NFS: add readdir cache array

This patch adds the readdir cache array and functions to retreive the array
stored on a cache page, clear the array by freeing allocated memory, add an
entry to the array, and search the array for a given cookie.

It then modifies readdir to make use of the new cache array.
With the new cache array method, we no longer need some of this code.

Finally, nfs_llseek_dir() will set file->f_pos to a value greater than 0 and
desc->dir_cookie to zero.  When we see this, readdir needs to find the file
at position file->f_pos from the start of the directory.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Bryan Schumaker 2010-09-24 14:48:42 -04:00 committed by Trond Myklebust
parent 8c7597f6ce
commit d1bacf9eb2

View File

@ -55,6 +55,7 @@ static int nfs_rename(struct inode *, struct dentry *,
struct inode *, struct dentry *);
static int nfs_fsync_dir(struct file *, int);
static loff_t nfs_llseek_dir(struct file *, loff_t, int);
static int nfs_readdir_clear_array(struct page*, gfp_t);
const struct file_operations nfs_dir_operations = {
.llseek = nfs_llseek_dir,
@ -80,6 +81,10 @@ const struct inode_operations nfs_dir_inode_operations = {
.setattr = nfs_setattr,
};
const struct address_space_operations nfs_dir_addr_space_ops = {
.releasepage = nfs_readdir_clear_array,
};
#ifdef CONFIG_NFS_V3
const struct inode_operations nfs3_dir_inode_operations = {
.create = nfs_create,
@ -151,51 +156,188 @@ nfs_opendir(struct inode *inode, struct file *filp)
return res;
}
struct nfs_cache_array_entry {
u64 cookie;
u64 ino;
struct qstr string;
};
struct nfs_cache_array {
unsigned int size;
int eof_index;
u64 last_cookie;
struct nfs_cache_array_entry array[0];
};
#define MAX_READDIR_ARRAY ((PAGE_SIZE - sizeof(struct nfs_cache_array)) / sizeof(struct nfs_cache_array_entry))
typedef __be32 * (*decode_dirent_t)(__be32 *, struct nfs_entry *, int);
typedef struct {
struct file *file;
struct page *page;
unsigned long page_index;
__be32 *ptr;
u64 *dir_cookie;
loff_t current_index;
struct nfs_entry *entry;
decode_dirent_t decode;
int plus;
unsigned long timestamp;
unsigned long gencount;
int timestamp_valid;
unsigned int cache_entry_index;
unsigned int plus:1;
unsigned int eof:1;
} 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.
/*
* The caller is responsible for calling nfs_readdir_release_array(page)
*/
static
int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page)
struct nfs_cache_array *nfs_readdir_get_array(struct page *page)
{
if (page == NULL)
return ERR_PTR(-EIO);
return (struct nfs_cache_array *)kmap(page);
}
static
void nfs_readdir_release_array(struct page *page)
{
kunmap(page);
}
/*
* we are freeing strings created by nfs_add_to_readdir_array()
*/
static
int nfs_readdir_clear_array(struct page *page, gfp_t mask)
{
struct nfs_cache_array *array = nfs_readdir_get_array(page);
int i;
for (i = 0; i < array->size; i++)
kfree(array->array[i].string.name);
nfs_readdir_release_array(page);
return 0;
}
/*
* the caller is responsible for freeing qstr.name
* when called by nfs_readdir_add_to_array, the strings will be freed in
* nfs_clear_readdir_array()
*/
static
void nfs_readdir_make_qstr(struct qstr *string, const char *name, unsigned int len)
{
string->len = len;
string->name = kmemdup(name, len, GFP_KERNEL);
string->hash = full_name_hash(string->name, string->len);
}
static
int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
{
struct nfs_cache_array *array = nfs_readdir_get_array(page);
if (IS_ERR(array))
return PTR_ERR(array);
if (array->size >= MAX_READDIR_ARRAY) {
nfs_readdir_release_array(page);
return -EIO;
}
array->array[array->size].cookie = entry->prev_cookie;
array->last_cookie = entry->cookie;
array->array[array->size].ino = entry->ino;
nfs_readdir_make_qstr(&array->array[array->size].string, entry->name, entry->len);
if (entry->eof == 1)
array->eof_index = array->size;
array->size++;
nfs_readdir_release_array(page);
return 0;
}
static
int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc)
{
loff_t diff = desc->file->f_pos - desc->current_index;
unsigned int index;
if (diff < 0)
goto out_eof;
if (diff >= array->size) {
if (array->eof_index > 0)
goto out_eof;
desc->current_index += array->size;
return -EAGAIN;
}
index = (unsigned int)diff;
*desc->dir_cookie = array->array[index].cookie;
desc->cache_entry_index = index;
if (index == array->eof_index)
desc->eof = 1;
return 0;
out_eof:
desc->eof = 1;
return -EBADCOOKIE;
}
static
int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc)
{
int i;
int status = -EAGAIN;
for (i = 0; i < array->size; i++) {
if (i == array->eof_index) {
desc->eof = 1;
status = -EBADCOOKIE;
}
if (array->array[i].cookie == *desc->dir_cookie) {
desc->cache_entry_index = i;
status = 0;
break;
}
}
return status;
}
static
int nfs_readdir_search_array(nfs_readdir_descriptor_t *desc)
{
struct nfs_cache_array *array;
int status = -EBADCOOKIE;
if (desc->dir_cookie == NULL)
goto out;
array = nfs_readdir_get_array(desc->page);
if (IS_ERR(array)) {
status = PTR_ERR(array);
goto out;
}
if (*desc->dir_cookie == 0)
status = nfs_readdir_search_for_pos(array, desc);
else
status = nfs_readdir_search_for_cookie(array, desc);
nfs_readdir_release_array(desc->page);
out:
return status;
}
/* Fill a page with xdr information before transferring to the cache page */
static
int nfs_readdir_xdr_filler(struct page *xdr_page, nfs_readdir_descriptor_t *desc,
struct nfs_entry *entry, struct file *file, struct inode *inode)
{
struct file *file = desc->file;
struct inode *inode = file->f_path.dentry->d_inode;
struct rpc_cred *cred = nfs_file_cred(file);
unsigned long timestamp, gencount;
int error;
dfprintk(DIRCACHE, "NFS: %s: reading cookie %Lu into page %lu\n",
__func__, (long long)desc->entry->cookie,
page->index);
again:
timestamp = jiffies;
gencount = nfs_inc_attr_generation_counter();
error = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred, desc->entry->cookie, page,
error = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred, entry->cookie, xdr_page,
NFS_SERVER(inode)->dtsize, desc->plus);
if (error < 0) {
/* We requested READDIRPLUS, but the server doesn't grok it */
@ -209,12 +351,93 @@ int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page)
}
desc->timestamp = timestamp;
desc->gencount = gencount;
desc->timestamp_valid = 1;
error:
return error;
}
/* Fill in an entry based on the xdr code stored in desc->page */
static
int xdr_decode(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry, __be32 **ptr)
{
__be32 *p = *ptr;
p = desc->decode(p, entry, desc->plus);
if (IS_ERR(p))
return PTR_ERR(p);
*ptr = p;
entry->fattr->time_start = desc->timestamp;
entry->fattr->gencount = desc->gencount;
return 0;
}
/* Perform conversion from xdr to cache array */
static
void nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry,
struct page *xdr_page, struct page *page)
{
__be32 *ptr = kmap(xdr_page);
while (xdr_decode(desc, entry, &ptr) == 0) {
if (nfs_readdir_add_to_array(entry, page) == -1)
break;
}
kunmap(xdr_page);
}
static
int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, struct inode *inode)
{
struct page *xdr_page;
struct nfs_entry entry;
struct file *file = desc->file;
struct nfs_cache_array *array;
int status = 0;
entry.prev_cookie = 0;
entry.cookie = *desc->dir_cookie;
entry.eof = 0;
entry.fh = nfs_alloc_fhandle();
entry.fattr = nfs_alloc_fattr();
if (entry.fh == NULL || entry.fattr == NULL)
goto out;
array = nfs_readdir_get_array(page);
memset(array, 0, sizeof(struct nfs_cache_array));
array->eof_index = -1;
xdr_page = alloc_page(GFP_KERNEL);
if (!xdr_page)
goto out_release_array;
do {
status = nfs_readdir_xdr_filler(xdr_page, desc, &entry, file, inode);
if (status < 0)
break;
nfs_readdir_page_filler(desc, &entry, xdr_page, page);
} while (array->eof_index < 0 && array->size < MAX_READDIR_ARRAY);
put_page(xdr_page);
out_release_array:
nfs_readdir_release_array(page);
out:
nfs_free_fattr(entry.fattr);
nfs_free_fhandle(entry.fh);
return status;
}
/*
* Now we cache directories properly, by converting xdr information
* to an array that can be used for lookups later. This results in
* fewer cache pages, since we can store more information on each page.
* We only need to convert from xdr once so future lookups are much simpler
*/
static
int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page* page)
{
struct inode *inode = desc->file->f_path.dentry->d_inode;
if (nfs_readdir_xdr_to_array(desc, page, inode) == -1)
goto error;
SetPageUptodate(page);
/* Ensure consistent page alignment of the data.
* Note: assumes we have exclusive access to this mapping either
* through inode->i_mutex or some other mechanism.
*/
if (invalidate_inode_pages2_range(inode->i_mapping, page->index + 1, -1) < 0) {
/* Should never happen */
nfs_zap_mapping(inode, inode->i_mapping);
@ -226,173 +449,59 @@ int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page)
return -EIO;
}
static inline
int dir_decode(nfs_readdir_descriptor_t *desc)
static
void cache_page_release(nfs_readdir_descriptor_t *desc)
{
__be32 *p = desc->ptr;
p = desc->decode(p, desc->entry, desc->plus);
if (IS_ERR(p))
return PTR_ERR(p);
desc->ptr = p;
if (desc->timestamp_valid) {
desc->entry->fattr->time_start = desc->timestamp;
desc->entry->fattr->gencount = desc->gencount;
} else
desc->entry->fattr->valid &= ~NFS_ATTR_FATTR;
return 0;
}
static inline
void dir_page_release(nfs_readdir_descriptor_t *desc)
{
kunmap(desc->page);
page_cache_release(desc->page);
desc->page = NULL;
desc->ptr = NULL;
}
/*
* Given a pointer to a buffer that has already been filled by a call
* to readdir, find the next entry with cookie '*desc->dir_cookie'.
*
* If the end of the buffer has been reached, return -EAGAIN, if not,
* return the offset within the buffer of the next entry to be
* read.
*/
static inline
int find_dirent(nfs_readdir_descriptor_t *desc)
static
struct page *get_cache_page(nfs_readdir_descriptor_t *desc)
{
struct nfs_entry *entry = desc->entry;
int loop_count = 0,
status;
while((status = dir_decode(desc)) == 0) {
dfprintk(DIRCACHE, "NFS: %s: examining cookie %Lu\n",
__func__, (unsigned long long)entry->cookie);
if (entry->prev_cookie == *desc->dir_cookie)
break;
if (loop_count++ > 200) {
loop_count = 0;
schedule();
}
}
return status;
struct page *page;
page = read_cache_page(desc->file->f_path.dentry->d_inode->i_mapping,
desc->page_index, (filler_t *)nfs_readdir_filler, desc);
if (IS_ERR(page))
desc->eof = 1;
return page;
}
/*
* 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.
* Returns 0 if desc->dir_cookie was found on page desc->page_index
*/
static inline
int find_dirent_index(nfs_readdir_descriptor_t *desc)
static
int find_cache_page(nfs_readdir_descriptor_t *desc)
{
struct nfs_entry *entry = desc->entry;
int loop_count = 0,
status;
int res;
for(;;) {
status = dir_decode(desc);
if (status)
break;
desc->page = get_cache_page(desc);
if (IS_ERR(desc->page))
return PTR_ERR(desc->page);
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;
res = nfs_readdir_search_array(desc);
if (res == 0)
return 0;
cache_page_release(desc);
return res;
}
/*
* Find the given page, and call find_dirent() or find_dirent_index in
* order to try to return the next entry.
*/
static inline
int find_dirent_page(nfs_readdir_descriptor_t *desc)
{
struct inode *inode = desc->file->f_path.dentry->d_inode;
struct page *page;
int status;
dfprintk(DIRCACHE, "NFS: %s: searching page %ld for target %Lu\n",
__func__, desc->page_index,
(long long) *desc->dir_cookie);
/* If we find the page in the page_cache, we cannot be sure
* how fresh the data is, so we will ignore readdir_plus attributes.
*/
desc->timestamp_valid = 0;
page = read_cache_page(inode->i_mapping, desc->page_index,
(filler_t *)nfs_readdir_filler, desc);
if (IS_ERR(page)) {
status = PTR_ERR(page);
goto out;
}
/* NOTE: Someone else may have changed the READDIRPLUS flag */
desc->page = page;
desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */
if (*desc->dir_cookie != 0)
status = find_dirent(desc);
else
status = find_dirent_index(desc);
if (status < 0)
dir_page_release(desc);
out:
dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __func__, status);
return status;
}
/*
* Recurse through the page cache pages, and return a
* filled nfs_entry structure of the next directory entry if possible.
*
* The target for the search is '*desc->dir_cookie' if non-0,
* 'desc->file->f_pos' otherwise
*/
/* Search for desc->dir_cookie from the beginning of the page cache */
static inline
int readdir_search_pagecache(nfs_readdir_descriptor_t *desc)
{
int loop_count = 0;
int res;
int res = -EAGAIN;
desc->page_index = 0;
/* 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);
if (*desc->dir_cookie == 0)
desc->cache_entry_index = 0;
for (;;) {
res = find_dirent_page(desc);
while (1) {
res = find_cache_page(desc);
if (res != -EAGAIN)
break;
/* Align to beginning of next page */
desc->page_index ++;
if (loop_count++ > 200) {
loop_count = 0;
schedule();
}
desc->page_index++;
}
dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __func__, res);
return res;
}
@ -401,8 +510,6 @@ 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...
*/
@ -411,49 +518,36 @@ 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;
int i = 0;
int res = 0;
struct nfs_cache_array *array = NULL;
unsigned int d_type = DT_UNKNOWN;
struct dentry *dentry = NULL;
dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n",
(unsigned long long)entry->cookie);
array = nfs_readdir_get_array(desc->page);
for(;;) {
unsigned d_type = DT_UNKNOWN;
/* Note: entry->prev_cookie contains the cookie for
* retrieving the current dirent on the server */
fileid = entry->ino;
for (i = desc->cache_entry_index; i < array->size; i++) {
d_type = DT_UNKNOWN;
/* 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);
res = filldir(dirent, array->array[i].string.name,
array->array[i].string.len, file->f_pos,
nfs_compat_user_ino64(array->array[i].ino), d_type);
if (res < 0)
break;
file->f_pos++;
*desc->dir_cookie = entry->cookie;
if (dir_decode(desc) != 0) {
desc->page_index ++;
desc->cache_entry_index = i;
if (i < (array->size-1))
*desc->dir_cookie = array->array[i+1].cookie;
else
*desc->dir_cookie = array->last_cookie;
if (i == array->eof_index) {
desc->eof = 1;
break;
}
if (loop_count++ > 200) {
loop_count = 0;
schedule();
}
}
dir_page_release(desc);
nfs_readdir_release_array(desc->page);
cache_page_release(desc);
if (dentry != NULL)
dput(dentry);
dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n",
@ -477,12 +571,9 @@ static inline
int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent,
filldir_t filldir)
{
struct file *file = desc->file;
struct inode *inode = file->f_path.dentry->d_inode;
struct rpc_cred *cred = nfs_file_cred(file);
struct page *page = NULL;
int status;
unsigned long timestamp, gencount;
struct inode *inode = desc->file->f_path.dentry->d_inode;
dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n",
(unsigned long long)*desc->dir_cookie);
@ -492,38 +583,21 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent,
status = -ENOMEM;
goto out;
}
timestamp = jiffies;
gencount = nfs_inc_attr_generation_counter();
status = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred,
*desc->dir_cookie, page,
NFS_SERVER(inode)->dtsize,
desc->plus);
desc->page = page;
desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */
if (status >= 0) {
desc->timestamp = timestamp;
desc->gencount = gencount;
desc->timestamp_valid = 1;
if ((status = dir_decode(desc)) == 0)
desc->entry->prev_cookie = *desc->dir_cookie;
} else
status = -EIO;
if (status < 0)
goto out_release;
if (nfs_readdir_xdr_to_array(desc, page, inode) == -1) {
status = -EIO;
goto out_release;
}
desc->page = page;
status = nfs_do_filldir(desc, dirent, filldir);
/* Reset read descriptor so it searches the page cache from
* the start upon the next call to readdir_search_pagecache() */
desc->page_index = 0;
desc->entry->cookie = desc->entry->prev_cookie = 0;
desc->entry->eof = 0;
out:
dfprintk(DIRCACHE, "NFS: %s: returns %d\n",
__func__, status);
return status;
out_release:
dir_page_release(desc);
cache_page_release(desc);
goto out;
}
@ -537,7 +611,6 @@ static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
struct inode *inode = dentry->d_inode;
nfs_readdir_descriptor_t my_desc,
*desc = &my_desc;
struct nfs_entry my_entry;
int res = -ENOMEM;
dfprintk(FILE, "NFS: readdir(%s/%s) starting at cookie %llu\n",
@ -558,26 +631,17 @@ static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
desc->decode = NFS_PROTO(inode)->decode_dirent;
desc->plus = NFS_USE_READDIRPLUS(inode);
my_entry.cookie = my_entry.prev_cookie = 0;
my_entry.eof = 0;
my_entry.fh = nfs_alloc_fhandle();
my_entry.fattr = nfs_alloc_fattr();
if (my_entry.fh == NULL || my_entry.fattr == NULL)
goto out_alloc_failed;
desc->entry = &my_entry;
nfs_block_sillyrename(dentry);
res = nfs_revalidate_mapping(inode, filp->f_mapping);
if (res < 0)
goto out;
while(!desc->entry->eof) {
while (desc->eof != 1) {
res = readdir_search_pagecache(desc);
if (res == -EBADCOOKIE) {
/* This means either end of directory */
if (*desc->dir_cookie && desc->entry->cookie != *desc->dir_cookie) {
if (*desc->dir_cookie && desc->eof == 0) {
/* Or that the server has 'lost' a cookie */
res = uncached_readdir(desc, dirent, filldir);
if (res >= 0)
@ -590,7 +654,7 @@ static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
nfs_zap_caches(inode);
desc->plus = 0;
desc->entry->eof = 0;
desc->eof = 0;
continue;
}
if (res < 0)
@ -606,9 +670,6 @@ out:
nfs_unblock_sillyrename(dentry);
if (res > 0)
res = 0;
out_alloc_failed:
nfs_free_fattr(my_entry.fattr);
nfs_free_fhandle(my_entry.fh);
dfprintk(FILE, "NFS: readdir(%s/%s) returns %d\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
res);
@ -1292,81 +1353,6 @@ out_err:
#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.
*/