error);
goto out_unblock_sillyrename;
}
inode = nfs_fhget(dentry->d_sb, fhandle, fattr);
res = ERR_CAST(inode);
if (IS_ERR(res))
goto out_unblock_sillyrename;
/* Success: notify readdir to use READDIRPLUS */
nfs_advise_use_readdirplus(dir);
no_entry:
res = d_materialise_unique(dentry, inode);
if (res != NULL) {
if (IS_ERR(res))
goto out_unblock_sillyrename;
dentry = res;
}
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
out_unblock_sillyrename:
nfs_unblock_sillyrename(parent);
out:
nfs_free_fattr(fattr);
nfs_free_fhandle(fhandle);
return res;
}
EXPORT_SYMBOL_GPL(nfs_lookup);
#if IS_ENABLED(CONFIG_NFS_V4)
static int nfs4_lookup_revalidate(struct dentry *, unsigned int);
const struct dentry_operations nfs4_dentry_operations = {
.d_revalidate = nfs4_lookup_revalidate,
.d_delete = nfs_dentry_delete,
.d_iput = nfs_dentry_iput,
.d_automount = nfs_d_automount,
.d_release = nfs_d_release,
};
EXPORT_SYMBOL_GPL(nfs4_dentry_operations);
static fmode_t flags_to_mode(int flags)
{
fmode_t res = (__force fmode_t)flags & FMODE_EXEC;
if ((flags & O_ACCMODE) != O_WRONLY)
res |= FMODE_READ;
if ((flags & O_ACCMODE) != O_RDONLY)
res |= FMODE_WRITE;
return res;
}
static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags)
{
return alloc_nfs_open_context(dentry, flags_to_mode(open_flags));
}
static int do_open(struct inode *inode, struct file *filp)
{
nfs_fscache_set_inode_cookie(inode, filp);
return 0;
}
static int nfs_finish_open(struct nfs_open_context *ctx,
struct dentry *dentry,
struct file *file, unsigned open_flags,
int *opened)
{
int err;
if (ctx->dentry != dentry) {
dput(ctx->dentry);
ctx->dentry = dget(dentry);
}
/* If the open_intent is for execute, we have an extra check to make */
if (ctx->mode & FMODE_EXEC) {
err = nfs_may_open(dentry->d_inode, ctx->cred, open_flags);
if (err < 0)
goto out;
}
err = finish_open(file, dentry, do_open, opened);
if (err)
goto out;
nfs_file_set_open_context(file, ctx);
out:
put_nfs_open_context(ctx);
return err;
}
int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
struct file *file, unsigned open_flags,
umode_t mode, int *opened)
{
struct nfs_open_context *ctx;
struct dentry *res;
struct iattr attr = { .ia_valid = ATTR_OPEN };
struct inode *inode;
int err;
/* Expect a negative dentry */
BUG_ON(dentry->d_inode);
dfprintk(VFS, "NFS: atomic_open(%s/%ld), %s\n",
dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
/* NFS only supports OPEN on regular files */
if ((open_flags & O_DIRECTORY)) {
if (!d_unhashed(dentry)) {
/*
* Hashed negative dentry with O_DIRECTORY: dentry was
* revalidated and is fine, no need to perform lookup
* again
*/
return -ENOENT;
}
goto no_open;
}
if (dentry->d_name.len > NFS_SERVER(dir)->namelen)
return -ENAMETOOLONG;
if (open_flags & O_CREAT) {
attr.ia_valid |= ATTR_MODE;
attr.ia_mode = mode & ~current_umask();
}
if (open_flags & O_TRUNC) {
attr.ia_valid |= ATTR_SIZE;
attr.ia_size = 0;
}
ctx = create_nfs_open_context(dentry, open_flags);
err = PTR_ERR(ctx);
if (IS_ERR(ctx))
goto out;
nfs_block_sillyrename(dentry->d_parent);
inode = NFS_PROTO(dir)->open_context(dir, ctx, open_flags, &attr);
d_drop(dentry);
if (IS_ERR(inode)) {
nfs_unblock_sillyrename(dentry->d_parent);
put_nfs_open_context(ctx);
err = PTR_ERR(inode);
switch (err) {
case -ENOENT:
d_add(dentry, NULL);
break;
case -EISDIR:
case -ENOTDIR:
goto no_open;
case -ELOOP:
if (!(open_flags & O_NOFOLLOW))
goto no_open;
break;
/* case -EINVAL: */
default:
break;
}
goto out;
}
res = d_add_unique(dentry, inode);
if (res != NULL)
dentry = res;
nfs_unblock_sillyrename(dentry->d_parent);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
err = nfs_finish_open(ctx, dentry, file, open_flags, opened);
dput(res);
out:
return err;
no_open:
res = nfs_lookup(dir, dentry, 0);
err = PTR_ERR(res);
if (IS_ERR(res))
goto out;
return finish_no_open(file, res);
}
EXPORT_SYMBOL_GPL(nfs_atomic_open);
static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags)
{
struct dentry *parent = NULL;
struct inode *inode;
struct inode *dir;
int ret = 0;
if (flags & LOOKUP_RCU)
return -ECHILD;
if (!(flags & LOOKUP_OPEN) || (flags & LOOKUP_DIRECTORY))
goto no_open;
if (d_mountpoint(dentry))
goto no_open;
inode = dentry->d_inode;
parent = dget_parent(dentry);
dir = parent->d_inode;
/* We can't create new files in nfs_open_revalidate(), so we
* optimize away revalidation of negative dentries.
*/
if (inode == NULL) {
if (!nfs_neg_need_reval(dir, dentry, flags))
ret = 1;
goto out;
}
/* NFS only supports OPEN on regular files */
if (!S_ISREG(inode->i_mode))
goto no_open_dput;
/* We cannot do exclusive creation on a positive dentry */
if (flags & LOOKUP_EXCL)
goto no_open_dput;
/* Let f_op->open() actually open (and revalidate) the file */
ret = 1;
out:
dput(parent);
return ret;
no_open_dput:
dput(parent);
no_open:
return nfs_lookup_revalidate(dentry, flags);
}
#endif /* CONFIG_NFSV4 */
/*
* Code common to create, mkdir, and mknod.
*/
int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle,
struct nfs_fattr *fattr)
{
struct dentry *parent = dget_parent(dentry);
struct inode *dir = parent->d_inode;
struct inode *inode;
int error = -EACCES;
d_drop(dentry);
/* We may have been initialized further down */
if (dentry->d_inode)
goto out;
if (fhandle->size == 0) {
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
if (error)
goto out_error;
}
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
if (!(fattr->valid & NFS_ATTR_FATTR)) {
struct nfs_server *server = NFS_SB(dentry->d_sb);
error = server->nfs_client->rpc_ops->getattr(server, fhandle, fattr);
if (error < 0)
goto out_error;
}
inode = nfs_fhget(dentry->d_sb, fhandle, fattr);
error = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_error;
d_add(dentry, inode);
out:
dput(parent);
return 0;
out_error:
nfs_mark_for_revalidate(dir);
dput(parent);
return error;
}
EXPORT_SYMBOL_GPL(nfs_instantiate);
/*
* Following a failed create operation, we drop the dentry rather
* than retain a negative dentry. This avoids a problem in the event
* that the operation succeeded on the server, but an error in the
* reply path made it appear to have failed.
*/
int nfs_create(struct inode *dir, struct dentry *dentry,
umode_t mode, bool excl)
{
struct iattr attr;
int open_flags = excl ? O_CREAT | O_EXCL : O_CREAT;
int error;
dfprintk(VFS, "NFS: create(%s/%ld), %s\n",
dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
attr.ia_mode = mode;
attr.ia_valid = ATTR_MODE;
error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags);
if (error != 0)
goto out_err;
return 0;
out_err:
d_drop(dentry);
return error;
}
EXPORT_SYMBOL_GPL(nfs_create);
/*
* See comments for nfs_proc_create regarding failed operations.
*/
int
nfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
{
struct iattr attr;
int status;
dfprintk(VFS, "NFS: mknod(%s/%ld), %s\n",
dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
if (!new_valid_dev(rdev))
return -EINVAL;
attr.ia_mode = mode;
attr.ia_valid = ATTR_MODE;
status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev);
if (status != 0)
goto out_err;
return 0;
out_err:
d_drop(dentry);
return status;
}
EXPORT_SYMBOL_GPL(nfs_mknod);
/*
* See comments for nfs_proc_create regarding failed operations.
*/
int nfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
struct iattr attr;
int error;
dfprintk(VFS, "NFS: mkdir(%s/%ld), %s\n",
dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
attr.ia_valid = ATTR_MODE;
attr.ia_mode = mode | S_IFDIR;
error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr);
if (error != 0)
goto out_err;
return 0;
out_err:
d_drop(dentry);
return error;
}
EXPORT_SYMBOL_GPL(nfs_mkdir);
static void nfs_dentry_handle_enoent(struct dentry *dentry)
{
if (dentry->d_inode != NULL && !d_unhashed(dentry))
d_delete(dentry);
}
int nfs_rmdir(struct inode *dir, struct dentry *dentry)
{
int error;
dfprintk(VFS, "NFS: rmdir(%s/%ld), %s\n",
dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
/* Ensure the VFS deletes this inode */
if (error == 0 && dentry->d_inode != NULL)
clear_nlink(dentry->d_inode);
else if (error == -ENOENT)
nfs_dentry_handle_enoent(dentry);
return error;
}
EXPORT_SYMBOL_GPL(nfs_rmdir);
/*
* Remove a file after making sure there are no pending writes,
* and after checking that the file has only one user.
*
* We invalidate the attribute cache and free the inode prior to the operation
* to avoid possible races if the server reuses the inode.
*/
static int nfs_safe_remove(struct dentry *dentry)
{
struct inode *dir = dentry->d_parent->d_inode;
struct inode *inode = dentry->d_inode;
int error = -EBUSY;
dfprintk(VFS, "NFS: safe_remove(%s/%s)\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
/* If the dentry was sillyrenamed, we simply call d_delete() */
if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
error = 0;
goto out;
}
if (inode != NULL) {
NFS_PROTO(inode)->return_delegation(inode);
error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
/* The VFS may want to delete this inode */
if (error == 0)
nfs_drop_nlink(inode);
nfs_mark_for_revalidate(inode);
} else
error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
if (error == -ENOENT)
nfs_dentry_handle_enoent(dentry);
out:
return error;
}
/* We do silly rename. In case sillyrename() returns -EBUSY, the inode
* belongs to an active ".nfs..." file and we return -EBUSY.
*
* If sillyrename() returns 0, we do nothing, otherwise we unlink.
*/
int nfs_unlink(struct inode *dir, struct dentry *dentry)
{
int error;
int need_rehash = 0;
dfprintk(VFS, "NFS: unlink(%s/%ld, %s)\n", dir->i_sb->s_id,
dir->i_ino, dentry->d_name.name);
spin_lock(&dentry->d_lock);
if (dentry->d_count > 1) {
spin_unlock(&dentry->d_lock);
/* Start asynchronous writeout of the inode */
write_inode_now(dentry->d_inode, 0);
error = nfs_sillyrename(dir, dentry);
return error;
}
if (!d_unhashed(dentry)) {
__d_drop(dentry);
need_rehash = 1;
}
spin_unlock(&dentry->d_lock);
error = nfs_safe_remove(dentry);
if (!error || error == -ENOENT) {
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
} else if (need_rehash)
d_rehash(dentry);
return error;
}
EXPORT_SYMBOL_GPL(nfs_unlink);
/*
* To create a symbolic link, most file systems instantiate a new inode,
* add a page to it containing the path, then write it out to the disk
* using prepare_write/commit_write.
*
* Unfortunately the NFS client can't create the in-core inode first
* because it needs a file handle to create an in-core inode (see
* fs/nfs/inode.c:nfs_fhget). We only have a file handle *after* the
* symlink request has completed on the server.
*
* So instead we allocate a raw page, copy the symname into it, then do
* the SYMLINK request with the page as the buffer. If it succeeds, we
* now have a new file handle and can instantiate an in-core NFS inode
* and move the raw page into its mapping.
*/
int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
{
struct pagevec lru_pvec;
struct page *page;
char *kaddr;
struct iattr attr;
unsigned int pathlen = strlen(symname);
int error;
dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id,
dir->i_ino, dentry->d_name.name, symname);
if (pathlen > PAGE_SIZE)
return -ENAMETOOLONG;
attr.ia_mode = S_IFLNK | S_IRWXUGO;
attr.ia_valid = ATTR_MODE;
page = alloc_page(GFP_HIGHUSER);
if (!page)
return -ENOMEM;
kaddr = kmap_atomic(page);
memcpy(kaddr, symname, pathlen);
if (pathlen < PAGE_SIZE)
memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen);
kunmap_atomic(kaddr);
error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr);
if (error != 0) {
dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s) error %d\n",
dir->i_sb->s_id, dir->i_ino,
dentry->d_name.name, symname, error);
d_drop(dentry);
__free_page(page);
return error;
}
/*
* No big deal if we can't add this page to the page cache here.
* READLINK will get the missing page from the server if needed.
*/
pagevec_init(&lru_pvec, 0);
if (!add_to_page_cache(page, dentry->d_inode->i_mapping, 0,
GFP_KERNEL)) {
pagevec_add(&lru_pvec, page);
pagevec_lru_add_file(&lru_pvec);
SetPageUptodate(page);
unlock_page(page);
} else
__free_page(page);
return 0;
}
EXPORT_SYMBOL_GPL(nfs_symlink);
int
nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
{
struct inode *inode = old_dentry->d_inode;
int error;
dfprintk(VFS, "NFS: link(%s/%s -> %s/%s)\n",
old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
dentry->d_parent->d_name.name, dentry->d_name.name);
NFS_PROTO(inode)->return_delegation(inode);
d_drop(dentry);
error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
if (error == 0) {
ihold(inode);
d_add(dentry, inode);
}
return error;
}
EXPORT_SYMBOL_GPL(nfs_link);
/*
* RENAME
* FIXME: Some nfsds, like the Linux user space nfsd, may generate a
* different file handle for the same inode after a rename (e.g. when
* moving to a different directory). A fail-safe method to do so would
* be to look up old_dir/old_name, create a link to new_dir/new_name and
* rename the old file using the sillyrename stuff. This way, the original
* file in old_dir will go away when the last process iput()s the inode.
*
* FIXED.
*
* It actually works quite well. One needs to have the possibility for
* at least one ".nfs..." file in each directory the file ever gets
* moved or linked to which happens automagically with the new
* implementation that only depends on the dcache stuff instead of
* using the inode layer
*
* Unfortunately, things are a little more complicated than indicated
* above. For a cross-directory move, we want to make sure we can get
* rid of the old inode after the operation. This means there must be
* no pending writes (if it's a file), and the use count must be 1.
* If these conditions are met, we can drop the dentries before doing
* the rename.
*/
int nfs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry)
{
struct inode *old_inode = old_dentry->d_inode;
struct inode *new_inode = new_dentry->d_inode;
struct dentry *dentry = NULL, *rehash = NULL;
int error = -EBUSY;
dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n",
old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
new_dentry->d_parent->d_name.name, new_dentry->d_name.name,
new_dentry->d_count);
/*
* For non-directories, check whether the target is busy and if so,
* make a copy of the dentry and then do a silly-rename. If the
* silly-rename succeeds, the copied dentry is hashed and becomes
* the new target.
*/
if (new_inode && !S_ISDIR(new_inode->i_mode)) {
/*
* To prevent any new references to the target during the
* rename, we unhash the dentry in advance.
*/
if (!d_unhashed(new_dentry)) {
d_drop(new_dentry);
rehash = new_dentry;
}
if (new_dentry->d_count > 2) {
int err;
/* copy the target dentry's name */
dentry = d_alloc(new_dentry->d_parent,
&new_dentry->d_name);
if (!dentry)
goto out;
/* silly-rename the existing target ... */
err = nfs_sillyrename(new_dir, new_dentry);
if (err)
goto out;
new_dentry = dentry;
rehash = NULL;
new_inode = NULL;
}
}
NFS_PROTO(old_inode)->return_delegation(old_inode);
if (new_inode != NULL)
NFS_PROTO(new_inode)->return_delegation(new_inode);
error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name,
new_dir, &new_dentry->d_name);
nfs_mark_for_revalidate(old_inode);
out:
if (rehash)
d_rehash(rehash);
if (!error) {
if (new_inode != NULL)
nfs_drop_nlink(new_inode);
d_move(old_dentry, new_dentry);
nfs_set_verifier(new_dentry,
nfs_save_change_attribute(new_dir));
} else if (error == -ENOENT)
nfs_dentry_handle_enoent(old_dentry);
/* new dentry created? */
if (dentry)
dput(dentry);
return error;
}
EXPORT_SYMBOL_GPL(nfs_rename);
static DEFINE_SPINLOCK(nfs_access_lru_lock);
static LIST_HEAD(nfs_access_lru_list);
static atomic_long_t nfs_access_nr_entries;
static void nfs_access_free_entry(struct nfs_access_entry *entry)
{
put_rpccred(entry->cred);
kfree(entry);
smp_mb__before_atomic_dec();
atomic_long_dec(&nfs_access_nr_entries);
smp_mb__after_atomic_dec();
}
static void nfs_access_free_list(struct list_head *head)
{
struct nfs_access_entry *cache;
while (!list_empty(head)) {
cache = list_entry(head->next, struct nfs_access_entry, lru);
list_del(&cache->lru);
nfs_access_free_entry(cache);
}
}
int nfs_access_cache_shrinker(struct shrinker *shrink,
struct shrink_control *sc)
{
LIST_HEAD(head);
struct nfs_inode *nfsi, *next;
struct nfs_access_entry *cache;
int nr_to_scan = sc->nr_to_scan;
gfp_t gfp_mask = sc->gfp_mask;
if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL)
return (nr_to_scan == 0) ? 0 : -1;
spin_lock(&nfs_access_lru_lock);
list_for_each_entry_safe(nfsi, next, &nfs_access_lru_list, access_cache_inode_lru) {
struct inode *inode;
if (nr_to_scan-- == 0)
break;
inode = &nfsi->vfs_inode;
spin_lock(&inode->i_lock);
if (list_empty(&nfsi->access_cache_entry_lru))
goto remove_lru_entry;
cache = list_entry(nfsi->access_cache_entry_lru.next,
struct nfs_access_entry, lru);
list_move(&cache->lru, &head);
rb_erase(&cache->rb_node, &nfsi->access_cache);
if (!list_empty(&nfsi->access_cache_entry_lru))
list_move_tail(&nfsi->access_cache_inode_lru,
&nfs_access_lru_list);
else {
remove_lru_entry:
list_del_init(&nfsi->access_cache_inode_lru);
smp_mb__before_clear_bit();
clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags);
smp_mb__after_clear_bit();
}
spin_unlock(&inode->i_lock);
}
spin_unlock(&nfs_access_lru_lock);
nfs_access_free_list(&head);
return (atomic_long_read(&nfs_access_nr_entries) / 100) * sysctl_vfs_cache_pressure;
}
static void __nfs_access_zap_cache(struct nfs_inode *nfsi, struct list_head *head)
{
struct rb_root *root_node = &nfsi->access_cache;
struct rb_node *n;
struct nfs_access_entry *entry;
/* Unhook entries from the cache */
while ((n = rb_first(root_node)) != NULL) {
entry = rb_entry(n, struct nfs_access_entry, rb_node);
rb_erase(n, root_node);
list_move(&entry->lru, head);
}
nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS;
}
void nfs_access_zap_cache(struct inode *inode)
{
LIST_HEAD(head);
if (test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags) == 0)
return;
/* Remove from global LRU init */
spin_lock(&nfs_access_lru_lock);
if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags))
list_del_init(&NFS_I(inode)->access_cache_inode_lru);
spin_lock(&inode->i_lock);
__nfs_access_zap_cache(NFS_I(inode), &head);
spin_unlock(&inode->i_lock);
spin_unlock(&nfs_access_lru_lock);
nfs_access_free_list(&head);
}
EXPORT_SYMBOL_GPL(nfs_access_zap_cache);
static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, struct rpc_cred *cred)
{
struct rb_node *n = NFS_I(inode)->access_cache.rb_node;
struct nfs_access_entry *entry;
while (n != NULL) {
entry = rb_entry(n, struct nfs_access_entry, rb_node);
if (cred < entry->cred)
n = n->rb_left;
else if (cred > entry->cred)
n = n->rb_right;
else
return entry;
}
return NULL;
}
static int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_access_entry *cache;
int err = -ENOENT;
spin_lock(&inode->i_lock);
if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)
goto out_zap;
cache = nfs_access_search_rbtree(inode, cred);
if (cache == NULL)
goto out;
if (!nfs_have_delegated_attributes(inode) &&
!time_in_range_open(jiffies, cache->jiffies, cache->jiffies + nfsi->attrtimeo))
goto out_stale;
res->jiffies = cache->jiffies;
res->cred = cache->cred;
res->mask = cache->mask;
list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru);
err = 0;
out:
spin_unlock(&inode->i_lock);
return err;
out_stale:
rb_erase(&cache->rb_node, &nfsi->access_cache);
list_del(&cache->lru);
spin_unlock(&inode->i_lock);
nfs_access_free_entry(cache);
return -ENOENT;
out_zap:
spin_unlock(&inode->i_lock);
nfs_access_zap_cache(inode);
return -ENOENT;
}
static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct rb_root *root_node = &nfsi->access_cache;
struct rb_node **p = &root_node->rb_node;
struct rb_node *parent = NULL;
struct nfs_access_entry *entry;
spin_lock(&inode->i_lock);
while (*p != NULL) {
parent = *p;
entry = rb_entry(parent, struct nfs_access_entry, rb_node);
if (set->cred < entry->cred)
p = &parent->rb_left;
else if (set->cred > entry->cred)
p = &parent->rb_right;
else
goto found;
}
rb_link_node(&set->rb_node, parent, p);
rb_insert_color(&set->rb_node, root_node);
list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
spin_unlock(&inode->i_lock);
return;
found:
rb_replace_node(parent, &set->rb_node, root_node);
list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
list_del(&entry->lru);
spin_unlock(&inode->i_lock);
nfs_access_free_entry(entry);
}
static void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set)
{
struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL);
if (cache == NULL)
return;
RB_CLEAR_NODE(&cache->rb_node);
cache->jiffies = set->jiffies;
cache->cred = get_rpccred(set->cred);
cache->mask = set->mask;
nfs_access_add_rbtree(inode, cache);
/* Update accounting */
smp_mb__before_atomic_inc();
atomic_long_inc(&nfs_access_nr_entries);
smp_mb__after_atomic_inc();
/* Add inode to global LRU list */
if (!test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) {
spin_lock(&nfs_access_lru_lock);
if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags))
list_add_tail(&NFS_I(inode)->access_cache_inode_lru,
&nfs_access_lru_list);
spin_unlock(&nfs_access_lru_lock);
}
}
static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
{
struct nfs_access_entry cache;
int status;
status = nfs_access_get_cached(inode, cred, &cache);
if (status == 0)
goto out;
/* Be clever: ask server to check for all possible rights */
cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ;
cache.cred = cred;
cache.jiffies = jiffies;
status = NFS_PROTO(inode)->access(inode, &cache);
if (status != 0) {
if (status == -ESTALE) {
nfs_zap_caches(inode);
if (!S_ISDIR(inode->i_mode))
set_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
}
return status;
}
nfs_access_add_cache(inode, &cache);
out:
if ((mask & ~cache.mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0)
return 0;
return -EACCES;
}
static int nfs_open_permission_mask(int openflags)
{
int mask = 0;
if ((openflags & O_ACCMODE) != O_WRONLY)
mask |= MAY_READ;
if ((openflags & O_ACCMODE) != O_RDONLY)
mask |= MAY_WRITE;
if (openflags & __FMODE_EXEC)
mask |= MAY_EXEC;
return mask;
}
int nfs_may_open(struct inode *inode, struct rpc_cred *cred, int openflags)
{
return nfs_do_access(inode, cred, nfs_open_permission_mask(openflags));
}
EXPORT_SYMBOL_GPL(nfs_may_open);
int nfs_permission(struct inode *inode, int mask)
{
struct rpc_cred *cred;
int res = 0;
if (mask & MAY_NOT_BLOCK)
return -ECHILD;
nfs_inc_stats(inode, NFSIOS_VFSACCESS);
if ((mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0)
goto out;
/* Is this sys_access() ? */
if (mask & (MAY_ACCESS | MAY_CHDIR))
goto force_lookup;
switch (inode->i_mode & S_IFMT) {
case S_IFLNK:
goto out;
case S_IFREG:
/* NFSv4 has atomic_open... */
if (nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN)
&& (mask & MAY_OPEN)
&& !(mask & MAY_EXEC))
goto out;
break;
case S_IFDIR:
/*
* Optimize away all write operations, since the server
* will check permissions when we perform the op.
*/
if ((mask & MAY_WRITE) && !(mask & MAY_READ))
goto out;
}
force_lookup:
if (!NFS_PROTO(inode)->access)
goto out_notsup;
cred = rpc_lookup_cred();
if (!IS_ERR(cred)) {
res = nfs_do_access(inode, cred, mask);
put_rpccred(cred);
} else
res = PTR_ERR(cred);
out:
if (!res && (mask & MAY_EXEC) && !execute_ok(inode))
res = -EACCES;
dfprintk(VFS, "NFS: permission(%s/%ld), mask=0x%x, res=%d\n",
inode->i_sb->s_id, inode->i_ino, mask, res);
return res;
out_notsup:
res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
if (res == 0)
res = generic_permission(inode, mask);
goto out;
}
EXPORT_SYMBOL_GPL(nfs_permission);
/*
* Local variables:
* version-control: t
* kept-new-versions: 5
* End:
*/
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