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linux_old1/fs/nfs/dir.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/smp_lock.h>
#include <linux/namei.h>
#include "nfs4_fs.h"
#include "delegation.h"
#define NFS_PARANOIA 1
/* #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);
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,
};
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
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 *);
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 = 0;
lock_kernel();
/* Call generic open code in order to cache credentials */
if (!res)
res = nfs_open(inode, filp);
unlock_kernel();
return res;
}
typedef u32 * (*decode_dirent_t)(u32 *, struct nfs_entry *, int);
typedef struct {
struct file *file;
struct page *page;
unsigned long page_index;
u32 *ptr;
u64 *dir_cookie;
loff_t current_index;
struct nfs_entry *entry;
decode_dirent_t decode;
int plus;
int error;
} 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_dentry->d_inode;
struct rpc_cred *cred = nfs_file_cred(file);
unsigned long timestamp;
int error;
dfprintk(VFS, "NFS: nfs_readdir_filler() reading cookie %Lu into page %lu.\n", (long long)desc->entry->cookie, page->index);
again:
timestamp = jiffies;
error = NFS_PROTO(inode)->readdir(file->f_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;
}
SetPageUptodate(page);
spin_lock(&inode->i_lock);
NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATIME;
spin_unlock(&inode->i_lock);
/* 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);
unlock_page(page);
return 0;
error:
SetPageError(page);
unlock_page(page);
nfs_zap_caches(inode);
desc->error = error;
return -EIO;
}
static inline
int dir_decode(nfs_readdir_descriptor_t *desc)
{
u32 *p = desc->ptr;
p = desc->decode(p, desc->entry, desc->plus);
if (IS_ERR(p))
return PTR_ERR(p);
desc->ptr = p;
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(VFS, "NFS: found cookie %Lu\n", (unsigned long long)entry->cookie);
if (entry->prev_cookie == *desc->dir_cookie)
break;
if (loop_count++ > 200) {
loop_count = 0;
schedule();
}
}
dfprintk(VFS, "NFS: find_dirent() returns %d\n", status);
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(VFS, "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();
}
}
dfprintk(VFS, "NFS: find_dirent_index() returns %d\n", status);
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_dentry->d_inode;
struct page *page;
int status;
dfprintk(VFS, "NFS: find_dirent_page() searching directory page %ld\n", desc->page_index);
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;
}
if (!PageUptodate(page))
goto read_error;
/* 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(VFS, "NFS: find_dirent_page() returns %d\n", status);
return status;
read_error:
page_cache_release(page);
return -EIO;
}
/*
* 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(VFS, "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(VFS, "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(VFS, "NFS: readdir_search_pagecache() returned %d\n", 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;
unsigned long fileid;
int loop_count = 0,
res;
dfprintk(VFS, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n", (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 = nfs_fileid_to_ino_t(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 = dentry->d_inode->i_ino;
}
res = filldir(dirent, entry->name, entry->len,
file->f_pos, 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(VFS, "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_dentry->d_inode;
struct rpc_cred *cred = nfs_file_cred(file);
struct page *page = NULL;
int status;
dfprintk(VFS, "NFS: uncached_readdir() searching for cookie %Lu\n", (unsigned long long)*desc->dir_cookie);
page = alloc_page(GFP_HIGHUSER);
if (!page) {
status = -ENOMEM;
goto out;
}
desc->error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, *desc->dir_cookie,
page,
NFS_SERVER(inode)->dtsize,
desc->plus);
spin_lock(&inode->i_lock);
NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATIME;
spin_unlock(&inode->i_lock);
desc->page = page;
desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */
if (desc->error >= 0) {
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(VFS, "NFS: uncached_readdir() returns %d\n", 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_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;
lock_kernel();
res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
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 = &((struct nfs_open_context *)filp->private_data)->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;
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;
}
}
unlock_kernel();
if (res < 0)
return res;
return 0;
}
loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int origin)
{
mutex_lock(&filp->f_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;
((struct nfs_open_context *)filp->private_data)->dir_cookie = 0;
}
out:
mutex_unlock(&filp->f_dentry->d_inode->i_mutex);
return offset;
}
/*
* All directory operations under NFS are synchronous, so fsync()
* is a dummy operation.
*/
int nfs_fsync_dir(struct file *filp, struct dentry *dentry, int 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 inline int nfs_check_verifier(struct inode *dir, struct dentry *dentry)
{
if (IS_ROOT(dentry))
return 1;
if ((NFS_I(dir)->cache_validity & NFS_INO_INVALID_ATTR) != 0
|| nfs_attribute_timeout(dir))
return 0;
return nfs_verify_change_attribute(dir, (unsigned long)dentry->d_fsdata);
}
static inline void nfs_set_verifier(struct dentry * dentry, unsigned long verf)
{
dentry->d_fsdata = (void *)verf;
}
/*
* Whenever an NFS operation succeeds, we know that the dentry
* is valid, so we update the revalidation timestamp.
*/
static inline void nfs_renew_times(struct dentry * dentry)
{
dentry->d_time = jiffies;
}
/*
* 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;
}
/*
* 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))
goto out_force;
}
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;
unsigned long verifier;
parent = dget_parent(dentry);
lock_kernel();
dir = parent->d_inode;
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(VFS, "nfs_lookup_validate: %s/%s has dud inode\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
goto out_bad;
}
/* Revalidate parent directory attribute cache */
if (nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0)
goto out_zap_parent;
/* Force a full look up iff the parent directory has changed */
if (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;
verifier = nfs_save_change_attribute(dir);
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_renew_times(dentry);
nfs_set_verifier(dentry, verifier);
out_valid:
unlock_kernel();
dput(parent);
return 1;
out_zap_parent:
nfs_zap_caches(dir);
out_bad:
NFS_CACHEINV(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);
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 (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
lock_kernel();
inode->i_nlink--;
nfs_complete_unlink(dentry);
unlock_kernel();
}
/* When creating a negative dentry, we want to renew d_time */
nfs_renew_times(dentry);
iput(inode);
}
struct dentry_operations nfs_dentry_operations = {
.d_revalidate = nfs_lookup_revalidate,
.d_delete = nfs_dentry_delete,
.d_iput = nfs_dentry_iput,
};
/*
* Use intent information to check whether or not we're going to do
* an O_EXCL create using this path component.
*/
static inline
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;
}
static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
{
struct dentry *res;
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);
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 */
if (nfs_is_exclusive_create(dir, nd))
goto no_entry;
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_unlock;
}
res = ERR_PTR(-EACCES);
inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr);
if (!inode)
goto out_unlock;
no_entry:
res = d_add_unique(dentry, inode);
if (res != NULL)
dentry = res;
nfs_renew_times(dentry);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
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;
/* 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 */
if (nd->intent.open.flags & O_EXCL) {
d_add(dentry, NULL);
goto out;
}
/* Open the file on the server */
lock_kernel();
/* Revalidate parent directory attribute cache */
error = nfs_revalidate_inode(NFS_SERVER(dir), dir);
if (error < 0) {
res = ERR_PTR(error);
unlock_kernel();
goto out;
}
if (nd->intent.open.flags & O_CREAT) {
nfs_begin_data_update(dir);
res = nfs4_atomic_open(dir, dentry, nd);
nfs_end_data_update(dir);
} else
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;
nfs_renew_times(dentry);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
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;
unsigned long verifier;
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)
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();
verifier = nfs_save_change_attribute(dir);
ret = nfs4_open_revalidate(dir, dentry, openflags, nd);
if (!ret)
nfs_set_verifier(dentry, verifier);
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_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;
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);
}
name.hash = full_name_hash(name.name, name.len);
dentry = d_lookup(parent, &name);
if (dentry != NULL)
return dentry;
if (!desc->plus || !(entry->fattr->valid & NFS_ATTR_FATTR))
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 (!inode) {
dput(dentry);
return NULL;
}
alias = d_add_unique(dentry, inode);
if (alias != NULL) {
dput(dentry);
dentry = alias;
}
nfs_renew_times(dentry);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
return dentry;
}
/*
* Code common to create, mkdir, and mknod.
*/
int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle,
struct nfs_fattr *fattr)
{
struct inode *inode;
int error = -EACCES;
/* We may have been initialized further down */
if (dentry->d_inode)
return 0;
if (fhandle->size == 0) {
struct inode *dir = dentry->d_parent->d_inode;
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
if (error)
goto out_err;
}
if (!(fattr->valid & NFS_ATTR_FATTR)) {
struct nfs_server *server = NFS_SB(dentry->d_sb);
error = server->rpc_ops->getattr(server, fhandle, fattr);
if (error < 0)
goto out_err;
}
error = -ENOMEM;
inode = nfs_fhget(dentry->d_sb, fhandle, fattr);
if (inode == NULL)
goto out_err;
d_instantiate(dentry, inode);
return 0;
out_err:
d_drop(dentry);
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 && (nd->flags & LOOKUP_CREATE))
open_flags = nd->intent.open.flags;
lock_kernel();
nfs_begin_data_update(dir);
error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags, nd);
nfs_end_data_update(dir);
if (error != 0)
goto out_err;
nfs_renew_times(dentry);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
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();
nfs_begin_data_update(dir);
status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev);
nfs_end_data_update(dir);
if (status != 0)
goto out_err;
nfs_renew_times(dentry);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
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();
nfs_begin_data_update(dir);
error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr);
nfs_end_data_update(dir);
if (error != 0)
goto out_err;
nfs_renew_times(dentry);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
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();
nfs_begin_data_update(dir);
error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
/* Ensure the VFS deletes this inode */
if (error == 0 && dentry->d_inode != NULL)
dentry->d_inode->i_nlink = 0;
nfs_end_data_update(dir);
unlock_kernel();
return error;
}
static int nfs_sillyrename(struct inode *dir, struct dentry *dentry)
{
static unsigned int sillycounter;
const int i_inosize = sizeof(dir->i_ino)*2;
const int countersize = sizeof(sillycounter)*2;
const int slen = sizeof(".nfs") + i_inosize + 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));
#ifdef NFS_PARANOIA
if (!dentry->d_inode)
printk("NFS: silly-renaming %s/%s, negative dentry??\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
#endif
/*
* 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",
i_inosize, i_inosize, dentry->d_inode->i_ino);
/* 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, "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);
nfs_begin_data_update(dir);
if (dentry->d_inode) {
nfs_begin_data_update(dentry->d_inode);
error = NFS_PROTO(dir)->rename(dir, &dentry->d_name,
dir, &qsilly);
nfs_mark_for_revalidate(dentry->d_inode);
nfs_end_data_update(dentry->d_inode);
} else
error = NFS_PROTO(dir)->rename(dir, &dentry->d_name,
dir, &qsilly);
nfs_end_data_update(dir);
if (!error) {
nfs_renew_times(dentry);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
d_move(dentry, sdentry);
error = nfs_async_unlink(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;
}
nfs_begin_data_update(dir);
if (inode != NULL) {
nfs_inode_return_delegation(inode);
nfs_begin_data_update(inode);
error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
/* The VFS may want to delete this inode */
if (error == 0)
inode->i_nlink--;
nfs_mark_for_revalidate(inode);
nfs_end_data_update(inode);
} else
error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
nfs_end_data_update(dir);
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);
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_renew_times(dentry);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
} else if (need_rehash)
d_rehash(dentry);
unlock_kernel();
return error;
}
static int
nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
{
struct iattr attr;
struct nfs_fattr sym_attr;
struct nfs_fh sym_fh;
struct qstr qsymname;
int error;
dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id,
dir->i_ino, dentry->d_name.name, symname);
#ifdef NFS_PARANOIA
if (dentry->d_inode)
printk("nfs_proc_symlink: %s/%s not negative!\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
#endif
/*
* Fill in the sattr for the call.
* Note: SunOS 4.1.2 crashes if the mode isn't initialized!
*/
attr.ia_valid = ATTR_MODE;
attr.ia_mode = S_IFLNK | S_IRWXUGO;
qsymname.name = symname;
qsymname.len = strlen(symname);
lock_kernel();
nfs_begin_data_update(dir);
error = NFS_PROTO(dir)->symlink(dir, &dentry->d_name, &qsymname,
&attr, &sym_fh, &sym_attr);
nfs_end_data_update(dir);
if (!error) {
error = nfs_instantiate(dentry, &sym_fh, &sym_attr);
} else {
if (error == -EEXIST)
printk("nfs_proc_symlink: %s/%s already exists??\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
d_drop(dentry);
}
unlock_kernel();
return error;
}
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();
nfs_begin_data_update(dir);
nfs_begin_data_update(inode);
error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
if (error == 0) {
atomic_inc(&inode->i_count);
d_instantiate(dentry, inode);
}
nfs_end_data_update(inode);
nfs_end_data_update(dir);
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? */
#ifdef NFS_PARANOIA
printk("nfs_rename: target %s/%s busy, d_count=%d\n",
new_dentry->d_parent->d_name.name,
new_dentry->d_name.name,
atomic_read(&new_dentry->d_count));
#endif
goto out;
}
} else
new_inode->i_nlink--;
go_ahead:
/*
* ... prune child dentries and writebacks if needed.
*/
if (atomic_read(&old_dentry->d_count) > 1) {
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);
}
nfs_begin_data_update(old_dir);
nfs_begin_data_update(new_dir);
nfs_begin_data_update(old_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);
nfs_end_data_update(old_inode);
nfs_end_data_update(new_dir);
nfs_end_data_update(old_dir);
out:
if (rehash)
d_rehash(rehash);
if (!error) {
if (!S_ISDIR(old_inode->i_mode))
d_move(old_dentry, new_dentry);
nfs_renew_times(new_dentry);
nfs_set_verifier(new_dentry, nfs_save_change_attribute(new_dir));
}
/* new dentry created? */
if (dentry)
dput(dentry);
unlock_kernel();
return error;
}
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 = &nfsi->cache_access;
if (cache->cred != cred
|| time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode))
|| (nfsi->cache_validity & NFS_INO_INVALID_ACCESS))
return -ENOENT;
memcpy(res, cache, sizeof(*res));
return 0;
}
void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_access_entry *cache = &nfsi->cache_access;
if (cache->cred != set->cred) {
if (cache->cred)
put_rpccred(cache->cred);
cache->cred = get_rpccred(set->cred);
}
/* FIXME: replace current access_cache BKL reliance with inode->i_lock */
spin_lock(&inode->i_lock);
nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS;
spin_unlock(&inode->i_lock);
cache->jiffies = set->jiffies;
cache->mask = set->mask;
}
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;
}
int nfs_permission(struct inode *inode, int mask, struct nameidata *nd)
{
struct rpc_cred *cred;
int res = 0;
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:
return res;
out_notsup:
res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
if (res == 0)
res = generic_permission(inode, mask, NULL);
unlock_kernel();
return res;
}
/*
* Local variables:
* version-control: t
* kept-new-versions: 5
* End:
*/
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