diff options
Diffstat (limited to 'fs/nfs/dir.c')
| -rw-r--r-- | fs/nfs/dir.c | 3286 |
1 files changed, 3286 insertions, 0 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c new file mode 100644 index 000000000..f594dac43 --- /dev/null +++ b/fs/nfs/dir.c @@ -0,0 +1,3286 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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/compat.h> +#include <linux/module.h> +#include <linux/time.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/pagevec.h> +#include <linux/namei.h> +#include <linux/mount.h> +#include <linux/swap.h> +#include <linux/sched.h> +#include <linux/kmemleak.h> +#include <linux/xattr.h> +#include <linux/hash.h> + +#include "delegation.h" +#include "iostat.h" +#include "internal.h" +#include "fscache.h" + +#include "nfstrace.h" + +/* #define NFS_DEBUG_VERBOSE 1 */ + +static int nfs_opendir(struct inode *, struct file *); +static int nfs_closedir(struct inode *, struct file *); +static int nfs_readdir(struct file *, struct dir_context *); +static int nfs_fsync_dir(struct file *, loff_t, loff_t, int); +static loff_t nfs_llseek_dir(struct file *, loff_t, int); +static void nfs_readdir_free_folio(struct folio *); + +const struct file_operations nfs_dir_operations = { + .llseek = nfs_llseek_dir, + .read = generic_read_dir, + .iterate_shared = nfs_readdir, + .open = nfs_opendir, + .release = nfs_closedir, + .fsync = nfs_fsync_dir, +}; + +const struct address_space_operations nfs_dir_aops = { + .free_folio = nfs_readdir_free_folio, +}; + +#define NFS_INIT_DTSIZE PAGE_SIZE + +static struct nfs_open_dir_context * +alloc_nfs_open_dir_context(struct inode *dir) +{ + struct nfs_inode *nfsi = NFS_I(dir); + struct nfs_open_dir_context *ctx; + + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT); + if (ctx != NULL) { + ctx->attr_gencount = nfsi->attr_gencount; + ctx->dtsize = NFS_INIT_DTSIZE; + spin_lock(&dir->i_lock); + if (list_empty(&nfsi->open_files) && + (nfsi->cache_validity & NFS_INO_DATA_INVAL_DEFER)) + nfs_set_cache_invalid(dir, + NFS_INO_INVALID_DATA | + NFS_INO_REVAL_FORCED); + list_add_tail_rcu(&ctx->list, &nfsi->open_files); + memcpy(ctx->verf, nfsi->cookieverf, sizeof(ctx->verf)); + spin_unlock(&dir->i_lock); + return ctx; + } + return ERR_PTR(-ENOMEM); +} + +static void put_nfs_open_dir_context(struct inode *dir, struct nfs_open_dir_context *ctx) +{ + spin_lock(&dir->i_lock); + list_del_rcu(&ctx->list); + spin_unlock(&dir->i_lock); + kfree_rcu(ctx, rcu_head); +} + +/* + * Open file + */ +static int +nfs_opendir(struct inode *inode, struct file *filp) +{ + int res = 0; + struct nfs_open_dir_context *ctx; + + dfprintk(FILE, "NFS: open dir(%pD2)\n", filp); + + nfs_inc_stats(inode, NFSIOS_VFSOPEN); + + ctx = alloc_nfs_open_dir_context(inode); + if (IS_ERR(ctx)) { + res = PTR_ERR(ctx); + goto out; + } + filp->private_data = ctx; +out: + return res; +} + +static int +nfs_closedir(struct inode *inode, struct file *filp) +{ + put_nfs_open_dir_context(file_inode(filp), filp->private_data); + return 0; +} + +struct nfs_cache_array_entry { + u64 cookie; + u64 ino; + const char *name; + unsigned int name_len; + unsigned char d_type; +}; + +struct nfs_cache_array { + u64 change_attr; + u64 last_cookie; + unsigned int size; + unsigned char page_full : 1, + page_is_eof : 1, + cookies_are_ordered : 1; + struct nfs_cache_array_entry array[]; +}; + +struct nfs_readdir_descriptor { + struct file *file; + struct page *page; + struct dir_context *ctx; + pgoff_t page_index; + pgoff_t page_index_max; + u64 dir_cookie; + u64 last_cookie; + loff_t current_index; + + __be32 verf[NFS_DIR_VERIFIER_SIZE]; + unsigned long dir_verifier; + unsigned long timestamp; + unsigned long gencount; + unsigned long attr_gencount; + unsigned int cache_entry_index; + unsigned int buffer_fills; + unsigned int dtsize; + bool clear_cache; + bool plus; + bool eob; + bool eof; +}; + +static void nfs_set_dtsize(struct nfs_readdir_descriptor *desc, unsigned int sz) +{ + struct nfs_server *server = NFS_SERVER(file_inode(desc->file)); + unsigned int maxsize = server->dtsize; + + if (sz > maxsize) + sz = maxsize; + if (sz < NFS_MIN_FILE_IO_SIZE) + sz = NFS_MIN_FILE_IO_SIZE; + desc->dtsize = sz; +} + +static void nfs_shrink_dtsize(struct nfs_readdir_descriptor *desc) +{ + nfs_set_dtsize(desc, desc->dtsize >> 1); +} + +static void nfs_grow_dtsize(struct nfs_readdir_descriptor *desc) +{ + nfs_set_dtsize(desc, desc->dtsize << 1); +} + +static void nfs_readdir_page_init_array(struct page *page, u64 last_cookie, + u64 change_attr) +{ + struct nfs_cache_array *array; + + array = kmap_atomic(page); + array->change_attr = change_attr; + array->last_cookie = last_cookie; + array->size = 0; + array->page_full = 0; + array->page_is_eof = 0; + array->cookies_are_ordered = 1; + kunmap_atomic(array); +} + +/* + * we are freeing strings created by nfs_add_to_readdir_array() + */ +static void nfs_readdir_clear_array(struct page *page) +{ + struct nfs_cache_array *array; + unsigned int i; + + array = kmap_atomic(page); + for (i = 0; i < array->size; i++) + kfree(array->array[i].name); + array->size = 0; + kunmap_atomic(array); +} + +static void nfs_readdir_free_folio(struct folio *folio) +{ + nfs_readdir_clear_array(&folio->page); +} + +static void nfs_readdir_page_reinit_array(struct page *page, u64 last_cookie, + u64 change_attr) +{ + nfs_readdir_clear_array(page); + nfs_readdir_page_init_array(page, last_cookie, change_attr); +} + +static struct page * +nfs_readdir_page_array_alloc(u64 last_cookie, gfp_t gfp_flags) +{ + struct page *page = alloc_page(gfp_flags); + if (page) + nfs_readdir_page_init_array(page, last_cookie, 0); + return page; +} + +static void nfs_readdir_page_array_free(struct page *page) +{ + if (page) { + nfs_readdir_clear_array(page); + put_page(page); + } +} + +static u64 nfs_readdir_array_index_cookie(struct nfs_cache_array *array) +{ + return array->size == 0 ? array->last_cookie : array->array[0].cookie; +} + +static void nfs_readdir_array_set_eof(struct nfs_cache_array *array) +{ + array->page_is_eof = 1; + array->page_full = 1; +} + +static bool nfs_readdir_array_is_full(struct nfs_cache_array *array) +{ + return array->page_full; +} + +/* + * 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 const char *nfs_readdir_copy_name(const char *name, unsigned int len) +{ + const char *ret = kmemdup_nul(name, len, GFP_KERNEL); + + /* + * Avoid a kmemleak false positive. The pointer to the name is stored + * in a page cache page which kmemleak does not scan. + */ + if (ret != NULL) + kmemleak_not_leak(ret); + return ret; +} + +static size_t nfs_readdir_array_maxentries(void) +{ + return (PAGE_SIZE - sizeof(struct nfs_cache_array)) / + sizeof(struct nfs_cache_array_entry); +} + +/* + * Check that the next array entry lies entirely within the page bounds + */ +static int nfs_readdir_array_can_expand(struct nfs_cache_array *array) +{ + if (array->page_full) + return -ENOSPC; + if (array->size == nfs_readdir_array_maxentries()) { + array->page_full = 1; + return -ENOSPC; + } + return 0; +} + +static int nfs_readdir_page_array_append(struct page *page, + const struct nfs_entry *entry, + u64 *cookie) +{ + struct nfs_cache_array *array; + struct nfs_cache_array_entry *cache_entry; + const char *name; + int ret = -ENOMEM; + + name = nfs_readdir_copy_name(entry->name, entry->len); + + array = kmap_atomic(page); + if (!name) + goto out; + ret = nfs_readdir_array_can_expand(array); + if (ret) { + kfree(name); + goto out; + } + + cache_entry = &array->array[array->size]; + cache_entry->cookie = array->last_cookie; + cache_entry->ino = entry->ino; + cache_entry->d_type = entry->d_type; + cache_entry->name_len = entry->len; + cache_entry->name = name; + array->last_cookie = entry->cookie; + if (array->last_cookie <= cache_entry->cookie) + array->cookies_are_ordered = 0; + array->size++; + if (entry->eof != 0) + nfs_readdir_array_set_eof(array); +out: + *cookie = array->last_cookie; + kunmap_atomic(array); + return ret; +} + +#define NFS_READDIR_COOKIE_MASK (U32_MAX >> 14) +/* + * Hash algorithm allowing content addressible access to sequences + * of directory cookies. Content is addressed by the value of the + * cookie index of the first readdir entry in a page. + * + * We select only the first 18 bits to avoid issues with excessive + * memory use for the page cache XArray. 18 bits should allow the caching + * of 262144 pages of sequences of readdir entries. Since each page holds + * 127 readdir entries for a typical 64-bit system, that works out to a + * cache of ~ 33 million entries per directory. + */ +static pgoff_t nfs_readdir_page_cookie_hash(u64 cookie) +{ + if (cookie == 0) + return 0; + return hash_64(cookie, 18); +} + +static bool nfs_readdir_page_validate(struct page *page, u64 last_cookie, + u64 change_attr) +{ + struct nfs_cache_array *array = kmap_atomic(page); + int ret = true; + + if (array->change_attr != change_attr) + ret = false; + if (nfs_readdir_array_index_cookie(array) != last_cookie) + ret = false; + kunmap_atomic(array); + return ret; +} + +static void nfs_readdir_page_unlock_and_put(struct page *page) +{ + unlock_page(page); + put_page(page); +} + +static void nfs_readdir_page_init_and_validate(struct page *page, u64 cookie, + u64 change_attr) +{ + if (PageUptodate(page)) { + if (nfs_readdir_page_validate(page, cookie, change_attr)) + return; + nfs_readdir_clear_array(page); + } + nfs_readdir_page_init_array(page, cookie, change_attr); + SetPageUptodate(page); +} + +static struct page *nfs_readdir_page_get_locked(struct address_space *mapping, + u64 cookie, u64 change_attr) +{ + pgoff_t index = nfs_readdir_page_cookie_hash(cookie); + struct page *page; + + page = grab_cache_page(mapping, index); + if (!page) + return NULL; + nfs_readdir_page_init_and_validate(page, cookie, change_attr); + return page; +} + +static u64 nfs_readdir_page_last_cookie(struct page *page) +{ + struct nfs_cache_array *array; + u64 ret; + + array = kmap_atomic(page); + ret = array->last_cookie; + kunmap_atomic(array); + return ret; +} + +static bool nfs_readdir_page_needs_filling(struct page *page) +{ + struct nfs_cache_array *array; + bool ret; + + array = kmap_atomic(page); + ret = !nfs_readdir_array_is_full(array); + kunmap_atomic(array); + return ret; +} + +static void nfs_readdir_page_set_eof(struct page *page) +{ + struct nfs_cache_array *array; + + array = kmap_atomic(page); + nfs_readdir_array_set_eof(array); + kunmap_atomic(array); +} + +static struct page *nfs_readdir_page_get_next(struct address_space *mapping, + u64 cookie, u64 change_attr) +{ + pgoff_t index = nfs_readdir_page_cookie_hash(cookie); + struct page *page; + + page = grab_cache_page_nowait(mapping, index); + if (!page) + return NULL; + nfs_readdir_page_init_and_validate(page, cookie, change_attr); + if (nfs_readdir_page_last_cookie(page) != cookie) + nfs_readdir_page_reinit_array(page, cookie, change_attr); + return page; +} + +static inline +int is_32bit_api(void) +{ +#ifdef CONFIG_COMPAT + return in_compat_syscall(); +#else + return (BITS_PER_LONG == 32); +#endif +} + +static +bool nfs_readdir_use_cookie(const struct file *filp) +{ + if ((filp->f_mode & FMODE_32BITHASH) || + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api())) + return false; + return true; +} + +static void nfs_readdir_seek_next_array(struct nfs_cache_array *array, + struct nfs_readdir_descriptor *desc) +{ + if (array->page_full) { + desc->last_cookie = array->last_cookie; + desc->current_index += array->size; + desc->cache_entry_index = 0; + desc->page_index++; + } else + desc->last_cookie = nfs_readdir_array_index_cookie(array); +} + +static void nfs_readdir_rewind_search(struct nfs_readdir_descriptor *desc) +{ + desc->current_index = 0; + desc->last_cookie = 0; + desc->page_index = 0; +} + +static int nfs_readdir_search_for_pos(struct nfs_cache_array *array, + struct nfs_readdir_descriptor *desc) +{ + loff_t diff = desc->ctx->pos - desc->current_index; + unsigned int index; + + if (diff < 0) + goto out_eof; + if (diff >= array->size) { + if (array->page_is_eof) + goto out_eof; + nfs_readdir_seek_next_array(array, desc); + return -EAGAIN; + } + + index = (unsigned int)diff; + desc->dir_cookie = array->array[index].cookie; + desc->cache_entry_index = index; + return 0; +out_eof: + desc->eof = true; + return -EBADCOOKIE; +} + +static bool nfs_readdir_array_cookie_in_range(struct nfs_cache_array *array, + u64 cookie) +{ + if (!array->cookies_are_ordered) + return true; + /* Optimisation for monotonically increasing cookies */ + if (cookie >= array->last_cookie) + return false; + if (array->size && cookie < array->array[0].cookie) + return false; + return true; +} + +static int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, + struct nfs_readdir_descriptor *desc) +{ + unsigned int i; + int status = -EAGAIN; + + if (!nfs_readdir_array_cookie_in_range(array, desc->dir_cookie)) + goto check_eof; + + for (i = 0; i < array->size; i++) { + if (array->array[i].cookie == desc->dir_cookie) { + if (nfs_readdir_use_cookie(desc->file)) + desc->ctx->pos = desc->dir_cookie; + else + desc->ctx->pos = desc->current_index + i; + desc->cache_entry_index = i; + return 0; + } + } +check_eof: + if (array->page_is_eof) { + status = -EBADCOOKIE; + if (desc->dir_cookie == array->last_cookie) + desc->eof = true; + } else + nfs_readdir_seek_next_array(array, desc); + return status; +} + +static int nfs_readdir_search_array(struct nfs_readdir_descriptor *desc) +{ + struct nfs_cache_array *array; + int status; + + array = kmap_atomic(desc->page); + + if (desc->dir_cookie == 0) + status = nfs_readdir_search_for_pos(array, desc); + else + status = nfs_readdir_search_for_cookie(array, desc); + + kunmap_atomic(array); + return status; +} + +/* Fill a page with xdr information before transferring to the cache page */ +static int nfs_readdir_xdr_filler(struct nfs_readdir_descriptor *desc, + __be32 *verf, u64 cookie, + struct page **pages, size_t bufsize, + __be32 *verf_res) +{ + struct inode *inode = file_inode(desc->file); + struct nfs_readdir_arg arg = { + .dentry = file_dentry(desc->file), + .cred = desc->file->f_cred, + .verf = verf, + .cookie = cookie, + .pages = pages, + .page_len = bufsize, + .plus = desc->plus, + }; + struct nfs_readdir_res res = { + .verf = verf_res, + }; + unsigned long timestamp, gencount; + int error; + + again: + timestamp = jiffies; + gencount = nfs_inc_attr_generation_counter(); + desc->dir_verifier = nfs_save_change_attribute(inode); + error = NFS_PROTO(inode)->readdir(&arg, &res); + if (error < 0) { + /* We requested READDIRPLUS, but the server doesn't grok it */ + if (error == -ENOTSUPP && desc->plus) { + NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS; + desc->plus = arg.plus = false; + goto again; + } + goto error; + } + desc->timestamp = timestamp; + desc->gencount = gencount; +error: + return error; +} + +static int xdr_decode(struct nfs_readdir_descriptor *desc, + struct nfs_entry *entry, struct xdr_stream *xdr) +{ + struct inode *inode = file_inode(desc->file); + int error; + + error = NFS_PROTO(inode)->decode_dirent(xdr, entry, desc->plus); + if (error) + return error; + entry->fattr->time_start = desc->timestamp; + entry->fattr->gencount = desc->gencount; + return 0; +} + +/* Match file and dirent using either filehandle or fileid + * Note: caller is responsible for checking the fsid + */ +static +int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry) +{ + struct inode *inode; + struct nfs_inode *nfsi; + + if (d_really_is_negative(dentry)) + return 0; + + inode = d_inode(dentry); + if (is_bad_inode(inode) || NFS_STALE(inode)) + return 0; + + nfsi = NFS_I(inode); + if (entry->fattr->fileid != nfsi->fileid) + return 0; + if (entry->fh->size && nfs_compare_fh(entry->fh, &nfsi->fh) != 0) + return 0; + return 1; +} + +#define NFS_READDIR_CACHE_USAGE_THRESHOLD (8UL) + +static bool nfs_use_readdirplus(struct inode *dir, struct dir_context *ctx, + unsigned int cache_hits, + unsigned int cache_misses) +{ + if (!nfs_server_capable(dir, NFS_CAP_READDIRPLUS)) + return false; + if (ctx->pos == 0 || + cache_hits + cache_misses > NFS_READDIR_CACHE_USAGE_THRESHOLD) + return true; + return false; +} + +/* + * This function is called by the getattr code to request the + * use of readdirplus to accelerate any future lookups in the same + * directory. + */ +void nfs_readdir_record_entry_cache_hit(struct inode *dir) +{ + struct nfs_inode *nfsi = NFS_I(dir); + struct nfs_open_dir_context *ctx; + + if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) && + S_ISDIR(dir->i_mode)) { + rcu_read_lock(); + list_for_each_entry_rcu (ctx, &nfsi->open_files, list) + atomic_inc(&ctx->cache_hits); + rcu_read_unlock(); + } +} + +/* + * This function is mainly for use by nfs_getattr(). + * + * If this is an 'ls -l', we want to force use of readdirplus. + */ +void nfs_readdir_record_entry_cache_miss(struct inode *dir) +{ + struct nfs_inode *nfsi = NFS_I(dir); + struct nfs_open_dir_context *ctx; + + if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) && + S_ISDIR(dir->i_mode)) { + rcu_read_lock(); + list_for_each_entry_rcu (ctx, &nfsi->open_files, list) + atomic_inc(&ctx->cache_misses); + rcu_read_unlock(); + } +} + +static void nfs_lookup_advise_force_readdirplus(struct inode *dir, + unsigned int flags) +{ + if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE)) + return; + if (flags & (LOOKUP_EXCL | LOOKUP_PARENT | LOOKUP_REVAL)) + return; + nfs_readdir_record_entry_cache_miss(dir); +} + +static +void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry, + unsigned long dir_verifier) +{ + struct qstr filename = QSTR_INIT(entry->name, entry->len); + DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + struct dentry *dentry; + struct dentry *alias; + struct inode *inode; + int status; + + if (!(entry->fattr->valid & NFS_ATTR_FATTR_FILEID)) + return; + if (!(entry->fattr->valid & NFS_ATTR_FATTR_FSID)) + return; + if (filename.len == 0) + return; + /* Validate that the name doesn't contain any illegal '\0' */ + if (strnlen(filename.name, filename.len) != filename.len) + return; + /* ...or '/' */ + if (strnchr(filename.name, filename.len, '/')) + return; + if (filename.name[0] == '.') { + if (filename.len == 1) + return; + if (filename.len == 2 && filename.name[1] == '.') + return; + } + filename.hash = full_name_hash(parent, filename.name, filename.len); + + dentry = d_lookup(parent, &filename); +again: + if (!dentry) { + dentry = d_alloc_parallel(parent, &filename, &wq); + if (IS_ERR(dentry)) + return; + } + if (!d_in_lookup(dentry)) { + /* Is there a mountpoint here? If so, just exit */ + if (!nfs_fsid_equal(&NFS_SB(dentry->d_sb)->fsid, + &entry->fattr->fsid)) + goto out; + if (nfs_same_file(dentry, entry)) { + if (!entry->fh->size) + goto out; + nfs_set_verifier(dentry, dir_verifier); + status = nfs_refresh_inode(d_inode(dentry), entry->fattr); + if (!status) + nfs_setsecurity(d_inode(dentry), entry->fattr); + trace_nfs_readdir_lookup_revalidate(d_inode(parent), + dentry, 0, status); + goto out; + } else { + trace_nfs_readdir_lookup_revalidate_failed( + d_inode(parent), dentry, 0); + d_invalidate(dentry); + dput(dentry); + dentry = NULL; + goto again; + } + } + if (!entry->fh->size) { + d_lookup_done(dentry); + goto out; + } + + inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr); + alias = d_splice_alias(inode, dentry); + d_lookup_done(dentry); + if (alias) { + if (IS_ERR(alias)) + goto out; + dput(dentry); + dentry = alias; + } + nfs_set_verifier(dentry, dir_verifier); + trace_nfs_readdir_lookup(d_inode(parent), dentry, 0); +out: + dput(dentry); +} + +static int nfs_readdir_entry_decode(struct nfs_readdir_descriptor *desc, + struct nfs_entry *entry, + struct xdr_stream *stream) +{ + int ret; + + if (entry->fattr->label) + entry->fattr->label->len = NFS4_MAXLABELLEN; + ret = xdr_decode(desc, entry, stream); + if (ret || !desc->plus) + return ret; + nfs_prime_dcache(file_dentry(desc->file), entry, desc->dir_verifier); + return 0; +} + +/* Perform conversion from xdr to cache array */ +static int nfs_readdir_page_filler(struct nfs_readdir_descriptor *desc, + struct nfs_entry *entry, + struct page **xdr_pages, unsigned int buflen, + struct page **arrays, size_t narrays, + u64 change_attr) +{ + struct address_space *mapping = desc->file->f_mapping; + struct xdr_stream stream; + struct xdr_buf buf; + struct page *scratch, *new, *page = *arrays; + u64 cookie; + int status; + + scratch = alloc_page(GFP_KERNEL); + if (scratch == NULL) + return -ENOMEM; + + xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen); + xdr_set_scratch_page(&stream, scratch); + + do { + status = nfs_readdir_entry_decode(desc, entry, &stream); + if (status != 0) + break; + + status = nfs_readdir_page_array_append(page, entry, &cookie); + if (status != -ENOSPC) + continue; + + if (page->mapping != mapping) { + if (!--narrays) + break; + new = nfs_readdir_page_array_alloc(cookie, GFP_KERNEL); + if (!new) + break; + arrays++; + *arrays = page = new; + } else { + new = nfs_readdir_page_get_next(mapping, cookie, + change_attr); + if (!new) + break; + if (page != *arrays) + nfs_readdir_page_unlock_and_put(page); + page = new; + } + desc->page_index_max++; + status = nfs_readdir_page_array_append(page, entry, &cookie); + } while (!status && !entry->eof); + + switch (status) { + case -EBADCOOKIE: + if (!entry->eof) + break; + nfs_readdir_page_set_eof(page); + fallthrough; + case -EAGAIN: + status = 0; + break; + case -ENOSPC: + status = 0; + if (!desc->plus) + break; + while (!nfs_readdir_entry_decode(desc, entry, &stream)) + ; + } + + if (page != *arrays) + nfs_readdir_page_unlock_and_put(page); + + put_page(scratch); + return status; +} + +static void nfs_readdir_free_pages(struct page **pages, size_t npages) +{ + while (npages--) + put_page(pages[npages]); + kfree(pages); +} + +/* + * nfs_readdir_alloc_pages() will allocate pages that must be freed with a call + * to nfs_readdir_free_pages() + */ +static struct page **nfs_readdir_alloc_pages(size_t npages) +{ + struct page **pages; + size_t i; + + pages = kmalloc_array(npages, sizeof(*pages), GFP_KERNEL); + if (!pages) + return NULL; + for (i = 0; i < npages; i++) { + struct page *page = alloc_page(GFP_KERNEL); + if (page == NULL) + goto out_freepages; + pages[i] = page; + } + return pages; + +out_freepages: + nfs_readdir_free_pages(pages, i); + return NULL; +} + +static int nfs_readdir_xdr_to_array(struct nfs_readdir_descriptor *desc, + __be32 *verf_arg, __be32 *verf_res, + struct page **arrays, size_t narrays) +{ + u64 change_attr; + struct page **pages; + struct page *page = *arrays; + struct nfs_entry *entry; + size_t array_size; + struct inode *inode = file_inode(desc->file); + unsigned int dtsize = desc->dtsize; + unsigned int pglen; + int status = -ENOMEM; + + entry = kzalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) + return -ENOMEM; + entry->cookie = nfs_readdir_page_last_cookie(page); + entry->fh = nfs_alloc_fhandle(); + entry->fattr = nfs_alloc_fattr_with_label(NFS_SERVER(inode)); + entry->server = NFS_SERVER(inode); + if (entry->fh == NULL || entry->fattr == NULL) + goto out; + + array_size = (dtsize + PAGE_SIZE - 1) >> PAGE_SHIFT; + pages = nfs_readdir_alloc_pages(array_size); + if (!pages) + goto out; + + change_attr = inode_peek_iversion_raw(inode); + status = nfs_readdir_xdr_filler(desc, verf_arg, entry->cookie, pages, + dtsize, verf_res); + if (status < 0) + goto free_pages; + + pglen = status; + if (pglen != 0) + status = nfs_readdir_page_filler(desc, entry, pages, pglen, + arrays, narrays, change_attr); + else + nfs_readdir_page_set_eof(page); + desc->buffer_fills++; + +free_pages: + nfs_readdir_free_pages(pages, array_size); +out: + nfs_free_fattr(entry->fattr); + nfs_free_fhandle(entry->fh); + kfree(entry); + return status; +} + +static void nfs_readdir_page_put(struct nfs_readdir_descriptor *desc) +{ + put_page(desc->page); + desc->page = NULL; +} + +static void +nfs_readdir_page_unlock_and_put_cached(struct nfs_readdir_descriptor *desc) +{ + unlock_page(desc->page); + nfs_readdir_page_put(desc); +} + +static struct page * +nfs_readdir_page_get_cached(struct nfs_readdir_descriptor *desc) +{ + struct address_space *mapping = desc->file->f_mapping; + u64 change_attr = inode_peek_iversion_raw(mapping->host); + u64 cookie = desc->last_cookie; + struct page *page; + + page = nfs_readdir_page_get_locked(mapping, cookie, change_attr); + if (!page) + return NULL; + if (desc->clear_cache && !nfs_readdir_page_needs_filling(page)) + nfs_readdir_page_reinit_array(page, cookie, change_attr); + return page; +} + +/* + * Returns 0 if desc->dir_cookie was found on page desc->page_index + * and locks the page to prevent removal from the page cache. + */ +static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc) +{ + struct inode *inode = file_inode(desc->file); + struct nfs_inode *nfsi = NFS_I(inode); + __be32 verf[NFS_DIR_VERIFIER_SIZE]; + int res; + + desc->page = nfs_readdir_page_get_cached(desc); + if (!desc->page) + return -ENOMEM; + if (nfs_readdir_page_needs_filling(desc->page)) { + /* Grow the dtsize if we had to go back for more pages */ + if (desc->page_index == desc->page_index_max) + nfs_grow_dtsize(desc); + desc->page_index_max = desc->page_index; + trace_nfs_readdir_cache_fill(desc->file, nfsi->cookieverf, + desc->last_cookie, + desc->page->index, desc->dtsize); + res = nfs_readdir_xdr_to_array(desc, nfsi->cookieverf, verf, + &desc->page, 1); + if (res < 0) { + nfs_readdir_page_unlock_and_put_cached(desc); + trace_nfs_readdir_cache_fill_done(inode, res); + if (res == -EBADCOOKIE || res == -ENOTSYNC) { + invalidate_inode_pages2(desc->file->f_mapping); + nfs_readdir_rewind_search(desc); + trace_nfs_readdir_invalidate_cache_range( + inode, 0, MAX_LFS_FILESIZE); + return -EAGAIN; + } + return res; + } + /* + * Set the cookie verifier if the page cache was empty + */ + if (desc->last_cookie == 0 && + memcmp(nfsi->cookieverf, verf, sizeof(nfsi->cookieverf))) { + memcpy(nfsi->cookieverf, verf, + sizeof(nfsi->cookieverf)); + invalidate_inode_pages2_range(desc->file->f_mapping, 1, + -1); + trace_nfs_readdir_invalidate_cache_range( + inode, 1, MAX_LFS_FILESIZE); + } + desc->clear_cache = false; + } + res = nfs_readdir_search_array(desc); + if (res == 0) + return 0; + nfs_readdir_page_unlock_and_put_cached(desc); + return res; +} + +/* Search for desc->dir_cookie from the beginning of the page cache */ +static int readdir_search_pagecache(struct nfs_readdir_descriptor *desc) +{ + int res; + + do { + res = find_and_lock_cache_page(desc); + } while (res == -EAGAIN); + return res; +} + +/* + * Once we've found the start of the dirent within a page: fill 'er up... + */ +static void nfs_do_filldir(struct nfs_readdir_descriptor *desc, + const __be32 *verf) +{ + struct file *file = desc->file; + struct nfs_cache_array *array; + unsigned int i; + + array = kmap_local_page(desc->page); + for (i = desc->cache_entry_index; i < array->size; i++) { + struct nfs_cache_array_entry *ent; + + ent = &array->array[i]; + if (!dir_emit(desc->ctx, ent->name, ent->name_len, + nfs_compat_user_ino64(ent->ino), ent->d_type)) { + desc->eob = true; + break; + } + memcpy(desc->verf, verf, sizeof(desc->verf)); + if (i == array->size - 1) { + desc->dir_cookie = array->last_cookie; + nfs_readdir_seek_next_array(array, desc); + } else { + desc->dir_cookie = array->array[i + 1].cookie; + desc->last_cookie = array->array[0].cookie; + } + if (nfs_readdir_use_cookie(file)) + desc->ctx->pos = desc->dir_cookie; + else + desc->ctx->pos++; + } + if (array->page_is_eof) + desc->eof = !desc->eob; + + kunmap_local(array); + dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %llu\n", + (unsigned long long)desc->dir_cookie); +} + +/* + * 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 int uncached_readdir(struct nfs_readdir_descriptor *desc) +{ + struct page **arrays; + size_t i, sz = 512; + __be32 verf[NFS_DIR_VERIFIER_SIZE]; + int status = -ENOMEM; + + dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %llu\n", + (unsigned long long)desc->dir_cookie); + + arrays = kcalloc(sz, sizeof(*arrays), GFP_KERNEL); + if (!arrays) + goto out; + arrays[0] = nfs_readdir_page_array_alloc(desc->dir_cookie, GFP_KERNEL); + if (!arrays[0]) + goto out; + + desc->page_index = 0; + desc->cache_entry_index = 0; + desc->last_cookie = desc->dir_cookie; + desc->page_index_max = 0; + + trace_nfs_readdir_uncached(desc->file, desc->verf, desc->last_cookie, + -1, desc->dtsize); + + status = nfs_readdir_xdr_to_array(desc, desc->verf, verf, arrays, sz); + if (status < 0) { + trace_nfs_readdir_uncached_done(file_inode(desc->file), status); + goto out_free; + } + + for (i = 0; !desc->eob && i < sz && arrays[i]; i++) { + desc->page = arrays[i]; + nfs_do_filldir(desc, verf); + } + desc->page = NULL; + + /* + * Grow the dtsize if we have to go back for more pages, + * or shrink it if we're reading too many. + */ + if (!desc->eof) { + if (!desc->eob) + nfs_grow_dtsize(desc); + else if (desc->buffer_fills == 1 && + i < (desc->page_index_max >> 1)) + nfs_shrink_dtsize(desc); + } +out_free: + for (i = 0; i < sz && arrays[i]; i++) + nfs_readdir_page_array_free(arrays[i]); +out: + if (!nfs_readdir_use_cookie(desc->file)) + nfs_readdir_rewind_search(desc); + desc->page_index_max = -1; + kfree(arrays); + dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __func__, status); + return status; +} + +#define NFS_READDIR_CACHE_MISS_THRESHOLD (16UL) + +static bool nfs_readdir_handle_cache_misses(struct inode *inode, + struct nfs_readdir_descriptor *desc, + unsigned int cache_misses, + bool force_clear) +{ + if (desc->ctx->pos == 0 || !desc->plus) + return false; + if (cache_misses <= NFS_READDIR_CACHE_MISS_THRESHOLD && !force_clear) + return false; + trace_nfs_readdir_force_readdirplus(inode); + return true; +} + +/* The file offset position represents the dirent entry number. A + last cookie cache takes care of the common case of reading the + whole directory. + */ +static int nfs_readdir(struct file *file, struct dir_context *ctx) +{ + struct dentry *dentry = file_dentry(file); + struct inode *inode = d_inode(dentry); + struct nfs_inode *nfsi = NFS_I(inode); + struct nfs_open_dir_context *dir_ctx = file->private_data; + struct nfs_readdir_descriptor *desc; + unsigned int cache_hits, cache_misses; + bool force_clear; + int res; + + dfprintk(FILE, "NFS: readdir(%pD2) starting at cookie %llu\n", + file, (long long)ctx->pos); + nfs_inc_stats(inode, NFSIOS_VFSGETDENTS); + + /* + * ctx->pos points to the dirent entry number. + * *desc->dir_cookie has the cookie for the next entry. We have + * to either find the entry with the appropriate number or + * revalidate the cookie. + */ + nfs_revalidate_mapping(inode, file->f_mapping); + + res = -ENOMEM; + desc = kzalloc(sizeof(*desc), GFP_KERNEL); + if (!desc) + goto out; + desc->file = file; + desc->ctx = ctx; + desc->page_index_max = -1; + + spin_lock(&file->f_lock); + desc->dir_cookie = dir_ctx->dir_cookie; + desc->page_index = dir_ctx->page_index; + desc->last_cookie = dir_ctx->last_cookie; + desc->attr_gencount = dir_ctx->attr_gencount; + desc->eof = dir_ctx->eof; + nfs_set_dtsize(desc, dir_ctx->dtsize); + memcpy(desc->verf, dir_ctx->verf, sizeof(desc->verf)); + cache_hits = atomic_xchg(&dir_ctx->cache_hits, 0); + cache_misses = atomic_xchg(&dir_ctx->cache_misses, 0); + force_clear = dir_ctx->force_clear; + spin_unlock(&file->f_lock); + + if (desc->eof) { + res = 0; + goto out_free; + } + + desc->plus = nfs_use_readdirplus(inode, ctx, cache_hits, cache_misses); + force_clear = nfs_readdir_handle_cache_misses(inode, desc, cache_misses, + force_clear); + desc->clear_cache = force_clear; + + do { + res = readdir_search_pagecache(desc); + + if (res == -EBADCOOKIE) { + res = 0; + /* This means either end of directory */ + if (desc->dir_cookie && !desc->eof) { + /* Or that the server has 'lost' a cookie */ + res = uncached_readdir(desc); + if (res == 0) + continue; + if (res == -EBADCOOKIE || res == -ENOTSYNC) + res = 0; + } + break; + } + if (res == -ETOOSMALL && desc->plus) { + nfs_zap_caches(inode); + desc->plus = false; + desc->eof = false; + continue; + } + if (res < 0) + break; + + nfs_do_filldir(desc, nfsi->cookieverf); + nfs_readdir_page_unlock_and_put_cached(desc); + if (desc->page_index == desc->page_index_max) + desc->clear_cache = force_clear; + } while (!desc->eob && !desc->eof); + + spin_lock(&file->f_lock); + dir_ctx->dir_cookie = desc->dir_cookie; + dir_ctx->last_cookie = desc->last_cookie; + dir_ctx->attr_gencount = desc->attr_gencount; + dir_ctx->page_index = desc->page_index; + dir_ctx->force_clear = force_clear; + dir_ctx->eof = desc->eof; + dir_ctx->dtsize = desc->dtsize; + memcpy(dir_ctx->verf, desc->verf, sizeof(dir_ctx->verf)); + spin_unlock(&file->f_lock); +out_free: + kfree(desc); + +out: + dfprintk(FILE, "NFS: readdir(%pD2) returns %d\n", file, res); + return res; +} + +static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence) +{ + struct nfs_open_dir_context *dir_ctx = filp->private_data; + + dfprintk(FILE, "NFS: llseek dir(%pD2, %lld, %d)\n", + filp, offset, whence); + + switch (whence) { + default: + return -EINVAL; + case SEEK_SET: + if (offset < 0) + return -EINVAL; + spin_lock(&filp->f_lock); + break; + case SEEK_CUR: + if (offset == 0) + return filp->f_pos; + spin_lock(&filp->f_lock); + offset += filp->f_pos; + if (offset < 0) { + spin_unlock(&filp->f_lock); + return -EINVAL; + } + } + if (offset != filp->f_pos) { + filp->f_pos = offset; + dir_ctx->page_index = 0; + if (!nfs_readdir_use_cookie(filp)) { + dir_ctx->dir_cookie = 0; + dir_ctx->last_cookie = 0; + } else { + dir_ctx->dir_cookie = offset; + dir_ctx->last_cookie = offset; + } + dir_ctx->eof = false; + } + spin_unlock(&filp->f_lock); + return offset; +} + +/* + * All directory operations under NFS are synchronous, so fsync() + * is a dummy operation. + */ +static int nfs_fsync_dir(struct file *filp, loff_t start, loff_t end, + int datasync) +{ + dfprintk(FILE, "NFS: fsync dir(%pD2) datasync %d\n", filp, datasync); + + nfs_inc_stats(file_inode(filp), NFSIOS_VFSFSYNC); + return 0; +} + +/** + * nfs_force_lookup_revalidate - Mark the directory as having changed + * @dir: pointer to directory inode + * + * This forces the revalidation code in nfs_lookup_revalidate() to do a + * full lookup on all child dentries of 'dir' whenever a change occurs + * on the server that might have invalidated our dcache. + * + * Note that we reserve bit '0' as a tag to let us know when a dentry + * was revalidated while holding a delegation on its inode. + * + * The caller should be holding dir->i_lock + */ +void nfs_force_lookup_revalidate(struct inode *dir) +{ + NFS_I(dir)->cache_change_attribute += 2; +} +EXPORT_SYMBOL_GPL(nfs_force_lookup_revalidate); + +/** + * nfs_verify_change_attribute - Detects NFS remote directory changes + * @dir: pointer to parent directory inode + * @verf: previously saved change attribute + * + * Return "false" if the verifiers doesn't match the change attribute. + * This would usually indicate that the directory contents have changed on + * the server, and that any dentries need revalidating. + */ +static bool nfs_verify_change_attribute(struct inode *dir, unsigned long verf) +{ + return (verf & ~1UL) == nfs_save_change_attribute(dir); +} + +static void nfs_set_verifier_delegated(unsigned long *verf) +{ + *verf |= 1UL; +} + +#if IS_ENABLED(CONFIG_NFS_V4) +static void nfs_unset_verifier_delegated(unsigned long *verf) +{ + *verf &= ~1UL; +} +#endif /* IS_ENABLED(CONFIG_NFS_V4) */ + +static bool nfs_test_verifier_delegated(unsigned long verf) +{ + return verf & 1; +} + +static bool nfs_verifier_is_delegated(struct dentry *dentry) +{ + return nfs_test_verifier_delegated(dentry->d_time); +} + +static void nfs_set_verifier_locked(struct dentry *dentry, unsigned long verf) +{ + struct inode *inode = d_inode(dentry); + struct inode *dir = d_inode(dentry->d_parent); + + if (!nfs_verify_change_attribute(dir, verf)) + return; + if (inode && NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) + nfs_set_verifier_delegated(&verf); + dentry->d_time = verf; +} + +/** + * nfs_set_verifier - save a parent directory verifier in the dentry + * @dentry: pointer to dentry + * @verf: verifier to save + * + * Saves the parent directory verifier in @dentry. If the inode has + * a delegation, we also tag the dentry as having been revalidated + * while holding a delegation so that we know we don't have to + * look it up again after a directory change. + */ +void nfs_set_verifier(struct dentry *dentry, unsigned long verf) +{ + + spin_lock(&dentry->d_lock); + nfs_set_verifier_locked(dentry, verf); + spin_unlock(&dentry->d_lock); +} +EXPORT_SYMBOL_GPL(nfs_set_verifier); + +#if IS_ENABLED(CONFIG_NFS_V4) +/** + * nfs_clear_verifier_delegated - clear the dir verifier delegation tag + * @inode: pointer to inode + * + * Iterates through the dentries in the inode alias list and clears + * the tag used to indicate that the dentry has been revalidated + * while holding a delegation. + * This function is intended for use when the delegation is being + * returned or revoked. + */ +void nfs_clear_verifier_delegated(struct inode *inode) +{ + struct dentry *alias; + + if (!inode) + return; + spin_lock(&inode->i_lock); + hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) { + spin_lock(&alias->d_lock); + nfs_unset_verifier_delegated(&alias->d_time); + spin_unlock(&alias->d_lock); + } + spin_unlock(&inode->i_lock); +} +EXPORT_SYMBOL_GPL(nfs_clear_verifier_delegated); +#endif /* IS_ENABLED(CONFIG_NFS_V4) */ + +static int nfs_dentry_verify_change(struct inode *dir, struct dentry *dentry) +{ + if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE) && + d_really_is_negative(dentry)) + return dentry->d_time == inode_peek_iversion_raw(dir); + return nfs_verify_change_attribute(dir, dentry->d_time); +} + +/* + * A check for whether or not the parent directory has changed. + * In the case it has, we assume that the dentries are untrustworthy + * and may need to be looked up again. + * If rcu_walk prevents us from performing a full check, return 0. + */ +static int nfs_check_verifier(struct inode *dir, struct dentry *dentry, + int rcu_walk) +{ + if (IS_ROOT(dentry)) + return 1; + if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONE) + return 0; + if (!nfs_dentry_verify_change(dir, dentry)) + return 0; + /* Revalidate nfsi->cache_change_attribute before we declare a match */ + if (nfs_mapping_need_revalidate_inode(dir)) { + if (rcu_walk) + return 0; + if (__nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0) + return 0; + } + if (!nfs_dentry_verify_change(dir, dentry)) + return 0; + return 1; +} + +/* + * Use intent information to check whether or not we're going to do + * an O_EXCL create using this path component. + */ +static int nfs_is_exclusive_create(struct inode *dir, unsigned int flags) +{ + if (NFS_PROTO(dir)->version == 2) + return 0; + return flags & LOOKUP_EXCL; +} + +/* + * Inode and filehandle revalidation for lookups. + * + * We force revalidation in the cases where the VFS sets LOOKUP_REVAL, + * or if the intent information indicates that we're about to open this + * particular file and the "nocto" mount flag is not set. + * + */ +static +int nfs_lookup_verify_inode(struct inode *inode, unsigned int flags) +{ + struct nfs_server *server = NFS_SERVER(inode); + int ret; + + if (IS_AUTOMOUNT(inode)) + return 0; + + if (flags & LOOKUP_OPEN) { + switch (inode->i_mode & S_IFMT) { + case S_IFREG: + /* A NFSv4 OPEN will revalidate later */ + if (server->caps & NFS_CAP_ATOMIC_OPEN) + goto out; + fallthrough; + case S_IFDIR: + if (server->flags & NFS_MOUNT_NOCTO) + break; + /* NFS close-to-open cache consistency validation */ + goto out_force; + } + } + + /* VFS wants an on-the-wire revalidation */ + if (flags & LOOKUP_REVAL) + goto out_force; +out: + if (inode->i_nlink > 0 || + (inode->i_nlink == 0 && + test_bit(NFS_INO_PRESERVE_UNLINKED, &NFS_I(inode)->flags))) + return 0; + else + return -ESTALE; +out_force: + if (flags & LOOKUP_RCU) + return -ECHILD; + ret = __nfs_revalidate_inode(server, inode); + if (ret != 0) + return ret; + goto out; +} + +static void nfs_mark_dir_for_revalidate(struct inode *inode) +{ + spin_lock(&inode->i_lock); + nfs_set_cache_invalid(inode, NFS_INO_INVALID_CHANGE); + spin_unlock(&inode->i_lock); +} + +/* + * We judge how long we want to trust negative + * dentries by looking at the parent inode mtime. + * + * If parent mtime has changed, we revalidate, else we wait for a + * period corresponding to the parent's attribute cache timeout value. + * + * If LOOKUP_RCU prevents us from performing a full check, return 1 + * suggesting a reval is needed. + * + * Note that when creating a new file, or looking up a rename target, + * then it shouldn't be necessary to revalidate a negative dentry. + */ +static inline +int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, + unsigned int flags) +{ + if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET)) + return 0; + if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) + return 1; + /* Case insensitive server? Revalidate negative dentries */ + if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE)) + return 1; + return !nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU); +} + +static int +nfs_lookup_revalidate_done(struct inode *dir, struct dentry *dentry, + struct inode *inode, int error) +{ + switch (error) { + case 1: + break; + case 0: + /* + * We can't d_drop the root of a disconnected tree: + * its d_hash is on the s_anon list and d_drop() would hide + * it from shrink_dcache_for_unmount(), leading to busy + * inodes on unmount and further oopses. + */ + if (inode && IS_ROOT(dentry)) + error = 1; + break; + } + trace_nfs_lookup_revalidate_exit(dir, dentry, 0, error); + return error; +} + +static int +nfs_lookup_revalidate_negative(struct inode *dir, struct dentry *dentry, + unsigned int flags) +{ + int ret = 1; + if (nfs_neg_need_reval(dir, dentry, flags)) { + if (flags & LOOKUP_RCU) + return -ECHILD; + ret = 0; + } + return nfs_lookup_revalidate_done(dir, dentry, NULL, ret); +} + +static int +nfs_lookup_revalidate_delegated(struct inode *dir, struct dentry *dentry, + struct inode *inode) +{ + nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + return nfs_lookup_revalidate_done(dir, dentry, inode, 1); +} + +static int nfs_lookup_revalidate_dentry(struct inode *dir, + struct dentry *dentry, + struct inode *inode, unsigned int flags) +{ + struct nfs_fh *fhandle; + struct nfs_fattr *fattr; + unsigned long dir_verifier; + int ret; + + trace_nfs_lookup_revalidate_enter(dir, dentry, flags); + + ret = -ENOMEM; + fhandle = nfs_alloc_fhandle(); + fattr = nfs_alloc_fattr_with_label(NFS_SERVER(inode)); + if (fhandle == NULL || fattr == NULL) + goto out; + + dir_verifier = nfs_save_change_attribute(dir); + ret = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr); + if (ret < 0) { + switch (ret) { + case -ESTALE: + case -ENOENT: + ret = 0; + break; + case -ETIMEDOUT: + if (NFS_SERVER(inode)->flags & NFS_MOUNT_SOFTREVAL) + ret = 1; + } + goto out; + } + + /* Request help from readdirplus */ + nfs_lookup_advise_force_readdirplus(dir, flags); + + ret = 0; + if (nfs_compare_fh(NFS_FH(inode), fhandle)) + goto out; + if (nfs_refresh_inode(inode, fattr) < 0) + goto out; + + nfs_setsecurity(inode, fattr); + nfs_set_verifier(dentry, dir_verifier); + + ret = 1; +out: + nfs_free_fattr(fattr); + nfs_free_fhandle(fhandle); + + /* + * If the lookup failed despite the dentry change attribute being + * a match, then we should revalidate the directory cache. + */ + if (!ret && nfs_dentry_verify_change(dir, dentry)) + nfs_mark_dir_for_revalidate(dir); + return nfs_lookup_revalidate_done(dir, dentry, inode, ret); +} + +/* + * 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_do_lookup_revalidate(struct inode *dir, struct dentry *dentry, + unsigned int flags) +{ + struct inode *inode; + int error; + + nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE); + inode = d_inode(dentry); + + if (!inode) + return nfs_lookup_revalidate_negative(dir, dentry, flags); + + if (is_bad_inode(inode)) { + dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n", + __func__, dentry); + goto out_bad; + } + + if ((flags & LOOKUP_RENAME_TARGET) && d_count(dentry) < 2 && + nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE)) + goto out_bad; + + if (nfs_verifier_is_delegated(dentry)) + return nfs_lookup_revalidate_delegated(dir, dentry, inode); + + /* Force a full look up iff the parent directory has changed */ + if (!(flags & (LOOKUP_EXCL | LOOKUP_REVAL)) && + nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU)) { + error = nfs_lookup_verify_inode(inode, flags); + if (error) { + if (error == -ESTALE) + nfs_mark_dir_for_revalidate(dir); + goto out_bad; + } + goto out_valid; + } + + if (flags & LOOKUP_RCU) + return -ECHILD; + + if (NFS_STALE(inode)) + goto out_bad; + + return nfs_lookup_revalidate_dentry(dir, dentry, inode, flags); +out_valid: + return nfs_lookup_revalidate_done(dir, dentry, inode, 1); +out_bad: + if (flags & LOOKUP_RCU) + return -ECHILD; + return nfs_lookup_revalidate_done(dir, dentry, inode, 0); +} + +static int +__nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags, + int (*reval)(struct inode *, struct dentry *, unsigned int)) +{ + struct dentry *parent; + struct inode *dir; + int ret; + + if (flags & LOOKUP_RCU) { + if (dentry->d_fsdata == NFS_FSDATA_BLOCKED) + return -ECHILD; + parent = READ_ONCE(dentry->d_parent); + dir = d_inode_rcu(parent); + if (!dir) + return -ECHILD; + ret = reval(dir, dentry, flags); + if (parent != READ_ONCE(dentry->d_parent)) + return -ECHILD; + } else { + /* Wait for unlink to complete */ + wait_var_event(&dentry->d_fsdata, + dentry->d_fsdata != NFS_FSDATA_BLOCKED); + parent = dget_parent(dentry); + ret = reval(d_inode(parent), dentry, flags); + dput(parent); + } + return ret; +} + +static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags) +{ + return __nfs_lookup_revalidate(dentry, flags, nfs_do_lookup_revalidate); +} + +/* + * A weaker form of d_revalidate for revalidating just the d_inode(dentry) + * when we don't really care about the dentry name. This is called when a + * pathwalk ends on a dentry that was not found via a normal lookup in the + * parent dir (e.g.: ".", "..", procfs symlinks or mountpoint traversals). + * + * In this situation, we just want to verify that the inode itself is OK + * since the dentry might have changed on the server. + */ +static int nfs_weak_revalidate(struct dentry *dentry, unsigned int flags) +{ + struct inode *inode = d_inode(dentry); + int error = 0; + + /* + * I believe we can only get a negative dentry here in the case of a + * procfs-style symlink. Just assume it's correct for now, but we may + * eventually need to do something more here. + */ + if (!inode) { + dfprintk(LOOKUPCACHE, "%s: %pd2 has negative inode\n", + __func__, dentry); + return 1; + } + + if (is_bad_inode(inode)) { + dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n", + __func__, dentry); + return 0; + } + + error = nfs_lookup_verify_inode(inode, flags); + dfprintk(LOOKUPCACHE, "NFS: %s: inode %lu is %s\n", + __func__, inode->i_ino, error ? "invalid" : "valid"); + return !error; +} + +/* + * This is called from dput() when d_count is going to 0. + */ +static int nfs_dentry_delete(const struct dentry *dentry) +{ + dfprintk(VFS, "NFS: dentry_delete(%pd2, %x)\n", + dentry, dentry->d_flags); + + /* Unhash any dentry with a stale inode */ + if (d_really_is_positive(dentry) && NFS_STALE(d_inode(dentry))) + return 1; + + if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { + /* Unhash it, so that ->d_iput() would be called */ + return 1; + } + if (!(dentry->d_sb->s_flags & SB_ACTIVE)) { + /* Unhash it, so that ancestors of killed async unlink + * files will be cleaned up during umount */ + return 1; + } + return 0; + +} + +/* Ensure that we revalidate inode->i_nlink */ +static void nfs_drop_nlink(struct inode *inode) +{ + spin_lock(&inode->i_lock); + /* drop the inode if we're reasonably sure this is the last link */ + if (inode->i_nlink > 0) + drop_nlink(inode); + NFS_I(inode)->attr_gencount = nfs_inc_attr_generation_counter(); + nfs_set_cache_invalid( + inode, NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_CTIME | + NFS_INO_INVALID_NLINK); + spin_unlock(&inode->i_lock); +} + +/* + * 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) { + nfs_complete_unlink(dentry, inode); + nfs_drop_nlink(inode); + } + iput(inode); +} + +static void nfs_d_release(struct dentry *dentry) +{ + /* free cached devname value, if it survived that far */ + if (unlikely(dentry->d_fsdata)) { + if (dentry->d_flags & DCACHE_NFSFS_RENAMED) + WARN_ON(1); + else + kfree(dentry->d_fsdata); + } +} + +const struct dentry_operations nfs_dentry_operations = { + .d_revalidate = nfs_lookup_revalidate, + .d_weak_revalidate = nfs_weak_revalidate, + .d_delete = nfs_dentry_delete, + .d_iput = nfs_dentry_iput, + .d_automount = nfs_d_automount, + .d_release = nfs_d_release, +}; +EXPORT_SYMBOL_GPL(nfs_dentry_operations); + +struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags) +{ + struct dentry *res; + struct inode *inode = NULL; + struct nfs_fh *fhandle = NULL; + struct nfs_fattr *fattr = NULL; + unsigned long dir_verifier; + int error; + + dfprintk(VFS, "NFS: lookup(%pd2)\n", dentry); + nfs_inc_stats(dir, NFSIOS_VFSLOOKUP); + + if (unlikely(dentry->d_name.len > NFS_SERVER(dir)->namelen)) + return ERR_PTR(-ENAMETOOLONG); + + /* + * If we're doing an exclusive create, optimize away the lookup + * but don't hash the dentry. + */ + if (nfs_is_exclusive_create(dir, flags) || flags & LOOKUP_RENAME_TARGET) + return NULL; + + res = ERR_PTR(-ENOMEM); + fhandle = nfs_alloc_fhandle(); + fattr = nfs_alloc_fattr_with_label(NFS_SERVER(dir)); + if (fhandle == NULL || fattr == NULL) + goto out; + + dir_verifier = nfs_save_change_attribute(dir); + trace_nfs_lookup_enter(dir, dentry, flags); + error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr); + if (error == -ENOENT) { + if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE)) + dir_verifier = inode_peek_iversion_raw(dir); + goto no_entry; + } + if (error < 0) { + res = ERR_PTR(error); + goto out; + } + inode = nfs_fhget(dentry->d_sb, fhandle, fattr); + res = ERR_CAST(inode); + if (IS_ERR(res)) + goto out; + + /* Notify readdir to use READDIRPLUS */ + nfs_lookup_advise_force_readdirplus(dir, flags); + +no_entry: + res = d_splice_alias(inode, dentry); + if (res != NULL) { + if (IS_ERR(res)) + goto out; + dentry = res; + } + nfs_set_verifier(dentry, dir_verifier); +out: + trace_nfs_lookup_exit(dir, dentry, flags, PTR_ERR_OR_ZERO(res)); + nfs_free_fattr(fattr); + nfs_free_fhandle(fhandle); + return res; +} +EXPORT_SYMBOL_GPL(nfs_lookup); + +void nfs_d_prune_case_insensitive_aliases(struct inode *inode) +{ + /* Case insensitive server? Revalidate dentries */ + if (inode && nfs_server_capable(inode, NFS_CAP_CASE_INSENSITIVE)) + d_prune_aliases(inode); +} +EXPORT_SYMBOL_GPL(nfs_d_prune_case_insensitive_aliases); + +#if IS_ENABLED(CONFIG_NFS_V4) +static int nfs4_lookup_revalidate(struct dentry *, unsigned int); + +const struct dentry_operations nfs4_dentry_operations = { + .d_revalidate = nfs4_lookup_revalidate, + .d_weak_revalidate = nfs_weak_revalidate, + .d_delete = nfs_dentry_delete, + .d_iput = nfs_dentry_iput, + .d_automount = nfs_d_automount, + .d_release = nfs_d_release, +}; +EXPORT_SYMBOL_GPL(nfs4_dentry_operations); + +static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags, struct file *filp) +{ + return alloc_nfs_open_context(dentry, flags_to_mode(open_flags), filp); +} + +static int do_open(struct inode *inode, struct file *filp) +{ + nfs_fscache_open_file(inode, filp); + return 0; +} + +static int nfs_finish_open(struct nfs_open_context *ctx, + struct dentry *dentry, + struct file *file, unsigned open_flags) +{ + int err; + + err = finish_open(file, dentry, do_open); + if (err) + goto out; + if (S_ISREG(file_inode(file)->i_mode)) + nfs_file_set_open_context(file, ctx); + else + err = -EOPENSTALE; +out: + return err; +} + +int nfs_atomic_open(struct inode *dir, struct dentry *dentry, + struct file *file, unsigned open_flags, + umode_t mode) +{ + DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + struct nfs_open_context *ctx; + struct dentry *res; + struct iattr attr = { .ia_valid = ATTR_OPEN }; + struct inode *inode; + unsigned int lookup_flags = 0; + unsigned long dir_verifier; + bool switched = false; + int created = 0; + int err; + + /* Expect a negative dentry */ + BUG_ON(d_inode(dentry)); + + dfprintk(VFS, "NFS: atomic_open(%s/%lu), %pd\n", + dir->i_sb->s_id, dir->i_ino, dentry); + + err = nfs_check_flags(open_flags); + if (err) + return err; + + /* NFS only supports OPEN on regular files */ + if ((open_flags & O_DIRECTORY)) { + if (!d_in_lookup(dentry)) { + /* + * Hashed negative dentry with O_DIRECTORY: dentry was + * revalidated and is fine, no need to perform lookup + * again + */ + return -ENOENT; + } + lookup_flags = LOOKUP_OPEN|LOOKUP_DIRECTORY; + goto no_open; + } + + if (dentry->d_name.len > NFS_SERVER(dir)->namelen) + return -ENAMETOOLONG; + + if (open_flags & O_CREAT) { + struct nfs_server *server = NFS_SERVER(dir); + + if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK)) + mode &= ~current_umask(); + + attr.ia_valid |= ATTR_MODE; + attr.ia_mode = mode; + } + if (open_flags & O_TRUNC) { + attr.ia_valid |= ATTR_SIZE; + attr.ia_size = 0; + } + + if (!(open_flags & O_CREAT) && !d_in_lookup(dentry)) { + d_drop(dentry); + switched = true; + dentry = d_alloc_parallel(dentry->d_parent, + &dentry->d_name, &wq); + if (IS_ERR(dentry)) + return PTR_ERR(dentry); + if (unlikely(!d_in_lookup(dentry))) + return finish_no_open(file, dentry); + } + + ctx = create_nfs_open_context(dentry, open_flags, file); + err = PTR_ERR(ctx); + if (IS_ERR(ctx)) + goto out; + + trace_nfs_atomic_open_enter(dir, ctx, open_flags); + inode = NFS_PROTO(dir)->open_context(dir, ctx, open_flags, &attr, &created); + if (created) + file->f_mode |= FMODE_CREATED; + if (IS_ERR(inode)) { + err = PTR_ERR(inode); + trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); + put_nfs_open_context(ctx); + d_drop(dentry); + switch (err) { + case -ENOENT: + d_splice_alias(NULL, dentry); + if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE)) + dir_verifier = inode_peek_iversion_raw(dir); + else + dir_verifier = nfs_save_change_attribute(dir); + nfs_set_verifier(dentry, dir_verifier); + break; + case -EISDIR: + case -ENOTDIR: + goto no_open; + case -ELOOP: + if (!(open_flags & O_NOFOLLOW)) + goto no_open; + break; + /* case -EINVAL: */ + default: + break; + } + goto out; + } + file->f_mode |= FMODE_CAN_ODIRECT; + + err = nfs_finish_open(ctx, ctx->dentry, file, open_flags); + trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); + put_nfs_open_context(ctx); +out: + if (unlikely(switched)) { + d_lookup_done(dentry); + dput(dentry); + } + return err; + +no_open: + res = nfs_lookup(dir, dentry, lookup_flags); + if (!res) { + inode = d_inode(dentry); + if ((lookup_flags & LOOKUP_DIRECTORY) && inode && + !(S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))) + res = ERR_PTR(-ENOTDIR); + else if (inode && S_ISREG(inode->i_mode)) + res = ERR_PTR(-EOPENSTALE); + } else if (!IS_ERR(res)) { + inode = d_inode(res); + if ((lookup_flags & LOOKUP_DIRECTORY) && inode && + !(S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))) { + dput(res); + res = ERR_PTR(-ENOTDIR); + } else if (inode && S_ISREG(inode->i_mode)) { + dput(res); + res = ERR_PTR(-EOPENSTALE); + } + } + if (switched) { + d_lookup_done(dentry); + if (!res) + res = dentry; + else + dput(dentry); + } + if (IS_ERR(res)) + return PTR_ERR(res); + return finish_no_open(file, res); +} +EXPORT_SYMBOL_GPL(nfs_atomic_open); + +static int +nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry, + unsigned int flags) +{ + struct inode *inode; + + if (!(flags & LOOKUP_OPEN) || (flags & LOOKUP_DIRECTORY)) + goto full_reval; + if (d_mountpoint(dentry)) + goto full_reval; + + inode = d_inode(dentry); + + /* We can't create new files in nfs_open_revalidate(), so we + * optimize away revalidation of negative dentries. + */ + if (inode == NULL) + goto full_reval; + + if (nfs_verifier_is_delegated(dentry)) + return nfs_lookup_revalidate_delegated(dir, dentry, inode); + + /* NFS only supports OPEN on regular files */ + if (!S_ISREG(inode->i_mode)) + goto full_reval; + + /* We cannot do exclusive creation on a positive dentry */ + if (flags & (LOOKUP_EXCL | LOOKUP_REVAL)) + goto reval_dentry; + + /* Check if the directory changed */ + if (!nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU)) + goto reval_dentry; + + /* Let f_op->open() actually open (and revalidate) the file */ + return 1; +reval_dentry: + if (flags & LOOKUP_RCU) + return -ECHILD; + return nfs_lookup_revalidate_dentry(dir, dentry, inode, flags); + +full_reval: + return nfs_do_lookup_revalidate(dir, dentry, flags); +} + +static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags) +{ + return __nfs_lookup_revalidate(dentry, flags, + nfs4_do_lookup_revalidate); +} + +#endif /* CONFIG_NFSV4 */ + +struct dentry * +nfs_add_or_obtain(struct dentry *dentry, struct nfs_fh *fhandle, + struct nfs_fattr *fattr) +{ + struct dentry *parent = dget_parent(dentry); + struct inode *dir = d_inode(parent); + struct inode *inode; + struct dentry *d; + int error; + + d_drop(dentry); + + if (fhandle->size == 0) { + error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr); + if (error) + goto out_error; + } + nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + if (!(fattr->valid & NFS_ATTR_FATTR)) { + struct nfs_server *server = NFS_SB(dentry->d_sb); + error = server->nfs_client->rpc_ops->getattr(server, fhandle, + fattr, NULL); + if (error < 0) + goto out_error; + } + inode = nfs_fhget(dentry->d_sb, fhandle, fattr); + d = d_splice_alias(inode, dentry); +out: + dput(parent); + return d; +out_error: + d = ERR_PTR(error); + goto out; +} +EXPORT_SYMBOL_GPL(nfs_add_or_obtain); + +/* + * Code common to create, mkdir, and mknod. + */ +int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle, + struct nfs_fattr *fattr) +{ + struct dentry *d; + + d = nfs_add_or_obtain(dentry, fhandle, fattr); + if (IS_ERR(d)) + return PTR_ERR(d); + + /* Callers don't care */ + dput(d); + return 0; +} +EXPORT_SYMBOL_GPL(nfs_instantiate); + +/* + * 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. + */ +int nfs_create(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, umode_t mode, bool excl) +{ + struct iattr attr; + int open_flags = excl ? O_CREAT | O_EXCL : O_CREAT; + int error; + + dfprintk(VFS, "NFS: create(%s/%lu), %pd\n", + dir->i_sb->s_id, dir->i_ino, dentry); + + attr.ia_mode = mode; + attr.ia_valid = ATTR_MODE; + + trace_nfs_create_enter(dir, dentry, open_flags); + error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags); + trace_nfs_create_exit(dir, dentry, open_flags, error); + if (error != 0) + goto out_err; + return 0; +out_err: + d_drop(dentry); + return error; +} +EXPORT_SYMBOL_GPL(nfs_create); + +/* + * See comments for nfs_proc_create regarding failed operations. + */ +int +nfs_mknod(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, umode_t mode, dev_t rdev) +{ + struct iattr attr; + int status; + + dfprintk(VFS, "NFS: mknod(%s/%lu), %pd\n", + dir->i_sb->s_id, dir->i_ino, dentry); + + attr.ia_mode = mode; + attr.ia_valid = ATTR_MODE; + + trace_nfs_mknod_enter(dir, dentry); + status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev); + trace_nfs_mknod_exit(dir, dentry, status); + if (status != 0) + goto out_err; + return 0; +out_err: + d_drop(dentry); + return status; +} +EXPORT_SYMBOL_GPL(nfs_mknod); + +/* + * See comments for nfs_proc_create regarding failed operations. + */ +int nfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, umode_t mode) +{ + struct iattr attr; + int error; + + dfprintk(VFS, "NFS: mkdir(%s/%lu), %pd\n", + dir->i_sb->s_id, dir->i_ino, dentry); + + attr.ia_valid = ATTR_MODE; + attr.ia_mode = mode | S_IFDIR; + + trace_nfs_mkdir_enter(dir, dentry); + error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr); + trace_nfs_mkdir_exit(dir, dentry, error); + if (error != 0) + goto out_err; + return 0; +out_err: + d_drop(dentry); + return error; +} +EXPORT_SYMBOL_GPL(nfs_mkdir); + +static void nfs_dentry_handle_enoent(struct dentry *dentry) +{ + if (simple_positive(dentry)) + d_delete(dentry); +} + +static void nfs_dentry_remove_handle_error(struct inode *dir, + struct dentry *dentry, int error) +{ + switch (error) { + case -ENOENT: + if (d_really_is_positive(dentry)) + d_delete(dentry); + nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + break; + case 0: + nfs_d_prune_case_insensitive_aliases(d_inode(dentry)); + nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + } +} + +int nfs_rmdir(struct inode *dir, struct dentry *dentry) +{ + int error; + + dfprintk(VFS, "NFS: rmdir(%s/%lu), %pd\n", + dir->i_sb->s_id, dir->i_ino, dentry); + + trace_nfs_rmdir_enter(dir, dentry); + if (d_really_is_positive(dentry)) { + down_write(&NFS_I(d_inode(dentry))->rmdir_sem); + error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); + /* Ensure the VFS deletes this inode */ + switch (error) { + case 0: + clear_nlink(d_inode(dentry)); + break; + case -ENOENT: + nfs_dentry_handle_enoent(dentry); + } + up_write(&NFS_I(d_inode(dentry))->rmdir_sem); + } else + error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); + nfs_dentry_remove_handle_error(dir, dentry, error); + trace_nfs_rmdir_exit(dir, dentry, error); + + return error; +} +EXPORT_SYMBOL_GPL(nfs_rmdir); + +/* + * 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 = d_inode(dentry->d_parent); + struct inode *inode = d_inode(dentry); + int error = -EBUSY; + + dfprintk(VFS, "NFS: safe_remove(%pd2)\n", dentry); + + /* If the dentry was sillyrenamed, we simply call d_delete() */ + if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { + error = 0; + goto out; + } + + trace_nfs_remove_enter(dir, dentry); + if (inode != NULL) { + error = NFS_PROTO(dir)->remove(dir, dentry); + if (error == 0) + nfs_drop_nlink(inode); + } else + error = NFS_PROTO(dir)->remove(dir, dentry); + if (error == -ENOENT) + nfs_dentry_handle_enoent(dentry); + trace_nfs_remove_exit(dir, dentry, error); +out: + 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. + */ +int nfs_unlink(struct inode *dir, struct dentry *dentry) +{ + int error; + + dfprintk(VFS, "NFS: unlink(%s/%lu, %pd)\n", dir->i_sb->s_id, + dir->i_ino, dentry); + + trace_nfs_unlink_enter(dir, dentry); + spin_lock(&dentry->d_lock); + if (d_count(dentry) > 1 && !test_bit(NFS_INO_PRESERVE_UNLINKED, + &NFS_I(d_inode(dentry))->flags)) { + spin_unlock(&dentry->d_lock); + /* Start asynchronous writeout of the inode */ + write_inode_now(d_inode(dentry), 0); + error = nfs_sillyrename(dir, dentry); + goto out; + } + /* We must prevent any concurrent open until the unlink + * completes. ->d_revalidate will wait for ->d_fsdata + * to clear. We set it here to ensure no lookup succeeds until + * the unlink is complete on the server. + */ + error = -ETXTBSY; + if (WARN_ON(dentry->d_flags & DCACHE_NFSFS_RENAMED) || + WARN_ON(dentry->d_fsdata == NFS_FSDATA_BLOCKED)) { + spin_unlock(&dentry->d_lock); + goto out; + } + /* old devname */ + kfree(dentry->d_fsdata); + dentry->d_fsdata = NFS_FSDATA_BLOCKED; + + spin_unlock(&dentry->d_lock); + error = nfs_safe_remove(dentry); + nfs_dentry_remove_handle_error(dir, dentry, error); + dentry->d_fsdata = NULL; + wake_up_var(&dentry->d_fsdata); +out: + trace_nfs_unlink_exit(dir, dentry, error); + return error; +} +EXPORT_SYMBOL_GPL(nfs_unlink); + +/* + * To create a symbolic link, most file systems instantiate a new inode, + * add a page to it containing the path, then write it out to the disk + * using prepare_write/commit_write. + * + * Unfortunately the NFS client can't create the in-core inode first + * because it needs a file handle to create an in-core inode (see + * fs/nfs/inode.c:nfs_fhget). We only have a file handle *after* the + * symlink request has completed on the server. + * + * So instead we allocate a raw page, copy the symname into it, then do + * the SYMLINK request with the page as the buffer. If it succeeds, we + * now have a new file handle and can instantiate an in-core NFS inode + * and move the raw page into its mapping. + */ +int nfs_symlink(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, const char *symname) +{ + struct page *page; + char *kaddr; + struct iattr attr; + unsigned int pathlen = strlen(symname); + int error; + + dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s)\n", dir->i_sb->s_id, + dir->i_ino, dentry, symname); + + if (pathlen > PAGE_SIZE) + return -ENAMETOOLONG; + + attr.ia_mode = S_IFLNK | S_IRWXUGO; + attr.ia_valid = ATTR_MODE; + + page = alloc_page(GFP_USER); + if (!page) + return -ENOMEM; + + kaddr = page_address(page); + memcpy(kaddr, symname, pathlen); + if (pathlen < PAGE_SIZE) + memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen); + + trace_nfs_symlink_enter(dir, dentry); + error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr); + trace_nfs_symlink_exit(dir, dentry, error); + if (error != 0) { + dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s) error %d\n", + dir->i_sb->s_id, dir->i_ino, + dentry, symname, error); + d_drop(dentry); + __free_page(page); + return error; + } + + nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + + /* + * No big deal if we can't add this page to the page cache here. + * READLINK will get the missing page from the server if needed. + */ + if (!add_to_page_cache_lru(page, d_inode(dentry)->i_mapping, 0, + GFP_KERNEL)) { + SetPageUptodate(page); + unlock_page(page); + /* + * add_to_page_cache_lru() grabs an extra page refcount. + * Drop it here to avoid leaking this page later. + */ + put_page(page); + } else + __free_page(page); + + return 0; +} +EXPORT_SYMBOL_GPL(nfs_symlink); + +int +nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) +{ + struct inode *inode = d_inode(old_dentry); + int error; + + dfprintk(VFS, "NFS: link(%pd2 -> %pd2)\n", + old_dentry, dentry); + + trace_nfs_link_enter(inode, dir, dentry); + d_drop(dentry); + if (S_ISREG(inode->i_mode)) + nfs_sync_inode(inode); + error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); + if (error == 0) { + nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + ihold(inode); + d_add(dentry, inode); + } + trace_nfs_link_exit(inode, dir, dentry, error); + return error; +} +EXPORT_SYMBOL_GPL(nfs_link); + +static void +nfs_unblock_rename(struct rpc_task *task, struct nfs_renamedata *data) +{ + struct dentry *new_dentry = data->new_dentry; + + new_dentry->d_fsdata = NULL; + wake_up_var(&new_dentry->d_fsdata); +} + +/* + * 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. + */ +int nfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir, + struct dentry *old_dentry, struct inode *new_dir, + struct dentry *new_dentry, unsigned int flags) +{ + struct inode *old_inode = d_inode(old_dentry); + struct inode *new_inode = d_inode(new_dentry); + struct dentry *dentry = NULL; + struct rpc_task *task; + bool must_unblock = false; + int error = -EBUSY; + + if (flags) + return -EINVAL; + + dfprintk(VFS, "NFS: rename(%pd2 -> %pd2, ct=%d)\n", + old_dentry, new_dentry, + d_count(new_dentry)); + + trace_nfs_rename_enter(old_dir, old_dentry, new_dir, new_dentry); + /* + * For non-directories, check whether the target is busy and if so, + * 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 && !S_ISDIR(new_inode->i_mode)) { + /* We must prevent any concurrent open until the unlink + * completes. ->d_revalidate will wait for ->d_fsdata + * to clear. We set it here to ensure no lookup succeeds until + * the unlink is complete on the server. + */ + error = -ETXTBSY; + if (WARN_ON(new_dentry->d_flags & DCACHE_NFSFS_RENAMED) || + WARN_ON(new_dentry->d_fsdata == NFS_FSDATA_BLOCKED)) + goto out; + if (new_dentry->d_fsdata) { + /* old devname */ + kfree(new_dentry->d_fsdata); + new_dentry->d_fsdata = NULL; + } + + spin_lock(&new_dentry->d_lock); + if (d_count(new_dentry) > 2) { + int err; + + spin_unlock(&new_dentry->d_lock); + + /* 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) + goto out; + + new_dentry = dentry; + new_inode = NULL; + } else { + new_dentry->d_fsdata = NFS_FSDATA_BLOCKED; + must_unblock = true; + spin_unlock(&new_dentry->d_lock); + } + + } + + if (S_ISREG(old_inode->i_mode)) + nfs_sync_inode(old_inode); + task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry, + must_unblock ? nfs_unblock_rename : NULL); + if (IS_ERR(task)) { + error = PTR_ERR(task); + goto out; + } + + error = rpc_wait_for_completion_task(task); + if (error != 0) { + ((struct nfs_renamedata *)task->tk_calldata)->cancelled = 1; + /* Paired with the atomic_dec_and_test() barrier in rpc_do_put_task() */ + smp_wmb(); + } else + error = task->tk_status; + rpc_put_task(task); + /* Ensure the inode attributes are revalidated */ + if (error == 0) { + spin_lock(&old_inode->i_lock); + NFS_I(old_inode)->attr_gencount = nfs_inc_attr_generation_counter(); + nfs_set_cache_invalid(old_inode, NFS_INO_INVALID_CHANGE | + NFS_INO_INVALID_CTIME | + NFS_INO_REVAL_FORCED); + spin_unlock(&old_inode->i_lock); + } +out: + trace_nfs_rename_exit(old_dir, old_dentry, + new_dir, new_dentry, error); + if (!error) { + if (new_inode != NULL) + nfs_drop_nlink(new_inode); + /* + * The d_move() should be here instead of in an async RPC completion + * handler because we need the proper locks to move the dentry. If + * we're interrupted by a signal, the async RPC completion handler + * should mark the directories for revalidation. + */ + d_move(old_dentry, new_dentry); + nfs_set_verifier(old_dentry, + nfs_save_change_attribute(new_dir)); + } else if (error == -ENOENT) + nfs_dentry_handle_enoent(old_dentry); + + /* new dentry created? */ + if (dentry) + dput(dentry); + return error; +} +EXPORT_SYMBOL_GPL(nfs_rename); + +static DEFINE_SPINLOCK(nfs_access_lru_lock); +static LIST_HEAD(nfs_access_lru_list); +static atomic_long_t nfs_access_nr_entries; + +static unsigned long nfs_access_max_cachesize = 4*1024*1024; +module_param(nfs_access_max_cachesize, ulong, 0644); +MODULE_PARM_DESC(nfs_access_max_cachesize, "NFS access maximum total cache length"); + +static void nfs_access_free_entry(struct nfs_access_entry *entry) +{ + put_group_info(entry->group_info); + kfree_rcu(entry, rcu_head); + smp_mb__before_atomic(); + atomic_long_dec(&nfs_access_nr_entries); + smp_mb__after_atomic(); +} + +static void nfs_access_free_list(struct list_head *head) +{ + struct nfs_access_entry *cache; + + while (!list_empty(head)) { + cache = list_entry(head->next, struct nfs_access_entry, lru); + list_del(&cache->lru); + nfs_access_free_entry(cache); + } +} + +static unsigned long +nfs_do_access_cache_scan(unsigned int nr_to_scan) +{ + LIST_HEAD(head); + struct nfs_inode *nfsi, *next; + struct nfs_access_entry *cache; + long freed = 0; + + spin_lock(&nfs_access_lru_lock); + list_for_each_entry_safe(nfsi, next, &nfs_access_lru_list, access_cache_inode_lru) { + struct inode *inode; + + if (nr_to_scan-- == 0) + break; + inode = &nfsi->vfs_inode; + spin_lock(&inode->i_lock); + if (list_empty(&nfsi->access_cache_entry_lru)) + goto remove_lru_entry; + cache = list_entry(nfsi->access_cache_entry_lru.next, + struct nfs_access_entry, lru); + list_move(&cache->lru, &head); + rb_erase(&cache->rb_node, &nfsi->access_cache); + freed++; + if (!list_empty(&nfsi->access_cache_entry_lru)) + list_move_tail(&nfsi->access_cache_inode_lru, + &nfs_access_lru_list); + else { +remove_lru_entry: + list_del_init(&nfsi->access_cache_inode_lru); + smp_mb__before_atomic(); + clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags); + smp_mb__after_atomic(); + } + spin_unlock(&inode->i_lock); + } + spin_unlock(&nfs_access_lru_lock); + nfs_access_free_list(&head); + return freed; +} + +unsigned long +nfs_access_cache_scan(struct shrinker *shrink, struct shrink_control *sc) +{ + int nr_to_scan = sc->nr_to_scan; + gfp_t gfp_mask = sc->gfp_mask; + + if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL) + return SHRINK_STOP; + return nfs_do_access_cache_scan(nr_to_scan); +} + + +unsigned long +nfs_access_cache_count(struct shrinker *shrink, struct shrink_control *sc) +{ + return vfs_pressure_ratio(atomic_long_read(&nfs_access_nr_entries)); +} + +static void +nfs_access_cache_enforce_limit(void) +{ + long nr_entries = atomic_long_read(&nfs_access_nr_entries); + unsigned long diff; + unsigned int nr_to_scan; + + if (nr_entries < 0 || nr_entries <= nfs_access_max_cachesize) + return; + nr_to_scan = 100; + diff = nr_entries - nfs_access_max_cachesize; + if (diff < nr_to_scan) + nr_to_scan = diff; + nfs_do_access_cache_scan(nr_to_scan); +} + +static void __nfs_access_zap_cache(struct nfs_inode *nfsi, struct list_head *head) +{ + struct rb_root *root_node = &nfsi->access_cache; + struct rb_node *n; + struct nfs_access_entry *entry; + + /* Unhook entries from the cache */ + while ((n = rb_first(root_node)) != NULL) { + entry = rb_entry(n, struct nfs_access_entry, rb_node); + rb_erase(n, root_node); + list_move(&entry->lru, head); + } + nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS; +} + +void nfs_access_zap_cache(struct inode *inode) +{ + LIST_HEAD(head); + + if (test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags) == 0) + return; + /* Remove from global LRU init */ + spin_lock(&nfs_access_lru_lock); + if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) + list_del_init(&NFS_I(inode)->access_cache_inode_lru); + + spin_lock(&inode->i_lock); + __nfs_access_zap_cache(NFS_I(inode), &head); + spin_unlock(&inode->i_lock); + spin_unlock(&nfs_access_lru_lock); + nfs_access_free_list(&head); +} +EXPORT_SYMBOL_GPL(nfs_access_zap_cache); + +static int access_cmp(const struct cred *a, const struct nfs_access_entry *b) +{ + struct group_info *ga, *gb; + int g; + + if (uid_lt(a->fsuid, b->fsuid)) + return -1; + if (uid_gt(a->fsuid, b->fsuid)) + return 1; + + if (gid_lt(a->fsgid, b->fsgid)) + return -1; + if (gid_gt(a->fsgid, b->fsgid)) + return 1; + + ga = a->group_info; + gb = b->group_info; + if (ga == gb) + return 0; + if (ga == NULL) + return -1; + if (gb == NULL) + return 1; + if (ga->ngroups < gb->ngroups) + return -1; + if (ga->ngroups > gb->ngroups) + return 1; + + for (g = 0; g < ga->ngroups; g++) { + if (gid_lt(ga->gid[g], gb->gid[g])) + return -1; + if (gid_gt(ga->gid[g], gb->gid[g])) + return 1; + } + return 0; +} + +static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, const struct cred *cred) +{ + struct rb_node *n = NFS_I(inode)->access_cache.rb_node; + + while (n != NULL) { + struct nfs_access_entry *entry = + rb_entry(n, struct nfs_access_entry, rb_node); + int cmp = access_cmp(cred, entry); + + if (cmp < 0) + n = n->rb_left; + else if (cmp > 0) + n = n->rb_right; + else + return entry; + } + return NULL; +} + +static int nfs_access_get_cached_locked(struct inode *inode, const struct cred *cred, u32 *mask, bool may_block) +{ + struct nfs_inode *nfsi = NFS_I(inode); + struct nfs_access_entry *cache; + bool retry = true; + int err; + + spin_lock(&inode->i_lock); + for(;;) { + if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) + goto out_zap; + cache = nfs_access_search_rbtree(inode, cred); + err = -ENOENT; + if (cache == NULL) + goto out; + /* Found an entry, is our attribute cache valid? */ + if (!nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS)) + break; + if (!retry) + break; + err = -ECHILD; + if (!may_block) + goto out; + spin_unlock(&inode->i_lock); + err = __nfs_revalidate_inode(NFS_SERVER(inode), inode); + if (err) + return err; + spin_lock(&inode->i_lock); + retry = false; + } + *mask = cache->mask; + list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru); + err = 0; +out: + spin_unlock(&inode->i_lock); + return err; +out_zap: + spin_unlock(&inode->i_lock); + nfs_access_zap_cache(inode); + return -ENOENT; +} + +static int nfs_access_get_cached_rcu(struct inode *inode, const struct cred *cred, u32 *mask) +{ + /* Only check the most recently returned cache entry, + * but do it without locking. + */ + struct nfs_inode *nfsi = NFS_I(inode); + struct nfs_access_entry *cache; + int err = -ECHILD; + struct list_head *lh; + + rcu_read_lock(); + if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) + goto out; + lh = rcu_dereference(list_tail_rcu(&nfsi->access_cache_entry_lru)); + cache = list_entry(lh, struct nfs_access_entry, lru); + if (lh == &nfsi->access_cache_entry_lru || + access_cmp(cred, cache) != 0) + cache = NULL; + if (cache == NULL) + goto out; + if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS)) + goto out; + *mask = cache->mask; + err = 0; +out: + rcu_read_unlock(); + return err; +} + +int nfs_access_get_cached(struct inode *inode, const struct cred *cred, + u32 *mask, bool may_block) +{ + int status; + + status = nfs_access_get_cached_rcu(inode, cred, mask); + if (status != 0) + status = nfs_access_get_cached_locked(inode, cred, mask, + may_block); + + return status; +} +EXPORT_SYMBOL_GPL(nfs_access_get_cached); + +static void nfs_access_add_rbtree(struct inode *inode, + struct nfs_access_entry *set, + const struct cred *cred) +{ + struct nfs_inode *nfsi = NFS_I(inode); + struct rb_root *root_node = &nfsi->access_cache; + struct rb_node **p = &root_node->rb_node; + struct rb_node *parent = NULL; + struct nfs_access_entry *entry; + int cmp; + + spin_lock(&inode->i_lock); + while (*p != NULL) { + parent = *p; + entry = rb_entry(parent, struct nfs_access_entry, rb_node); + cmp = access_cmp(cred, entry); + + if (cmp < 0) + p = &parent->rb_left; + else if (cmp > 0) + p = &parent->rb_right; + else + goto found; + } + rb_link_node(&set->rb_node, parent, p); + rb_insert_color(&set->rb_node, root_node); + list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); + spin_unlock(&inode->i_lock); + return; +found: + rb_replace_node(parent, &set->rb_node, root_node); + list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); + list_del(&entry->lru); + spin_unlock(&inode->i_lock); + nfs_access_free_entry(entry); +} + +void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set, + const struct cred *cred) +{ + struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL); + if (cache == NULL) + return; + RB_CLEAR_NODE(&cache->rb_node); + cache->fsuid = cred->fsuid; + cache->fsgid = cred->fsgid; + cache->group_info = get_group_info(cred->group_info); + cache->mask = set->mask; + + /* The above field assignments must be visible + * before this item appears on the lru. We cannot easily + * use rcu_assign_pointer, so just force the memory barrier. + */ + smp_wmb(); + nfs_access_add_rbtree(inode, cache, cred); + + /* Update accounting */ + smp_mb__before_atomic(); + atomic_long_inc(&nfs_access_nr_entries); + smp_mb__after_atomic(); + + /* Add inode to global LRU list */ + if (!test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) { + spin_lock(&nfs_access_lru_lock); + if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) + list_add_tail(&NFS_I(inode)->access_cache_inode_lru, + &nfs_access_lru_list); + spin_unlock(&nfs_access_lru_lock); + } + nfs_access_cache_enforce_limit(); +} +EXPORT_SYMBOL_GPL(nfs_access_add_cache); + +#define NFS_MAY_READ (NFS_ACCESS_READ) +#define NFS_MAY_WRITE (NFS_ACCESS_MODIFY | \ + NFS_ACCESS_EXTEND | \ + NFS_ACCESS_DELETE) +#define NFS_FILE_MAY_WRITE (NFS_ACCESS_MODIFY | \ + NFS_ACCESS_EXTEND) +#define NFS_DIR_MAY_WRITE NFS_MAY_WRITE +#define NFS_MAY_LOOKUP (NFS_ACCESS_LOOKUP) +#define NFS_MAY_EXECUTE (NFS_ACCESS_EXECUTE) +static int +nfs_access_calc_mask(u32 access_result, umode_t umode) +{ + int mask = 0; + + if (access_result & NFS_MAY_READ) + mask |= MAY_READ; + if (S_ISDIR(umode)) { + if ((access_result & NFS_DIR_MAY_WRITE) == NFS_DIR_MAY_WRITE) + mask |= MAY_WRITE; + if ((access_result & NFS_MAY_LOOKUP) == NFS_MAY_LOOKUP) + mask |= MAY_EXEC; + } else if (S_ISREG(umode)) { + if ((access_result & NFS_FILE_MAY_WRITE) == NFS_FILE_MAY_WRITE) + mask |= MAY_WRITE; + if ((access_result & NFS_MAY_EXECUTE) == NFS_MAY_EXECUTE) + mask |= MAY_EXEC; + } else if (access_result & NFS_MAY_WRITE) + mask |= MAY_WRITE; + return mask; +} + +void nfs_access_set_mask(struct nfs_access_entry *entry, u32 access_result) +{ + entry->mask = access_result; +} +EXPORT_SYMBOL_GPL(nfs_access_set_mask); + +static int nfs_do_access(struct inode *inode, const struct cred *cred, int mask) +{ + struct nfs_access_entry cache; + bool may_block = (mask & MAY_NOT_BLOCK) == 0; + int cache_mask = -1; + int status; + + trace_nfs_access_enter(inode); + + status = nfs_access_get_cached(inode, cred, &cache.mask, may_block); + if (status == 0) + goto out_cached; + + status = -ECHILD; + if (!may_block) + goto out; + + /* + * Determine which access bits we want to ask for... + */ + cache.mask = NFS_ACCESS_READ | NFS_ACCESS_MODIFY | NFS_ACCESS_EXTEND | + nfs_access_xattr_mask(NFS_SERVER(inode)); + if (S_ISDIR(inode->i_mode)) + cache.mask |= NFS_ACCESS_DELETE | NFS_ACCESS_LOOKUP; + else + cache.mask |= NFS_ACCESS_EXECUTE; + status = NFS_PROTO(inode)->access(inode, &cache, cred); + if (status != 0) { + if (status == -ESTALE) { + if (!S_ISDIR(inode->i_mode)) + nfs_set_inode_stale(inode); + else + nfs_zap_caches(inode); + } + goto out; + } + nfs_access_add_cache(inode, &cache, cred); +out_cached: + cache_mask = nfs_access_calc_mask(cache.mask, inode->i_mode); + if ((mask & ~cache_mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0) + status = -EACCES; +out: + trace_nfs_access_exit(inode, mask, cache_mask, status); + return status; +} + +static int nfs_open_permission_mask(int openflags) +{ + int mask = 0; + + if (openflags & __FMODE_EXEC) { + /* ONLY check exec rights */ + mask = MAY_EXEC; + } else { + if ((openflags & O_ACCMODE) != O_WRONLY) + mask |= MAY_READ; + if ((openflags & O_ACCMODE) != O_RDONLY) + mask |= MAY_WRITE; + } + + return mask; +} + +int nfs_may_open(struct inode *inode, const struct cred *cred, int openflags) +{ + return nfs_do_access(inode, cred, nfs_open_permission_mask(openflags)); +} +EXPORT_SYMBOL_GPL(nfs_may_open); + +static int nfs_execute_ok(struct inode *inode, int mask) +{ + struct nfs_server *server = NFS_SERVER(inode); + int ret = 0; + + if (S_ISDIR(inode->i_mode)) + return 0; + if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_MODE)) { + if (mask & MAY_NOT_BLOCK) + return -ECHILD; + ret = __nfs_revalidate_inode(server, inode); + } + if (ret == 0 && !execute_ok(inode)) + ret = -EACCES; + return ret; +} + +int nfs_permission(struct user_namespace *mnt_userns, + struct inode *inode, + int mask) +{ + const struct cred *cred = current_cred(); + int res = 0; + + nfs_inc_stats(inode, NFSIOS_VFSACCESS); + + if ((mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0) + goto out; + /* Is this sys_access() ? */ + if (mask & (MAY_ACCESS | MAY_CHDIR)) + goto force_lookup; + + switch (inode->i_mode & S_IFMT) { + case S_IFLNK: + goto out; + case S_IFREG: + if ((mask & MAY_OPEN) && + nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN)) + return 0; + break; + case S_IFDIR: + /* + * Optimize away all write operations, since the server + * will check permissions when we perform the op. + */ + if ((mask & MAY_WRITE) && !(mask & MAY_READ)) + goto out; + } + +force_lookup: + if (!NFS_PROTO(inode)->access) + goto out_notsup; + + res = nfs_do_access(inode, cred, mask); +out: + if (!res && (mask & MAY_EXEC)) + res = nfs_execute_ok(inode, mask); + + dfprintk(VFS, "NFS: permission(%s/%lu), mask=0x%x, res=%d\n", + inode->i_sb->s_id, inode->i_ino, mask, res); + return res; +out_notsup: + if (mask & MAY_NOT_BLOCK) + return -ECHILD; + + res = nfs_revalidate_inode(inode, NFS_INO_INVALID_MODE | + NFS_INO_INVALID_OTHER); + if (res == 0) + res = generic_permission(&init_user_ns, inode, mask); + goto out; +} +EXPORT_SYMBOL_GPL(nfs_permission); |