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50d77739fa
linux-next/fs/nfs/dir.c
NeilBrown 50d77739fa NFS: fix two problems in lookup_revalidate in RCU-walk 
1/ rcu_dereference isn't correct: that field isn't
   RCU protected.   It could potentially change at any time
   so ACCESS_ONCE might be justified.

   changes to ->d_parent are protected by ->d_seq.  However
   that isn't always checked after ->d_revalidate is called,
   so it is safest to keep the double-check that ->d_parent
   hasn't changed at the end of these functions.

2/ in nfs4_lookup_revalidate, "->d_parent" was forgotten.
   So 'parent' was not the parent of 'dentry'.
   This fails safe is the context is that dentry->d_inode is
   NULL, and the result of parent->d_inode being NULL is
   that ECHILD is returned, which is always safe.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-08-04 09:22:08 -04:00

2506 lines
63 KiB
C
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/*
* 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/swap.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"
#include "nfstrace.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 *, struct dir_context *);
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,
.iterate = 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_inode *nfsi = NFS_I(dir);
struct nfs_open_dir_context *ctx;
ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
if (ctx != NULL) {
ctx->duped = 0;
ctx->attr_gencount = nfsi->attr_gencount;
ctx->dir_cookie = 0;
ctx->dup_cookie = 0;
ctx->cred = get_rpccred(cred);
spin_lock(&dir->i_lock);
list_add(&ctx->list, &nfsi->open_files);
spin_unlock(&dir->i_lock);
return ctx;
}
return ERR_PTR(-ENOMEM);
}
static void put_nfs_open_dir_context(struct inode *dir, struct nfs_open_dir_context *ctx)
{
spin_lock(&dir->i_lock);
list_del(&ctx->list);
spin_unlock(&dir->i_lock);
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(%pD2)\n", filp);
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->f_path.dentry->d_inode, 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;
struct dir_context *ctx;
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->ctx->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 bool
nfs_readdir_inode_mapping_valid(struct nfs_inode *nfsi)
{
if (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA))
return false;
smp_rmb();
return !test_bit(NFS_INO_INVALIDATING, &nfsi->flags);
}
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(file_inode(desc->file));
struct nfs_open_dir_context *ctx = desc->file->private_data;
new_pos = desc->current_index + i;
if (ctx->attr_gencount != nfsi->attr_gencount ||
!nfs_readdir_inode_mapping_valid(nfsi)) {
ctx->duped = 0;
ctx->attr_gencount = nfsi->attr_gencount;
} else if (new_pos < desc->ctx->pos) {
if (ctx->duped > 0
&& ctx->dup_cookie == *desc->dir_cookie) {
if (printk_ratelimit()) {
pr_notice("NFS: directory %pD2 contains a readdir loop."
"Please contact your server vendor. "
"The file: %.*s has duplicate cookie %llu\n",
desc->file, array->array[i].string.len,
array->array[i].string.name, *desc->dir_cookie);
}
status = -ELOOP;
goto out;
}
ctx->dup_cookie = *desc->dir_cookie;
ctx->duped = -1;
}
desc->ctx->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 dir_context *ctx)
{
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 (ctx->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);
}
/*
* This function is mainly for use by nfs_getattr().
*
* If this is an 'ls -l', we want to force use of readdirplus.
* Do this by checking if there is an active file descriptor
* and calling nfs_advise_use_readdirplus, then forcing a
* cache flush.
*/
void nfs_force_use_readdirplus(struct inode *dir)
{
if (!list_empty(&NFS_I(dir)->open_files)) {
nfs_advise_use_readdirplus(dir);
nfs_zap_mapping(dir, dir->i_mapping);
}
}
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;
int status;
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_set_verifier(dentry, nfs_save_change_attribute(dir));
status = nfs_refresh_inode(dentry->d_inode, entry->fattr);
if (!status)
nfs_setsecurity(dentry->d_inode, entry->fattr, entry->label);
goto out;
} else {
if (d_invalidate(dentry) != 0)
goto out;
dput(dentry);
}
}
dentry = d_alloc(parent, &filename);
if (dentry == NULL)
return;
inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr, entry->label);
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;
entry.label = nfs4_label_alloc(NFS_SERVER(inode), GFP_NOWAIT);
if (IS_ERR(entry.label)) {
status = PTR_ERR(entry.label);
goto out;
}
array = nfs_readdir_get_array(page);
if (IS_ERR(array)) {
status = PTR_ERR(array);
goto out_label_free;
}
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_label_free:
nfs4_label_free(entry.label);
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 = file_inode(desc->file);
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(file_inode(desc->file)->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)
{
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 (!dir_emit(desc->ctx, ent->string.name, ent->string.len,
nfs_compat_user_ino64(ent->ino), ent->d_type)) {
desc->eof = 1;
break;
}
desc->ctx->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)
{
struct page *page = NULL;
int status;
struct inode *inode = file_inode(desc->file);
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);
out:
dfprintk(DIRCACHE, "NFS: %s: returns %d\n",
__func__, status);
return status;
out_release:
cache_page_release(desc);
goto out;
}
static bool nfs_dir_mapping_need_revalidate(struct inode *dir)
{
struct nfs_inode *nfsi = NFS_I(dir);
if (nfs_attribute_cache_expired(dir))
return true;
if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
return true;
return false;
}
/* 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 *file, struct dir_context *ctx)
{
struct dentry *dentry = file->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 = file->private_data;
int res = 0;
dfprintk(FILE, "NFS: readdir(%pD2) starting at cookie %llu\n",
file, (long long)ctx->pos);
nfs_inc_stats(inode, NFSIOS_VFSGETDENTS);
/*
* ctx->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 = file;
desc->ctx = ctx;
desc->dir_cookie = &dir_ctx->dir_cookie;
desc->decode = NFS_PROTO(inode)->decode_dirent;
desc->plus = nfs_use_readdirplus(inode, ctx) ? 1 : 0;
nfs_block_sillyrename(dentry);
if (ctx->pos == 0 || nfs_dir_mapping_need_revalidate(inode))
res = nfs_revalidate_mapping(inode, file->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);
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);
if (res < 0)
break;
} while (!desc->eof);
out:
nfs_unblock_sillyrename(dentry);
if (res > 0)
res = 0;
dfprintk(FILE, "NFS: readdir(%pD2) returns %d\n", file, res);
return res;
}
static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence)
{
struct inode *inode = file_inode(filp);
struct nfs_open_dir_context *dir_ctx = filp->private_data;
dfprintk(FILE, "NFS: llseek dir(%pD2, %lld, %d)\n",
filp, offset, whence);
mutex_lock(&inode->i_mutex);
switch (whence) {
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 inode *inode = file_inode(filp);
dfprintk(FILE, "NFS: fsync dir(%pD2) datasync %d\n", filp, datasync);
mutex_lock(&inode->i_mutex);
nfs_inc_stats(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.
* If rcu_walk prevents us from performing a full check, return 0.
*/
static int nfs_check_verifier(struct inode *dir, struct dentry *dentry,
int rcu_walk)
{
int ret;
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 (rcu_walk)
ret = nfs_revalidate_inode_rcu(NFS_SERVER(dir), dir);
else
ret = nfs_revalidate_inode(NFS_SERVER(dir), dir);
if (ret < 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
int nfs_lookup_verify_inode(struct inode *inode, unsigned int flags)
{
struct nfs_server *server = NFS_SERVER(inode);
int ret;
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;
out:
return (inode->i_nlink == 0) ? -ENOENT : 0;
out_force:
if (flags & LOOKUP_RCU)
return -ECHILD;
ret = __nfs_revalidate_inode(server, inode);
if (ret != 0)
return ret;
goto out;
}
/*
* 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.
*
* If LOOKUP_RCU prevents us from performing a full check, return 1
* suggesting a reval is needed.
*/
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, flags & LOOKUP_RCU);
}
/*
* 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;
struct nfs4_label *label = NULL;
int error;
if (flags & LOOKUP_RCU) {
parent = ACCESS_ONCE(dentry->d_parent);
dir = ACCESS_ONCE(parent->d_inode);
if (!dir)
return -ECHILD;
} else {
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)) {
if (flags & LOOKUP_RCU)
return -ECHILD;
goto out_bad;
}
goto out_valid_noent;
}
if (is_bad_inode(inode)) {
if (flags & LOOKUP_RCU)
return -ECHILD;
dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n",
__func__, dentry);
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, flags & LOOKUP_RCU)) {
if (nfs_lookup_verify_inode(inode, flags)) {
if (flags & LOOKUP_RCU)
return -ECHILD;
goto out_zap_parent;
}
goto out_valid;
}
if (flags & LOOKUP_RCU)
return -ECHILD;
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;
label = nfs4_label_alloc(NFS_SERVER(inode), GFP_NOWAIT);
if (IS_ERR(label))
goto out_error;
trace_nfs_lookup_revalidate_enter(dir, dentry, flags);
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, label);
trace_nfs_lookup_revalidate_exit(dir, dentry, flags, error);
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_setsecurity(inode, fattr, label);
nfs_free_fattr(fattr);
nfs_free_fhandle(fhandle);
nfs4_label_free(label);
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:
if (flags & LOOKUP_RCU) {
if (parent != ACCESS_ONCE(dentry->d_parent))
return -ECHILD;
} else
dput(parent);
dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is valid\n",
__func__, dentry);
return 1;
out_zap_parent:
nfs_zap_caches(dir);
out_bad:
WARN_ON(flags & LOOKUP_RCU);
nfs_free_fattr(fattr);
nfs_free_fhandle(fhandle);
nfs4_label_free(label);
nfs_mark_for_revalidate(dir);
if (inode && S_ISDIR(inode->i_mode)) {
/* Purge readdir caches. */
nfs_zap_caches(inode);
/*
* We can't d_drop the root of a disconnected tree:
* its d_hash is on the s_anon list and d_drop() would hide
* it from shrink_dcache_for_unmount(), leading to busy
* inodes on unmount and further oopses.
*/
if (IS_ROOT(dentry))
goto out_valid;
}
/* If we have submounts, don't unhash ! */
if (check_submounts_and_drop(dentry) != 0)
goto out_valid;
dput(parent);
dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is invalid\n",
__func__, dentry);
return 0;
out_error:
WARN_ON(flags & LOOKUP_RCU);
nfs_free_fattr(fattr);
nfs_free_fhandle(fhandle);
nfs4_label_free(label);
dput(parent);
dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) lookup returned error %d\n",
__func__, dentry, error);
return error;
}
/*
* A weaker form of d_revalidate for revalidating just the dentry->d_inode
* when we don't really care about the dentry name. This is called when a
* pathwalk ends on a dentry that was not found via a normal lookup in the
* parent dir (e.g.: ".", "..", procfs symlinks or mountpoint traversals).
*
* In this situation, we just want to verify that the inode itself is OK
* since the dentry might have changed on the server.
*/
static int nfs_weak_revalidate(struct dentry *dentry, unsigned int flags)
{
int error;
struct inode *inode = dentry->d_inode;
/*
* I believe we can only get a negative dentry here in the case of a
* procfs-style symlink. Just assume it's correct for now, but we may
* eventually need to do something more here.
*/
if (!inode) {
dfprintk(LOOKUPCACHE, "%s: %pd2 has negative inode\n",
__func__, dentry);
return 1;
}
if (is_bad_inode(inode)) {
dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n",
__func__, dentry);
return 0;
}
error = nfs_revalidate_inode(NFS_SERVER(inode), inode);
dfprintk(LOOKUPCACHE, "NFS: %s: inode %lu is %s\n",
__func__, inode->i_ino, error ? "invalid" : "valid");
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(%pd2, %x)\n",
dentry, 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;
}
/* Ensure that we revalidate inode->i_nlink */
static void nfs_drop_nlink(struct inode *inode)
{
spin_lock(&inode->i_lock);
/* drop the inode if we're reasonably sure this is the last link */
if (inode->i_nlink == 1)
clear_nlink(inode);
NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATTR;
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) {
nfs_complete_unlink(dentry, inode);
nfs_drop_nlink(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_weak_revalidate = nfs_weak_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;
struct nfs4_label *label = NULL;
int error;
dfprintk(VFS, "NFS: lookup(%pd2)\n", dentry);
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;
label = nfs4_label_alloc(NFS_SERVER(dir), GFP_NOWAIT);
if (IS_ERR(label))
goto out;
parent = dentry->d_parent;
/* Protect against concurrent sillydeletes */
trace_nfs_lookup_enter(dir, dentry, flags);
nfs_block_sillyrename(parent);
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, label);
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, label);
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);
trace_nfs_lookup_exit(dir, dentry, flags, error);
nfs4_label_free(label);
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_open_file(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 ((open_flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
*opened |= FILE_CREATED;
err = finish_open(file, dentry, do_open, opened);
if (err)
goto out;
nfs_file_set_open_context(file, ctx);
out:
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;
unsigned int lookup_flags = 0;
int err;
/* Expect a negative dentry */
BUG_ON(dentry->d_inode);
dfprintk(VFS, "NFS: atomic_open(%s/%lu), %pd\n",
dir->i_sb->s_id, dir->i_ino, dentry);
err = nfs_check_flags(open_flags);
if (err)
return err;
/* 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;
}
lookup_flags = LOOKUP_OPEN|LOOKUP_DIRECTORY;
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;
trace_nfs_atomic_open_enter(dir, ctx, open_flags);
nfs_block_sillyrename(dentry->d_parent);
inode = NFS_PROTO(dir)->open_context(dir, ctx, open_flags, &attr, opened);
nfs_unblock_sillyrename(dentry->d_parent);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
trace_nfs_atomic_open_exit(dir, ctx, open_flags, err);
put_nfs_open_context(ctx);
switch (err) {
case -ENOENT:
d_drop(dentry);
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;
}
err = nfs_finish_open(ctx, ctx->dentry, file, open_flags, opened);
trace_nfs_atomic_open_exit(dir, ctx, open_flags, err);
put_nfs_open_context(ctx);
out:
return err;
no_open:
res = nfs_lookup(dir, dentry, lookup_flags);
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 inode *inode;
int ret = 0;
if (!(flags & LOOKUP_OPEN) || (flags & LOOKUP_DIRECTORY))
goto no_open;
if (d_mountpoint(dentry))
goto no_open;
if (NFS_SB(dentry->d_sb)->caps & NFS_CAP_ATOMIC_OPEN_V1)
goto no_open;
inode = dentry->d_inode;
/* We can't create new files in nfs_open_revalidate(), so we
* optimize away revalidation of negative dentries.
*/
if (inode == NULL) {
struct dentry *parent;
struct inode *dir;
if (flags & LOOKUP_RCU) {
parent = ACCESS_ONCE(dentry->d_parent);
dir = ACCESS_ONCE(parent->d_inode);
if (!dir)
return -ECHILD;
} else {
parent = dget_parent(dentry);
dir = parent->d_inode;
}
if (!nfs_neg_need_reval(dir, dentry, flags))
ret = 1;
else if (flags & LOOKUP_RCU)
ret = -ECHILD;
if (!(flags & LOOKUP_RCU))
dput(parent);
else if (parent != ACCESS_ONCE(dentry->d_parent))
return -ECHILD;
goto out;
}
/* NFS only supports OPEN on regular files */
if (!S_ISREG(inode->i_mode))
goto no_open;
/* We cannot do exclusive creation on a positive dentry */
if (flags & LOOKUP_EXCL)
goto no_open;
/* Let f_op->open() actually open (and revalidate) the file */
ret = 1;
out:
return ret;
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 nfs4_label *label)
{
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, NULL);
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, NULL);
if (error < 0)
goto out_error;
}
inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label);
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/%lu), %pd\n",
dir->i_sb->s_id, dir->i_ino, dentry);
attr.ia_mode = mode;
attr.ia_valid = ATTR_MODE;
trace_nfs_create_enter(dir, dentry, open_flags);
error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags);
trace_nfs_create_exit(dir, dentry, open_flags, error);
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/%lu), %pd\n",
dir->i_sb->s_id, dir->i_ino, dentry);
if (!new_valid_dev(rdev))
return -EINVAL;
attr.ia_mode = mode;
attr.ia_valid = ATTR_MODE;
trace_nfs_mknod_enter(dir, dentry);
status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev);
trace_nfs_mknod_exit(dir, dentry, status);
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/%lu), %pd\n",
dir->i_sb->s_id, dir->i_ino, dentry);
attr.ia_valid = ATTR_MODE;
attr.ia_mode = mode | S_IFDIR;
trace_nfs_mkdir_enter(dir, dentry);
error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr);
trace_nfs_mkdir_exit(dir, dentry, error);
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/%lu), %pd\n",
dir->i_sb->s_id, dir->i_ino, dentry);
trace_nfs_rmdir_enter(dir, dentry);
if (dentry->d_inode) {
nfs_wait_on_sillyrename(dentry);
error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
/* Ensure the VFS deletes this inode */
switch (error) {
case 0:
clear_nlink(dentry->d_inode);
break;
case -ENOENT:
nfs_dentry_handle_enoent(dentry);
}
} else
error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
trace_nfs_rmdir_exit(dir, dentry, error);
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(%pd2)\n", dentry);
/* If the dentry was sillyrenamed, we simply call d_delete() */
if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
error = 0;
goto out;
}
trace_nfs_remove_enter(dir, dentry);
if (inode != NULL) {
NFS_PROTO(inode)->return_delegation(inode);
error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
if (error == 0)
nfs_drop_nlink(inode);
} else
error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
if (error == -ENOENT)
nfs_dentry_handle_enoent(dentry);
trace_nfs_remove_exit(dir, dentry, error);
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/%lu, %pd)\n", dir->i_sb->s_id,
dir->i_ino, dentry);
trace_nfs_unlink_enter(dir, dentry);
spin_lock(&dentry->d_lock);
if (d_count(dentry) > 1) {
spin_unlock(&dentry->d_lock);
/* Start asynchronous writeout of the inode */
write_inode_now(dentry->d_inode, 0);
error = nfs_sillyrename(dir, dentry);
goto out;
}
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);
out:
trace_nfs_unlink_exit(dir, dentry, error);
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 page *page;
char *kaddr;
struct iattr attr;
unsigned int pathlen = strlen(symname);
int error;
dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s)\n", dir->i_sb->s_id,
dir->i_ino, dentry, 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);
trace_nfs_symlink_enter(dir, dentry);
error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr);
trace_nfs_symlink_exit(dir, dentry, error);
if (error != 0) {
dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s) error %d\n",
dir->i_sb->s_id, dir->i_ino,
dentry, 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.
*/
if (!add_to_page_cache_lru(page, dentry->d_inode->i_mapping, 0,
GFP_KERNEL)) {
SetPageUptodate(page);
unlock_page(page);
/*
* add_to_page_cache_lru() grabs an extra page refcount.
* Drop it here to avoid leaking this page later.
*/
page_cache_release(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(%pd2 -> %pd2)\n",
old_dentry, dentry);
trace_nfs_link_enter(inode, dir, dentry);
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);
}
trace_nfs_link_exit(inode, dir, dentry, error);
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;
struct rpc_task *task;
int error = -EBUSY;
dfprintk(VFS, "NFS: rename(%pd2 -> %pd2, ct=%d)\n",
old_dentry, new_dentry,
d_count(new_dentry));
trace_nfs_rename_enter(old_dir, old_dentry, new_dir, new_dentry);
/*
* 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 (d_count(new_dentry) > 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);
task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry, NULL);
if (IS_ERR(task)) {
error = PTR_ERR(task);
goto out;
}
error = rpc_wait_for_completion_task(task);
if (error == 0)
error = task->tk_status;
rpc_put_task(task);
nfs_mark_for_revalidate(old_inode);
out:
if (rehash)
d_rehash(rehash);
trace_nfs_rename_exit(old_dir, old_dentry,
new_dir, new_dentry, error);
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 unsigned long nfs_access_max_cachesize = ULONG_MAX;
module_param(nfs_access_max_cachesize, ulong, 0644);
MODULE_PARM_DESC(nfs_access_max_cachesize, "NFS access maximum total cache length");
static void nfs_access_free_entry(struct nfs_access_entry *entry)
{
put_rpccred(entry->cred);
kfree_rcu(entry, rcu_head);
smp_mb__before_atomic();
atomic_long_dec(&nfs_access_nr_entries);
smp_mb__after_atomic();
}
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);
}
}
static unsigned long
nfs_do_access_cache_scan(unsigned int nr_to_scan)
{
LIST_HEAD(head);
struct nfs_inode *nfsi, *next;
struct nfs_access_entry *cache;
long freed = 0;
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);
freed++;
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_atomic();
clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags);
smp_mb__after_atomic();
}
spin_unlock(&inode->i_lock);
}
spin_unlock(&nfs_access_lru_lock);
nfs_access_free_list(&head);
return freed;
}
unsigned long
nfs_access_cache_scan(struct shrinker *shrink, struct shrink_control *sc)
{
int nr_to_scan = sc->nr_to_scan;
gfp_t gfp_mask = sc->gfp_mask;
if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL)
return SHRINK_STOP;
return nfs_do_access_cache_scan(nr_to_scan);
}
unsigned long
nfs_access_cache_count(struct shrinker *shrink, struct shrink_control *sc)
{
return vfs_pressure_ratio(atomic_long_read(&nfs_access_nr_entries));
}
static void
nfs_access_cache_enforce_limit(void)
{
long nr_entries = atomic_long_read(&nfs_access_nr_entries);
unsigned long diff;
unsigned int nr_to_scan;
if (nr_entries < 0 || nr_entries <= nfs_access_max_cachesize)
return;
nr_to_scan = 100;
diff = nr_entries - nfs_access_max_cachesize;
if (diff < nr_to_scan)
nr_to_scan = diff;
nfs_do_access_cache_scan(nr_to_scan);
}
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 int nfs_access_get_cached_rcu(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res)
{
/* Only check the most recently returned cache entry,
* but do it without locking.
*/
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_access_entry *cache;
int err = -ECHILD;
struct list_head *lh;
rcu_read_lock();
if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)
goto out;
lh = rcu_dereference(nfsi->access_cache_entry_lru.prev);
cache = list_entry(lh, struct nfs_access_entry, lru);
if (lh == &nfsi->access_cache_entry_lru ||
cred != cache->cred)
cache = NULL;
if (cache == NULL)
goto out;
if (!nfs_have_delegated_attributes(inode) &&
!time_in_range_open(jiffies, cache->jiffies, cache->jiffies + nfsi->attrtimeo))
goto out;
res->jiffies = cache->jiffies;
res->cred = cache->cred;
res->mask = cache->mask;
err = 0;
out:
rcu_read_unlock();
return err;
}
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);
}
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;
/* The above field assignments must be visible
* before this item appears on the lru. We cannot easily
* use rcu_assign_pointer, so just force the memory barrier.
*/
smp_wmb();
nfs_access_add_rbtree(inode, cache);
/* Update accounting */
smp_mb__before_atomic();
atomic_long_inc(&nfs_access_nr_entries);
smp_mb__after_atomic();
/* 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);
}
nfs_access_cache_enforce_limit();
}
EXPORT_SYMBOL_GPL(nfs_access_add_cache);
void nfs_access_set_mask(struct nfs_access_entry *entry, u32 access_result)
{
entry->mask = 0;
if (access_result & NFS4_ACCESS_READ)
entry->mask |= MAY_READ;
if (access_result &
(NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND | NFS4_ACCESS_DELETE))
entry->mask |= MAY_WRITE;
if (access_result & (NFS4_ACCESS_LOOKUP|NFS4_ACCESS_EXECUTE))
entry->mask |= MAY_EXEC;
}
EXPORT_SYMBOL_GPL(nfs_access_set_mask);
static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
{
struct nfs_access_entry cache;
int status;
trace_nfs_access_enter(inode);
status = nfs_access_get_cached_rcu(inode, cred, &cache);
if (status != 0)
status = nfs_access_get_cached(inode, cred, &cache);
if (status == 0)
goto out_cached;
status = -ECHILD;
if (mask & MAY_NOT_BLOCK)
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);
}
goto out;
}
nfs_access_add_cache(inode, &cache);
out_cached:
if ((mask & ~cache.mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0)
status = -EACCES;
out:
trace_nfs_access_exit(inode, status);
return status;
}
static int nfs_open_permission_mask(int openflags)
{
int mask = 0;
if (openflags & __FMODE_EXEC) {
/* ONLY check exec rights */
mask = MAY_EXEC;
} else {
if ((openflags & O_ACCMODE) != O_WRONLY)
mask |= MAY_READ;
if ((openflags & O_ACCMODE) != O_RDONLY)
mask |= MAY_WRITE;
}
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;
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:
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;
/* Always try fast lookups first */
rcu_read_lock();
cred = rpc_lookup_cred_nonblock();
if (!IS_ERR(cred))
res = nfs_do_access(inode, cred, mask|MAY_NOT_BLOCK);
else
res = PTR_ERR(cred);
rcu_read_unlock();
if (res == -ECHILD && !(mask & MAY_NOT_BLOCK)) {
/* Fast lookup failed, try the slow way */
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/%lu), mask=0x%x, res=%d\n",
inode->i_sb->s_id, inode->i_ino, mask, res);
return res;
out_notsup:
if (mask & MAY_NOT_BLOCK)
return -ECHILD;
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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