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);
error = 0;
}
nfs_renew_times(dentry);
}
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;
/* We may have been initialized further down */
if (dentry->d_inode)
return 0;
if (fhandle->size == 0 || !(fattr->valid & NFS_ATTR_FATTR)) {
struct inode *dir = dentry->d_parent->d_inode;
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
if (error)
goto out_err;
}
inode = nfs_fhget(dentry->d_sb, fhandle, fattr);
if (inode) {
d_instantiate(dentry, inode);
nfs_renew_times(dentry);
nfs_set_verifier(dentry, nfs_save_change_attribute(dentry->d_parent->d_inode));
return 0;
}
error = -ENOMEM;
out_err:
d_drop(dentry);
return error;
}
/*
* 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, 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 (!inode) {
if (nfs_neg_need_reval(dir, 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;
}
/* Force a full look up iff the parent directory has changed */
if (nfs_check_verifier(dir, dentry)) {
if (nfs_lookup_verify_inode(inode, flags))
goto out_bad;
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 (memcmp(NFS_FH(inode), &fhandle, sizeof(struct nfs_fh))!= 0)
goto out_bad;
if ((error = nfs_refresh_inode(inode, &fattr)) != 0)
goto out_bad;
nfs_renew_times(dentry);
out_valid:
unlock_kernel();
return 1;
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();
return 0;
}
/* 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 struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
{
struct inode *inode = NULL;
int error = 0;
/* 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) {
error = -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)
goto no_entry;
/* Open the file on the server */
lock_kernel();
/* Revalidate parent directory attribute cache */
nfs_revalidate_inode(NFS_SERVER(dir), dir);
if (nd->intent.open.flags & O_CREAT) {
nfs_begin_data_update(dir);
inode = nfs4_atomic_open(dir, dentry, nd);
nfs_end_data_update(dir);
} else
inode = nfs4_atomic_open(dir, dentry, nd);
unlock_kernel();
if (IS_ERR(inode)) {
error = PTR_ERR(inode);
switch (error) {
/* Make a negative dentry */
case -ENOENT:
inode = NULL;
break;
/* This turned out not to be a regular file */
case -ELOOP:
if (!(nd->intent.open.flags & O_NOFOLLOW))
goto no_open;
/* case -EISDIR: */
/* case -EINVAL: */
default:
goto out;
}
}
no_entry:
d_add(dentry, inode);
nfs_renew_times(dentry);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
out:
BUG_ON(error > 0);
return ERR_PTR(error);
no_open:
return nfs_lookup(dir, dentry, nd);
}
/*
* 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();
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);
}
static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
{
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);
error = -ENAMETOOLONG;
if (dentry->d_name.len > NFS_SERVER(dir)->namelen)
goto out;
error = -ENOMEM;
dentry->d_op = NFS_PROTO(dir)->dentry_ops;
lock_kernel();
/* Revalidate parent directory attribute cache */
nfs_revalidate_inode(NFS_SERVER(dir), dir);
/* If we're doing an exclusive create, optimize away the lookup */
if (nfs_is_exclusive_create(dir, nd))
goto no_entry;
error = nfs_cached_lookup(dir, dentry, &fhandle, &fattr);
if (error != 0) {
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name,
&fhandle, &fattr);
if (error == -ENOENT)
goto no_entry;
if (error != 0)
goto out_unlock;
}
error = -EACCES;
inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr);
if (!inode)
goto out_unlock;
no_entry:
error = 0;
d_add(dentry, inode);
nfs_renew_times(dentry);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
out_unlock:
unlock_kernel();
out:
BUG_ON(error > 0);
return ERR_PTR(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;
}
/*
* 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;
struct inode *inode;
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;
/*
* 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.
*/
lock_kernel();
nfs_begin_data_update(dir);
inode = NFS_PROTO(dir)->create(dir, &dentry->d_name, &attr, open_flags);
nfs_end_data_update(dir);
if (!IS_ERR(inode)) {
d_instantiate(dentry, inode);
nfs_renew_times(dentry);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
error = 0;
} else {
error = PTR_ERR(inode);
d_drop(dentry);
}
unlock_kernel();
return 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;
if (fhandle->size == 0 || !(fattr->valid & NFS_ATTR_FATTR)) {
struct inode *dir = dentry->d_parent->d_inode;
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
if (error)
goto out_err;
}
inode = nfs_fhget(dentry, fhandle, fattr);
if (inode) {
d_instantiate(dentry, inode);
nfs_renew_times(dentry);
error = 0;
}
return error;
out_err:
d_drop(dentry);
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;
}
/*
* 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;
int isopen = 0;
parent = dget_parent(dentry);
lock_kernel();
dir = parent->d_inode;
inode = dentry->d_inode;
if (nd && !(nd->flags & LOOKUP_CONTINUE) && (nd->flags & LOOKUP_OPEN))
isopen = 1;
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 */
nfs_revalidate_inode(NFS_SERVER(dir), dir);
/* Force a full look up iff the parent directory has changed */
if (nfs_check_verifier(dir, dentry)) {
if (nfs_lookup_verify_inode(inode, isopen))
goto out_zap_parent;
goto out_valid;
}
/*
* Note: we're not holding inode->i_sem and so may be racing with
* operations that change the directory. We therefore save the
* change attribute *before* we do the RPC call.
*/
verifier = nfs_save_change_attribute(dir);
error = nfs_cached_lookup(dir, dentry, &fhandle, &fattr);
if (!error) {
if (memcmp(NFS_FH(inode), &fhandle, sizeof(struct nfs_fh))!= 0)
goto out_bad;
if (nfs_lookup_verify_inode(inode, isopen))
goto out_zap_parent;
goto out_valid_renew;
}
if (NFS_STALE(inode))
goto out_bad;
error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
if (error)
goto out_bad;
if (memcmp(NFS_FH(inode), &fhandle, sizeof(struct nfs_fh))!= 0)
goto out_bad;
if ((error = nfs_refresh_inode(inode, &fattr)) != 0)
goto out_bad;
out_valid_renew:
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;
}
/*
* 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))
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_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_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;
}
