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android_kernel_xiaomi_sm8350/fs/nfs/dir.c
Trond Myklebust 565277f63c NFS: Fix a race in sillyrename 
lookup() and sillyrename() can race one another because the sillyrename()
completion cannot take the parent directory's inode->i_mutex since the
latter may be held by whoever is calling dput().

We therefore have little option but to add extra locking to ensure that
nfs_lookup() and nfs_atomic_open() do not race with the sillyrename
completion.
If somebody has looked up the sillyrenamed file in the meantime, we just
transfer the sillydelete information to the new dentry.

Please refer to the bug-report at
	http://bugzilla.linux-nfs.org/show_bug.cgi?id=150

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-19 17:19:16 -04:00

1958 lines
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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/smp_lock.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"
/* #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(VFS, "NFS: opendir(%s/%ld)\n",
inode->i_sb->s_id, inode->i_ino);
lock_kernel();
/* Call generic open code in order to cache credentials */
res = nfs_open(inode, filp);
unlock_kernel();
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;
int error;
unsigned long timestamp;
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;
int error;
dfprintk(DIRCACHE, "NFS: %s: reading cookie %Lu into page %lu\n",
__FUNCTION__, (long long)desc->entry->cookie,
page->index);
again:
timestamp = jiffies;
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_FLAGS(inode));
desc->plus = 0;
goto again;
}
goto error;
}
desc->timestamp = timestamp;
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 (page->index == 0 && invalidate_inode_pages2_range(inode->i_mapping, PAGE_CACHE_SIZE, -1) < 0) {
/* Should never happen */
nfs_zap_mapping(inode, inode->i_mapping);
}
unlock_page(page);
return 0;
error:
unlock_page(page);
desc->error = error;
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;
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",
__FUNCTION__, (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",
__FUNCTION__, 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", __FUNCTION__, 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", __FUNCTION__, 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;
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;
desc->error = 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 (desc->error >= 0) {
desc->timestamp = timestamp;
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",
__FUNCTION__, 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;
struct nfs_fh fh;
struct nfs_fattr fattr;
long res;
dfprintk(VFS, "NFS: readdir(%s/%s) starting at cookie %Lu\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
(long long)filp->f_pos);
nfs_inc_stats(inode, NFSIOS_VFSGETDENTS);
lock_kernel();
res = nfs_revalidate_mapping_nolock(inode, filp->f_mapping);
if (res < 0) {
unlock_kernel();
return res;
}
/*
* 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 = &fh;
my_entry.fattr = &fattr;
nfs_fattr_init(&fattr);
desc->entry = &my_entry;
nfs_block_sillyrename(dentry);
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_FLAGS(inode));
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;
}
}
nfs_unblock_sillyrename(dentry);
unlock_kernel();
if (res > 0)
res = 0;
dfprintk(VFS, "NFS: readdir(%s/%s) returns %ld\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)
{
mutex_lock(&filp->f_path.dentry->d_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(&filp->f_path.dentry->d_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(VFS, "NFS: fsync_dir(%s/%s) datasync %d\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
datasync);
return 0;
}
/*
* 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_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;
if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_CREATE) == 0)
return 0;
return (nd->intent.open.flags & O_EXCL) != 0;
}
/*
* 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 (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;
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;
int error;
struct nfs_fh fhandle;
struct nfs_fattr fattr;
parent = dget_parent(dentry);
lock_kernel();
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",
__FUNCTION__, dentry->d_parent->d_name.name,
dentry->d_name.name);
goto out_bad;
}
/* 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 = 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_set_verifier(dentry, nfs_save_change_attribute(dir));
out_valid:
unlock_kernel();
dput(parent);
dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is valid\n",
__FUNCTION__, 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;
shrink_dcache_parent(dentry);
}
d_drop(dentry);
unlock_kernel();
dput(parent);
dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is invalid\n",
__FUNCTION__, dentry->d_parent->d_name.name,
dentry->d_name.name);
return 0;
}
/*
* 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);
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;
}
/*
* 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)
{
nfs_inode_return_delegation(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) {
lock_kernel();
drop_nlink(inode);
nfs_complete_unlink(dentry, inode);
unlock_kernel();
}
iput(inode);
}
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;
int error;
struct nfs_fh fhandle;
struct nfs_fattr fattr;
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;
res = ERR_PTR(-ENOMEM);
dentry->d_op = NFS_PROTO(dir)->dentry_ops;
lock_kernel();
/*
* 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_unlock;
}
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_unlock:
unlock_kernel();
out:
return res;
}
#ifdef CONFIG_NFS_V4
static int nfs_open_revalidate(struct dentry *, struct nameidata *);
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 inode *dir, 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 (IS_RDONLY(dir) && (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(dir, 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->intent.open.flags & O_EXCL) {
d_instantiate(dentry, NULL);
goto out;
}
/* Open the file on the server */
lock_kernel();
res = nfs4_atomic_open(dir, dentry, nd);
unlock_kernel();
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;
parent = dget_parent(dentry);
dir = parent->d_inode;
if (!is_atomic_open(dir, nd))
goto no_open;
/* 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;
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;
/* 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.
*/
lock_kernel();
ret = nfs4_open_revalidate(dir, dentry, openflags, nd);
unlock_kernel();
out:
dput(parent);
if (!ret)
d_drop(dentry);
return ret;
no_open:
dput(parent);
if (inode != NULL && nfs_have_delegation(inode, FMODE_READ))
return 1;
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;
lock_kernel();
error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags, nd);
if (error != 0)
goto out_err;
unlock_kernel();
return 0;
out_err:
unlock_kernel();
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;
lock_kernel();
status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev);
if (status != 0)
goto out_err;
unlock_kernel();
return 0;
out_err:
unlock_kernel();
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;
lock_kernel();
error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr);
if (error != 0)
goto out_err;
unlock_kernel();
return 0;
out_err:
d_drop(dentry);
unlock_kernel();
return error;
}
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);
lock_kernel();
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);
unlock_kernel();
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)
drop_nlink(inode);
nfs_mark_for_revalidate(inode);
} else
error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
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);
lock_kernel();
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);
unlock_kernel();
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) {
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
} else if (need_rehash)
d_rehash(dentry);
unlock_kernel();
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;
lock_kernel();
page = alloc_page(GFP_HIGHUSER);
if (!page) {
unlock_kernel();
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);
unlock_kernel();
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(&lru_pvec);
SetPageUptodate(page);
unlock_page(page);
} else
__free_page(page);
unlock_kernel();
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);
lock_kernel();
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);
}
unlock_kernel();
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;
/*
* To prevent any new references to the target during the rename,
* we unhash the dentry and free the inode in advance.
*/
lock_kernel();
if (!d_unhashed(new_dentry)) {
d_drop(new_dentry);
rehash = new_dentry;
}
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));
/*
* First check whether the target is busy ... we can't
* safely do _any_ rename if the target is in use.
*
* For files, 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)
goto go_ahead;
if (S_ISDIR(new_inode->i_mode)) {
error = -EISDIR;
if (!S_ISDIR(old_inode->i_mode))
goto out;
} else 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) {
new_dentry = rehash = dentry;
new_inode = NULL;
/* instantiate the replacement target */
d_instantiate(new_dentry, NULL);
} else if (atomic_read(&new_dentry->d_count) > 1)
/* dentry still busy? */
goto out;
} else
drop_nlink(new_inode);
go_ahead:
/*
* ... 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);
d_delete(new_dentry);
}
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) {
d_move(old_dentry, new_dentry);
nfs_set_verifier(new_dentry,
nfs_save_change_attribute(new_dir));
}
/* new dentry created? */
if (dentry)
dput(dentry);
unlock_kernel();
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();
}
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;
restart:
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 = igrab(&nfsi->vfs_inode);
if (inode == NULL)
continue;
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);
clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags);
}
spin_unlock(&inode->i_lock);
spin_unlock(&nfs_access_lru_lock);
iput(inode);
goto restart;
}
spin_unlock(&nfs_access_lru_lock);
while (!list_empty(&head)) {
cache = list_entry(head.next, struct nfs_access_entry, lru);
list_del(&cache->lru);
nfs_access_free_entry(cache);
}
return (atomic_long_read(&nfs_access_nr_entries) / 100) * sysctl_vfs_cache_pressure;
}
static void __nfs_access_zap_cache(struct inode *inode)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct rb_root *root_node = &nfsi->access_cache;
struct rb_node *n, *dispose = NULL;
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_del(&entry->lru);
n->rb_left = dispose;
dispose = n;
}
nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS;
spin_unlock(&inode->i_lock);
/* Now kill them all! */
while (dispose != NULL) {
n = dispose;
dispose = n->rb_left;
nfs_access_free_entry(rb_entry(n, struct nfs_access_entry, rb_node));
}
}
void nfs_access_zap_cache(struct inode *inode)
{
/* Remove from global LRU init */
if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_FLAGS(inode))) {
spin_lock(&nfs_access_lru_lock);
list_del_init(&NFS_I(inode)->access_cache_inode_lru);
spin_unlock(&nfs_access_lru_lock);
}
spin_lock(&inode->i_lock);
/* This will release the spinlock */
__nfs_access_zap_cache(inode);
}
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 (!time_in_range(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:
/* This will release the spinlock */
__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_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_FLAGS(inode))) {
spin_lock(&nfs_access_lru_lock);
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)
return status;
nfs_access_add_cache(inode, &cache);
out:
if ((cache.mask & mask) == mask)
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 nameidata *nd)
{
struct rpc_cred *cred;
int res = 0;
nfs_inc_stats(inode, NFSIOS_VFSACCESS);
if (mask == 0)
goto out;
/* Is this sys_access() ? */
if (nd != NULL && (nd->flags & LOOKUP_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)
&& nd != NULL
&& (nd->flags & LOOKUP_OPEN))
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:
lock_kernel();
if (!NFS_PROTO(inode)->access)
goto out_notsup;
cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0);
if (!IS_ERR(cred)) {
res = nfs_do_access(inode, cred, mask);
put_rpccred(cred);
} else
res = PTR_ERR(cred);
unlock_kernel();
out:
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);
unlock_kernel();
goto out;
}
/*
* Local variables:
* version-control: t
* kept-new-versions: 5
* End:
*/
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