// 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/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 "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_clear_array(struct page*); 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 = { .freepage = nfs_readdir_clear_array, }; static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct inode *dir, const struct cred *cred) { struct nfs_inode *nfsi = NFS_I(dir); struct nfs_open_dir_context *ctx; ctx = kmalloc(sizeof(*ctx), GFP_KERNEL); if (ctx != NULL) { ctx->duped = 0; ctx->attr_gencount = nfsi->attr_gencount; ctx->dir_cookie = 0; ctx->dup_cookie = 0; ctx->cred = get_cred(cred); spin_lock(&dir->i_lock); if (list_empty(&nfsi->open_files) && (nfsi->cache_validity & NFS_INO_DATA_INVAL_DEFER)) nfsi->cache_validity |= NFS_INO_INVALID_DATA | NFS_INO_REVAL_FORCED; list_add(&ctx->list, &nfsi->open_files); 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(&ctx->list); spin_unlock(&dir->i_lock); put_cred(ctx->cred); kfree(ctx); } /* * 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, current_cred()); 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; struct qstr string; unsigned char d_type; }; struct nfs_cache_array { int size; int eof_index; u64 last_cookie; struct nfs_cache_array_entry array[]; }; typedef struct { struct file *file; struct page *page; struct dir_context *ctx; unsigned long page_index; u64 *dir_cookie; u64 last_cookie; loff_t current_index; loff_t prev_index; unsigned long dir_verifier; unsigned long timestamp; unsigned long gencount; unsigned int cache_entry_index; bool plus; bool eof; } nfs_readdir_descriptor_t; static void nfs_readdir_init_array(struct page *page) { struct nfs_cache_array *array; array = kmap_atomic(page); memset(array, 0, sizeof(struct nfs_cache_array)); array->eof_index = -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; int i; array = kmap_atomic(page); for (i = 0; i < array->size; i++) kfree(array->array[i].string.name); array->size = 0; kunmap_atomic(array); } /* * 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 int nfs_readdir_make_qstr(struct qstr *string, const char *name, unsigned int len) { string->len = len; string->name = kmemdup_nul(name, len, GFP_KERNEL); if (string->name == NULL) return -ENOMEM; /* * Avoid a kmemleak false positive. The pointer to the name is stored * in a page cache page which kmemleak does not scan. */ kmemleak_not_leak(string->name); string->hash = full_name_hash(NULL, name, len); return 0; } static int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page) { struct nfs_cache_array *array = kmap(page); struct nfs_cache_array_entry *cache_entry; int ret; cache_entry = &array->array[array->size]; /* Check that this entry lies within the page bounds */ ret = -ENOSPC; if ((char *)&cache_entry[1] - (char *)page_address(page) > PAGE_SIZE) goto out; cache_entry->cookie = entry->prev_cookie; cache_entry->ino = entry->ino; cache_entry->d_type = entry->d_type; ret = nfs_readdir_make_qstr(&cache_entry->string, entry->name, entry->len); if (ret) goto out; array->last_cookie = entry->cookie; array->size++; if (entry->eof != 0) array->eof_index = array->size; out: kunmap(page); return ret; } 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 int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descriptor_t *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->eof_index >= 0) goto out_eof; 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_inode_mapping_valid(struct nfs_inode *nfsi) { if (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA)) return false; smp_rmb(); return !test_bit(NFS_INO_INVALIDATING, &nfsi->flags); } static int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc) { int i; loff_t new_pos; int status = -EAGAIN; for (i = 0; i < array->size; i++) { if (array->array[i].cookie == *desc->dir_cookie) { struct nfs_inode *nfsi = NFS_I(file_inode(desc->file)); struct nfs_open_dir_context *ctx = desc->file->private_data; new_pos = desc->current_index + i; if (ctx->attr_gencount != nfsi->attr_gencount || !nfs_readdir_inode_mapping_valid(nfsi)) { ctx->duped = 0; ctx->attr_gencount = nfsi->attr_gencount; } else if (new_pos < desc->prev_index) { if (ctx->duped > 0 && ctx->dup_cookie == *desc->dir_cookie) { if (printk_ratelimit()) { pr_notice("NFS: directory %pD2 contains a readdir loop." "Please contact your server vendor. " "The file: %.*s has duplicate cookie %llu\n", desc->file, array->array[i].string.len, array->array[i].string.name, *desc->dir_cookie); } status = -ELOOP; goto out; } ctx->dup_cookie = *desc->dir_cookie; ctx->duped = -1; } if (nfs_readdir_use_cookie(desc->file)) desc->ctx->pos = *desc->dir_cookie; else desc->ctx->pos = new_pos; desc->prev_index = new_pos; desc->cache_entry_index = i; return 0; } } if (array->eof_index >= 0) { status = -EBADCOOKIE; if (*desc->dir_cookie == array->last_cookie) desc->eof = true; } out: return status; } static int nfs_readdir_search_array(nfs_readdir_descriptor_t *desc) { struct nfs_cache_array *array; int status; array = kmap(desc->page); if (*desc->dir_cookie == 0) status = nfs_readdir_search_for_pos(array, desc); else status = nfs_readdir_search_for_cookie(array, desc); if (status == -EAGAIN) { desc->last_cookie = array->last_cookie; desc->current_index += array->size; desc->page_index++; } kunmap(desc->page); return status; } /* Fill a page with xdr information before transferring to the cache page */ static int nfs_readdir_xdr_filler(struct page **pages, nfs_readdir_descriptor_t *desc, struct nfs_entry *entry, struct file *file, struct inode *inode) { struct nfs_open_dir_context *ctx = file->private_data; const struct cred *cred = ctx->cred; 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(file_dentry(file), cred, entry->cookie, pages, NFS_SERVER(inode)->dtsize, desc->plus); 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; clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags); desc->plus = false; goto again; } goto error; } desc->timestamp = timestamp; desc->gencount = gencount; error: return error; } static int xdr_decode(nfs_readdir_descriptor_t *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; } static bool nfs_use_readdirplus(struct inode *dir, struct dir_context *ctx) { if (!nfs_server_capable(dir, NFS_CAP_READDIRPLUS)) return false; if (test_and_clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags)) return true; if (ctx->pos == 0) return true; return false; } /* * This function is called by the lookup and getattr code to request the * use of readdirplus to accelerate any future lookups in the same * directory. */ void nfs_advise_use_readdirplus(struct inode *dir) { struct nfs_inode *nfsi = NFS_I(dir); if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) && !list_empty(&nfsi->open_files)) set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags); } /* * This function is mainly for use by nfs_getattr(). * * If this is an 'ls -l', we want to force use of readdirplus. * Do this by checking if there is an active file descriptor * and calling nfs_advise_use_readdirplus, then forcing a * cache flush. */ void nfs_force_use_readdirplus(struct inode *dir) { struct nfs_inode *nfsi = NFS_I(dir); if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) && !list_empty(&nfsi->open_files)) { set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags); invalidate_mapping_pages(dir->i_mapping, nfsi->page_index + 1, -1); } } 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, entry->label); goto out; } else { 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, entry->label); 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); out: dput(dentry); } /* Perform conversion from xdr to cache array */ static int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry, struct page **xdr_pages, struct page *page, unsigned int buflen) { struct xdr_stream stream; struct xdr_buf buf; struct page *scratch; struct nfs_cache_array *array; unsigned int count = 0; int status; scratch = alloc_page(GFP_KERNEL); if (scratch == NULL) return -ENOMEM; if (buflen == 0) goto out_nopages; xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen); xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE); do { status = xdr_decode(desc, entry, &stream); if (status != 0) { if (status == -EAGAIN) status = 0; break; } count++; if (desc->plus) nfs_prime_dcache(file_dentry(desc->file), entry, desc->dir_verifier); status = nfs_readdir_add_to_array(entry, page); if (status != 0) break; } while (!entry->eof); out_nopages: if (count == 0 || (status == -EBADCOOKIE && entry->eof != 0)) { array = kmap(page); array->eof_index = array->size; status = 0; kunmap(page); } put_page(scratch); return status; } static void nfs_readdir_free_pages(struct page **pages, unsigned int npages) { unsigned int i; for (i = 0; i < npages; i++) put_page(pages[i]); } /* * nfs_readdir_alloc_pages() will allocate pages that must be freed with a call * to nfs_readdir_free_pages() */ static int nfs_readdir_alloc_pages(struct page **pages, unsigned int npages) { unsigned int i; for (i = 0; i < npages; i++) { struct page *page = alloc_page(GFP_KERNEL); if (page == NULL) goto out_freepages; pages[i] = page; } return 0; out_freepages: nfs_readdir_free_pages(pages, i); return -ENOMEM; } static int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, struct inode *inode) { struct page *pages[NFS_MAX_READDIR_PAGES]; struct nfs_entry entry; struct file *file = desc->file; struct nfs_cache_array *array; int status = -ENOMEM; unsigned int array_size = ARRAY_SIZE(pages); nfs_readdir_init_array(page); entry.prev_cookie = 0; entry.cookie = desc->last_cookie; entry.eof = 0; entry.fh = nfs_alloc_fhandle(); entry.fattr = nfs_alloc_fattr(); entry.server = NFS_SERVER(inode); if (entry.fh == NULL || entry.fattr == NULL) goto out; entry.label = nfs4_label_alloc(NFS_SERVER(inode), GFP_NOWAIT); if (IS_ERR(entry.label)) { status = PTR_ERR(entry.label); goto out; } array = kmap(page); status = nfs_readdir_alloc_pages(pages, array_size); if (status < 0) goto out_release_array; do { unsigned int pglen; status = nfs_readdir_xdr_filler(pages, desc, &entry, file, inode); if (status < 0) break; pglen = status; status = nfs_readdir_page_filler(desc, &entry, pages, page, pglen); if (status < 0) { if (status == -ENOSPC) status = 0; break; } } while (array->eof_index < 0); nfs_readdir_free_pages(pages, array_size); out_release_array: kunmap(page); nfs4_label_free(entry.label); out: nfs_free_fattr(entry.fattr); nfs_free_fhandle(entry.fh); return status; } /* * Now we cache directories properly, by converting xdr information * to an array that can be used for lookups later. This results in * fewer cache pages, since we can store more information on each page. * We only need to convert from xdr once so future lookups are much simpler */ static int nfs_readdir_filler(void *data, struct page* page) { nfs_readdir_descriptor_t *desc = data; struct inode *inode = file_inode(desc->file); int ret; ret = nfs_readdir_xdr_to_array(desc, page, inode); if (ret < 0) goto error; SetPageUptodate(page); 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: nfs_readdir_clear_array(page); unlock_page(page); return ret; } static void cache_page_release(nfs_readdir_descriptor_t *desc) { put_page(desc->page); desc->page = NULL; } static struct page *get_cache_page(nfs_readdir_descriptor_t *desc) { return read_cache_page(desc->file->f_mapping, desc->page_index, nfs_readdir_filler, desc); } /* * 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(nfs_readdir_descriptor_t *desc) { struct inode *inode = file_inode(desc->file); struct nfs_inode *nfsi = NFS_I(inode); int res; desc->page = get_cache_page(desc); if (IS_ERR(desc->page)) return PTR_ERR(desc->page); res = lock_page_killable(desc->page); if (res != 0) goto error; res = -EAGAIN; if (desc->page->mapping != NULL) { res = nfs_readdir_search_array(desc); if (res == 0) { nfsi->page_index = desc->page_index; return 0; } } unlock_page(desc->page); error: 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 res; if (desc->page_index == 0) { desc->current_index = 0; desc->prev_index = 0; desc->last_cookie = 0; } 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 int nfs_do_filldir(nfs_readdir_descriptor_t *desc) { struct file *file = desc->file; int i = 0; int res = 0; struct nfs_cache_array *array = NULL; struct nfs_open_dir_context *ctx = file->private_data; array = kmap(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->string.name, ent->string.len, nfs_compat_user_ino64(ent->ino), ent->d_type)) { desc->eof = true; break; } if (i < (array->size-1)) *desc->dir_cookie = array->array[i+1].cookie; else *desc->dir_cookie = array->last_cookie; if (nfs_readdir_use_cookie(file)) desc->ctx->pos = *desc->dir_cookie; else desc->ctx->pos++; if (ctx->duped != 0) ctx->duped = 1; } if (array->eof_index >= 0) desc->eof = true; kunmap(desc->page); dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", (unsigned long long)*desc->dir_cookie, res); return res; } /* * 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 inline int uncached_readdir(nfs_readdir_descriptor_t *desc) { struct page *page = NULL; int status; struct inode *inode = file_inode(desc->file); struct nfs_open_dir_context *ctx = desc->file->private_data; dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n", (unsigned long long)*desc->dir_cookie); page = alloc_page(GFP_HIGHUSER); if (!page) { status = -ENOMEM; goto out; } desc->page_index = 0; desc->last_cookie = *desc->dir_cookie; desc->page = page; ctx->duped = 0; status = nfs_readdir_xdr_to_array(desc, page, inode); if (status < 0) goto out_release; status = nfs_do_filldir(desc); out_release: nfs_readdir_clear_array(desc->page); cache_page_release(desc); out: dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __func__, status); return status; } /* 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_open_dir_context *dir_ctx = file->private_data; nfs_readdir_descriptor_t my_desc = { .file = file, .ctx = ctx, .dir_cookie = &dir_ctx->dir_cookie, .plus = nfs_use_readdirplus(inode, ctx), }, *desc = &my_desc; int res = 0; 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. */ if (ctx->pos == 0 || nfs_attribute_cache_expired(inode)) res = nfs_revalidate_mapping(inode, file->f_mapping); if (res < 0) goto out; 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; } break; } if (res == -ETOOSMALL && desc->plus) { clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags); nfs_zap_caches(inode); desc->page_index = 0; desc->plus = false; desc->eof = false; continue; } if (res < 0) break; res = nfs_do_filldir(desc); unlock_page(desc->page); cache_page_release(desc); if (res < 0) break; } while (!desc->eof); out: if (res > 0) res = 0; 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 inode *inode = file_inode(filp); 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; inode_lock(inode); break; case SEEK_CUR: if (offset == 0) return filp->f_pos; inode_lock(inode); offset += filp->f_pos; if (offset < 0) { inode_unlock(inode); return -EINVAL; } } if (offset != filp->f_pos) { filp->f_pos = offset; if (nfs_readdir_use_cookie(filp)) dir_ctx->dir_cookie = offset; else dir_ctx->dir_cookie = 0; dir_ctx->duped = 0; } inode_unlock(inode); 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) { struct inode *inode = file_inode(filp); dfprintk(FILE, "NFS: fsync dir(%pD2) datasync %d\n", filp, datasync); inode_lock(inode); nfs_inc_stats(inode, NFSIOS_VFSFSYNC); inode_unlock(inode); 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); if (!nfs_verifier_is_delegated(dentry) && !nfs_verify_change_attribute(d_inode(dentry->d_parent), verf)) goto out; if (inode && NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) nfs_set_verifier_delegated(&verf); out: 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) */ /* * 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_verify_change_attribute(dir, dentry->d_time)) 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_verify_change_attribute(dir, dentry->d_time)) 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: return (inode->i_nlink == 0) ? -ESTALE : 0; out_force: if (flags & LOOKUP_RCU) return -ECHILD; ret = __nfs_revalidate_inode(server, inode); if (ret != 0) return ret; goto out; } /* * 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; 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: dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is valid\n", __func__, dentry); return 1; case 0: nfs_mark_for_revalidate(dir); if (inode && S_ISDIR(inode->i_mode)) { /* Purge readdir caches. */ nfs_zap_caches(inode); /* * 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 (IS_ROOT(dentry)) return 1; } dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is invalid\n", __func__, dentry); return 0; } dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) lookup returned error %d\n", __func__, dentry, 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) { struct nfs_fh *fhandle; struct nfs_fattr *fattr; struct nfs4_label *label; unsigned long dir_verifier; int ret; ret = -ENOMEM; fhandle = nfs_alloc_fhandle(); fattr = nfs_alloc_fattr(); label = nfs4_label_alloc(NFS_SERVER(inode), GFP_KERNEL); if (fhandle == NULL || fattr == NULL || IS_ERR(label)) goto out; dir_verifier = nfs_save_change_attribute(dir); ret = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, label); 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; } 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, label); nfs_set_verifier(dentry, dir_verifier); /* set a readdirplus hint that we had a cache miss */ nfs_force_use_readdirplus(dir); ret = 1; out: nfs_free_fattr(fattr); nfs_free_fhandle(fhandle); nfs4_label_free(label); 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 (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_zap_caches(dir); goto out_bad; } nfs_advise_use_readdirplus(dir); goto out_valid; } if (flags & LOOKUP_RCU) return -ECHILD; if (NFS_STALE(inode)) goto out_bad; trace_nfs_lookup_revalidate_enter(dir, dentry, flags); error = nfs_lookup_revalidate_dentry(dir, dentry, inode); trace_nfs_lookup_revalidate_exit(dir, dentry, flags, error); return error; 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) { 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 { 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_I(inode)->cache_validity |= NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_CTIME | NFS_INO_INVALID_OTHER | NFS_INO_REVAL_FORCED; 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 (S_ISDIR(inode->i_mode)) /* drop any readdir cache as it could easily be old */ NFS_I(inode)->cache_validity |= NFS_INO_INVALID_DATA; 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; struct nfs4_label *label = 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(); if (fhandle == NULL || fattr == NULL) goto out; label = nfs4_label_alloc(NFS_SERVER(dir), GFP_NOWAIT); if (IS_ERR(label)) 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, label); if (error == -ENOENT) goto no_entry; if (error < 0) { res = ERR_PTR(error); goto out_label; } inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label); res = ERR_CAST(inode); if (IS_ERR(res)) goto out_label; /* Notify readdir to use READDIRPLUS */ nfs_force_use_readdirplus(dir); no_entry: res = d_splice_alias(inode, dentry); if (res != NULL) { if (IS_ERR(res)) goto out_label; dentry = res; } nfs_set_verifier(dentry, dir_verifier); out_label: trace_nfs_lookup_exit(dir, dentry, flags, error); nfs4_label_free(label); out: nfs_free_fattr(fattr); nfs_free_fhandle(fhandle); return res; } EXPORT_SYMBOL_GPL(nfs_lookup); #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 fmode_t flags_to_mode(int flags) { fmode_t res = (__force fmode_t)flags & FMODE_EXEC; if ((flags & O_ACCMODE) != O_WRONLY) res |= FMODE_READ; if ((flags & O_ACCMODE) != O_RDONLY) res |= FMODE_WRITE; return res; } 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->f_path.dentry->d_inode->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; 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); nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 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; } 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 (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); 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 nfs4_label *label) { 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, NULL); 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, NULL); if (error < 0) goto out_error; } inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label); d = d_splice_alias(inode, dentry); out: dput(parent); return d; out_error: nfs_mark_for_revalidate(dir); 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 nfs4_label *label) { struct dentry *d; d = nfs_add_or_obtain(dentry, fhandle, fattr, label); 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 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 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 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); } 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); 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; int need_rehash = 0; 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) { 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; } if (!d_unhashed(dentry)) { __d_drop(dentry); need_rehash = 1; } spin_unlock(&dentry->d_lock); error = nfs_safe_remove(dentry); if (!error || error == -ENOENT) { nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); } else if (need_rehash) d_rehash(dentry); 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 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; } /* * 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); error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); if (error == 0) { ihold(inode); d_add(dentry, inode); } trace_nfs_link_exit(inode, dir, dentry, error); return error; } EXPORT_SYMBOL_GPL(nfs_link); /* * 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 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, *rehash = NULL; struct rpc_task *task; 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)) { /* * To prevent any new references to the target during the * rename, we unhash the dentry in advance. */ if (!d_unhashed(new_dentry)) { d_drop(new_dentry); rehash = new_dentry; } if (d_count(new_dentry) > 2) { int err; /* copy the target dentry's name */ dentry = d_alloc(new_dentry->d_parent, &new_dentry->d_name); if (!dentry) goto out; /* silly-rename the existing target ... */ err = nfs_sillyrename(new_dir, new_dentry); if (err) goto out; new_dentry = dentry; rehash = NULL; new_inode = NULL; } } task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry, 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_I(old_inode)->cache_validity |= NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_CTIME | NFS_INO_REVAL_FORCED; spin_unlock(&old_inode->i_lock); } out: if (rehash) d_rehash(rehash); 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_cred(entry->cred); 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 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 = cred_fscmp(cred, entry->cred); 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(struct inode *inode, const struct cred *cred, struct nfs_access_entry *res, 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; } res->cred = cache->cred; res->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, struct nfs_access_entry *res) { /* 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 || cred_fscmp(cred, cache->cred) != 0) cache = NULL; if (cache == NULL) goto out; if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS)) goto out; res->cred = cache->cred; res->mask = cache->mask; err = 0; out: rcu_read_unlock(); return err; } static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set) { 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 = cred_fscmp(set->cred, entry->cred); 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) { struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL); if (cache == NULL) return; RB_CLEAR_NODE(&cache->rb_node); cache->cred = get_cred(set->cred); 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); /* 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_rcu(inode, cred, &cache); if (status != 0) status = nfs_access_get_cached(inode, cred, &cache, 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; if (S_ISDIR(inode->i_mode)) cache.mask |= NFS_ACCESS_DELETE | NFS_ACCESS_LOOKUP; else cache.mask |= NFS_ACCESS_EXECUTE; cache.cred = cred; status = NFS_PROTO(inode)->access(inode, &cache); 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); 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_OTHER)) { 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 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(NFS_SERVER(inode), inode); if (res == 0) res = generic_permission(inode, mask); goto out; } EXPORT_SYMBOL_GPL(nfs_permission); /* * Local variables: * version-control: t * kept-new-versions: 5 * End: */