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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/sched.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>
#define NFS_PARANOIA 1
/* #define NFS_DEBUG_VERBOSE 1 */
static int nfs_readdir(struct file *, void *, filldir_t);
static struct dentry *nfs_lookup(struct inode *, struct dentry *);
static int nfs_create(struct inode *, struct dentry *, int);
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, int);
static int nfs_rename(struct inode *, struct dentry *,
struct inode *, struct dentry *);
struct file_operations nfs_dir_operations = {
read: generic_read_dir,
readdir: nfs_readdir,
open: nfs_open,
release: nfs_release,
};
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,
revalidate: nfs_revalidate,
setattr: nfs_notify_change,
};
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 target;
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);
void *buffer = kmap(page);
int error;
dfprintk(VFS, "NFS: nfs_readdir_filler() reading cookie %Lu into page %lu.\n", (long long)desc->entry->cookie, page->index);
again:
error = NFS_PROTO(inode)->readdir(inode, cred, desc->entry->cookie, buffer,
NFS_SERVER(inode)->dtsize, desc->plus);
/* We requested READDIRPLUS, but the server doesn't grok it */
if (desc->plus && error == -ENOTSUPP) {
NFS_FLAGS(inode) &= ~NFS_INO_ADVISE_RDPLUS;
desc->plus = 0;
goto again;
}
if (error < 0)
goto error;
SetPageUptodate(page);
kunmap(page);
/* Ensure consistent page alignment of the data.
* Note: assumes we have exclusive access to this mapping either
* throught inode->i_sem or some other mechanism.
*/
if (page->index == 0)
invalidate_inode_pages(inode);
UnlockPage(page);
return 0;
error:
SetPageError(page);
kunmap(page);
UnlockPage(page);
invalidate_inode_pages(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.
*
* 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 page *page)
{
struct nfs_entry *entry = desc->entry;
int loop_count = 0,
status;
while((status = dir_decode(desc)) == 0) {
dfprintk(VFS, "NFS: found cookie %Lu\n", (long long)entry->cookie);
if (entry->prev_cookie == desc->target)
break;
if (loop_count++ > 200) {
loop_count = 0;
schedule();
}
}
dfprintk(VFS, "NFS: find_dirent() returns %d\n", status);
return status;
}
/*
* Find the given page, and call find_dirent() 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);
desc->plus = NFS_USE_READDIRPLUS(inode);
page = read_cache_page(&inode->i_data, desc->page_index,
(filler_t *)nfs_readdir_filler, desc);
if (IS_ERR(page)) {
status = PTR_ERR(page);
goto out;
}
if (!Page_Uptodate(page))
goto read_error;
/* NOTE: Someone else may have changed the READDIRPLUS flag */
desc->page = page;
desc->ptr = kmap(page);
status = find_dirent(desc, page);
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->target'.
*/
static inline
int readdir_search_pagecache(nfs_readdir_descriptor_t *desc)
{
int loop_count = 0;
int res;
dfprintk(VFS, "NFS: readdir_search_pagecache() searching for cookie %Lu\n", (long long)desc->target);
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;
}
/*
* 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;
unsigned long fileid;
int loop_count = 0,
res;
dfprintk(VFS, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n", (long long)desc->target);
for(;;) {
/* Note: entry->prev_cookie contains the cookie for
* retrieving the current dirent on the server */
fileid = nfs_fileid_to_ino_t(entry->ino);
res = filldir(dirent, entry->name, entry->len,
entry->prev_cookie, fileid, DT_UNKNOWN);
if (res < 0)
break;
file->f_pos = desc->target = entry->cookie;
if (dir_decode(desc) != 0) {
desc->page_index ++;
break;
}
if (loop_count++ > 200) {
loop_count = 0;
schedule();
}
}
dir_page_release(desc);
dfprintk(VFS, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", (long long)desc->target, 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", (long long)desc->target);
page = alloc_page(GFP_HIGHUSER);
if (!page) {
status = -ENOMEM;
goto out;
}
desc->page = page;
desc->ptr = kmap(page);
desc->error = NFS_PROTO(inode)->readdir(inode, cred, desc->target,
desc->ptr,
NFS_SERVER(inode)->dtsize,
desc->plus);
if (desc->error >= 0) {
if ((status = dir_decode(desc)) == 0)
desc->entry->prev_cookie = desc->target;
} 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;
memset(desc->entry, 0, sizeof(*desc->entry));
out:
dfprintk(VFS, "NFS: uncached_readdir() returns %d\n", status);
return status;
out_release:
dir_page_release(desc);
goto out;
}
/* The file offset position is now represented as a true offset into the
* page cache as is the case in most of the other filesystems.
*/
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;
long res;
res = nfs_revalidate(dentry);
if (res < 0)
return res;
/*
* filp->f_pos points to the file offset in the page cache.
* but if the cache has meanwhile been zapped, we need to
* read from the last dirent to revalidate f_pos
* itself.
*/
memset(desc, 0, sizeof(*desc));
memset(&my_entry, 0, sizeof(my_entry));
desc->file = filp;
desc->target = filp->f_pos;
desc->entry = &my_entry;
desc->decode = NFS_PROTO(inode)->decode_dirent;
while(!desc->entry->eof) {
res = readdir_search_pagecache(desc);
if (res == -EBADCOOKIE) {
/* This means either end of directory */
if (desc->entry->cookie != desc->target) {
/* Or that the server has 'lost' a cookie */
res = uncached_readdir(desc, dirent, filldir);
if (res >= 0)
continue;
}
res = 0;
break;
} else if (res < 0)
break;
res = nfs_do_filldir(desc, dirent, filldir);
if (res < 0) {
res = 0;
break;
}
}
if (desc->error < 0)
return desc->error;
if (res < 0)
return res;
return 0;
}
/*
* 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;
}
static inline int nfs_dentry_force_reval(struct dentry *dentry, int flags)
{
struct inode *inode = dentry->d_inode;
unsigned long timeout = NFS_ATTRTIMEO(inode);
/*
* If it's the last lookup in a series, we use a stricter
* cache consistency check by looking at the parent mtime.
*
* If it's been modified in the last hour, be really strict.
* (This still means that we can avoid doing unnecessary
* work on directories like /usr/share/bin etc which basically
* never change).
*/
if (!(flags & LOOKUP_CONTINUE)) {
long diff = CURRENT_TIME - dentry->d_parent->d_inode->i_mtime;
if (diff < 15*60)
timeout = 0;
}
return time_after(jiffies,dentry->d_time + timeout);
}
/*
* We judge how long we want to trust negative
* dentries by looking at the parent inode mtime.
*
* If mtime is close to present time, we revalidate
* more often.
*/
#define NFS_REVALIDATE_NEGATIVE (1 * HZ)
static inline int nfs_neg_need_reval(struct dentry *dentry)
{
struct inode *dir = dentry->d_parent->d_inode;
unsigned long timeout = NFS_ATTRTIMEO(dir);
long diff = CURRENT_TIME - dir->i_mtime;
if (diff < 5*60 && timeout > NFS_REVALIDATE_NEGATIVE)
timeout = NFS_REVALIDATE_NEGATIVE;
return time_after(jiffies, dentry->d_time + timeout);
}
/*
* 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 dentry is older than the revalidation interval,
* we do a new lookup and verify that the dentry is still
* correct.
*/
static int nfs_lookup_revalidate(struct dentry * dentry, int flags)
{
struct inode *dir;
struct inode *inode;
int error;
struct nfs_fh fhandle;
struct nfs_fattr fattr;
lock_kernel();
dir = dentry->d_parent->d_inode;
inode = dentry->d_inode;
/*
* If we don't have an inode, let's look at the parent
* directory mtime to get a hint about how often we
* should validate things..
*/
if (!inode) {
if (nfs_neg_need_reval(dentry))
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;
}
if (!nfs_dentry_force_reval(dentry, flags))
goto out_valid;
if (IS_ROOT(dentry)) {
__nfs_revalidate_inode(NFS_SERVER(inode), inode);
goto out_valid_renew;
}
/*
* Do a new lookup and check the dentry attributes.
*/
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
if (error)
goto out_bad;
/* Inode number matches? */
if (!(fattr.valid & NFS_ATTR_FATTR) ||
NFS_FSID(inode) != fattr.fsid ||
NFS_FILEID(inode) != fattr.fileid)
goto out_bad;
/* Ok, remember that we successfully checked it.. */
nfs_refresh_inode(inode, &fattr);
if (nfs_inode_is_stale(inode, &fhandle, &fattr))
goto out_bad;
out_valid_renew:
nfs_renew_times(dentry);
out_valid:
unlock_kernel();
return 1;
out_bad:
shrink_dcache_parent(dentry);
/* If we have submounts, don't unhash ! */
if (have_submounts(dentry))
goto out_valid;
d_drop(dentry);
/* Purge readdir caches. */
nfs_zap_caches(dir);
if (inode && S_ISDIR(inode->i_mode))
nfs_zap_caches(inode);
unlock_kernel();
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;
}
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)
{
if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
lock_kernel();
nfs_complete_unlink(dentry);
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 inode *inode;
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);
error = -ENAMETOOLONG;
if (dentry->d_name.len > NFS_SERVER(dir)->namelen)
goto out;
error = -ENOMEM;
dentry->d_op = &nfs_dentry_operations;
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
inode = NULL;
if (error == -ENOENT)
goto no_entry;
if (!error) {
error = -EACCES;
inode = nfs_fhget(dentry, &fhandle, &fattr);
if (inode) {
no_entry:
d_add(dentry, inode);
nfs_renew_times(dentry);
error = 0;
}
}
out:
return ERR_PTR(error);
}
/*
* Code common to create, mkdir, and mknod.
*/
static int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle,
struct nfs_fattr *fattr)
{
struct inode *inode;
int error = -EACCES;
inode = nfs_fhget(dentry, fhandle, fattr);
if (inode) {
d_instantiate(dentry, inode);
nfs_renew_times(dentry);
error = 0;
}
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 iattr attr;
struct nfs_fattr fattr;
struct nfs_fh fhandle;
int error;
dfprintk(VFS, "NFS: create(%x/%ld, %s\n",
dir->i_dev, dir->i_ino, dentry->d_name.name);
attr.ia_mode = mode;
attr.ia_valid = ATTR_MODE;
/*
* The 0 argument passed into the create function should one day
* contain the O_EXCL flag if requested. This allows NFSv3 to
* select the appropriate create strategy. Currently open_namei
* does not pass the create flags.
*/
nfs_zap_caches(dir);
error = NFS_PROTO(dir)->create(dir, &dentry->d_name,
&attr, 0, &fhandle, &fattr);
if (!error && fhandle.size != 0)
error = nfs_instantiate(dentry, &fhandle, &fattr);
if (error || fhandle.size == 0)
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, int rdev)
{
struct iattr attr;
struct nfs_fattr fattr;
struct nfs_fh fhandle;
int error;
dfprintk(VFS, "NFS: mknod(%x/%ld, %s\n",
dir->i_dev, dir->i_ino, dentry->d_name.name);
attr.ia_mode = mode;
attr.ia_valid = ATTR_MODE;
nfs_zap_caches(dir);
error = NFS_PROTO(dir)->mknod(dir, &dentry->d_name, &attr, rdev,
&fhandle, &fattr);
if (!error && fhandle.size != 0)
error = nfs_instantiate(dentry, &fhandle, &fattr);
if (error || fhandle.size == 0)
d_drop(dentry);
return error;
}
/*
* See comments for nfs_proc_create regarding failed operations.
*/
static int nfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
struct iattr attr;
struct nfs_fattr fattr;
struct nfs_fh fhandle;
int error;
dfprintk(VFS, "NFS: mkdir(%x/%ld, %s\n",
dir->i_dev, dir->i_ino, dentry->d_name.name);
attr.ia_valid = ATTR_MODE;
attr.ia_mode = mode | S_IFDIR;
#if 0
/*
* Always drop the dentry, we can't always depend on
* the fattr returned by the server (AIX seems to be
* broken). We're better off doing another lookup than
* depending on potentially bogus information.
*/
d_drop(dentry);
#endif
nfs_zap_caches(dir);
error = NFS_PROTO(dir)->mkdir(dir, &dentry->d_name, &attr, &fhandle,
&fattr);
if (!error && fhandle.size != 0)
error = nfs_instantiate(dentry, &fhandle, &fattr);
if (error || fhandle.size == 0)
d_drop(dentry);
return error;
}
static int nfs_rmdir(struct inode *dir, struct dentry *dentry)
{
int error;
dfprintk(VFS, "NFS: rmdir(%x/%ld, %s\n",
dir->i_dev, dir->i_ino, dentry->d_name.name);
nfs_zap_caches(dir);
error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
if (!error)
dentry->d_inode->i_nlink = 0;
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 = strlen(".nfs") + i_inosize + countersize;
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));
if (atomic_read(&dentry->d_count) == 1)
goto out; /* No need to silly rename. */
#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);
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 */
nfs_zap_caches(dir);
qsilly.name = silly;
qsilly.len = strlen(silly);
error = NFS_PROTO(dir)->rename(dir, &dentry->d_name, dir, &qsilly);
if (!error) {
nfs_renew_times(dentry);
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, rehash = 0;
dfprintk(VFS, "NFS: safe_remove(%s/%s)\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
/*
* Unhash the dentry while we remove the file ...
*/
if (!d_unhashed(dentry)) {
d_drop(dentry);
rehash = 1;
}
if (atomic_read(&dentry->d_count) > 1) {
#ifdef NFS_PARANOIA
printk("nfs_safe_remove: %s/%s busy, d_count=%d\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
atomic_read(&dentry->d_count));
#endif
goto out;
}
/* If the dentry was sillyrenamed, we simply call d_delete() */
if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
error = 0;
goto out_delete;
}
nfs_zap_caches(dir);
if (inode)
NFS_CACHEINV(inode);
error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
if (error < 0)
goto out;
if (inode)
inode->i_nlink--;
out_delete:
/*
* Free the inode
*/
d_delete(dentry);
out:
if (rehash)
d_rehash(dentry);
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;
dfprintk(VFS, "NFS: unlink(%x/%ld, %s)\n",
dir->i_dev, dir->i_ino, dentry->d_name.name);
error = nfs_sillyrename(dir, dentry);
if (error && error != -EBUSY) {
error = nfs_safe_remove(dentry);
if (!error) {
nfs_renew_times(dentry);
}
}
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;
unsigned int maxlen;
int error;
dfprintk(VFS, "NFS: symlink(%x/%ld, %s, %s)\n",
dir->i_dev, dir->i_ino, dentry->d_name.name, symname);
error = -ENAMETOOLONG;
maxlen = (NFS_PROTO(dir)->version==2) ? NFS2_MAXPATHLEN : NFS3_MAXPATHLEN;
if (strlen(symname) > maxlen)
goto out;
#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);
nfs_zap_caches(dir);
error = NFS_PROTO(dir)->symlink(dir, &dentry->d_name, &qsymname,
&attr, &sym_fh, &sym_attr);
if (!error && sym_fh.size != 0 && (sym_attr.valid & NFS_ATTR_FATTR)) {
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);
}
out:
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);
/*
* Drop the dentry in advance to force a new lookup.
* Since nfs_proc_link doesn't return a file handle,
* we can't use the existing dentry.
*/
d_drop(dentry);
nfs_zap_caches(dir);
NFS_CACHEINV(inode);
error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
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.
*/
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))
goto out;
else if (atomic_read(&new_dentry->d_count) > 1) {
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);
}
/* dentry still busy? */
if (atomic_read(&new_dentry->d_count) > 1) {
#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;
}
}
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);
}
if (new_inode)
d_delete(new_dentry);
nfs_zap_caches(new_dir);
nfs_zap_caches(old_dir);
error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name,
new_dir, &new_dentry->d_name);
out:
if (rehash)
d_rehash(rehash);
if (!error && !S_ISDIR(old_inode->i_mode))
d_move(old_dentry, new_dentry);
/* new dentry created? */
if (dentry)
dput(dentry);
return error;
}
int
nfs_permission(struct inode *inode, int mask)
{
int error = vfs_permission(inode, mask);
if (!NFS_PROTO(inode)->access)
goto out;
if (error == -EROFS)
goto out;
/*
* Trust UNIX mode bits except:
*
* 1) When override capabilities may have been invoked
* 2) When root squashing may be involved
* 3) When ACLs may overturn a negative answer */
if (!capable(CAP_DAC_OVERRIDE) && !capable(CAP_DAC_READ_SEARCH)
&& (current->fsuid != 0) && (current->fsgid != 0)
&& error != -EACCES)
goto out;
error = NFS_PROTO(inode)->access(inode, mask, 0);
if (error == -EACCES && NFS_CLIENT(inode)->cl_droppriv &&
current->uid != 0 && current->gid != 0 &&
(current->fsuid != current->uid || current->fsgid != current->gid))
error = NFS_PROTO(inode)->access(inode, mask, 1);
out:
return error;
}
/*
* Local variables:
* version-control: t
* kept-new-versions: 5
* End:
*/
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