/* * 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/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/smp_lock.h> #include <linux/namei.h> #include "nfs4_fs.h" #include "delegation.h" #define NFS_PARANOIA 1 /* #define NFS_DEBUG_VERBOSE 1 */ static int nfs_opendir(struct inode *, struct file *); static int nfs_readdir(struct file *, void *, filldir_t); static struct dentry *nfs_lookup(struct inode *, struct dentry *, struct nameidata *); static int nfs_create(struct inode *, struct dentry *, int, struct nameidata *); static int nfs_mkdir(struct inode *, struct dentry *, int); static int nfs_rmdir(struct inode *, struct dentry *); static int nfs_unlink(struct inode *, struct dentry *); static int nfs_symlink(struct inode *, struct dentry *, const char *); static int nfs_link(struct dentry *, struct inode *, struct dentry *); static int nfs_mknod(struct inode *, struct dentry *, int, dev_t); static int nfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *); static int nfs_fsync_dir(struct file *, struct dentry *, int); static loff_t nfs_llseek_dir(struct file *, loff_t, int); struct file_operations nfs_dir_operations = { .llseek = nfs_llseek_dir, .read = generic_read_dir, .readdir = nfs_readdir, .open = nfs_opendir, .release = nfs_release, .fsync = nfs_fsync_dir, }; struct inode_operations nfs_dir_inode_operations = { .create = nfs_create, .lookup = nfs_lookup, .link = nfs_link, .unlink = nfs_unlink, .symlink = nfs_symlink, .mkdir = nfs_mkdir, .rmdir = nfs_rmdir, .mknod = nfs_mknod, .rename = nfs_rename, .permission = nfs_permission, .getattr = nfs_getattr, .setattr = nfs_setattr, }; #ifdef CONFIG_NFS_V3 struct inode_operations nfs3_dir_inode_operations = { .create = nfs_create, .lookup = nfs_lookup, .link = nfs_link, .unlink = nfs_unlink, .symlink = nfs_symlink, .mkdir = nfs_mkdir, .rmdir = nfs_rmdir, .mknod = nfs_mknod, .rename = nfs_rename, .permission = nfs_permission, .getattr = nfs_getattr, .setattr = nfs_setattr, .listxattr = nfs3_listxattr, .getxattr = nfs3_getxattr, .setxattr = nfs3_setxattr, .removexattr = nfs3_removexattr, }; #endif /* CONFIG_NFS_V3 */ #ifdef CONFIG_NFS_V4 static struct dentry *nfs_atomic_lookup(struct inode *, struct dentry *, struct nameidata *); struct inode_operations nfs4_dir_inode_operations = { .create = nfs_create, .lookup = nfs_atomic_lookup, .link = nfs_link, .unlink = nfs_unlink, .symlink = nfs_symlink, .mkdir = nfs_mkdir, .rmdir = nfs_rmdir, .mknod = nfs_mknod, .rename = nfs_rename, .permission = nfs_permission, .getattr = nfs_getattr, .setattr = nfs_setattr, .getxattr = nfs4_getxattr, .setxattr = nfs4_setxattr, .listxattr = nfs4_listxattr, }; #endif /* CONFIG_NFS_V4 */ /* * Open file */ static int nfs_opendir(struct inode *inode, struct file *filp) { int res = 0; lock_kernel(); /* Call generic open code in order to cache credentials */ if (!res) res = nfs_open(inode, filp); unlock_kernel(); return res; } typedef u32 * (*decode_dirent_t)(u32 *, struct nfs_entry *, int); typedef struct { struct file *file; struct page *page; unsigned long page_index; u32 *ptr; u64 *dir_cookie; loff_t current_index; struct nfs_entry *entry; decode_dirent_t decode; int plus; int error; } nfs_readdir_descriptor_t; /* Now we cache directories properly, by stuffing the dirent * data directly in the page cache. * * Inode invalidation due to refresh etc. takes care of * _everything_, no sloppy entry flushing logic, no extraneous * copying, network direct to page cache, the way it was meant * to be. * * NOTE: Dirent information verification is done always by the * page-in of the RPC reply, nowhere else, this simplies * things substantially. */ static int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page) { struct file *file = desc->file; struct inode *inode = file->f_dentry->d_inode; struct rpc_cred *cred = nfs_file_cred(file); unsigned long timestamp; int error; dfprintk(VFS, "NFS: nfs_readdir_filler() reading cookie %Lu into page %lu.\n", (long long)desc->entry->cookie, page->index); again: timestamp = jiffies; error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, desc->entry->cookie, page, 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_FLAGS(inode)); desc->plus = 0; goto again; } goto error; } SetPageUptodate(page); spin_lock(&inode->i_lock); NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATIME; spin_unlock(&inode->i_lock); /* Ensure consistent page alignment of the data. * Note: assumes we have exclusive access to this mapping either * through inode->i_sem or some other mechanism. */ if (page->index == 0) invalidate_inode_pages2_range(inode->i_mapping, PAGE_CACHE_SIZE, -1); unlock_page(page); return 0; error: SetPageError(page); unlock_page(page); nfs_zap_caches(inode); desc->error = error; return -EIO; } static inline int dir_decode(nfs_readdir_descriptor_t *desc) { u32 *p = desc->ptr; p = desc->decode(p, desc->entry, desc->plus); if (IS_ERR(p)) return PTR_ERR(p); desc->ptr = p; return 0; } static inline void dir_page_release(nfs_readdir_descriptor_t *desc) { kunmap(desc->page); page_cache_release(desc->page); desc->page = NULL; desc->ptr = NULL; } /* * Given a pointer to a buffer that has already been filled by a call * to readdir, find the next entry with cookie '*desc->dir_cookie'. * * If the end of the buffer has been reached, return -EAGAIN, if not, * return the offset within the buffer of the next entry to be * read. */ static inline int find_dirent(nfs_readdir_descriptor_t *desc) { struct nfs_entry *entry = desc->entry; int loop_count = 0, status; while((status = dir_decode(desc)) == 0) { dfprintk(VFS, "NFS: found cookie %Lu\n", (unsigned long long)entry->cookie); if (entry->prev_cookie == *desc->dir_cookie) break; if (loop_count++ > 200) { loop_count = 0; schedule(); } } dfprintk(VFS, "NFS: find_dirent() returns %d\n", status); return status; } /* * Given a pointer to a buffer that has already been filled by a call * to readdir, find the entry at offset 'desc->file->f_pos'. * * If the end of the buffer has been reached, return -EAGAIN, if not, * return the offset within the buffer of the next entry to be * read. */ static inline int find_dirent_index(nfs_readdir_descriptor_t *desc) { struct nfs_entry *entry = desc->entry; int loop_count = 0, status; for(;;) { status = dir_decode(desc); if (status) break; dfprintk(VFS, "NFS: found cookie %Lu at index %Ld\n", (unsigned long long)entry->cookie, desc->current_index); if (desc->file->f_pos == desc->current_index) { *desc->dir_cookie = entry->cookie; break; } desc->current_index++; if (loop_count++ > 200) { loop_count = 0; schedule(); } } dfprintk(VFS, "NFS: find_dirent_index() returns %d\n", status); return status; } /* * Find the given page, and call find_dirent() or find_dirent_index in * order to try to return the next entry. */ static inline int find_dirent_page(nfs_readdir_descriptor_t *desc) { struct inode *inode = desc->file->f_dentry->d_inode; struct page *page; int status; dfprintk(VFS, "NFS: find_dirent_page() searching directory page %ld\n", desc->page_index); page = read_cache_page(inode->i_mapping, desc->page_index, (filler_t *)nfs_readdir_filler, desc); if (IS_ERR(page)) { status = PTR_ERR(page); goto out; } if (!PageUptodate(page)) goto read_error; /* NOTE: Someone else may have changed the READDIRPLUS flag */ desc->page = page; desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */ if (*desc->dir_cookie != 0) status = find_dirent(desc); else status = find_dirent_index(desc); if (status < 0) dir_page_release(desc); out: dfprintk(VFS, "NFS: find_dirent_page() returns %d\n", status); return status; read_error: page_cache_release(page); return -EIO; } /* * Recurse through the page cache pages, and return a * filled nfs_entry structure of the next directory entry if possible. * * The target for the search is '*desc->dir_cookie' if non-0, * 'desc->file->f_pos' otherwise */ static inline int readdir_search_pagecache(nfs_readdir_descriptor_t *desc) { int loop_count = 0; int res; /* Always search-by-index from the beginning of the cache */ if (*desc->dir_cookie == 0) { dfprintk(VFS, "NFS: readdir_search_pagecache() searching for offset %Ld\n", (long long)desc->file->f_pos); desc->page_index = 0; desc->entry->cookie = desc->entry->prev_cookie = 0; desc->entry->eof = 0; desc->current_index = 0; } else dfprintk(VFS, "NFS: readdir_search_pagecache() searching for cookie %Lu\n", (unsigned long long)*desc->dir_cookie); for (;;) { res = find_dirent_page(desc); if (res != -EAGAIN) break; /* Align to beginning of next page */ desc->page_index ++; if (loop_count++ > 200) { loop_count = 0; schedule(); } } dfprintk(VFS, "NFS: readdir_search_pagecache() returned %d\n", res); return res; } static inline unsigned int dt_type(struct inode *inode) { return (inode->i_mode >> 12) & 15; } static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc); /* * Once we've found the start of the dirent within a page: fill 'er up... */ static int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent, filldir_t filldir) { struct file *file = desc->file; struct nfs_entry *entry = desc->entry; struct dentry *dentry = NULL; unsigned long fileid; int loop_count = 0, res; dfprintk(VFS, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n", (long long)entry->cookie); for(;;) { unsigned d_type = DT_UNKNOWN; /* Note: entry->prev_cookie contains the cookie for * retrieving the current dirent on the server */ fileid = nfs_fileid_to_ino_t(entry->ino); /* Get a dentry if we have one */ if (dentry != NULL) dput(dentry); dentry = nfs_readdir_lookup(desc); /* Use readdirplus info */ if (dentry != NULL && dentry->d_inode != NULL) { d_type = dt_type(dentry->d_inode); fileid = dentry->d_inode->i_ino; } res = filldir(dirent, entry->name, entry->len, file->f_pos, fileid, d_type); if (res < 0) break; file->f_pos++; *desc->dir_cookie = entry->cookie; if (dir_decode(desc) != 0) { desc->page_index ++; break; } if (loop_count++ > 200) { loop_count = 0; schedule(); } } dir_page_release(desc); if (dentry != NULL) dput(dentry); dfprintk(VFS, "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, void *dirent, filldir_t filldir) { struct file *file = desc->file; struct inode *inode = file->f_dentry->d_inode; struct rpc_cred *cred = nfs_file_cred(file); struct page *page = NULL; int status; dfprintk(VFS, "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->error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, *desc->dir_cookie, page, NFS_SERVER(inode)->dtsize, desc->plus); spin_lock(&inode->i_lock); NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATIME; spin_unlock(&inode->i_lock); desc->page = page; desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */ if (desc->error >= 0) { if ((status = dir_decode(desc)) == 0) desc->entry->prev_cookie = *desc->dir_cookie; } else status = -EIO; if (status < 0) goto out_release; status = nfs_do_filldir(desc, dirent, filldir); /* Reset read descriptor so it searches the page cache from * the start upon the next call to readdir_search_pagecache() */ desc->page_index = 0; desc->entry->cookie = desc->entry->prev_cookie = 0; desc->entry->eof = 0; out: dfprintk(VFS, "NFS: uncached_readdir() returns %d\n", status); return status; out_release: dir_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 *filp, void *dirent, filldir_t filldir) { struct dentry *dentry = filp->f_dentry; struct inode *inode = dentry->d_inode; nfs_readdir_descriptor_t my_desc, *desc = &my_desc; struct nfs_entry my_entry; struct nfs_fh fh; struct nfs_fattr fattr; long res; lock_kernel(); res = nfs_revalidate_inode(NFS_SERVER(inode), inode); if (res < 0) { unlock_kernel(); return res; } /* * filp->f_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 = filp; desc->dir_cookie = &((struct nfs_open_context *)filp->private_data)->dir_cookie; desc->decode = NFS_PROTO(inode)->decode_dirent; desc->plus = NFS_USE_READDIRPLUS(inode); my_entry.cookie = my_entry.prev_cookie = 0; my_entry.eof = 0; my_entry.fh = &fh; my_entry.fattr = &fattr; nfs_fattr_init(&fattr); desc->entry = &my_entry; while(!desc->entry->eof) { res = readdir_search_pagecache(desc); if (res == -EBADCOOKIE) { /* This means either end of directory */ if (*desc->dir_cookie && desc->entry->cookie != *desc->dir_cookie) { /* Or that the server has 'lost' a cookie */ res = uncached_readdir(desc, dirent, filldir); if (res >= 0) continue; } res = 0; break; } if (res == -ETOOSMALL && desc->plus) { clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode)); nfs_zap_caches(inode); desc->plus = 0; desc->entry->eof = 0; continue; } if (res < 0) break; res = nfs_do_filldir(desc, dirent, filldir); if (res < 0) { res = 0; break; } } unlock_kernel(); if (res < 0) return res; return 0; } loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int origin) { down(&filp->f_dentry->d_inode->i_sem); switch (origin) { 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; ((struct nfs_open_context *)filp->private_data)->dir_cookie = 0; } out: up(&filp->f_dentry->d_inode->i_sem); return offset; } /* * All directory operations under NFS are synchronous, so fsync() * is a dummy operation. */ int nfs_fsync_dir(struct file *filp, struct dentry *dentry, int datasync) { return 0; } /* * 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 inline int nfs_check_verifier(struct inode *dir, struct dentry *dentry) { if (IS_ROOT(dentry)) return 1; if ((NFS_I(dir)->cache_validity & NFS_INO_INVALID_ATTR) != 0 || nfs_attribute_timeout(dir)) return 0; return nfs_verify_change_attribute(dir, (unsigned long)dentry->d_fsdata); } static inline void nfs_set_verifier(struct dentry * dentry, unsigned long verf) { dentry->d_fsdata = (void *)verf; } /* * Whenever an NFS operation succeeds, we know that the dentry * is valid, so we update the revalidation timestamp. */ static inline void nfs_renew_times(struct dentry * dentry) { dentry->d_time = jiffies; } /* * Return the intent data that applies to this particular path component * * Note that the current set of intents only apply to the very last * component of the path. * We check for this using LOOKUP_CONTINUE and LOOKUP_PARENT. */ static inline unsigned int nfs_lookup_check_intent(struct nameidata *nd, unsigned int mask) { if (nd->flags & (LOOKUP_CONTINUE|LOOKUP_PARENT)) return 0; return nd->flags & mask; } /* * 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 inline int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd) { struct nfs_server *server = NFS_SERVER(inode); if (nd != NULL) { /* VFS wants an on-the-wire revalidation */ if (nd->flags & LOOKUP_REVAL) goto out_force; /* This is an open(2) */ if (nfs_lookup_check_intent(nd, LOOKUP_OPEN) != 0 && !(server->flags & NFS_MOUNT_NOCTO)) goto out_force; } return nfs_revalidate_inode(server, inode); out_force: return __nfs_revalidate_inode(server, inode); } /* * 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, struct nameidata *nd) { /* Don't revalidate a negative dentry if we're creating a new file */ if (nd != NULL && nfs_lookup_check_intent(nd, LOOKUP_CREATE) != 0) return 0; 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, struct nameidata *nd) { struct inode *dir; struct inode *inode; struct dentry *parent; int error; struct nfs_fh fhandle; struct nfs_fattr fattr; unsigned long verifier; parent = dget_parent(dentry); lock_kernel(); dir = parent->d_inode; inode = dentry->d_inode; if (!inode) { if (nfs_neg_need_reval(dir, dentry, nd)) goto out_bad; goto out_valid; } if (is_bad_inode(inode)) { dfprintk(VFS, "nfs_lookup_validate: %s/%s has dud inode\n", dentry->d_parent->d_name.name, dentry->d_name.name); goto out_bad; } /* Revalidate parent directory attribute cache */ if (nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0) goto out_zap_parent; /* Force a full look up iff the parent directory has changed */ if (nfs_check_verifier(dir, dentry)) { if (nfs_lookup_verify_inode(inode, nd)) goto out_zap_parent; goto out_valid; } if (NFS_STALE(inode)) goto out_bad; verifier = nfs_save_change_attribute(dir); error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); 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_renew_times(dentry); nfs_set_verifier(dentry, verifier); out_valid: unlock_kernel(); dput(parent); return 1; out_zap_parent: nfs_zap_caches(dir); out_bad: NFS_CACHEINV(dir); if (inode && S_ISDIR(inode->i_mode)) { /* Purge readdir caches. */ nfs_zap_caches(inode); /* If we have submounts, don't unhash ! */ if (have_submounts(dentry)) goto out_valid; shrink_dcache_parent(dentry); } d_drop(dentry); unlock_kernel(); dput(parent); return 0; } /* * This is called from dput() when d_count is going to 0. */ static int nfs_dentry_delete(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); 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; } /* * 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) { nfs_inode_return_delegation(inode); if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { lock_kernel(); inode->i_nlink--; nfs_complete_unlink(dentry); unlock_kernel(); } /* When creating a negative dentry, we want to renew d_time */ nfs_renew_times(dentry); iput(inode); } struct dentry_operations nfs_dentry_operations = { .d_revalidate = nfs_lookup_revalidate, .d_delete = nfs_dentry_delete, .d_iput = nfs_dentry_iput, }; /* * Use intent information to check whether or not we're going to do * an O_EXCL create using this path component. */ static inline int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd) { if (NFS_PROTO(dir)->version == 2) return 0; if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_CREATE) == 0) return 0; return (nd->intent.open.flags & O_EXCL) != 0; } static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd) { struct dentry *res; struct inode *inode = NULL; int error; struct nfs_fh fhandle; struct nfs_fattr fattr; dfprintk(VFS, "NFS: lookup(%s/%s)\n", dentry->d_parent->d_name.name, dentry->d_name.name); res = ERR_PTR(-ENAMETOOLONG); if (dentry->d_name.len > NFS_SERVER(dir)->namelen) goto out; res = ERR_PTR(-ENOMEM); dentry->d_op = NFS_PROTO(dir)->dentry_ops; lock_kernel(); /* If we're doing an exclusive create, optimize away the lookup */ if (nfs_is_exclusive_create(dir, nd)) goto no_entry; error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); if (error == -ENOENT) goto no_entry; if (error < 0) { res = ERR_PTR(error); goto out_unlock; } res = ERR_PTR(-EACCES); inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr); if (!inode) goto out_unlock; no_entry: res = d_add_unique(dentry, inode); if (res != NULL) dentry = res; nfs_renew_times(dentry); nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); out_unlock: unlock_kernel(); out: return res; } #ifdef CONFIG_NFS_V4 static int nfs_open_revalidate(struct dentry *, struct nameidata *); struct dentry_operations nfs4_dentry_operations = { .d_revalidate = nfs_open_revalidate, .d_delete = nfs_dentry_delete, .d_iput = nfs_dentry_iput, }; /* * Use intent information to determine whether we need to substitute * the NFSv4-style stateful OPEN for the LOOKUP call */ static int is_atomic_open(struct inode *dir, struct nameidata *nd) { if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_OPEN) == 0) return 0; /* NFS does not (yet) have a stateful open for directories */ if (nd->flags & LOOKUP_DIRECTORY) return 0; /* Are we trying to write to a read only partition? */ if (IS_RDONLY(dir) && (nd->intent.open.flags & (O_CREAT|O_TRUNC|FMODE_WRITE))) return 0; return 1; } static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) { struct dentry *res = NULL; int error; /* Check that we are indeed trying to open this file */ if (!is_atomic_open(dir, nd)) goto no_open; if (dentry->d_name.len > NFS_SERVER(dir)->namelen) { res = ERR_PTR(-ENAMETOOLONG); goto out; } dentry->d_op = NFS_PROTO(dir)->dentry_ops; /* Let vfs_create() deal with O_EXCL */ if (nd->intent.open.flags & O_EXCL) { d_add(dentry, NULL); goto out; } /* Open the file on the server */ lock_kernel(); /* Revalidate parent directory attribute cache */ error = nfs_revalidate_inode(NFS_SERVER(dir), dir); if (error < 0) { res = ERR_PTR(error); unlock_kernel(); goto out; } if (nd->intent.open.flags & O_CREAT) { nfs_begin_data_update(dir); res = nfs4_atomic_open(dir, dentry, nd); nfs_end_data_update(dir); } else res = nfs4_atomic_open(dir, dentry, nd); unlock_kernel(); if (IS_ERR(res)) { error = PTR_ERR(res); switch (error) { /* Make a negative dentry */ case -ENOENT: res = NULL; goto out; /* This turned out not to be a regular file */ case -EISDIR: case -ENOTDIR: goto no_open; case -ELOOP: if (!(nd->intent.open.flags & O_NOFOLLOW)) goto no_open; /* case -EINVAL: */ default: goto out; } } else if (res != NULL) dentry = res; nfs_renew_times(dentry); nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); out: return res; no_open: return nfs_lookup(dir, dentry, nd); } static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd) { struct dentry *parent = NULL; struct inode *inode = dentry->d_inode; struct inode *dir; unsigned long verifier; int openflags, ret = 0; parent = dget_parent(dentry); dir = parent->d_inode; if (!is_atomic_open(dir, nd)) goto no_open; /* We can't create new files in nfs_open_revalidate(), so we * optimize away revalidation of negative dentries. */ if (inode == NULL) goto out; /* NFS only supports OPEN on regular files */ if (!S_ISREG(inode->i_mode)) goto no_open; openflags = nd->intent.open.flags; /* We cannot do exclusive creation on a positive dentry */ if ((openflags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL)) goto no_open; /* We can't create new files, or truncate existing ones here */ openflags &= ~(O_CREAT|O_TRUNC); /* * Note: we're not holding inode->i_sem and so may be racing with * operations that change the directory. We therefore save the * change attribute *before* we do the RPC call. */ lock_kernel(); verifier = nfs_save_change_attribute(dir); ret = nfs4_open_revalidate(dir, dentry, openflags, nd); if (!ret) nfs_set_verifier(dentry, verifier); unlock_kernel(); out: dput(parent); if (!ret) d_drop(dentry); return ret; no_open: dput(parent); if (inode != NULL && nfs_have_delegation(inode, FMODE_READ)) return 1; return nfs_lookup_revalidate(dentry, nd); } #endif /* CONFIG_NFSV4 */ static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc) { struct dentry *parent = desc->file->f_dentry; struct inode *dir = parent->d_inode; struct nfs_entry *entry = desc->entry; struct dentry *dentry, *alias; struct qstr name = { .name = entry->name, .len = entry->len, }; struct inode *inode; switch (name.len) { case 2: if (name.name[0] == '.' && name.name[1] == '.') return dget_parent(parent); break; case 1: if (name.name[0] == '.') return dget(parent); } name.hash = full_name_hash(name.name, name.len); dentry = d_lookup(parent, &name); if (dentry != NULL) return dentry; if (!desc->plus || !(entry->fattr->valid & NFS_ATTR_FATTR)) return NULL; /* Note: caller is already holding the dir->i_sem! */ dentry = d_alloc(parent, &name); if (dentry == NULL) return NULL; dentry->d_op = NFS_PROTO(dir)->dentry_ops; inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr); if (!inode) { dput(dentry); return NULL; } alias = d_add_unique(dentry, inode); if (alias != NULL) { dput(dentry); dentry = alias; } nfs_renew_times(dentry); nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); return dentry; } /* * Code common to create, mkdir, and mknod. */ int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle, struct nfs_fattr *fattr) { struct inode *inode; int error = -EACCES; /* We may have been initialized further down */ if (dentry->d_inode) return 0; if (fhandle->size == 0) { struct inode *dir = dentry->d_parent->d_inode; error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr); if (error) goto out_err; } if (!(fattr->valid & NFS_ATTR_FATTR)) { struct nfs_server *server = NFS_SB(dentry->d_sb); error = server->rpc_ops->getattr(server, fhandle, fattr); if (error < 0) goto out_err; } error = -ENOMEM; inode = nfs_fhget(dentry->d_sb, fhandle, fattr); if (inode == NULL) goto out_err; d_instantiate(dentry, inode); return 0; out_err: d_drop(dentry); return error; } /* * 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. */ static int nfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd) { struct iattr attr; int error; int open_flags = 0; 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; if (nd && (nd->flags & LOOKUP_CREATE)) open_flags = nd->intent.open.flags; lock_kernel(); nfs_begin_data_update(dir); error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags, nd); nfs_end_data_update(dir); if (error != 0) goto out_err; nfs_renew_times(dentry); nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); unlock_kernel(); return 0; out_err: unlock_kernel(); d_drop(dentry); return error; } /* * See comments for nfs_proc_create regarding failed operations. */ static int nfs_mknod(struct inode *dir, struct dentry *dentry, int 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; lock_kernel(); nfs_begin_data_update(dir); status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev); nfs_end_data_update(dir); if (status != 0) goto out_err; nfs_renew_times(dentry); nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); unlock_kernel(); return 0; out_err: unlock_kernel(); d_drop(dentry); return status; } /* * See comments for nfs_proc_create regarding failed operations. */ static int nfs_mkdir(struct inode *dir, struct dentry *dentry, int 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; lock_kernel(); nfs_begin_data_update(dir); error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr); nfs_end_data_update(dir); if (error != 0) goto out_err; nfs_renew_times(dentry); nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); unlock_kernel(); return 0; out_err: d_drop(dentry); unlock_kernel(); return error; } static 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); lock_kernel(); nfs_begin_data_update(dir); error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); /* Ensure the VFS deletes this inode */ if (error == 0 && dentry->d_inode != NULL) dentry->d_inode->i_nlink = 0; nfs_end_data_update(dir); unlock_kernel(); return error; } static int nfs_sillyrename(struct inode *dir, struct dentry *dentry) { static unsigned int sillycounter; const int i_inosize = sizeof(dir->i_ino)*2; const int countersize = sizeof(sillycounter)*2; const int slen = sizeof(".nfs") + i_inosize + countersize - 1; char silly[slen+1]; struct qstr qsilly; struct dentry *sdentry; int error = -EIO; dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n", dentry->d_parent->d_name.name, dentry->d_name.name, atomic_read(&dentry->d_count)); #ifdef NFS_PARANOIA if (!dentry->d_inode) printk("NFS: silly-renaming %s/%s, negative dentry??\n", dentry->d_parent->d_name.name, dentry->d_name.name); #endif /* * We don't allow a dentry to be silly-renamed twice. */ error = -EBUSY; if (dentry->d_flags & DCACHE_NFSFS_RENAMED) goto out; sprintf(silly, ".nfs%*.*lx", i_inosize, i_inosize, dentry->d_inode->i_ino); /* Return delegation in anticipation of the rename */ nfs_inode_return_delegation(dentry->d_inode); sdentry = NULL; do { char *suffix = silly + slen - countersize; dput(sdentry); sillycounter++; sprintf(suffix, "%*.*x", countersize, countersize, sillycounter); dfprintk(VFS, "trying to rename %s to %s\n", dentry->d_name.name, silly); sdentry = lookup_one_len(silly, dentry->d_parent, slen); /* * N.B. Better to return EBUSY here ... it could be * dangerous to delete the file while it's in use. */ if (IS_ERR(sdentry)) goto out; } while(sdentry->d_inode != NULL); /* need negative lookup */ qsilly.name = silly; qsilly.len = strlen(silly); nfs_begin_data_update(dir); if (dentry->d_inode) { nfs_begin_data_update(dentry->d_inode); error = NFS_PROTO(dir)->rename(dir, &dentry->d_name, dir, &qsilly); nfs_mark_for_revalidate(dentry->d_inode); nfs_end_data_update(dentry->d_inode); } else error = NFS_PROTO(dir)->rename(dir, &dentry->d_name, dir, &qsilly); nfs_end_data_update(dir); if (!error) { nfs_renew_times(dentry); nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); d_move(dentry, sdentry); error = nfs_async_unlink(dentry); /* If we return 0 we don't unlink */ } dput(sdentry); out: return error; } /* * 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; } nfs_begin_data_update(dir); if (inode != NULL) { nfs_inode_return_delegation(inode); nfs_begin_data_update(inode); error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); /* The VFS may want to delete this inode */ if (error == 0) inode->i_nlink--; nfs_mark_for_revalidate(inode); nfs_end_data_update(inode); } else error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); nfs_end_data_update(dir); 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. */ static 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); lock_kernel(); spin_lock(&dcache_lock); spin_lock(&dentry->d_lock); if (atomic_read(&dentry->d_count) > 1) { spin_unlock(&dentry->d_lock); spin_unlock(&dcache_lock); error = nfs_sillyrename(dir, dentry); unlock_kernel(); return error; } if (!d_unhashed(dentry)) { __d_drop(dentry); need_rehash = 1; } spin_unlock(&dentry->d_lock); spin_unlock(&dcache_lock); error = nfs_safe_remove(dentry); if (!error) { nfs_renew_times(dentry); nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); } else if (need_rehash) d_rehash(dentry); unlock_kernel(); return error; } static int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) { struct iattr attr; struct nfs_fattr sym_attr; struct nfs_fh sym_fh; struct qstr qsymname; int error; dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id, dir->i_ino, dentry->d_name.name, symname); #ifdef NFS_PARANOIA if (dentry->d_inode) printk("nfs_proc_symlink: %s/%s not negative!\n", dentry->d_parent->d_name.name, dentry->d_name.name); #endif /* * Fill in the sattr for the call. * Note: SunOS 4.1.2 crashes if the mode isn't initialized! */ attr.ia_valid = ATTR_MODE; attr.ia_mode = S_IFLNK | S_IRWXUGO; qsymname.name = symname; qsymname.len = strlen(symname); lock_kernel(); nfs_begin_data_update(dir); error = NFS_PROTO(dir)->symlink(dir, &dentry->d_name, &qsymname, &attr, &sym_fh, &sym_attr); nfs_end_data_update(dir); if (!error) { error = nfs_instantiate(dentry, &sym_fh, &sym_attr); } else { if (error == -EEXIST) printk("nfs_proc_symlink: %s/%s already exists??\n", dentry->d_parent->d_name.name, dentry->d_name.name); d_drop(dentry); } unlock_kernel(); return error; } static 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); lock_kernel(); nfs_begin_data_update(dir); nfs_begin_data_update(inode); error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); if (error == 0) { atomic_inc(&inode->i_count); d_instantiate(dentry, inode); } nfs_end_data_update(inode); nfs_end_data_update(dir); unlock_kernel(); return error; } /* * 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. */ static 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; /* * To prevent any new references to the target during the rename, * we unhash the dentry and free the inode in advance. */ lock_kernel(); if (!d_unhashed(new_dentry)) { d_drop(new_dentry); rehash = new_dentry; } 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, atomic_read(&new_dentry->d_count)); /* * First check whether the target is busy ... we can't * safely do _any_ rename if the target is in use. * * For files, 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) goto go_ahead; if (S_ISDIR(new_inode->i_mode)) { error = -EISDIR; if (!S_ISDIR(old_inode->i_mode)) goto out; } else if (atomic_read(&new_dentry->d_count) > 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) { new_dentry = rehash = dentry; new_inode = NULL; /* instantiate the replacement target */ d_instantiate(new_dentry, NULL); } else if (atomic_read(&new_dentry->d_count) > 1) { /* dentry still busy? */ #ifdef NFS_PARANOIA printk("nfs_rename: target %s/%s busy, d_count=%d\n", new_dentry->d_parent->d_name.name, new_dentry->d_name.name, atomic_read(&new_dentry->d_count)); #endif goto out; } } else new_inode->i_nlink--; go_ahead: /* * ... prune child dentries and writebacks if needed. */ if (atomic_read(&old_dentry->d_count) > 1) { nfs_wb_all(old_inode); shrink_dcache_parent(old_dentry); } nfs_inode_return_delegation(old_inode); if (new_inode) d_delete(new_dentry); nfs_begin_data_update(old_dir); nfs_begin_data_update(new_dir); nfs_begin_data_update(old_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); nfs_end_data_update(old_inode); nfs_end_data_update(new_dir); nfs_end_data_update(old_dir); out: if (rehash) d_rehash(rehash); if (!error) { if (!S_ISDIR(old_inode->i_mode)) d_move(old_dentry, new_dentry); nfs_renew_times(new_dentry); nfs_set_verifier(new_dentry, nfs_save_change_attribute(new_dir)); } /* new dentry created? */ if (dentry) dput(dentry); unlock_kernel(); return error; } 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 = &nfsi->cache_access; if (cache->cred != cred || time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode)) || (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)) return -ENOENT; memcpy(res, cache, sizeof(*res)); return 0; } void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set) { struct nfs_inode *nfsi = NFS_I(inode); struct nfs_access_entry *cache = &nfsi->cache_access; if (cache->cred != set->cred) { if (cache->cred) put_rpccred(cache->cred); cache->cred = get_rpccred(set->cred); } /* FIXME: replace current access_cache BKL reliance with inode->i_lock */ spin_lock(&inode->i_lock); nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS; spin_unlock(&inode->i_lock); cache->jiffies = set->jiffies; cache->mask = set->mask; } static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask) { struct nfs_access_entry cache; int status; status = nfs_access_get_cached(inode, cred, &cache); if (status == 0) goto out; /* 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) return status; nfs_access_add_cache(inode, &cache); out: if ((cache.mask & mask) == mask) return 0; return -EACCES; } int nfs_permission(struct inode *inode, int mask, struct nameidata *nd) { struct rpc_cred *cred; int res = 0; if (mask == 0) goto out; /* Is this sys_access() ? */ if (nd != NULL && (nd->flags & LOOKUP_ACCESS)) goto force_lookup; switch (inode->i_mode & S_IFMT) { case S_IFLNK: goto out; case S_IFREG: /* NFSv4 has atomic_open... */ if (nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN) && nd != NULL && (nd->flags & LOOKUP_OPEN)) goto out; 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: lock_kernel(); if (!NFS_PROTO(inode)->access) goto out_notsup; cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0); if (!IS_ERR(cred)) { res = nfs_do_access(inode, cred, mask); put_rpccred(cred); } else res = PTR_ERR(cred); unlock_kernel(); out: return res; out_notsup: res = nfs_revalidate_inode(NFS_SERVER(inode), inode); if (res == 0) res = generic_permission(inode, mask, NULL); unlock_kernel(); return res; } /* * Local variables: * version-control: t * kept-new-versions: 5 * End: */