/* * 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> #define NFS_PARANOIA 1 /* #define NFS_DEBUG_VERBOSE 1 */ static int nfs_readdir(struct file *, void *, filldir_t); static struct dentry *nfs_lookup(struct inode *, struct dentry *); static int nfs_create(struct inode *, struct dentry *, int); 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, int); static int nfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *); struct file_operations nfs_dir_operations = { read: generic_read_dir, readdir: nfs_readdir, open: nfs_open, release: nfs_release, }; 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, }; 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 target; 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); int error; dfprintk(VFS, "NFS: nfs_readdir_filler() reading cookie %Lu into page %lu.\n", (long long)desc->entry->cookie, page->index); again: error = NFS_PROTO(inode)->readdir(inode, cred, desc->entry->cookie, page, NFS_SERVER(inode)->dtsize, desc->plus); /* We requested READDIRPLUS, but the server doesn't grok it */ if (desc->plus && error == -ENOTSUPP) { NFS_FLAGS(inode) &= ~NFS_INO_ADVISE_RDPLUS; desc->plus = 0; goto again; } if (error < 0) goto error; SetPageUptodate(page); /* Ensure consistent page alignment of the data. * Note: assumes we have exclusive access to this mapping either * throught inode->i_sem or some other mechanism. */ if (page->index == 0) invalidate_inode_pages(inode); unlock_page(page); return 0; error: SetPageError(page); kunmap(page); unlock_page(page); invalidate_inode_pages(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. * * 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 page *page) { struct nfs_entry *entry = desc->entry; int loop_count = 0, status; while((status = dir_decode(desc)) == 0) { dfprintk(VFS, "NFS: found cookie %Lu\n", (long long)entry->cookie); if (entry->prev_cookie == desc->target) break; if (loop_count++ > 200) { loop_count = 0; schedule(); } } dfprintk(VFS, "NFS: find_dirent() returns %d\n", status); return status; } /* * Find the given page, and call find_dirent() 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); desc->plus = NFS_USE_READDIRPLUS(inode); page = read_cache_page(&inode->i_data, 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); status = find_dirent(desc, page); 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->target'. */ static inline int readdir_search_pagecache(nfs_readdir_descriptor_t *desc) { int loop_count = 0; int res; dfprintk(VFS, "NFS: readdir_search_pagecache() searching for cookie %Lu\n", (long long)desc->target); 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; } /* * 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; unsigned long fileid; int loop_count = 0, res; dfprintk(VFS, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n", (long long)desc->target); for(;;) { /* Note: entry->prev_cookie contains the cookie for * retrieving the current dirent on the server */ fileid = nfs_fileid_to_ino_t(entry->ino); res = filldir(dirent, entry->name, entry->len, entry->prev_cookie, fileid, DT_UNKNOWN); if (res < 0) break; file->f_pos = desc->target = entry->cookie; if (dir_decode(desc) != 0) { desc->page_index ++; break; } if (loop_count++ > 200) { loop_count = 0; schedule(); } } dir_page_release(desc); dfprintk(VFS, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", (long long)desc->target, 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", (long long)desc->target); page = alloc_page(GFP_HIGHUSER); if (!page) { status = -ENOMEM; goto out; } desc->error = NFS_PROTO(inode)->readdir(inode, cred, desc->target, page, NFS_SERVER(inode)->dtsize, desc->plus); desc->page = page; desc->ptr = kmap(page); if (desc->error >= 0) { if ((status = dir_decode(desc)) == 0) desc->entry->prev_cookie = desc->target; } 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; memset(desc->entry, 0, sizeof(*desc->entry)); out: dfprintk(VFS, "NFS: uncached_readdir() returns %d\n", status); return status; out_release: dir_page_release(desc); goto out; } /* The file offset position is now represented as a true offset into the * page cache as is the case in most of the other filesystems. */ 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; 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 file offset in the page cache. * but if the cache has meanwhile been zapped, we need to * read from the last dirent to revalidate f_pos * itself. */ memset(desc, 0, sizeof(*desc)); memset(&my_entry, 0, sizeof(my_entry)); desc->file = filp; desc->target = filp->f_pos; desc->entry = &my_entry; desc->decode = NFS_PROTO(inode)->decode_dirent; while(!desc->entry->eof) { res = readdir_search_pagecache(desc); if (res == -EBADCOOKIE) { /* This means either end of directory */ if (desc->entry->cookie != desc->target) { /* Or that the server has 'lost' a cookie */ res = uncached_readdir(desc, dirent, filldir); if (res >= 0) continue; } res = 0; break; } else if (res < 0) break; res = nfs_do_filldir(desc, dirent, filldir); if (res < 0) { res = 0; break; } } unlock_kernel(); if (desc->error < 0) return desc->error; if (res < 0) return res; 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_revalidate_inode(NFS_SERVER(dir), dir)) return 0; return time_after(dentry->d_time, NFS_MTIME_UPDATE(dir)); } /* * 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; } static inline int nfs_lookup_verify_inode(struct inode *inode, int flags) { struct nfs_server *server = NFS_SERVER(inode); /* * If we're interested in close-to-open cache consistency, * then we revalidate the inode upon lookup. */ if (!(server->flags & NFS_MOUNT_NOCTO) && !(flags & LOOKUP_CONTINUE)) NFS_CACHEINV(inode); 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) { if (!nfs_check_verifier(dir, dentry)) return 1; return time_after(jiffies, dentry->d_time + NFS_ATTRTIMEO(dir)); } /* * 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, int flags) { struct inode *dir; struct inode *inode; struct dentry *parent; int error; struct nfs_fh fhandle; struct nfs_fattr fattr; read_lock(&dparent_lock); parent = dget(dentry->d_parent); read_unlock(&dparent_lock); lock_kernel(); dir = parent->d_inode; inode = dentry->d_inode; if (!inode) { if (nfs_neg_need_reval(dir, dentry)) 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; } /* Force a full look up iff the parent directory has changed */ if (nfs_check_verifier(dir, dentry)) { if (nfs_lookup_verify_inode(inode, flags)) goto out_bad; goto out_valid; } if (NFS_STALE(inode)) goto out_bad; error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); if (error) goto out_bad; if (memcmp(NFS_FH(inode), &fhandle, sizeof(struct nfs_fh))!= 0) goto out_bad; if ((error = nfs_refresh_inode(inode, &fattr)) != 0) goto out_bad; nfs_renew_times(dentry); out_valid: unlock_kernel(); dput(parent); return 1; 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; } 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) { if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { lock_kernel(); inode->i_nlink--; nfs_complete_unlink(dentry); unlock_kernel(); } iput(inode); } struct dentry_operations nfs_dentry_operations = { d_revalidate: nfs_lookup_revalidate, d_delete: nfs_dentry_delete, d_iput: nfs_dentry_iput, }; static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry) { struct inode *inode; 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); error = -ENAMETOOLONG; if (dentry->d_name.len > NFS_SERVER(dir)->namelen) goto out; error = -ENOMEM; dentry->d_op = &nfs_dentry_operations; lock_kernel(); error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); inode = NULL; if (error == -ENOENT) goto no_entry; if (!error) { error = -EACCES; inode = nfs_fhget(dentry, &fhandle, &fattr); if (inode) { no_entry: d_add(dentry, inode); error = 0; } nfs_renew_times(dentry); } unlock_kernel(); out: return ERR_PTR(error); } /* * Code common to create, mkdir, and mknod. */ static int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle, struct nfs_fattr *fattr) { struct inode *inode; int error = -EACCES; if (fhandle->size == 0 || !(fattr->valid & NFS_ATTR_FATTR)) { struct inode *dir = dentry->d_parent->d_inode; error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr); if (error) goto out_err; } inode = nfs_fhget(dentry, fhandle, fattr); if (inode) { d_instantiate(dentry, inode); nfs_renew_times(dentry); error = 0; } return error; 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 iattr attr; struct nfs_fattr fattr; struct nfs_fh fhandle; 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; /* * The 0 argument passed into the create function should one day * contain the O_EXCL flag if requested. This allows NFSv3 to * select the appropriate create strategy. Currently open_namei * does not pass the create flags. */ lock_kernel(); nfs_zap_caches(dir); error = NFS_PROTO(dir)->create(dir, &dentry->d_name, &attr, 0, &fhandle, &fattr); if (!error) error = nfs_instantiate(dentry, &fhandle, &fattr); else d_drop(dentry); unlock_kernel(); return error; } /* * See comments for nfs_proc_create regarding failed operations. */ static int nfs_mknod(struct inode *dir, struct dentry *dentry, int mode, int rdev) { struct iattr attr; struct nfs_fattr fattr; struct nfs_fh fhandle; int error; dfprintk(VFS, "NFS: mknod(%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; lock_kernel(); nfs_zap_caches(dir); error = NFS_PROTO(dir)->mknod(dir, &dentry->d_name, &attr, rdev, &fhandle, &fattr); if (!error) error = nfs_instantiate(dentry, &fhandle, &fattr); else d_drop(dentry); unlock_kernel(); return error; } /* * See comments for nfs_proc_create regarding failed operations. */ static int nfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) { struct iattr attr; struct nfs_fattr fattr; struct nfs_fh fhandle; 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(); #if 0 /* * Always drop the dentry, we can't always depend on * the fattr returned by the server (AIX seems to be * broken). We're better off doing another lookup than * depending on potentially bogus information. */ d_drop(dentry); #endif nfs_zap_caches(dir); error = NFS_PROTO(dir)->mkdir(dir, &dentry->d_name, &attr, &fhandle, &fattr); if (!error) error = nfs_instantiate(dentry, &fhandle, &fattr); else 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_zap_caches(dir); error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); if (!error) dentry->d_inode->i_nlink = 0; 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 = strlen(".nfs") + i_inosize + countersize; 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)); if (atomic_read(&dentry->d_count) == 1) goto out; /* No need to silly rename. */ #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); 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 */ nfs_zap_caches(dir); qsilly.name = silly; qsilly.len = strlen(silly); error = NFS_PROTO(dir)->rename(dir, &dentry->d_name, dir, &qsilly); if (!error) { nfs_renew_times(dentry); 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, rehash = 0; dfprintk(VFS, "NFS: safe_remove(%s/%s)\n", dentry->d_parent->d_name.name, dentry->d_name.name); /* * Unhash the dentry while we remove the file ... */ if (!d_unhashed(dentry)) { d_drop(dentry); rehash = 1; } if (atomic_read(&dentry->d_count) > 1) { #ifdef NFS_PARANOIA printk("nfs_safe_remove: %s/%s busy, d_count=%d\n", dentry->d_parent->d_name.name, dentry->d_name.name, atomic_read(&dentry->d_count)); #endif goto out; } /* If the dentry was sillyrenamed, we simply call d_delete() */ if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { error = 0; goto out_delete; } nfs_zap_caches(dir); if (inode) NFS_CACHEINV(inode); error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); if (error < 0) goto out; if (inode) inode->i_nlink--; out_delete: /* * Free the inode */ d_delete(dentry); out: if (rehash) d_rehash(dentry); 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; dfprintk(VFS, "NFS: unlink(%s/%ld, %s)\n", dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); lock_kernel(); error = nfs_sillyrename(dir, dentry); if (error && error != -EBUSY) { error = nfs_safe_remove(dentry); if (!error) { nfs_renew_times(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; unsigned int maxlen; int error; dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id, dir->i_ino, dentry->d_name.name, symname); error = -ENAMETOOLONG; maxlen = (NFS_PROTO(dir)->version==2) ? NFS2_MAXPATHLEN : NFS3_MAXPATHLEN; if (strlen(symname) > maxlen) goto out; #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_zap_caches(dir); error = NFS_PROTO(dir)->symlink(dir, &dentry->d_name, &qsymname, &attr, &sym_fh, &sym_attr); 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(); out: 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); /* * Drop the dentry in advance to force a new lookup. * Since nfs_proc_link doesn't return a file handle, * we can't use the existing dentry. */ lock_kernel(); d_drop(dentry); nfs_zap_caches(dir); NFS_CACHEINV(inode); error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); 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)) goto out; else if (atomic_read(&new_dentry->d_count) > 1) { 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); } /* dentry still busy? */ if (atomic_read(&new_dentry->d_count) > 1) { #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; } } 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); } if (new_inode) d_delete(new_dentry); nfs_zap_caches(new_dir); nfs_zap_caches(old_dir); error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name, new_dir, &new_dentry->d_name); out: if (rehash) d_rehash(rehash); if (!error && !S_ISDIR(old_inode->i_mode)) d_move(old_dentry, new_dentry); /* new dentry created? */ if (dentry) dput(dentry); unlock_kernel(); return error; } int nfs_permission(struct inode *inode, int mask) { int error = vfs_permission(inode, mask); if (!NFS_PROTO(inode)->access) goto out; if (error == -EROFS) goto out; /* * Trust UNIX mode bits except: * * 1) When override capabilities may have been invoked * 2) When root squashing may be involved * 3) When ACLs may overturn a negative answer */ if (!capable(CAP_DAC_OVERRIDE) && !capable(CAP_DAC_READ_SEARCH) && (current->fsuid != 0) && (current->fsgid != 0) && error != -EACCES) goto out; error = NFS_PROTO(inode)->access(inode, mask, 0); if (error == -EACCES && NFS_CLIENT(inode)->cl_droppriv && current->uid != 0 && current->gid != 0 && (current->fsuid != current->uid || current->fsgid != current->gid)) error = NFS_PROTO(inode)->access(inode, mask, 1); out: return error; } /* * Local variables: * version-control: t * kept-new-versions: 5 * End: */