Return-Path: Received: from mx2.netapp.com ([216.240.18.37]:3926 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757159Ab0JVOOj (ORCPT ); Fri, 22 Oct 2010 10:14:39 -0400 Message-ID: <4CC19C3B.4050708@netapp.com> Date: Fri, 22 Oct 2010 10:14:19 -0400 From: Bryan Schumaker To: "linux-nfs@vger.kernel.org" CC: "Myklebust, Trond" Subject: [PATCH 01/10] NFS: add readdir cache array Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 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 Signed-off-by: Trond Myklebust --- fs/nfs/dir.c | 632 ++++++++++++++++++++++++++++------------------------------ 1 files changed, 309 insertions(+), 323 deletions(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index fe549f5..1d4138d 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -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 */ @@ -209,190 +351,157 @@ int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page) } desc->timestamp = timestamp; desc->gencount = gencount; - desc->timestamp_valid = 1; - 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); - } - unlock_page(page); - return 0; - error: - unlock_page(page); - return -EIO; +error: + return error; } -static inline -int dir_decode(nfs_readdir_descriptor_t *desc) +/* 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 = desc->ptr; - p = desc->decode(p, desc->entry, desc->plus); + __be32 *p = *ptr; + p = desc->decode(p, 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; -} + *ptr = p; -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; + entry->fattr->time_start = desc->timestamp; + entry->fattr->gencount = desc->gencount; + return 0; } -/* - * 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) +/* 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) { - 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) + __be32 *ptr = kmap(xdr_page); + while (xdr_decode(desc, entry, &ptr) == 0) { + if (nfs_readdir_add_to_array(entry, page) == -1) break; - if (loop_count++ > 200) { - loop_count = 0; - schedule(); - } } - return status; + kunmap(xdr_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. - */ -static inline -int find_dirent_index(nfs_readdir_descriptor_t *desc) +static +int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, struct inode *inode) { - struct nfs_entry *entry = desc->entry; - int loop_count = 0, - status; - - for(;;) { - status = dir_decode(desc); - if (status) - break; + 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; - dfprintk(DIRCACHE, "NFS: found cookie %Lu at index %Ld\n", - (unsigned long long)entry->cookie, desc->current_index); + array = nfs_readdir_get_array(page); + memset(array, 0, sizeof(struct nfs_cache_array)); + array->eof_index = -1; - if (desc->file->f_pos == desc->current_index) { - *desc->dir_cookie = entry->cookie; + 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; - } - desc->current_index++; - if (loop_count++ > 200) { - loop_count = 0; - schedule(); - } - } + 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; } /* - * Find the given page, and call find_dirent() or find_dirent_index in - * order to try to return the next entry. + * 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 inline -int find_dirent_page(nfs_readdir_descriptor_t *desc) +static +int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page* page) { 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 (nfs_readdir_xdr_to_array(desc, page, inode) == -1) + goto error; + SetPageUptodate(page); - /* 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; + if (invalidate_inode_pages2_range(inode->i_mapping, page->index + 1, -1) < 0) { + /* Should never happen */ + nfs_zap_mapping(inode, inode->i_mapping); } + unlock_page(page); + return 0; + error: + unlock_page(page); + return -EIO; +} - /* 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; +static +void cache_page_release(nfs_readdir_descriptor_t *desc) +{ + page_cache_release(desc->page); + desc->page = NULL; +} + +static +struct page *get_cache_page(nfs_readdir_descriptor_t *desc) +{ + 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; } /* - * 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 + * Returns 0 if desc->dir_cookie was found on page desc->page_index */ +static +int find_cache_page(nfs_readdir_descriptor_t *desc) +{ + int res; + + desc->page = get_cache_page(desc); + if (IS_ERR(desc->page)) + return PTR_ERR(desc->page); + + res = nfs_readdir_search_array(desc); + if (res == 0) + return 0; + cache_page_release(desc); + return res; +} + +/* 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; - - /* 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); + int res = -EAGAIN; + desc->page_index = 0; - for (;;) { - res = find_dirent_page(desc); + if (*desc->dir_cookie == 0) + desc->cache_entry_index = 0; + + 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; - - dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n", - (unsigned 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 = 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 = NFS_FILEID(dentry->d_inode); - } + int i = 0; + int res = 0; + struct nfs_cache_array *array = NULL; + unsigned int d_type = DT_UNKNOWN; + struct dentry *dentry = NULL; - res = filldir(dirent, entry->name, entry->len, - file->f_pos, nfs_compat_user_ino64(fileid), - d_type); + array = nfs_readdir_get_array(desc->page); + + for (i = desc->cache_entry_index; i < array->size; i++) { + d_type = DT_UNKNOWN; + + 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 + + if (nfs_readdir_xdr_to_array(desc, page, inode) == -1) { status = -EIO; - if (status < 0) 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); @@ -1281,81 +1342,6 @@ 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. */