diff options
Diffstat (limited to 'drivers/staging/lustre/lustre/llite/symlink.c')
| -rw-r--r-- | drivers/staging/lustre/lustre/llite/symlink.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/drivers/staging/lustre/lustre/llite/symlink.c b/drivers/staging/lustre/lustre/llite/symlink.c new file mode 100644 index 000000000000..5260e989a4e5 --- /dev/null +++ b/drivers/staging/lustre/lustre/llite/symlink.c @@ -0,0 +1,192 @@ +/* + * GPL HEADER START + * + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 only, + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License version 2 for more details (a copy is included + * in the LICENSE file that accompanied this code). + * + * You should have received a copy of the GNU General Public License + * version 2 along with this program; If not, see + * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + * GPL HEADER END + */ +/* + * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved. + * Use is subject to license terms. + * + * Copyright (c) 2011, 2012, Intel Corporation. + */ +/* + * This file is part of Lustre, http://www.lustre.org/ + * Lustre is a trademark of Sun Microsystems, Inc. + */ + +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/stat.h> +#include <linux/version.h> +#define DEBUG_SUBSYSTEM S_LLITE + +#include <lustre_lite.h> +#include "llite_internal.h" + +static int ll_readlink_internal(struct inode *inode, + struct ptlrpc_request **request, char **symname) +{ + struct ll_inode_info *lli = ll_i2info(inode); + struct ll_sb_info *sbi = ll_i2sbi(inode); + int rc, symlen = i_size_read(inode) + 1; + struct mdt_body *body; + struct md_op_data *op_data; + ENTRY; + + *request = NULL; + + if (lli->lli_symlink_name) { + int print_limit = min_t(int, PAGE_SIZE - 128, symlen); + + *symname = lli->lli_symlink_name; + /* If the total CDEBUG() size is larger than a page, it + * will print a warning to the console, avoid this by + * printing just the last part of the symlink. */ + CDEBUG(D_INODE, "using cached symlink %s%.*s, len = %d\n", + print_limit < symlen ? "..." : "", print_limit, + (*symname) + symlen - print_limit, symlen); + RETURN(0); + } + + op_data = ll_prep_md_op_data(NULL, inode, NULL, NULL, 0, symlen, + LUSTRE_OPC_ANY, NULL); + if (IS_ERR(op_data)) + RETURN(PTR_ERR(op_data)); + + op_data->op_valid = OBD_MD_LINKNAME; + rc = md_getattr(sbi->ll_md_exp, op_data, request); + ll_finish_md_op_data(op_data); + if (rc) { + if (rc != -ENOENT) + CERROR("inode %lu: rc = %d\n", inode->i_ino, rc); + GOTO (failed, rc); + } + + body = req_capsule_server_get(&(*request)->rq_pill, &RMF_MDT_BODY); + LASSERT(body != NULL); + if ((body->valid & OBD_MD_LINKNAME) == 0) { + CERROR("OBD_MD_LINKNAME not set on reply\n"); + GOTO(failed, rc = -EPROTO); + } + + LASSERT(symlen != 0); + if (body->eadatasize != symlen) { + CERROR("inode %lu: symlink length %d not expected %d\n", + inode->i_ino, body->eadatasize - 1, symlen - 1); + GOTO(failed, rc = -EPROTO); + } + + *symname = req_capsule_server_get(&(*request)->rq_pill, &RMF_MDT_MD); + if (*symname == NULL || + strnlen(*symname, symlen) != symlen - 1) { + /* not full/NULL terminated */ + CERROR("inode %lu: symlink not NULL terminated string" + "of length %d\n", inode->i_ino, symlen - 1); + GOTO(failed, rc = -EPROTO); + } + + OBD_ALLOC(lli->lli_symlink_name, symlen); + /* do not return an error if we cannot cache the symlink locally */ + if (lli->lli_symlink_name) { + memcpy(lli->lli_symlink_name, *symname, symlen); + *symname = lli->lli_symlink_name; + } + RETURN(0); + +failed: + RETURN (rc); +} + +static int ll_readlink(struct dentry *dentry, char *buffer, int buflen) +{ + struct inode *inode = dentry->d_inode; + struct ptlrpc_request *request; + char *symname; + int rc; + ENTRY; + + CDEBUG(D_VFSTRACE, "VFS Op\n"); + + ll_inode_size_lock(inode); + rc = ll_readlink_internal(inode, &request, &symname); + if (rc) + GOTO(out, rc); + + rc = vfs_readlink(dentry, buffer, buflen, symname); + out: + ptlrpc_req_finished(request); + ll_inode_size_unlock(inode); + RETURN(rc); +} + +static void *ll_follow_link(struct dentry *dentry, struct nameidata *nd) +{ + struct inode *inode = dentry->d_inode; + struct ptlrpc_request *request = NULL; + int rc; + char *symname; + ENTRY; + + CDEBUG(D_VFSTRACE, "VFS Op\n"); + /* Limit the recursive symlink depth to 5 instead of default + * 8 links when kernel has 4k stack to prevent stack overflow. + * For 8k stacks we need to limit it to 7 for local servers. */ + if (THREAD_SIZE < 8192 && current->link_count >= 6) { + rc = -ELOOP; + } else if (THREAD_SIZE == 8192 && current->link_count >= 8) { + rc = -ELOOP; + } else { + ll_inode_size_lock(inode); + rc = ll_readlink_internal(inode, &request, &symname); + ll_inode_size_unlock(inode); + } + if (rc) { + ptlrpc_req_finished(request); + request = NULL; + symname = ERR_PTR(rc); + } + + nd_set_link(nd, symname); + /* symname may contain a pointer to the request message buffer, + * we delay request releasing until ll_put_link then. + */ + RETURN(request); +} + +static void ll_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) +{ + ptlrpc_req_finished(cookie); +} + +struct inode_operations ll_fast_symlink_inode_operations = { + .readlink = ll_readlink, + .setattr = ll_setattr, + .follow_link = ll_follow_link, + .put_link = ll_put_link, + .getattr = ll_getattr, + .permission = ll_inode_permission, + .setxattr = ll_setxattr, + .getxattr = ll_getxattr, + .listxattr = ll_listxattr, + .removexattr = ll_removexattr, +}; |