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linux-hardened/fs/nfs/dir.c
Benjamin Coddington b044f64513 NFS: switch back to to ->iterate() 
NFS has some optimizations for readdir to choose between using READDIR or
READDIRPLUS based on workload, and which NFS operation to use is determined
by subsequent interactions with lookup, d_revalidate, and getattr.

Concurrent use of nfs_readdir() via ->iterate_shared() can cause those
optimizations to repeatedly invalidate the pagecache used to store
directory entries during readdir(), which causes some very bad performance
for directories with many entries (more than about 10000).

There's a couple ways to fix this in NFS, but no fix would be as simple as
going back to ->iterate() to serialize nfs_readdir(), and neither fix I
tested performed as well as going back to ->iterate().

The first required taking the directory's i_lock for each entry, with the
result of terrible contention.

The second way adds another flag to the nfs_inode, and so keeps the
optimizations working for large directories.  The difference from using
->iterate() here is that much more memory is consumed for a given workload
without any performance gain.

The workings of nfs_readdir() are such that concurrent users are serialized
within read_cache_page() waiting to retrieve pages of entries from the
server.  By serializing this work in iterate_dir() instead, contention for
cache pages is reduced.  Waiting processes can have an uncontended pass at
the entirety of the directory's pagecache once previous processes have
completed filling it.

v2 - Keep the bits needed for parallel lookup

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2017-04-20 13:33:09 -04:00

2576 lines
64 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(file_inode(filp), 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(NULL, 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_dentry(file), 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;
}
/* Match file and dirent using either filehandle or fileid
* Note: caller is responsible for checking the fsid
*/
static
int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry)
{
struct inode *inode;
struct nfs_inode *nfsi;
if (d_really_is_negative(dentry))
return 0;
inode = d_inode(dentry);
if (is_bad_inode(inode) || NFS_STALE(inode))
return 0;
nfsi = NFS_I(inode);
if (entry->fattr->fileid != nfsi->fileid)
return 0;
if (entry->fh->size && nfs_compare_fh(entry->fh, &nfsi->fh) != 0)
return 0;
return 1;
}
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 and getattr code to request the
* use of readdirplus to accelerate any future lookups in the same
* directory.
*/
void nfs_advise_use_readdirplus(struct inode *dir)
{
struct nfs_inode *nfsi = NFS_I(dir);
if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) &&
!list_empty(&nfsi->open_files))
set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->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)
{
struct nfs_inode *nfsi = NFS_I(dir);
if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) &&
!list_empty(&nfsi->open_files)) {
set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags);
invalidate_mapping_pages(dir->i_mapping, 0, -1);
}
}
static
void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry)
{
struct qstr filename = QSTR_INIT(entry->name, entry->len);
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
struct dentry *dentry;
struct dentry *alias;
struct inode *dir = d_inode(parent);
struct inode *inode;
int status;
if (!(entry->fattr->valid & NFS_ATTR_FATTR_FILEID))
return;
if (!(entry->fattr->valid & NFS_ATTR_FATTR_FSID))
return;
if (filename.len == 0)
return;
/* Validate that the name doesn't contain any illegal '\0' */
if (strnlen(filename.name, filename.len) != filename.len)
return;
/* ...or '/' */
if (strnchr(filename.name, filename.len, '/'))
return;
if (filename.name[0] == '.') {
if (filename.len == 1)
return;
if (filename.len == 2 && filename.name[1] == '.')
return;
}
filename.hash = full_name_hash(parent, filename.name, filename.len);
dentry = d_lookup(parent, &filename);
again:
if (!dentry) {
dentry = d_alloc_parallel(parent, &filename, &wq);
if (IS_ERR(dentry))
return;
}
if (!d_in_lookup(dentry)) {
/* Is there a mountpoint here? If so, just exit */
if (!nfs_fsid_equal(&NFS_SB(dentry->d_sb)->fsid,
&entry->fattr->fsid))
goto out;
if (nfs_same_file(dentry, entry)) {
if (!entry->fh->size)
goto out;
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
status = nfs_refresh_inode(d_inode(dentry), entry->fattr);
if (!status)
nfs_setsecurity(d_inode(dentry), entry->fattr, entry->label);
goto out;
} else {
d_invalidate(dentry);
dput(dentry);
dentry = NULL;
goto again;
}
}
if (!entry->fh->size) {
d_lookup_done(dentry);
goto out;
}
inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr, entry->label);
alias = d_splice_alias(inode, dentry);
d_lookup_done(dentry);
if (alias) {
if (IS_ERR(alias))
goto out;
dput(dentry);
dentry = alias;
}
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;
if (buflen == 0)
goto out_nopages;
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(file_dentry(desc->file), entry);
status = nfs_readdir_add_to_array(entry, page);
if (status != 0)
break;
} while (!entry->eof);
out_nopages:
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_pages(struct page **pages, unsigned int npages)
{
unsigned int i;
for (i = 0; i < npages; i++)
put_page(pages[i]);
}
/*
* nfs_readdir_large_page will allocate pages that must be freed with a call
* to nfs_readdir_free_pagearray
*/
static
int nfs_readdir_alloc_pages(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_pages(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];
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_alloc_pages(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_pages(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);
put_page(desc->page);
desc->page = NULL;
}
static
struct page *get_cache_page(nfs_readdir_descriptor_t *desc)
{
return read_cache_page(desc->file->f_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;
}
/* 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_dentry(file);
struct inode *inode = d_inode(dentry);
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;
if (ctx->pos == 0 || nfs_attribute_cache_expired(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:
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);
inode_lock(inode);
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:
inode_unlock(inode);
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);
inode_lock(inode);
nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
inode_unlock(inode);
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)
{
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_mapping_need_revalidate_inode(dir)) {
if (rcu_walk)
return 0;
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
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 = d_inode_rcu(parent);
if (!dir)
return -ECHILD;
} else {
parent = dget_parent(dentry);
dir = d_inode(parent);
}
nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE);
inode = d_inode(dentry);
if (!inode) {
if (nfs_neg_need_reval(dir, dentry, flags)) {
if (flags & LOOKUP_RCU)
return -ECHILD;
goto out_bad;
}
goto out_valid;
}
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;
}
nfs_advise_use_readdirplus(dir);
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);
/* set a readdirplus hint that we had a cache miss */
nfs_force_use_readdirplus(dir);
out_set_verifier:
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
out_valid:
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;
}
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 d_inode(dentry)
* 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)
{
struct inode *inode = d_inode(dentry);
int error = 0;
/*
* 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;
}
if (nfs_mapping_need_revalidate_inode(inode))
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 (d_really_is_positive(dentry) && NFS_STALE(d_inode(dentry)))
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 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);
if (unlikely(dentry->d_name.len > NFS_SERVER(dir)->namelen))
return ERR_PTR(-ENAMETOOLONG);
/*
* If we're doing an exclusive create, optimize away the lookup
* but don't hash the dentry.
*/
if (nfs_is_exclusive_create(dir, flags))
return NULL;
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;
trace_nfs_lookup_enter(dir, dentry, flags);
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_label;
}
inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label);
res = ERR_CAST(inode);
if (IS_ERR(res))
goto out_label;
/* Notify readdir to use READDIRPLUS */
nfs_force_use_readdirplus(dir);
no_entry:
res = d_splice_alias(inode, dentry);
if (res != NULL) {
if (IS_ERR(res))
goto out_label;
dentry = res;
}
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
out_label:
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, struct file *filp)
{
return alloc_nfs_open_context(dentry, flags_to_mode(open_flags), filp);
}
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;
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)
{
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
struct nfs_open_context *ctx;
struct dentry *res;
struct iattr attr = { .ia_valid = ATTR_OPEN };
struct inode *inode;
unsigned int lookup_flags = 0;
bool switched = false;
int err;
/* Expect a negative dentry */
BUG_ON(d_inode(dentry));
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_in_lookup(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) {
struct nfs_server *server = NFS_SERVER(dir);
if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK))
mode &= ~current_umask();
attr.ia_valid |= ATTR_MODE;
attr.ia_mode = mode;
}
if (open_flags & O_TRUNC) {
attr.ia_valid |= ATTR_SIZE;
attr.ia_size = 0;
}
if (!(open_flags & O_CREAT) && !d_in_lookup(dentry)) {
d_drop(dentry);
switched = true;
dentry = d_alloc_parallel(dentry->d_parent,
&dentry->d_name, &wq);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
if (unlikely(!d_in_lookup(dentry)))
return finish_no_open(file, dentry);
}
ctx = create_nfs_open_context(dentry, open_flags, file);
err = PTR_ERR(ctx);
if (IS_ERR(ctx))
goto out;
trace_nfs_atomic_open_enter(dir, ctx, open_flags);
inode = NFS_PROTO(dir)->open_context(dir, ctx, open_flags, &attr, opened);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
trace_nfs_atomic_open_exit(dir, ctx, open_flags, err);
put_nfs_open_context(ctx);
d_drop(dentry);
switch (err) {
case -ENOENT:
d_add(dentry, NULL);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
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:
if (unlikely(switched)) {
d_lookup_done(dentry);
dput(dentry);
}
return err;
no_open:
res = nfs_lookup(dir, dentry, lookup_flags);
if (switched) {
d_lookup_done(dentry);
if (!res)
res = dentry;
else
dput(dentry);
}
if (IS_ERR(res))
return PTR_ERR(res);
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 = d_inode(dentry);
/* 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 = d_inode_rcu(parent);
if (!dir)
return -ECHILD;
} else {
parent = dget_parent(dentry);
dir = d_inode(parent);
}
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 = d_inode(parent);
struct inode *inode;
int error = -EACCES;
d_drop(dentry);
/* We may have been initialized further down */
if (d_really_is_positive(dentry))
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);
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 (simple_positive(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 (d_really_is_positive(dentry)) {
down_write(&NFS_I(d_inode(dentry))->rmdir_sem);
error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
/* Ensure the VFS deletes this inode */
switch (error) {
case 0:
clear_nlink(d_inode(dentry));
break;
case -ENOENT:
nfs_dentry_handle_enoent(dentry);
}
up_write(&NFS_I(d_inode(dentry))->rmdir_sem);
} 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 = d_inode(dentry->d_parent);
struct inode *inode = d_inode(dentry);
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(d_inode(dentry), 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_USER);
if (!page)
return -ENOMEM;
kaddr = page_address(page);
memcpy(kaddr, symname, pathlen);
if (pathlen < PAGE_SIZE)
memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen);
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, d_inode(dentry)->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.
*/
put_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 = d_inode(old_dentry);
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);
static void
nfs_complete_rename(struct rpc_task *task, struct nfs_renamedata *data)
{
struct dentry *old_dentry = data->old_dentry;
struct dentry *new_dentry = data->new_dentry;
struct inode *old_inode = d_inode(old_dentry);
struct inode *new_inode = d_inode(new_dentry);
nfs_mark_for_revalidate(old_inode);
switch (task->tk_status) {
case 0:
if (new_inode != NULL)
nfs_drop_nlink(new_inode);
d_move(old_dentry, new_dentry);
nfs_set_verifier(new_dentry,
nfs_save_change_attribute(data->new_dir));
break;
case -ENOENT:
nfs_dentry_handle_enoent(old_dentry);
}
}
/*
* 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,
unsigned int flags)
{
struct inode *old_inode = d_inode(old_dentry);
struct inode *new_inode = d_inode(new_dentry);
struct dentry *dentry = NULL;
struct rpc_task *task;
int error = -EBUSY;
if (flags)
return -EINVAL;
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);
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;
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,
nfs_complete_rename);
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);
out:
trace_nfs_rename_exit(old_dir, old_dentry,
new_dir, new_dentry, error);
/* 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, bool may_block)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_access_entry *cache;
bool retry = true;
int err;
spin_lock(&inode->i_lock);
for(;;) {
if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)
goto out_zap;
cache = nfs_access_search_rbtree(inode, cred);
err = -ENOENT;
if (cache == NULL)
goto out;
/* Found an entry, is our attribute cache valid? */
if (!nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS))
break;
err = -ECHILD;
if (!may_block)
goto out;
if (!retry)
goto out_zap;
spin_unlock(&inode->i_lock);
err = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
if (err)
return err;
spin_lock(&inode->i_lock);
retry = false;
}
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_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_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS))
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;
bool may_block = (mask & MAY_NOT_BLOCK) == 0;
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, may_block);
if (status == 0)
goto out_cached;
status = -ECHILD;
if (!may_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);
static int nfs_execute_ok(struct inode *inode, int mask)
{
struct nfs_server *server = NFS_SERVER(inode);
int ret = 0;
if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS)) {
if (mask & MAY_NOT_BLOCK)
return -ECHILD;
ret = __nfs_revalidate_inode(server, inode);
}
if (ret == 0 && !execute_ok(inode))
ret = -EACCES;
return ret;
}
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:
if ((mask & MAY_OPEN) &&
nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN))
return 0;
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))
res = nfs_execute_ok(inode, mask);
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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