/* * 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 = 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, struct rpc_cred *cred) { struct nfs_open_dir_context *ctx; ctx = kmalloc(sizeof(*ctx), GFP_KERNEL); if (ctx != NULL) { ctx->duped = 0; ctx->attr_gencount = NFS_I(dir)->attr_gencount; ctx->dir_cookie = 0; ctx->dup_cookie = 0; ctx->cred = get_rpccred(cred); return ctx; } return ERR_PTR(-ENOMEM); } static void put_nfs_open_dir_context(struct nfs_open_dir_context *ctx) { put_rpccred(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; struct rpc_cred *cred; dfprintk(FILE, "NFS: open dir(%s/%s)\n", filp->f_path.dentry->d_parent->d_name.name, filp->f_path.dentry->d_name.name); nfs_inc_stats(inode, NFSIOS_VFSOPEN); cred = rpc_lookup_cred(); if (IS_ERR(cred)) return PTR_ERR(cred); ctx = alloc_nfs_open_dir_context(inode, cred); if (IS_ERR(ctx)) { res = PTR_ERR(ctx); goto out; } filp->private_data = ctx; if (filp->f_path.dentry == filp->f_path.mnt->mnt_root) { /* This is a mountpoint, so d_revalidate will never * have been called, so we need to refresh the * inode (for close-open consistency) ourselves. */ __nfs_revalidate_inode(NFS_SERVER(inode), inode); } out: put_rpccred(cred); return res; } static int nfs_closedir(struct inode *inode, struct file *filp) { put_nfs_open_dir_context(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[0]; }; typedef int (*decode_dirent_t)(struct xdr_stream *, struct nfs_entry *, int); 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; decode_dirent_t decode; unsigned long timestamp; unsigned long gencount; unsigned int cache_entry_index; unsigned int plus:1; unsigned int eof:1; } nfs_readdir_descriptor_t; /* * The caller is responsible for calling nfs_readdir_release_array(page) */ static struct nfs_cache_array *nfs_readdir_get_array(struct page *page) { void *ptr; if (page == NULL) return ERR_PTR(-EIO); ptr = kmap(page); if (ptr == NULL) return ERR_PTR(-ENOMEM); return ptr; } static void nfs_readdir_release_array(struct page *page) { kunmap(page); } /* * 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); 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(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(name, len); return 0; } static int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page) { struct nfs_cache_array *array = nfs_readdir_get_array(page); struct nfs_cache_array_entry *cache_entry; int ret; if (IS_ERR(array)) return PTR_ERR(array); 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: nfs_readdir_release_array(page); return ret; } 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 = 1; return -EBADCOOKIE; } 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 || (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA))) { ctx->duped = 0; ctx->attr_gencount = nfsi->attr_gencount; } else if (new_pos < desc->ctx->pos) { if (ctx->duped > 0 && ctx->dup_cookie == *desc->dir_cookie) { if (printk_ratelimit()) { pr_notice("NFS: directory %s/%s contains a readdir loop." "Please contact your server vendor. " "The file: %s has duplicate cookie %llu\n", desc->file->f_dentry->d_parent->d_name.name, desc->file->f_dentry->d_name.name, array->array[i].string.name, *desc->dir_cookie); } status = -ELOOP; goto out; } ctx->dup_cookie = *desc->dir_cookie; ctx->duped = -1; } desc->ctx->pos = 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 = 1; } out: return status; } static int nfs_readdir_search_array(nfs_readdir_descriptor_t *desc) { struct nfs_cache_array *array; int status; array = nfs_readdir_get_array(desc->page); if (IS_ERR(array)) { status = PTR_ERR(array); goto out; } if (*desc->dir_cookie == 0) status = nfs_readdir_search_for_pos(array, desc); else status = nfs_readdir_search_for_cookie(array, desc); if (status == -EAGAIN) { desc->last_cookie = array->last_cookie; desc->current_index += array->size; desc->page_index++; } nfs_readdir_release_array(desc->page); out: return status; } /* Fill a page with xdr information before transferring to the cache page */ static int nfs_readdir_xdr_filler(struct page **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; struct rpc_cred *cred = ctx->cred; unsigned long timestamp, gencount; int error; again: timestamp = jiffies; gencount = nfs_inc_attr_generation_counter(); error = NFS_PROTO(inode)->readdir(file->f_path.dentry, 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 = 0; 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) { int error; error = desc->decode(xdr, entry, desc->plus); if (error) return error; entry->fattr->time_start = desc->timestamp; entry->fattr->gencount = desc->gencount; return 0; } static int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry) { if (dentry->d_inode == NULL) goto different; if (nfs_compare_fh(entry->fh, NFS_FH(dentry->d_inode)) != 0) goto different; return 1; different: return 0; } 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 code to request the use of * readdirplus to accelerate any future lookups in the same * directory. */ static void nfs_advise_use_readdirplus(struct inode *dir) { set_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags); } static void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry) { struct qstr filename = QSTR_INIT(entry->name, entry->len); struct dentry *dentry; struct dentry *alias; struct inode *dir = parent->d_inode; struct inode *inode; int status; if (filename.name[0] == '.') { if (filename.len == 1) return; if (filename.len == 2 && filename.name[1] == '.') return; } filename.hash = full_name_hash(filename.name, filename.len); dentry = d_lookup(parent, &filename); if (dentry != NULL) { if (nfs_same_file(dentry, entry)) { nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); status = nfs_refresh_inode(dentry->d_inode, entry->fattr); if (!status) nfs_setsecurity(dentry->d_inode, entry->fattr, entry->label); goto out; } else { if (d_invalidate(dentry) != 0) goto out; dput(dentry); } } dentry = d_alloc(parent, &filename); if (dentry == NULL) return; inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr, entry->label); if (IS_ERR(inode)) goto out; alias = d_materialise_unique(dentry, inode); if (IS_ERR(alias)) goto out; else if (alias) { nfs_set_verifier(alias, nfs_save_change_attribute(dir)); dput(alias); } else nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 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; 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 != 0) nfs_prime_dcache(desc->file->f_path.dentry, entry); status = nfs_readdir_add_to_array(entry, page); if (status != 0) break; } while (!entry->eof); if (count == 0 || (status == -EBADCOOKIE && entry->eof != 0)) { array = nfs_readdir_get_array(page); if (!IS_ERR(array)) { array->eof_index = array->size; status = 0; nfs_readdir_release_array(page); } else status = PTR_ERR(array); } put_page(scratch); return status; } static void nfs_readdir_free_pagearray(struct page **pages, unsigned int npages) { unsigned int i; for (i = 0; i < npages; i++) put_page(pages[i]); } static void nfs_readdir_free_large_page(void *ptr, struct page **pages, unsigned int npages) { nfs_readdir_free_pagearray(pages, npages); } /* * nfs_readdir_large_page will allocate pages that must be freed with a call * to nfs_readdir_free_large_page */ static int nfs_readdir_large_page(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_pagearray(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]; void *pages_ptr = NULL; struct nfs_entry entry; struct file *file = desc->file; struct nfs_cache_array *array; int status = -ENOMEM; unsigned int array_size = ARRAY_SIZE(pages); 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 = nfs_readdir_get_array(page); if (IS_ERR(array)) { status = PTR_ERR(array); goto out_label_free; } memset(array, 0, sizeof(struct nfs_cache_array)); array->eof_index = -1; status = nfs_readdir_large_page(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_large_page(pages_ptr, pages, array_size); out_release_array: nfs_readdir_release_array(page); out_label_free: 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(nfs_readdir_descriptor_t *desc, struct page* page) { 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: unlock_page(page); return ret; } static void cache_page_release(nfs_readdir_descriptor_t *desc) { if (!desc->page->mapping) nfs_readdir_clear_array(desc->page); page_cache_release(desc->page); desc->page = NULL; } static struct page *get_cache_page(nfs_readdir_descriptor_t *desc) { return read_cache_page(file_inode(desc->file)->i_mapping, desc->page_index, (filler_t *)nfs_readdir_filler, desc); } /* * Returns 0 if desc->dir_cookie was found on page desc->page_index */ static int find_cache_page(nfs_readdir_descriptor_t *desc) { int res; desc->page = get_cache_page(desc); if (IS_ERR(desc->page)) return PTR_ERR(desc->page); res = nfs_readdir_search_array(desc); if (res != 0) 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->last_cookie = 0; } do { res = find_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 = nfs_readdir_get_array(desc->page); if (IS_ERR(array)) { res = PTR_ERR(array); goto out; } 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 = 1; break; } desc->ctx->pos++; if (i < (array->size-1)) *desc->dir_cookie = array->array[i+1].cookie; else *desc->dir_cookie = array->last_cookie; if (ctx->duped != 0) ctx->duped = 1; } if (array->eof_index >= 0) desc->eof = 1; nfs_readdir_release_array(desc->page); out: cache_page_release(desc); 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: dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __func__, status); return status; out_release: cache_page_release(desc); goto out; } /* 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->f_path.dentry; struct inode *inode = dentry->d_inode; nfs_readdir_descriptor_t my_desc, *desc = &my_desc; struct nfs_open_dir_context *dir_ctx = file->private_data; int res = 0; dfprintk(FILE, "NFS: readdir(%s/%s) starting at cookie %llu\n", dentry->d_parent->d_name.name, dentry->d_name.name, (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. */ memset(desc, 0, sizeof(*desc)); desc->file = file; desc->ctx = ctx; desc->dir_cookie = &dir_ctx->dir_cookie; desc->decode = NFS_PROTO(inode)->decode_dirent; desc->plus = nfs_use_readdirplus(inode, ctx) ? 1 : 0; nfs_block_sillyrename(dentry); 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 == 0) { /* 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 = 0; desc->eof = 0; continue; } if (res < 0) break; res = nfs_do_filldir(desc); if (res < 0) break; } while (!desc->eof); out: nfs_unblock_sillyrename(dentry); if (res > 0) res = 0; dfprintk(FILE, "NFS: readdir(%s/%s) returns %d\n", dentry->d_parent->d_name.name, dentry->d_name.name, res); return res; } static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence) { struct dentry *dentry = filp->f_path.dentry; struct inode *inode = dentry->d_inode; struct nfs_open_dir_context *dir_ctx = filp->private_data; dfprintk(FILE, "NFS: llseek dir(%s/%s, %lld, %d)\n", dentry->d_parent->d_name.name, dentry->d_name.name, offset, whence); mutex_lock(&inode->i_mutex); switch (whence) { case 1: offset += filp->f_pos; case 0: if (offset >= 0) break; default: offset = -EINVAL; goto out; } if (offset != filp->f_pos) { filp->f_pos = offset; dir_ctx->dir_cookie = 0; dir_ctx->duped = 0; } out: mutex_unlock(&inode->i_mutex); 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 dentry *dentry = filp->f_path.dentry; struct inode *inode = dentry->d_inode; dfprintk(FILE, "NFS: fsync dir(%s/%s) datasync %d\n", dentry->d_parent->d_name.name, dentry->d_name.name, datasync); mutex_lock(&inode->i_mutex); nfs_inc_stats(dentry->d_inode, NFSIOS_VFSFSYNC); mutex_unlock(&inode->i_mutex); 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. * * The caller should be holding dir->i_lock */ void nfs_force_lookup_revalidate(struct inode *dir) { NFS_I(dir)->cache_change_attribute++; } EXPORT_SYMBOL_GPL(nfs_force_lookup_revalidate); /* * 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. */ static int nfs_check_verifier(struct inode *dir, struct dentry *dentry) { 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_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; /* VFS wants an on-the-wire revalidation */ if (flags & LOOKUP_REVAL) goto out_force; /* This is an open(2) */ if ((flags & LOOKUP_OPEN) && !(server->flags & NFS_MOUNT_NOCTO) && (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))) goto out_force; out: return (inode->i_nlink == 0) ? -ENOENT : 0; out_force: 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. */ static inline int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, unsigned int flags) { /* Don't revalidate a negative dentry if we're creating a new file */ if (flags & LOOKUP_CREATE) return 0; if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) return 1; return !nfs_check_verifier(dir, dentry); } /* * 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_lookup_revalidate(struct dentry *dentry, unsigned int flags) { struct inode *dir; struct inode *inode; struct dentry *parent; struct nfs_fh *fhandle = NULL; struct nfs_fattr *fattr = NULL; struct nfs4_label *label = NULL; int error; if (flags & LOOKUP_RCU) return -ECHILD; parent = dget_parent(dentry); dir = parent->d_inode; nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE); inode = dentry->d_inode; if (!inode) { if (nfs_neg_need_reval(dir, dentry, flags)) goto out_bad; goto out_valid_noent; } if (is_bad_inode(inode)) { dfprintk(LOOKUPCACHE, "%s: %s/%s has dud inode\n", __func__, dentry->d_parent->d_name.name, dentry->d_name.name); goto out_bad; } if (NFS_PROTO(dir)->have_delegation(inode, FMODE_READ)) goto out_set_verifier; /* Force a full look up iff the parent directory has changed */ if (!nfs_is_exclusive_create(dir, flags) && nfs_check_verifier(dir, dentry)) { if (nfs_lookup_verify_inode(inode, flags)) goto out_zap_parent; goto out_valid; } if (NFS_STALE(inode)) goto out_bad; error = -ENOMEM; fhandle = nfs_alloc_fhandle(); fattr = nfs_alloc_fattr(); if (fhandle == NULL || fattr == NULL) goto out_error; label = nfs4_label_alloc(NFS_SERVER(inode), GFP_NOWAIT); if (IS_ERR(label)) goto out_error; trace_nfs_lookup_revalidate_enter(dir, dentry, flags); error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, label); trace_nfs_lookup_revalidate_exit(dir, dentry, flags, error); if (error) goto out_bad; if (nfs_compare_fh(NFS_FH(inode), fhandle)) goto out_bad; if ((error = nfs_refresh_inode(inode, fattr)) != 0) goto out_bad; nfs_setsecurity(inode, fattr, label); nfs_free_fattr(fattr); nfs_free_fhandle(fhandle); nfs4_label_free(label); out_set_verifier: nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); out_valid: /* Success: notify readdir to use READDIRPLUS */ nfs_advise_use_readdirplus(dir); out_valid_noent: dput(parent); dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is valid\n", __func__, dentry->d_parent->d_name.name, dentry->d_name.name); return 1; out_zap_parent: nfs_zap_caches(dir); out_bad: nfs_free_fattr(fattr); nfs_free_fhandle(fhandle); nfs4_label_free(label); nfs_mark_for_revalidate(dir); if (inode && S_ISDIR(inode->i_mode)) { /* Purge readdir caches. */ nfs_zap_caches(inode); if (dentry->d_flags & DCACHE_DISCONNECTED) goto out_valid; } /* If we have submounts, don't unhash ! */ if (check_submounts_and_drop(dentry) != 0) goto out_valid; dput(parent); dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is invalid\n", __func__, dentry->d_parent->d_name.name, dentry->d_name.name); return 0; out_error: nfs_free_fattr(fattr); nfs_free_fhandle(fhandle); nfs4_label_free(label); dput(parent); dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) lookup returned error %d\n", __func__, dentry->d_parent->d_name.name, dentry->d_name.name, error); return error; } /* * A weaker form of d_revalidate for revalidating just the dentry->d_inode * 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) { int error; struct inode *inode = dentry->d_inode; /* * 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: %s/%s has negative inode\n", __func__, dentry->d_parent->d_name.name, dentry->d_name.name); return 1; } if (is_bad_inode(inode)) { dfprintk(LOOKUPCACHE, "%s: %s/%s has dud inode\n", __func__, dentry->d_parent->d_name.name, dentry->d_name.name); return 0; } error = nfs_revalidate_inode(NFS_SERVER(inode), inode); 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(%s/%s, %x)\n", dentry->d_parent->d_name.name, dentry->d_name.name, dentry->d_flags); /* Unhash any dentry with a stale inode */ if (dentry->d_inode != NULL && NFS_STALE(dentry->d_inode)) 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 & MS_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 == 1) clear_nlink(inode); NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATTR; 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 dentry *parent; struct inode *inode = NULL; struct nfs_fh *fhandle = NULL; struct nfs_fattr *fattr = NULL; struct nfs4_label *label = NULL; int error; dfprintk(VFS, "NFS: lookup(%s/%s)\n", dentry->d_parent->d_name.name, dentry->d_name.name); nfs_inc_stats(dir, NFSIOS_VFSLOOKUP); res = ERR_PTR(-ENAMETOOLONG); if (dentry->d_name.len > NFS_SERVER(dir)->namelen) goto out; /* * If we're doing an exclusive create, optimize away the lookup * but don't hash the dentry. */ if (nfs_is_exclusive_create(dir, flags)) { d_instantiate(dentry, NULL); res = NULL; goto out; } 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; parent = dentry->d_parent; /* Protect against concurrent sillydeletes */ trace_nfs_lookup_enter(dir, dentry, flags); nfs_block_sillyrename(parent); error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, label); if (error == -ENOENT) goto no_entry; if (error < 0) { res = ERR_PTR(error); goto out_unblock_sillyrename; } inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label); res = ERR_CAST(inode); if (IS_ERR(res)) goto out_unblock_sillyrename; /* Success: notify readdir to use READDIRPLUS */ nfs_advise_use_readdirplus(dir); no_entry: res = d_materialise_unique(dentry, inode); if (res != NULL) { if (IS_ERR(res)) goto out_unblock_sillyrename; dentry = res; } nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); out_unblock_sillyrename: nfs_unblock_sillyrename(parent); 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_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) { return alloc_nfs_open_context(dentry, flags_to_mode(open_flags)); } static int do_open(struct inode *inode, struct file *filp) { nfs_fscache_set_inode_cookie(inode, filp); return 0; } static int nfs_finish_open(struct nfs_open_context *ctx, struct dentry *dentry, struct file *file, unsigned open_flags, int *opened) { int err; if ((open_flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL)) *opened |= FILE_CREATED; err = finish_open(file, dentry, do_open, opened); if (err) goto out; nfs_file_set_open_context(file, ctx); out: return err; } int nfs_atomic_open(struct inode *dir, struct dentry *dentry, struct file *file, unsigned open_flags, umode_t mode, int *opened) { struct nfs_open_context *ctx; struct dentry *res; struct iattr attr = { .ia_valid = ATTR_OPEN }; struct inode *inode; unsigned int lookup_flags = 0; int err; /* Expect a negative dentry */ BUG_ON(dentry->d_inode); dfprintk(VFS, "NFS: atomic_open(%s/%ld), %s\n", dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); err = nfs_check_flags(open_flags); if (err) return err; /* NFS only supports OPEN on regular files */ if ((open_flags & O_DIRECTORY)) { if (!d_unhashed(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) { attr.ia_valid |= ATTR_MODE; attr.ia_mode = mode & ~current_umask(); } if (open_flags & O_TRUNC) { attr.ia_valid |= ATTR_SIZE; attr.ia_size = 0; } ctx = create_nfs_open_context(dentry, open_flags); err = PTR_ERR(ctx); if (IS_ERR(ctx)) goto out; trace_nfs_atomic_open_enter(dir, ctx, open_flags); nfs_block_sillyrename(dentry->d_parent); inode = NFS_PROTO(dir)->open_context(dir, ctx, open_flags, &attr); nfs_unblock_sillyrename(dentry->d_parent); if (IS_ERR(inode)) { err = PTR_ERR(inode); trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); put_nfs_open_context(ctx); switch (err) { case -ENOENT: d_drop(dentry); d_add(dentry, NULL); 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, opened); trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); put_nfs_open_context(ctx); out: return err; no_open: res = nfs_lookup(dir, dentry, lookup_flags); err = PTR_ERR(res); if (IS_ERR(res)) goto out; return finish_no_open(file, res); } EXPORT_SYMBOL_GPL(nfs_atomic_open); static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags) { struct dentry *parent = NULL; struct inode *inode; struct inode *dir; int ret = 0; if (flags & LOOKUP_RCU) return -ECHILD; if (!(flags & LOOKUP_OPEN) || (flags & LOOKUP_DIRECTORY)) goto no_open; if (d_mountpoint(dentry)) goto no_open; if (NFS_SB(dentry->d_sb)->caps & NFS_CAP_ATOMIC_OPEN_V1) goto no_open; inode = dentry->d_inode; parent = dget_parent(dentry); dir = parent->d_inode; /* We can't create new files in nfs_open_revalidate(), so we * optimize away revalidation of negative dentries. */ if (inode == NULL) { if (!nfs_neg_need_reval(dir, dentry, flags)) ret = 1; goto out; } /* NFS only supports OPEN on regular files */ if (!S_ISREG(inode->i_mode)) goto no_open_dput; /* We cannot do exclusive creation on a positive dentry */ if (flags & LOOKUP_EXCL) goto no_open_dput; /* Let f_op->open() actually open (and revalidate) the file */ ret = 1; out: dput(parent); return ret; no_open_dput: dput(parent); no_open: return nfs_lookup_revalidate(dentry, flags); } #endif /* CONFIG_NFSV4 */ /* * 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 *parent = dget_parent(dentry); struct inode *dir = parent->d_inode; struct inode *inode; int error = -EACCES; d_drop(dentry); /* We may have been initialized further down */ if (dentry->d_inode) goto out; if (fhandle->size == 0) { error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, 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); if (error < 0) goto out_error; } inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label); error = PTR_ERR(inode); if (IS_ERR(inode)) goto out_error; d_add(dentry, inode); out: dput(parent); return 0; out_error: nfs_mark_for_revalidate(dir); dput(parent); return error; } 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/%ld), %s\n", dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 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/%ld), %s\n", dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); if (!new_valid_dev(rdev)) return -EINVAL; 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/%ld), %s\n", dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 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 (dentry->d_inode != NULL && !d_unhashed(dentry)) d_delete(dentry); } int nfs_rmdir(struct inode *dir, struct dentry *dentry) { int error; dfprintk(VFS, "NFS: rmdir(%s/%ld), %s\n", dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); trace_nfs_rmdir_enter(dir, dentry); if (dentry->d_inode) { nfs_wait_on_sillyrename(dentry); error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); /* Ensure the VFS deletes this inode */ switch (error) { case 0: clear_nlink(dentry->d_inode); break; case -ENOENT: nfs_dentry_handle_enoent(dentry); } } 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 = dentry->d_parent->d_inode; struct inode *inode = dentry->d_inode; int error = -EBUSY; dfprintk(VFS, "NFS: safe_remove(%s/%s)\n", dentry->d_parent->d_name.name, dentry->d_name.name); /* 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) { NFS_PROTO(inode)->return_delegation(inode); error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); if (error == 0) nfs_drop_nlink(inode); } else error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); 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/%ld, %s)\n", dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 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(dentry->d_inode, 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/%ld, %s, %s)\n", dir->i_sb->s_id, dir->i_ino, dentry->d_name.name, symname); if (pathlen > PAGE_SIZE) return -ENAMETOOLONG; attr.ia_mode = S_IFLNK | S_IRWXUGO; attr.ia_valid = ATTR_MODE; page = alloc_page(GFP_HIGHUSER); if (!page) return -ENOMEM; kaddr = kmap_atomic(page); memcpy(kaddr, symname, pathlen); if (pathlen < PAGE_SIZE) memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen); kunmap_atomic(kaddr); 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/%ld, %s, %s) error %d\n", dir->i_sb->s_id, dir->i_ino, dentry->d_name.name, 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, dentry->d_inode->i_mapping, 0, GFP_KERNEL)) { SetPageUptodate(page); unlock_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 = old_dentry->d_inode; int error; dfprintk(VFS, "NFS: link(%s/%s -> %s/%s)\n", old_dentry->d_parent->d_name.name, old_dentry->d_name.name, dentry->d_parent->d_name.name, dentry->d_name.name); trace_nfs_link_enter(inode, dir, dentry); NFS_PROTO(inode)->return_delegation(inode); 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) { struct inode *old_inode = old_dentry->d_inode; struct inode *new_inode = new_dentry->d_inode; struct dentry *dentry = NULL, *rehash = NULL; int error = -EBUSY; dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n", old_dentry->d_parent->d_name.name, old_dentry->d_name.name, new_dentry->d_parent->d_name.name, new_dentry->d_name.name, 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; } } NFS_PROTO(old_inode)->return_delegation(old_inode); if (new_inode != NULL) NFS_PROTO(new_inode)->return_delegation(new_inode); error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name, new_dir, &new_dentry->d_name); nfs_mark_for_revalidate(old_inode); 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); d_move(old_dentry, new_dentry); nfs_set_verifier(new_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 void nfs_access_free_entry(struct nfs_access_entry *entry) { put_rpccred(entry->cred); kfree(entry); smp_mb__before_atomic_dec(); atomic_long_dec(&nfs_access_nr_entries); smp_mb__after_atomic_dec(); } 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); } } unsigned long nfs_access_cache_scan(struct shrinker *shrink, struct shrink_control *sc) { LIST_HEAD(head); struct nfs_inode *nfsi, *next; struct nfs_access_entry *cache; int nr_to_scan = sc->nr_to_scan; gfp_t gfp_mask = sc->gfp_mask; long freed = 0; if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL) return SHRINK_STOP; 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_clear_bit(); clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags); smp_mb__after_clear_bit(); } spin_unlock(&inode->i_lock); } spin_unlock(&nfs_access_lru_lock); nfs_access_free_list(&head); return freed; } 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_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, struct rpc_cred *cred) { struct rb_node *n = NFS_I(inode)->access_cache.rb_node; struct nfs_access_entry *entry; while (n != NULL) { entry = rb_entry(n, struct nfs_access_entry, rb_node); if (cred < entry->cred) n = n->rb_left; else if (cred > entry->cred) n = n->rb_right; else return entry; } return NULL; } static int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res) { struct nfs_inode *nfsi = NFS_I(inode); struct nfs_access_entry *cache; int err = -ENOENT; spin_lock(&inode->i_lock); if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) goto out_zap; cache = nfs_access_search_rbtree(inode, cred); if (cache == NULL) goto out; if (!nfs_have_delegated_attributes(inode) && !time_in_range_open(jiffies, cache->jiffies, cache->jiffies + nfsi->attrtimeo)) goto out_stale; res->jiffies = cache->jiffies; 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_stale: rb_erase(&cache->rb_node, &nfsi->access_cache); list_del(&cache->lru); spin_unlock(&inode->i_lock); nfs_access_free_entry(cache); return -ENOENT; out_zap: spin_unlock(&inode->i_lock); nfs_access_zap_cache(inode); return -ENOENT; } 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; spin_lock(&inode->i_lock); while (*p != NULL) { parent = *p; entry = rb_entry(parent, struct nfs_access_entry, rb_node); if (set->cred < entry->cred) p = &parent->rb_left; else if (set->cred > entry->cred) 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->jiffies = set->jiffies; cache->cred = get_rpccred(set->cred); cache->mask = set->mask; nfs_access_add_rbtree(inode, cache); /* Update accounting */ smp_mb__before_atomic_inc(); atomic_long_inc(&nfs_access_nr_entries); smp_mb__after_atomic_inc(); /* 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); } } EXPORT_SYMBOL_GPL(nfs_access_add_cache); void nfs_access_set_mask(struct nfs_access_entry *entry, u32 access_result) { entry->mask = 0; if (access_result & NFS4_ACCESS_READ) entry->mask |= MAY_READ; if (access_result & (NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND | NFS4_ACCESS_DELETE)) entry->mask |= MAY_WRITE; if (access_result & (NFS4_ACCESS_LOOKUP|NFS4_ACCESS_EXECUTE)) entry->mask |= MAY_EXEC; } EXPORT_SYMBOL_GPL(nfs_access_set_mask); static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask) { struct nfs_access_entry cache; int status; trace_nfs_access_enter(inode); status = nfs_access_get_cached(inode, cred, &cache); if (status == 0) goto out_cached; /* Be clever: ask server to check for all possible rights */ cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ; cache.cred = cred; cache.jiffies = jiffies; status = NFS_PROTO(inode)->access(inode, &cache); if (status != 0) { if (status == -ESTALE) { nfs_zap_caches(inode); if (!S_ISDIR(inode->i_mode)) set_bit(NFS_INO_STALE, &NFS_I(inode)->flags); } goto out; } nfs_access_add_cache(inode, &cache); out_cached: if ((mask & ~cache.mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0) status = -EACCES; out: trace_nfs_access_exit(inode, 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, struct rpc_cred *cred, int openflags) { return nfs_do_access(inode, cred, nfs_open_permission_mask(openflags)); } EXPORT_SYMBOL_GPL(nfs_may_open); int nfs_permission(struct inode *inode, int mask) { struct rpc_cred *cred; int res = 0; if (mask & MAY_NOT_BLOCK) return -ECHILD; 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: 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; cred = rpc_lookup_cred(); if (!IS_ERR(cred)) { res = nfs_do_access(inode, cred, mask); put_rpccred(cred); } else res = PTR_ERR(cred); out: if (!res && (mask & MAY_EXEC) && !execute_ok(inode)) res = -EACCES; dfprintk(VFS, "NFS: permission(%s/%ld), mask=0x%x, res=%d\n", inode->i_sb->s_id, inode->i_ino, mask, res); return res; out_notsup: 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: */