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>
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index a847acf..f772439 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -55,6 +55,7 @@
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 @@
.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 @@
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)
{
- struct file *file = desc->file;
- struct inode *inode = file->f_path.dentry->d_inode;
+ 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 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 @@
}
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
#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.
*/