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kernel-fxtec-pro1x/fs/nfs/dir.c
Trond Myklebust 9c7e7e2337 NFS: Don't call iput() in nfs_access_cache_shrinker 
iput() can potentially attempt to allocate memory, so we should avoid
calling it in a memory shrinker. Instead, rely on the fact that iput() will
call nfs_access_zap_cache().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2010-05-14 15:09:36 -04:00

2004 lines
53 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/time.h>
#include <linux/errno.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/pagemap.h>
#include <linux/pagevec.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/sched.h>
#include "nfs4_fs.h"
#include "delegation.h"
#include "iostat.h"
#include "internal.h"
/* #define NFS_DEBUG_VERBOSE 1 */
static int nfs_opendir(struct inode *, struct file *);
static int nfs_readdir(struct file *, void *, filldir_t);
static struct dentry *nfs_lookup(struct inode *, struct dentry *, struct nameidata *);
static int nfs_create(struct inode *, struct dentry *, int, struct nameidata *);
static int nfs_mkdir(struct inode *, struct dentry *, int);
static int nfs_rmdir(struct inode *, struct dentry *);
static int nfs_unlink(struct inode *, struct dentry *);
static int nfs_symlink(struct inode *, struct dentry *, const char *);
static int nfs_link(struct dentry *, struct inode *, struct dentry *);
static int nfs_mknod(struct inode *, struct dentry *, int, dev_t);
static int nfs_rename(struct inode *, struct dentry *,
struct inode *, struct dentry *);
static int nfs_fsync_dir(struct file *, struct dentry *, int);
static loff_t nfs_llseek_dir(struct file *, loff_t, int);
const struct file_operations nfs_dir_operations = {
.llseek = nfs_llseek_dir,
.read = generic_read_dir,
.readdir = nfs_readdir,
.open = nfs_opendir,
.release = nfs_release,
.fsync = nfs_fsync_dir,
};
const struct inode_operations nfs_dir_inode_operations = {
.create = nfs_create,
.lookup = nfs_lookup,
.link = nfs_link,
.unlink = nfs_unlink,
.symlink = nfs_symlink,
.mkdir = nfs_mkdir,
.rmdir = nfs_rmdir,
.mknod = nfs_mknod,
.rename = nfs_rename,
.permission = nfs_permission,
.getattr = nfs_getattr,
.setattr = nfs_setattr,
};
#ifdef CONFIG_NFS_V3
const struct inode_operations nfs3_dir_inode_operations = {
.create = nfs_create,
.lookup = nfs_lookup,
.link = nfs_link,
.unlink = nfs_unlink,
.symlink = nfs_symlink,
.mkdir = nfs_mkdir,
.rmdir = nfs_rmdir,
.mknod = nfs_mknod,
.rename = nfs_rename,
.permission = nfs_permission,
.getattr = nfs_getattr,
.setattr = nfs_setattr,
.listxattr = nfs3_listxattr,
.getxattr = nfs3_getxattr,
.setxattr = nfs3_setxattr,
.removexattr = nfs3_removexattr,
};
#endif /* CONFIG_NFS_V3 */
#ifdef CONFIG_NFS_V4
static struct dentry *nfs_atomic_lookup(struct inode *, struct dentry *, struct nameidata *);
const struct inode_operations nfs4_dir_inode_operations = {
.create = nfs_create,
.lookup = nfs_atomic_lookup,
.link = nfs_link,
.unlink = nfs_unlink,
.symlink = nfs_symlink,
.mkdir = nfs_mkdir,
.rmdir = nfs_rmdir,
.mknod = nfs_mknod,
.rename = nfs_rename,
.permission = nfs_permission,
.getattr = nfs_getattr,
.setattr = nfs_setattr,
.getxattr = nfs4_getxattr,
.setxattr = nfs4_setxattr,
.listxattr = nfs4_listxattr,
};
#endif /* CONFIG_NFS_V4 */
/*
* Open file
*/
static int
nfs_opendir(struct inode *inode, struct file *filp)
{
int res;
dfprintk(FILE, "NFS: open dir(%s/%s)\n",
filp->f_path.dentry->d_parent->d_name.name,
filp->f_path.dentry->d_name.name);
nfs_inc_stats(inode, NFSIOS_VFSOPEN);
/* Call generic open code in order to cache credentials */
res = nfs_open(inode, filp);
return res;
}
typedef __be32 * (*decode_dirent_t)(__be32 *, struct nfs_entry *, int);
typedef struct {
struct file *file;
struct page *page;
unsigned long page_index;
__be32 *ptr;
u64 *dir_cookie;
loff_t current_index;
struct nfs_entry *entry;
decode_dirent_t decode;
int plus;
unsigned long timestamp;
unsigned long gencount;
int timestamp_valid;
} nfs_readdir_descriptor_t;
/* Now we cache directories properly, by stuffing the dirent
* data directly in the page cache.
*
* Inode invalidation due to refresh etc. takes care of
* _everything_, no sloppy entry flushing logic, no extraneous
* copying, network direct to page cache, the way it was meant
* to be.
*
* NOTE: Dirent information verification is done always by the
* page-in of the RPC reply, nowhere else, this simplies
* things substantially.
*/
static
int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page)
{
struct file *file = desc->file;
struct inode *inode = file->f_path.dentry->d_inode;
struct rpc_cred *cred = nfs_file_cred(file);
unsigned long timestamp, gencount;
int error;
dfprintk(DIRCACHE, "NFS: %s: reading cookie %Lu into page %lu\n",
__func__, (long long)desc->entry->cookie,
page->index);
again:
timestamp = jiffies;
gencount = nfs_inc_attr_generation_counter();
error = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred, desc->entry->cookie, page,
NFS_SERVER(inode)->dtsize, desc->plus);
if (error < 0) {
/* We requested READDIRPLUS, but the server doesn't grok it */
if (error == -ENOTSUPP && desc->plus) {
NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS;
clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
desc->plus = 0;
goto again;
}
goto error;
}
desc->timestamp = timestamp;
desc->gencount = gencount;
desc->timestamp_valid = 1;
SetPageUptodate(page);
/* Ensure consistent page alignment of the data.
* Note: assumes we have exclusive access to this mapping either
* through inode->i_mutex or some other mechanism.
*/
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 -EIO;
}
static inline
int dir_decode(nfs_readdir_descriptor_t *desc)
{
__be32 *p = desc->ptr;
p = desc->decode(p, desc->entry, desc->plus);
if (IS_ERR(p))
return PTR_ERR(p);
desc->ptr = p;
if (desc->timestamp_valid) {
desc->entry->fattr->time_start = desc->timestamp;
desc->entry->fattr->gencount = desc->gencount;
} else
desc->entry->fattr->valid &= ~NFS_ATTR_FATTR;
return 0;
}
static inline
void dir_page_release(nfs_readdir_descriptor_t *desc)
{
kunmap(desc->page);
page_cache_release(desc->page);
desc->page = NULL;
desc->ptr = NULL;
}
/*
* Given a pointer to a buffer that has already been filled by a call
* to readdir, find the next entry with cookie '*desc->dir_cookie'.
*
* If the end of the buffer has been reached, return -EAGAIN, if not,
* return the offset within the buffer of the next entry to be
* read.
*/
static inline
int find_dirent(nfs_readdir_descriptor_t *desc)
{
struct nfs_entry *entry = desc->entry;
int loop_count = 0,
status;
while((status = dir_decode(desc)) == 0) {
dfprintk(DIRCACHE, "NFS: %s: examining cookie %Lu\n",
__func__, (unsigned long long)entry->cookie);
if (entry->prev_cookie == *desc->dir_cookie)
break;
if (loop_count++ > 200) {
loop_count = 0;
schedule();
}
}
return status;
}
/*
* Given a pointer to a buffer that has already been filled by a call
* to readdir, find the entry at offset 'desc->file->f_pos'.
*
* If the end of the buffer has been reached, return -EAGAIN, if not,
* return the offset within the buffer of the next entry to be
* read.
*/
static inline
int find_dirent_index(nfs_readdir_descriptor_t *desc)
{
struct nfs_entry *entry = desc->entry;
int loop_count = 0,
status;
for(;;) {
status = dir_decode(desc);
if (status)
break;
dfprintk(DIRCACHE, "NFS: found cookie %Lu at index %Ld\n",
(unsigned long long)entry->cookie, desc->current_index);
if (desc->file->f_pos == desc->current_index) {
*desc->dir_cookie = entry->cookie;
break;
}
desc->current_index++;
if (loop_count++ > 200) {
loop_count = 0;
schedule();
}
}
return status;
}
/*
* Find the given page, and call find_dirent() or find_dirent_index in
* order to try to return the next entry.
*/
static inline
int find_dirent_page(nfs_readdir_descriptor_t *desc)
{
struct inode *inode = desc->file->f_path.dentry->d_inode;
struct page *page;
int status;
dfprintk(DIRCACHE, "NFS: %s: searching page %ld for target %Lu\n",
__func__, desc->page_index,
(long long) *desc->dir_cookie);
/* If we find the page in the page_cache, we cannot be sure
* how fresh the data is, so we will ignore readdir_plus attributes.
*/
desc->timestamp_valid = 0;
page = read_cache_page(inode->i_mapping, desc->page_index,
(filler_t *)nfs_readdir_filler, desc);
if (IS_ERR(page)) {
status = PTR_ERR(page);
goto out;
}
/* NOTE: Someone else may have changed the READDIRPLUS flag */
desc->page = page;
desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */
if (*desc->dir_cookie != 0)
status = find_dirent(desc);
else
status = find_dirent_index(desc);
if (status < 0)
dir_page_release(desc);
out:
dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __func__, status);
return status;
}
/*
* Recurse through the page cache pages, and return a
* filled nfs_entry structure of the next directory entry if possible.
*
* The target for the search is '*desc->dir_cookie' if non-0,
* 'desc->file->f_pos' otherwise
*/
static inline
int readdir_search_pagecache(nfs_readdir_descriptor_t *desc)
{
int loop_count = 0;
int res;
/* Always search-by-index from the beginning of the cache */
if (*desc->dir_cookie == 0) {
dfprintk(DIRCACHE, "NFS: readdir_search_pagecache() searching for offset %Ld\n",
(long long)desc->file->f_pos);
desc->page_index = 0;
desc->entry->cookie = desc->entry->prev_cookie = 0;
desc->entry->eof = 0;
desc->current_index = 0;
} else
dfprintk(DIRCACHE, "NFS: readdir_search_pagecache() searching for cookie %Lu\n",
(unsigned long long)*desc->dir_cookie);
for (;;) {
res = find_dirent_page(desc);
if (res != -EAGAIN)
break;
/* Align to beginning of next page */
desc->page_index ++;
if (loop_count++ > 200) {
loop_count = 0;
schedule();
}
}
dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __func__, res);
return res;
}
static inline unsigned int dt_type(struct inode *inode)
{
return (inode->i_mode >> 12) & 15;
}
static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc);
/*
* Once we've found the start of the dirent within a page: fill 'er up...
*/
static
int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent,
filldir_t filldir)
{
struct file *file = desc->file;
struct nfs_entry *entry = desc->entry;
struct dentry *dentry = NULL;
u64 fileid;
int loop_count = 0,
res;
dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n",
(unsigned long long)entry->cookie);
for(;;) {
unsigned d_type = DT_UNKNOWN;
/* Note: entry->prev_cookie contains the cookie for
* retrieving the current dirent on the server */
fileid = entry->ino;
/* Get a dentry if we have one */
if (dentry != NULL)
dput(dentry);
dentry = nfs_readdir_lookup(desc);
/* Use readdirplus info */
if (dentry != NULL && dentry->d_inode != NULL) {
d_type = dt_type(dentry->d_inode);
fileid = NFS_FILEID(dentry->d_inode);
}
res = filldir(dirent, entry->name, entry->len,
file->f_pos, nfs_compat_user_ino64(fileid),
d_type);
if (res < 0)
break;
file->f_pos++;
*desc->dir_cookie = entry->cookie;
if (dir_decode(desc) != 0) {
desc->page_index ++;
break;
}
if (loop_count++ > 200) {
loop_count = 0;
schedule();
}
}
dir_page_release(desc);
if (dentry != NULL)
dput(dentry);
dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n",
(unsigned long long)*desc->dir_cookie, res);
return res;
}
/*
* If we cannot find a cookie in our cache, we suspect that this is
* because it points to a deleted file, so we ask the server to return
* whatever it thinks is the next entry. We then feed this to filldir.
* If all goes well, we should then be able to find our way round the
* cache on the next call to readdir_search_pagecache();
*
* NOTE: we cannot add the anonymous page to the pagecache because
* the data it contains might not be page aligned. Besides,
* we should already have a complete representation of the
* directory in the page cache by the time we get here.
*/
static inline
int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent,
filldir_t filldir)
{
struct file *file = desc->file;
struct inode *inode = file->f_path.dentry->d_inode;
struct rpc_cred *cred = nfs_file_cred(file);
struct page *page = NULL;
int status;
unsigned long timestamp, gencount;
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;
}
timestamp = jiffies;
gencount = nfs_inc_attr_generation_counter();
status = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred,
*desc->dir_cookie, page,
NFS_SERVER(inode)->dtsize,
desc->plus);
desc->page = page;
desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */
if (status >= 0) {
desc->timestamp = timestamp;
desc->gencount = gencount;
desc->timestamp_valid = 1;
if ((status = dir_decode(desc)) == 0)
desc->entry->prev_cookie = *desc->dir_cookie;
} else
status = -EIO;
if (status < 0)
goto out_release;
status = nfs_do_filldir(desc, dirent, filldir);
/* Reset read descriptor so it searches the page cache from
* the start upon the next call to readdir_search_pagecache() */
desc->page_index = 0;
desc->entry->cookie = desc->entry->prev_cookie = 0;
desc->entry->eof = 0;
out:
dfprintk(DIRCACHE, "NFS: %s: returns %d\n",
__func__, status);
return status;
out_release:
dir_page_release(desc);
goto out;
}
/* The file offset position represents the dirent entry number. A
last cookie cache takes care of the common case of reading the
whole directory.
*/
static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;
nfs_readdir_descriptor_t my_desc,
*desc = &my_desc;
struct nfs_entry my_entry;
int res = -ENOMEM;
dfprintk(FILE, "NFS: readdir(%s/%s) starting at cookie %llu\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
(long long)filp->f_pos);
nfs_inc_stats(inode, NFSIOS_VFSGETDENTS);
/*
* filp->f_pos points to the dirent entry number.
* *desc->dir_cookie has the cookie for the next entry. We have
* to either find the entry with the appropriate number or
* revalidate the cookie.
*/
memset(desc, 0, sizeof(*desc));
desc->file = filp;
desc->dir_cookie = &nfs_file_open_context(filp)->dir_cookie;
desc->decode = NFS_PROTO(inode)->decode_dirent;
desc->plus = NFS_USE_READDIRPLUS(inode);
my_entry.cookie = my_entry.prev_cookie = 0;
my_entry.eof = 0;
my_entry.fh = nfs_alloc_fhandle();
my_entry.fattr = nfs_alloc_fattr();
if (my_entry.fh == NULL || my_entry.fattr == NULL)
goto out_alloc_failed;
desc->entry = &my_entry;
nfs_block_sillyrename(dentry);
res = nfs_revalidate_mapping(inode, filp->f_mapping);
if (res < 0)
goto out;
while(!desc->entry->eof) {
res = readdir_search_pagecache(desc);
if (res == -EBADCOOKIE) {
/* This means either end of directory */
if (*desc->dir_cookie && desc->entry->cookie != *desc->dir_cookie) {
/* Or that the server has 'lost' a cookie */
res = uncached_readdir(desc, dirent, filldir);
if (res >= 0)
continue;
}
res = 0;
break;
}
if (res == -ETOOSMALL && desc->plus) {
clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
nfs_zap_caches(inode);
desc->plus = 0;
desc->entry->eof = 0;
continue;
}
if (res < 0)
break;
res = nfs_do_filldir(desc, dirent, filldir);
if (res < 0) {
res = 0;
break;
}
}
out:
nfs_unblock_sillyrename(dentry);
if (res > 0)
res = 0;
out_alloc_failed:
nfs_free_fattr(my_entry.fattr);
nfs_free_fhandle(my_entry.fh);
dfprintk(FILE, "NFS: readdir(%s/%s) returns %d\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
res);
return res;
}
static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int origin)
{
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;
dfprintk(FILE, "NFS: llseek dir(%s/%s, %lld, %d)\n",
dentry->d_parent->d_name.name,
dentry->d_name.name,
offset, origin);
mutex_lock(&inode->i_mutex);
switch (origin) {
case 1:
offset += filp->f_pos;
case 0:
if (offset >= 0)
break;
default:
offset = -EINVAL;
goto out;
}
if (offset != filp->f_pos) {
filp->f_pos = offset;
nfs_file_open_context(filp)->dir_cookie = 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, struct dentry *dentry, int datasync)
{
dfprintk(FILE, "NFS: fsync dir(%s/%s) datasync %d\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
datasync);
nfs_inc_stats(dentry->d_inode, NFSIOS_VFSFSYNC);
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++;
}
/*
* A check for whether or not the parent directory has changed.
* In the case it has, we assume that the dentries are untrustworthy
* and may need to be looked up again.
*/
static int nfs_check_verifier(struct inode *dir, struct dentry *dentry)
{
if (IS_ROOT(dentry))
return 1;
if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
return 0;
if (!nfs_verify_change_attribute(dir, dentry->d_time))
return 0;
/* Revalidate nfsi->cache_change_attribute before we declare a match */
if (nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0)
return 0;
if (!nfs_verify_change_attribute(dir, dentry->d_time))
return 0;
return 1;
}
/*
* Return the intent data that applies to this particular path component
*
* Note that the current set of intents only apply to the very last
* component of the path.
* We check for this using LOOKUP_CONTINUE and LOOKUP_PARENT.
*/
static inline unsigned int nfs_lookup_check_intent(struct nameidata *nd, unsigned int mask)
{
if (nd->flags & (LOOKUP_CONTINUE|LOOKUP_PARENT))
return 0;
return nd->flags & mask;
}
/*
* 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, struct nameidata *nd)
{
if (NFS_PROTO(dir)->version == 2)
return 0;
return nd && nfs_lookup_check_intent(nd, LOOKUP_EXCL);
}
/*
* Inode and filehandle revalidation for lookups.
*
* We force revalidation in the cases where the VFS sets LOOKUP_REVAL,
* or if the intent information indicates that we're about to open this
* particular file and the "nocto" mount flag is not set.
*
*/
static inline
int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd)
{
struct nfs_server *server = NFS_SERVER(inode);
if (test_bit(NFS_INO_MOUNTPOINT, &NFS_I(inode)->flags))
return 0;
if (nd != NULL) {
/* VFS wants an on-the-wire revalidation */
if (nd->flags & LOOKUP_REVAL)
goto out_force;
/* This is an open(2) */
if (nfs_lookup_check_intent(nd, LOOKUP_OPEN) != 0 &&
!(server->flags & NFS_MOUNT_NOCTO) &&
(S_ISREG(inode->i_mode) ||
S_ISDIR(inode->i_mode)))
goto out_force;
return 0;
}
return nfs_revalidate_inode(server, inode);
out_force:
return __nfs_revalidate_inode(server, inode);
}
/*
* We judge how long we want to trust negative
* dentries by looking at the parent inode mtime.
*
* If parent mtime has changed, we revalidate, else we wait for a
* period corresponding to the parent's attribute cache timeout value.
*/
static inline
int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry,
struct nameidata *nd)
{
/* Don't revalidate a negative dentry if we're creating a new file */
if (nd != NULL && nfs_lookup_check_intent(nd, LOOKUP_CREATE) != 0)
return 0;
if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG)
return 1;
return !nfs_check_verifier(dir, dentry);
}
/*
* This is called every time the dcache has a lookup hit,
* and we should check whether we can really trust that
* lookup.
*
* NOTE! The hit can be a negative hit too, don't assume
* we have an inode!
*
* If the parent directory is seen to have changed, we throw out the
* cached dentry and do a new lookup.
*/
static int nfs_lookup_revalidate(struct dentry * dentry, struct nameidata *nd)
{
struct inode *dir;
struct inode *inode;
struct dentry *parent;
struct nfs_fh *fhandle = NULL;
struct nfs_fattr *fattr = NULL;
int error;
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, nd))
goto out_bad;
goto out_valid;
}
if (is_bad_inode(inode)) {
dfprintk(LOOKUPCACHE, "%s: %s/%s has dud inode\n",
__func__, dentry->d_parent->d_name.name,
dentry->d_name.name);
goto out_bad;
}
if (nfs_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, nd) && nfs_check_verifier(dir, dentry)) {
if (nfs_lookup_verify_inode(inode, nd))
goto out_zap_parent;
goto out_valid;
}
if (NFS_STALE(inode))
goto out_bad;
error = -ENOMEM;
fhandle = nfs_alloc_fhandle();
fattr = nfs_alloc_fattr();
if (fhandle == NULL || fattr == NULL)
goto out_error;
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
if (error)
goto out_bad;
if (nfs_compare_fh(NFS_FH(inode), fhandle))
goto out_bad;
if ((error = nfs_refresh_inode(inode, fattr)) != 0)
goto out_bad;
nfs_free_fattr(fattr);
nfs_free_fhandle(fhandle);
out_set_verifier:
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
out_valid:
dput(parent);
dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is valid\n",
__func__, dentry->d_parent->d_name.name,
dentry->d_name.name);
return 1;
out_zap_parent:
nfs_zap_caches(dir);
out_bad:
nfs_mark_for_revalidate(dir);
if (inode && S_ISDIR(inode->i_mode)) {
/* Purge readdir caches. */
nfs_zap_caches(inode);
/* If we have submounts, don't unhash ! */
if (have_submounts(dentry))
goto out_valid;
if (dentry->d_flags & DCACHE_DISCONNECTED)
goto out_valid;
shrink_dcache_parent(dentry);
}
d_drop(dentry);
nfs_free_fattr(fattr);
nfs_free_fhandle(fhandle);
dput(parent);
dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is invalid\n",
__func__, dentry->d_parent->d_name.name,
dentry->d_name.name);
return 0;
out_error:
nfs_free_fattr(fattr);
nfs_free_fhandle(fhandle);
dput(parent);
dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) lookup returned error %d\n",
__func__, dentry->d_parent->d_name.name,
dentry->d_name.name, error);
return error;
}
/*
* This is called from dput() when d_count is going to 0.
*/
static int nfs_dentry_delete(struct dentry *dentry)
{
dfprintk(VFS, "NFS: dentry_delete(%s/%s, %x)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
dentry->d_flags);
/* Unhash any dentry with a stale inode */
if (dentry->d_inode != NULL && NFS_STALE(dentry->d_inode))
return 1;
if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
/* Unhash it, so that ->d_iput() would be called */
return 1;
}
if (!(dentry->d_sb->s_flags & MS_ACTIVE)) {
/* Unhash it, so that ancestors of killed async unlink
* files will be cleaned up during umount */
return 1;
}
return 0;
}
static void nfs_drop_nlink(struct inode *inode)
{
spin_lock(&inode->i_lock);
if (inode->i_nlink > 0)
drop_nlink(inode);
spin_unlock(&inode->i_lock);
}
/*
* Called when the dentry loses inode.
* We use it to clean up silly-renamed files.
*/
static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode)
{
if (S_ISDIR(inode->i_mode))
/* drop any readdir cache as it could easily be old */
NFS_I(inode)->cache_validity |= NFS_INO_INVALID_DATA;
if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
drop_nlink(inode);
nfs_complete_unlink(dentry, inode);
}
iput(inode);
}
const struct dentry_operations nfs_dentry_operations = {
.d_revalidate = nfs_lookup_revalidate,
.d_delete = nfs_dentry_delete,
.d_iput = nfs_dentry_iput,
};
static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
{
struct dentry *res;
struct dentry *parent;
struct inode *inode = NULL;
struct nfs_fh *fhandle = NULL;
struct nfs_fattr *fattr = NULL;
int error;
dfprintk(VFS, "NFS: lookup(%s/%s)\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
nfs_inc_stats(dir, NFSIOS_VFSLOOKUP);
res = ERR_PTR(-ENAMETOOLONG);
if (dentry->d_name.len > NFS_SERVER(dir)->namelen)
goto out;
dentry->d_op = NFS_PROTO(dir)->dentry_ops;
/*
* If we're doing an exclusive create, optimize away the lookup
* but don't hash the dentry.
*/
if (nfs_is_exclusive_create(dir, nd)) {
d_instantiate(dentry, NULL);
res = NULL;
goto out;
}
res = ERR_PTR(-ENOMEM);
fhandle = nfs_alloc_fhandle();
fattr = nfs_alloc_fattr();
if (fhandle == NULL || fattr == NULL)
goto out;
parent = dentry->d_parent;
/* Protect against concurrent sillydeletes */
nfs_block_sillyrename(parent);
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
if (error == -ENOENT)
goto no_entry;
if (error < 0) {
res = ERR_PTR(error);
goto out_unblock_sillyrename;
}
inode = nfs_fhget(dentry->d_sb, fhandle, fattr);
res = (struct dentry *)inode;
if (IS_ERR(res))
goto out_unblock_sillyrename;
no_entry:
res = d_materialise_unique(dentry, inode);
if (res != NULL) {
if (IS_ERR(res))
goto out_unblock_sillyrename;
dentry = res;
}
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
out_unblock_sillyrename:
nfs_unblock_sillyrename(parent);
out:
nfs_free_fattr(fattr);
nfs_free_fhandle(fhandle);
return res;
}
#ifdef CONFIG_NFS_V4
static int nfs_open_revalidate(struct dentry *, struct nameidata *);
const struct dentry_operations nfs4_dentry_operations = {
.d_revalidate = nfs_open_revalidate,
.d_delete = nfs_dentry_delete,
.d_iput = nfs_dentry_iput,
};
/*
* Use intent information to determine whether we need to substitute
* the NFSv4-style stateful OPEN for the LOOKUP call
*/
static int is_atomic_open(struct nameidata *nd)
{
if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_OPEN) == 0)
return 0;
/* NFS does not (yet) have a stateful open for directories */
if (nd->flags & LOOKUP_DIRECTORY)
return 0;
/* Are we trying to write to a read only partition? */
if (__mnt_is_readonly(nd->path.mnt) &&
(nd->intent.open.flags & (O_CREAT|O_TRUNC|FMODE_WRITE)))
return 0;
return 1;
}
static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
{
struct dentry *res = NULL;
int error;
dfprintk(VFS, "NFS: atomic_lookup(%s/%ld), %s\n",
dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
/* Check that we are indeed trying to open this file */
if (!is_atomic_open(nd))
goto no_open;
if (dentry->d_name.len > NFS_SERVER(dir)->namelen) {
res = ERR_PTR(-ENAMETOOLONG);
goto out;
}
dentry->d_op = NFS_PROTO(dir)->dentry_ops;
/* Let vfs_create() deal with O_EXCL. Instantiate, but don't hash
* the dentry. */
if (nd->flags & LOOKUP_EXCL) {
d_instantiate(dentry, NULL);
goto out;
}
/* Open the file on the server */
res = nfs4_atomic_open(dir, dentry, nd);
if (IS_ERR(res)) {
error = PTR_ERR(res);
switch (error) {
/* Make a negative dentry */
case -ENOENT:
res = NULL;
goto out;
/* This turned out not to be a regular file */
case -EISDIR:
case -ENOTDIR:
goto no_open;
case -ELOOP:
if (!(nd->intent.open.flags & O_NOFOLLOW))
goto no_open;
/* case -EINVAL: */
default:
goto out;
}
} else if (res != NULL)
dentry = res;
out:
return res;
no_open:
return nfs_lookup(dir, dentry, nd);
}
static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd)
{
struct dentry *parent = NULL;
struct inode *inode = dentry->d_inode;
struct inode *dir;
int openflags, ret = 0;
if (!is_atomic_open(nd) || d_mountpoint(dentry))
goto no_open;
parent = dget_parent(dentry);
dir = parent->d_inode;
/* We can't create new files in nfs_open_revalidate(), so we
* optimize away revalidation of negative dentries.
*/
if (inode == NULL) {
if (!nfs_neg_need_reval(dir, dentry, nd))
ret = 1;
goto out;
}
/* NFS only supports OPEN on regular files */
if (!S_ISREG(inode->i_mode))
goto no_open_dput;
openflags = nd->intent.open.flags;
/* We cannot do exclusive creation on a positive dentry */
if ((openflags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
goto no_open_dput;
/* We can't create new files, or truncate existing ones here */
openflags &= ~(O_CREAT|O_TRUNC);
/*
* Note: we're not holding inode->i_mutex and so may be racing with
* operations that change the directory. We therefore save the
* change attribute *before* we do the RPC call.
*/
ret = nfs4_open_revalidate(dir, dentry, openflags, nd);
out:
dput(parent);
if (!ret)
d_drop(dentry);
return ret;
no_open_dput:
dput(parent);
no_open:
return nfs_lookup_revalidate(dentry, nd);
}
#endif /* CONFIG_NFSV4 */
static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc)
{
struct dentry *parent = desc->file->f_path.dentry;
struct inode *dir = parent->d_inode;
struct nfs_entry *entry = desc->entry;
struct dentry *dentry, *alias;
struct qstr name = {
.name = entry->name,
.len = entry->len,
};
struct inode *inode;
unsigned long verf = nfs_save_change_attribute(dir);
switch (name.len) {
case 2:
if (name.name[0] == '.' && name.name[1] == '.')
return dget_parent(parent);
break;
case 1:
if (name.name[0] == '.')
return dget(parent);
}
spin_lock(&dir->i_lock);
if (NFS_I(dir)->cache_validity & NFS_INO_INVALID_DATA) {
spin_unlock(&dir->i_lock);
return NULL;
}
spin_unlock(&dir->i_lock);
name.hash = full_name_hash(name.name, name.len);
dentry = d_lookup(parent, &name);
if (dentry != NULL) {
/* Is this a positive dentry that matches the readdir info? */
if (dentry->d_inode != NULL &&
(NFS_FILEID(dentry->d_inode) == entry->ino ||
d_mountpoint(dentry))) {
if (!desc->plus || entry->fh->size == 0)
return dentry;
if (nfs_compare_fh(NFS_FH(dentry->d_inode),
entry->fh) == 0)
goto out_renew;
}
/* No, so d_drop to allow one to be created */
d_drop(dentry);
dput(dentry);
}
if (!desc->plus || !(entry->fattr->valid & NFS_ATTR_FATTR))
return NULL;
if (name.len > NFS_SERVER(dir)->namelen)
return NULL;
/* Note: caller is already holding the dir->i_mutex! */
dentry = d_alloc(parent, &name);
if (dentry == NULL)
return NULL;
dentry->d_op = NFS_PROTO(dir)->dentry_ops;
inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr);
if (IS_ERR(inode)) {
dput(dentry);
return NULL;
}
alias = d_materialise_unique(dentry, inode);
if (alias != NULL) {
dput(dentry);
if (IS_ERR(alias))
return NULL;
dentry = alias;
}
out_renew:
nfs_set_verifier(dentry, verf);
return dentry;
}
/*
* Code common to create, mkdir, and mknod.
*/
int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle,
struct nfs_fattr *fattr)
{
struct dentry *parent = dget_parent(dentry);
struct inode *dir = parent->d_inode;
struct inode *inode;
int error = -EACCES;
d_drop(dentry);
/* We may have been initialized further down */
if (dentry->d_inode)
goto out;
if (fhandle->size == 0) {
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
if (error)
goto out_error;
}
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
if (!(fattr->valid & NFS_ATTR_FATTR)) {
struct nfs_server *server = NFS_SB(dentry->d_sb);
error = server->nfs_client->rpc_ops->getattr(server, fhandle, fattr);
if (error < 0)
goto out_error;
}
inode = nfs_fhget(dentry->d_sb, fhandle, fattr);
error = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_error;
d_add(dentry, inode);
out:
dput(parent);
return 0;
out_error:
nfs_mark_for_revalidate(dir);
dput(parent);
return error;
}
/*
* 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.
*/
static int nfs_create(struct inode *dir, struct dentry *dentry, int mode,
struct nameidata *nd)
{
struct iattr attr;
int error;
int open_flags = 0;
dfprintk(VFS, "NFS: create(%s/%ld), %s\n",
dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
attr.ia_mode = mode;
attr.ia_valid = ATTR_MODE;
if ((nd->flags & LOOKUP_CREATE) != 0)
open_flags = nd->intent.open.flags;
error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags, nd);
if (error != 0)
goto out_err;
return 0;
out_err:
d_drop(dentry);
return error;
}
/*
* See comments for nfs_proc_create regarding failed operations.
*/
static int
nfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
{
struct iattr attr;
int status;
dfprintk(VFS, "NFS: mknod(%s/%ld), %s\n",
dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
if (!new_valid_dev(rdev))
return -EINVAL;
attr.ia_mode = mode;
attr.ia_valid = ATTR_MODE;
status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev);
if (status != 0)
goto out_err;
return 0;
out_err:
d_drop(dentry);
return status;
}
/*
* See comments for nfs_proc_create regarding failed operations.
*/
static int nfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
struct iattr attr;
int error;
dfprintk(VFS, "NFS: mkdir(%s/%ld), %s\n",
dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
attr.ia_valid = ATTR_MODE;
attr.ia_mode = mode | S_IFDIR;
error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr);
if (error != 0)
goto out_err;
return 0;
out_err:
d_drop(dentry);
return error;
}
static void nfs_dentry_handle_enoent(struct dentry *dentry)
{
if (dentry->d_inode != NULL && !d_unhashed(dentry))
d_delete(dentry);
}
static int nfs_rmdir(struct inode *dir, struct dentry *dentry)
{
int error;
dfprintk(VFS, "NFS: rmdir(%s/%ld), %s\n",
dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
/* Ensure the VFS deletes this inode */
if (error == 0 && dentry->d_inode != NULL)
clear_nlink(dentry->d_inode);
else if (error == -ENOENT)
nfs_dentry_handle_enoent(dentry);
return error;
}
static int nfs_sillyrename(struct inode *dir, struct dentry *dentry)
{
static unsigned int sillycounter;
const int fileidsize = sizeof(NFS_FILEID(dentry->d_inode))*2;
const int countersize = sizeof(sillycounter)*2;
const int slen = sizeof(".nfs")+fileidsize+countersize-1;
char silly[slen+1];
struct qstr qsilly;
struct dentry *sdentry;
int error = -EIO;
dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
atomic_read(&dentry->d_count));
nfs_inc_stats(dir, NFSIOS_SILLYRENAME);
/*
* We don't allow a dentry to be silly-renamed twice.
*/
error = -EBUSY;
if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
goto out;
sprintf(silly, ".nfs%*.*Lx",
fileidsize, fileidsize,
(unsigned long long)NFS_FILEID(dentry->d_inode));
/* Return delegation in anticipation of the rename */
nfs_inode_return_delegation(dentry->d_inode);
sdentry = NULL;
do {
char *suffix = silly + slen - countersize;
dput(sdentry);
sillycounter++;
sprintf(suffix, "%*.*x", countersize, countersize, sillycounter);
dfprintk(VFS, "NFS: trying to rename %s to %s\n",
dentry->d_name.name, silly);
sdentry = lookup_one_len(silly, dentry->d_parent, slen);
/*
* N.B. Better to return EBUSY here ... it could be
* dangerous to delete the file while it's in use.
*/
if (IS_ERR(sdentry))
goto out;
} while(sdentry->d_inode != NULL); /* need negative lookup */
qsilly.name = silly;
qsilly.len = strlen(silly);
if (dentry->d_inode) {
error = NFS_PROTO(dir)->rename(dir, &dentry->d_name,
dir, &qsilly);
nfs_mark_for_revalidate(dentry->d_inode);
} else
error = NFS_PROTO(dir)->rename(dir, &dentry->d_name,
dir, &qsilly);
if (!error) {
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
d_move(dentry, sdentry);
error = nfs_async_unlink(dir, dentry);
/* If we return 0 we don't unlink */
}
dput(sdentry);
out:
return error;
}
/*
* Remove a file after making sure there are no pending writes,
* and after checking that the file has only one user.
*
* We invalidate the attribute cache and free the inode prior to the operation
* to avoid possible races if the server reuses the inode.
*/
static int nfs_safe_remove(struct dentry *dentry)
{
struct inode *dir = dentry->d_parent->d_inode;
struct inode *inode = dentry->d_inode;
int error = -EBUSY;
dfprintk(VFS, "NFS: safe_remove(%s/%s)\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
/* If the dentry was sillyrenamed, we simply call d_delete() */
if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
error = 0;
goto out;
}
if (inode != NULL) {
nfs_inode_return_delegation(inode);
error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
/* The VFS may want to delete this inode */
if (error == 0)
nfs_drop_nlink(inode);
nfs_mark_for_revalidate(inode);
} else
error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
if (error == -ENOENT)
nfs_dentry_handle_enoent(dentry);
out:
return error;
}
/* We do silly rename. In case sillyrename() returns -EBUSY, the inode
* belongs to an active ".nfs..." file and we return -EBUSY.
*
* If sillyrename() returns 0, we do nothing, otherwise we unlink.
*/
static int nfs_unlink(struct inode *dir, struct dentry *dentry)
{
int error;
int need_rehash = 0;
dfprintk(VFS, "NFS: unlink(%s/%ld, %s)\n", dir->i_sb->s_id,
dir->i_ino, dentry->d_name.name);
spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
if (atomic_read(&dentry->d_count) > 1) {
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
/* Start asynchronous writeout of the inode */
write_inode_now(dentry->d_inode, 0);
error = nfs_sillyrename(dir, dentry);
return error;
}
if (!d_unhashed(dentry)) {
__d_drop(dentry);
need_rehash = 1;
}
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
error = nfs_safe_remove(dentry);
if (!error || error == -ENOENT) {
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
} else if (need_rehash)
d_rehash(dentry);
return error;
}
/*
* 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.
*/
static int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
{
struct pagevec lru_pvec;
struct page *page;
char *kaddr;
struct iattr attr;
unsigned int pathlen = strlen(symname);
int error;
dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id,
dir->i_ino, dentry->d_name.name, symname);
if (pathlen > PAGE_SIZE)
return -ENAMETOOLONG;
attr.ia_mode = S_IFLNK | S_IRWXUGO;
attr.ia_valid = ATTR_MODE;
page = alloc_page(GFP_HIGHUSER);
if (!page)
return -ENOMEM;
kaddr = kmap_atomic(page, KM_USER0);
memcpy(kaddr, symname, pathlen);
if (pathlen < PAGE_SIZE)
memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen);
kunmap_atomic(kaddr, KM_USER0);
error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr);
if (error != 0) {
dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s) error %d\n",
dir->i_sb->s_id, dir->i_ino,
dentry->d_name.name, symname, error);
d_drop(dentry);
__free_page(page);
return error;
}
/*
* No big deal if we can't add this page to the page cache here.
* READLINK will get the missing page from the server if needed.
*/
pagevec_init(&lru_pvec, 0);
if (!add_to_page_cache(page, dentry->d_inode->i_mapping, 0,
GFP_KERNEL)) {
pagevec_add(&lru_pvec, page);
pagevec_lru_add_file(&lru_pvec);
SetPageUptodate(page);
unlock_page(page);
} else
__free_page(page);
return 0;
}
static int
nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
{
struct inode *inode = old_dentry->d_inode;
int error;
dfprintk(VFS, "NFS: link(%s/%s -> %s/%s)\n",
old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
dentry->d_parent->d_name.name, dentry->d_name.name);
nfs_inode_return_delegation(inode);
d_drop(dentry);
error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
if (error == 0) {
atomic_inc(&inode->i_count);
d_add(dentry, inode);
}
return error;
}
/*
* 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.
*/
static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry)
{
struct inode *old_inode = old_dentry->d_inode;
struct inode *new_inode = new_dentry->d_inode;
struct dentry *dentry = NULL, *rehash = NULL;
int error = -EBUSY;
dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n",
old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
new_dentry->d_parent->d_name.name, new_dentry->d_name.name,
atomic_read(&new_dentry->d_count));
/*
* For non-directories, check whether the target is busy and if so,
* make a copy of the dentry and then do a silly-rename. If the
* silly-rename succeeds, the copied dentry is hashed and becomes
* the new target.
*/
if (new_inode && !S_ISDIR(new_inode->i_mode)) {
/*
* To prevent any new references to the target during the
* rename, we unhash the dentry in advance.
*/
if (!d_unhashed(new_dentry)) {
d_drop(new_dentry);
rehash = new_dentry;
}
if (atomic_read(&new_dentry->d_count) > 2) {
int err;
/* copy the target dentry's name */
dentry = d_alloc(new_dentry->d_parent,
&new_dentry->d_name);
if (!dentry)
goto out;
/* silly-rename the existing target ... */
err = nfs_sillyrename(new_dir, new_dentry);
if (err)
goto out;
new_dentry = dentry;
rehash = NULL;
new_inode = NULL;
}
}
/*
* ... prune child dentries and writebacks if needed.
*/
if (atomic_read(&old_dentry->d_count) > 1) {
if (S_ISREG(old_inode->i_mode))
nfs_wb_all(old_inode);
shrink_dcache_parent(old_dentry);
}
nfs_inode_return_delegation(old_inode);
if (new_inode != NULL)
nfs_inode_return_delegation(new_inode);
error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name,
new_dir, &new_dentry->d_name);
nfs_mark_for_revalidate(old_inode);
out:
if (rehash)
d_rehash(rehash);
if (!error) {
if (new_inode != NULL)
nfs_drop_nlink(new_inode);
d_move(old_dentry, new_dentry);
nfs_set_verifier(new_dentry,
nfs_save_change_attribute(new_dir));
} else if (error == -ENOENT)
nfs_dentry_handle_enoent(old_dentry);
/* new dentry created? */
if (dentry)
dput(dentry);
return error;
}
static DEFINE_SPINLOCK(nfs_access_lru_lock);
static LIST_HEAD(nfs_access_lru_list);
static atomic_long_t nfs_access_nr_entries;
static void nfs_access_free_entry(struct nfs_access_entry *entry)
{
put_rpccred(entry->cred);
kfree(entry);
smp_mb__before_atomic_dec();
atomic_long_dec(&nfs_access_nr_entries);
smp_mb__after_atomic_dec();
}
static void nfs_access_free_list(struct list_head *head)
{
struct nfs_access_entry *cache;
while (!list_empty(head)) {
cache = list_entry(head->next, struct nfs_access_entry, lru);
list_del(&cache->lru);
nfs_access_free_entry(cache);
}
}
int nfs_access_cache_shrinker(int nr_to_scan, gfp_t gfp_mask)
{
LIST_HEAD(head);
struct nfs_inode *nfsi;
struct nfs_access_entry *cache;
if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL)
return (nr_to_scan == 0) ? 0 : -1;
spin_lock(&nfs_access_lru_lock);
list_for_each_entry(nfsi, &nfs_access_lru_list, access_cache_inode_lru) {
struct inode *inode;
if (nr_to_scan-- == 0)
break;
inode = &nfsi->vfs_inode;
spin_lock(&inode->i_lock);
if (list_empty(&nfsi->access_cache_entry_lru))
goto remove_lru_entry;
cache = list_entry(nfsi->access_cache_entry_lru.next,
struct nfs_access_entry, lru);
list_move(&cache->lru, &head);
rb_erase(&cache->rb_node, &nfsi->access_cache);
if (!list_empty(&nfsi->access_cache_entry_lru))
list_move_tail(&nfsi->access_cache_inode_lru,
&nfs_access_lru_list);
else {
remove_lru_entry:
list_del_init(&nfsi->access_cache_inode_lru);
smp_mb__before_clear_bit();
clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags);
smp_mb__after_clear_bit();
}
}
spin_unlock(&nfs_access_lru_lock);
nfs_access_free_list(&head);
return (atomic_long_read(&nfs_access_nr_entries) / 100) * sysctl_vfs_cache_pressure;
}
static void __nfs_access_zap_cache(struct nfs_inode *nfsi, struct list_head *head)
{
struct rb_root *root_node = &nfsi->access_cache;
struct rb_node *n;
struct nfs_access_entry *entry;
/* Unhook entries from the cache */
while ((n = rb_first(root_node)) != NULL) {
entry = rb_entry(n, struct nfs_access_entry, rb_node);
rb_erase(n, root_node);
list_move(&entry->lru, head);
}
nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS;
}
void nfs_access_zap_cache(struct inode *inode)
{
LIST_HEAD(head);
if (test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags) == 0)
return;
/* Remove from global LRU init */
spin_lock(&nfs_access_lru_lock);
if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags))
list_del_init(&NFS_I(inode)->access_cache_inode_lru);
spin_lock(&inode->i_lock);
__nfs_access_zap_cache(NFS_I(inode), &head);
spin_unlock(&inode->i_lock);
spin_unlock(&nfs_access_lru_lock);
nfs_access_free_list(&head);
}
static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, struct rpc_cred *cred)
{
struct rb_node *n = NFS_I(inode)->access_cache.rb_node;
struct nfs_access_entry *entry;
while (n != NULL) {
entry = rb_entry(n, struct nfs_access_entry, rb_node);
if (cred < entry->cred)
n = n->rb_left;
else if (cred > entry->cred)
n = n->rb_right;
else
return entry;
}
return NULL;
}
static int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_access_entry *cache;
int err = -ENOENT;
spin_lock(&inode->i_lock);
if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)
goto out_zap;
cache = nfs_access_search_rbtree(inode, cred);
if (cache == NULL)
goto out;
if (!nfs_have_delegated_attributes(inode) &&
!time_in_range_open(jiffies, cache->jiffies, cache->jiffies + nfsi->attrtimeo))
goto out_stale;
res->jiffies = cache->jiffies;
res->cred = cache->cred;
res->mask = cache->mask;
list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru);
err = 0;
out:
spin_unlock(&inode->i_lock);
return err;
out_stale:
rb_erase(&cache->rb_node, &nfsi->access_cache);
list_del(&cache->lru);
spin_unlock(&inode->i_lock);
nfs_access_free_entry(cache);
return -ENOENT;
out_zap:
spin_unlock(&inode->i_lock);
nfs_access_zap_cache(inode);
return -ENOENT;
}
static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct rb_root *root_node = &nfsi->access_cache;
struct rb_node **p = &root_node->rb_node;
struct rb_node *parent = NULL;
struct nfs_access_entry *entry;
spin_lock(&inode->i_lock);
while (*p != NULL) {
parent = *p;
entry = rb_entry(parent, struct nfs_access_entry, rb_node);
if (set->cred < entry->cred)
p = &parent->rb_left;
else if (set->cred > entry->cred)
p = &parent->rb_right;
else
goto found;
}
rb_link_node(&set->rb_node, parent, p);
rb_insert_color(&set->rb_node, root_node);
list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
spin_unlock(&inode->i_lock);
return;
found:
rb_replace_node(parent, &set->rb_node, root_node);
list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
list_del(&entry->lru);
spin_unlock(&inode->i_lock);
nfs_access_free_entry(entry);
}
static void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set)
{
struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL);
if (cache == NULL)
return;
RB_CLEAR_NODE(&cache->rb_node);
cache->jiffies = set->jiffies;
cache->cred = get_rpccred(set->cred);
cache->mask = set->mask;
nfs_access_add_rbtree(inode, cache);
/* Update accounting */
smp_mb__before_atomic_inc();
atomic_long_inc(&nfs_access_nr_entries);
smp_mb__after_atomic_inc();
/* Add inode to global LRU list */
if (!test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) {
spin_lock(&nfs_access_lru_lock);
if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags))
list_add_tail(&NFS_I(inode)->access_cache_inode_lru,
&nfs_access_lru_list);
spin_unlock(&nfs_access_lru_lock);
}
}
static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
{
struct nfs_access_entry cache;
int status;
status = nfs_access_get_cached(inode, cred, &cache);
if (status == 0)
goto out;
/* Be clever: ask server to check for all possible rights */
cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ;
cache.cred = cred;
cache.jiffies = jiffies;
status = NFS_PROTO(inode)->access(inode, &cache);
if (status != 0) {
if (status == -ESTALE) {
nfs_zap_caches(inode);
if (!S_ISDIR(inode->i_mode))
set_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
}
return status;
}
nfs_access_add_cache(inode, &cache);
out:
if ((mask & ~cache.mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0)
return 0;
return -EACCES;
}
static int nfs_open_permission_mask(int openflags)
{
int mask = 0;
if (openflags & FMODE_READ)
mask |= MAY_READ;
if (openflags & FMODE_WRITE)
mask |= MAY_WRITE;
if (openflags & FMODE_EXEC)
mask |= MAY_EXEC;
return mask;
}
int nfs_may_open(struct inode *inode, struct rpc_cred *cred, int openflags)
{
return nfs_do_access(inode, cred, nfs_open_permission_mask(openflags));
}
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)
goto force_lookup;
switch (inode->i_mode & S_IFMT) {
case S_IFLNK:
goto out;
case S_IFREG:
/* NFSv4 has atomic_open... */
if (nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN)
&& (mask & MAY_OPEN)
&& !(mask & MAY_EXEC))
goto out;
break;
case S_IFDIR:
/*
* Optimize away all write operations, since the server
* will check permissions when we perform the op.
*/
if ((mask & MAY_WRITE) && !(mask & MAY_READ))
goto out;
}
force_lookup:
if (!NFS_PROTO(inode)->access)
goto out_notsup;
cred = rpc_lookup_cred();
if (!IS_ERR(cred)) {
res = nfs_do_access(inode, cred, mask);
put_rpccred(cred);
} else
res = PTR_ERR(cred);
out:
if (!res && (mask & MAY_EXEC) && !execute_ok(inode))
res = -EACCES;
dfprintk(VFS, "NFS: permission(%s/%ld), mask=0x%x, res=%d\n",
inode->i_sb->s_id, inode->i_ino, mask, res);
return res;
out_notsup:
res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
if (res == 0)
res = generic_permission(inode, mask, NULL);
goto out;
}
/*
* Local variables:
* version-control: t
* kept-new-versions: 5
* End:
*/
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