| /* NFS filesystem cache interface |
| * |
| * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public Licence |
| * as published by the Free Software Foundation; either version |
| * 2 of the Licence, or (at your option) any later version. |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/sched.h> |
| #include <linux/mm.h> |
| #include <linux/nfs_fs.h> |
| #include <linux/nfs_fs_sb.h> |
| #include <linux/in6.h> |
| #include <linux/seq_file.h> |
| #include <linux/slab.h> |
| #include <linux/iversion.h> |
| |
| #include "internal.h" |
| #include "iostat.h" |
| #include "fscache.h" |
| |
| #define NFSDBG_FACILITY NFSDBG_FSCACHE |
| |
| static struct rb_root nfs_fscache_keys = RB_ROOT; |
| static DEFINE_SPINLOCK(nfs_fscache_keys_lock); |
| |
| /* |
| * Layout of the key for an NFS server cache object. |
| */ |
| struct nfs_server_key { |
| struct { |
| uint16_t nfsversion; /* NFS protocol version */ |
| uint16_t family; /* address family */ |
| __be16 port; /* IP port */ |
| } hdr; |
| union { |
| struct in_addr ipv4_addr; /* IPv4 address */ |
| struct in6_addr ipv6_addr; /* IPv6 address */ |
| }; |
| } __packed; |
| |
| /* |
| * Get the per-client index cookie for an NFS client if the appropriate mount |
| * flag was set |
| * - We always try and get an index cookie for the client, but get filehandle |
| * cookies on a per-superblock basis, depending on the mount flags |
| */ |
| void nfs_fscache_get_client_cookie(struct nfs_client *clp) |
| { |
| const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr; |
| const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr; |
| struct nfs_server_key key; |
| uint16_t len = sizeof(key.hdr); |
| |
| memset(&key, 0, sizeof(key)); |
| key.hdr.nfsversion = clp->rpc_ops->version; |
| key.hdr.family = clp->cl_addr.ss_family; |
| |
| switch (clp->cl_addr.ss_family) { |
| case AF_INET: |
| key.hdr.port = sin->sin_port; |
| key.ipv4_addr = sin->sin_addr; |
| len += sizeof(key.ipv4_addr); |
| break; |
| |
| case AF_INET6: |
| key.hdr.port = sin6->sin6_port; |
| key.ipv6_addr = sin6->sin6_addr; |
| len += sizeof(key.ipv6_addr); |
| break; |
| |
| default: |
| printk(KERN_WARNING "NFS: Unknown network family '%d'\n", |
| clp->cl_addr.ss_family); |
| clp->fscache = NULL; |
| return; |
| } |
| |
| /* create a cache index for looking up filehandles */ |
| clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index, |
| &nfs_fscache_server_index_def, |
| &key, len, |
| NULL, 0, |
| clp, 0, true); |
| dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n", |
| clp, clp->fscache); |
| } |
| |
| /* |
| * Dispose of a per-client cookie |
| */ |
| void nfs_fscache_release_client_cookie(struct nfs_client *clp) |
| { |
| dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n", |
| clp, clp->fscache); |
| |
| fscache_relinquish_cookie(clp->fscache, NULL, false); |
| clp->fscache = NULL; |
| } |
| |
| /* |
| * Get the cache cookie for an NFS superblock. We have to handle |
| * uniquification here because the cache doesn't do it for us. |
| * |
| * The default uniquifier is just an empty string, but it may be overridden |
| * either by the 'fsc=xxx' option to mount, or by inheriting it from the parent |
| * superblock across an automount point of some nature. |
| */ |
| void nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen) |
| { |
| struct nfs_fscache_key *key, *xkey; |
| struct nfs_server *nfss = NFS_SB(sb); |
| struct rb_node **p, *parent; |
| int diff; |
| |
| if (!uniq) { |
| uniq = ""; |
| ulen = 1; |
| } |
| |
| key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL); |
| if (!key) |
| return; |
| |
| key->nfs_client = nfss->nfs_client; |
| key->key.super.s_flags = sb->s_flags & NFS_MS_MASK; |
| key->key.nfs_server.flags = nfss->flags; |
| key->key.nfs_server.rsize = nfss->rsize; |
| key->key.nfs_server.wsize = nfss->wsize; |
| key->key.nfs_server.acregmin = nfss->acregmin; |
| key->key.nfs_server.acregmax = nfss->acregmax; |
| key->key.nfs_server.acdirmin = nfss->acdirmin; |
| key->key.nfs_server.acdirmax = nfss->acdirmax; |
| key->key.nfs_server.fsid = nfss->fsid; |
| key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor; |
| |
| key->key.uniq_len = ulen; |
| memcpy(key->key.uniquifier, uniq, ulen); |
| |
| spin_lock(&nfs_fscache_keys_lock); |
| p = &nfs_fscache_keys.rb_node; |
| parent = NULL; |
| while (*p) { |
| parent = *p; |
| xkey = rb_entry(parent, struct nfs_fscache_key, node); |
| |
| if (key->nfs_client < xkey->nfs_client) |
| goto go_left; |
| if (key->nfs_client > xkey->nfs_client) |
| goto go_right; |
| |
| diff = memcmp(&key->key, &xkey->key, sizeof(key->key)); |
| if (diff < 0) |
| goto go_left; |
| if (diff > 0) |
| goto go_right; |
| |
| if (key->key.uniq_len == 0) |
| goto non_unique; |
| diff = memcmp(key->key.uniquifier, |
| xkey->key.uniquifier, |
| key->key.uniq_len); |
| if (diff < 0) |
| goto go_left; |
| if (diff > 0) |
| goto go_right; |
| goto non_unique; |
| |
| go_left: |
| p = &(*p)->rb_left; |
| continue; |
| go_right: |
| p = &(*p)->rb_right; |
| } |
| |
| rb_link_node(&key->node, parent, p); |
| rb_insert_color(&key->node, &nfs_fscache_keys); |
| spin_unlock(&nfs_fscache_keys_lock); |
| nfss->fscache_key = key; |
| |
| /* create a cache index for looking up filehandles */ |
| nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache, |
| &nfs_fscache_super_index_def, |
| key, sizeof(*key) + ulen, |
| NULL, 0, |
| nfss, 0, true); |
| dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n", |
| nfss, nfss->fscache); |
| return; |
| |
| non_unique: |
| spin_unlock(&nfs_fscache_keys_lock); |
| kfree(key); |
| nfss->fscache_key = NULL; |
| nfss->fscache = NULL; |
| printk(KERN_WARNING "NFS:" |
| " Cache request denied due to non-unique superblock keys\n"); |
| } |
| |
| /* |
| * release a per-superblock cookie |
| */ |
| void nfs_fscache_release_super_cookie(struct super_block *sb) |
| { |
| struct nfs_server *nfss = NFS_SB(sb); |
| |
| dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n", |
| nfss, nfss->fscache); |
| |
| fscache_relinquish_cookie(nfss->fscache, NULL, false); |
| nfss->fscache = NULL; |
| |
| if (nfss->fscache_key) { |
| spin_lock(&nfs_fscache_keys_lock); |
| rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys); |
| spin_unlock(&nfs_fscache_keys_lock); |
| kfree(nfss->fscache_key); |
| nfss->fscache_key = NULL; |
| } |
| } |
| |
| /* |
| * Initialise the per-inode cache cookie pointer for an NFS inode. |
| */ |
| void nfs_fscache_init_inode(struct inode *inode) |
| { |
| struct nfs_fscache_inode_auxdata auxdata; |
| struct nfs_inode *nfsi = NFS_I(inode); |
| |
| nfsi->fscache = NULL; |
| if (!S_ISREG(inode->i_mode)) |
| return; |
| |
| memset(&auxdata, 0, sizeof(auxdata)); |
| auxdata.mtime = nfsi->vfs_inode.i_mtime; |
| auxdata.ctime = nfsi->vfs_inode.i_ctime; |
| |
| if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4) |
| auxdata.change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode); |
| |
| nfsi->fscache = fscache_acquire_cookie(NFS_SB(inode->i_sb)->fscache, |
| &nfs_fscache_inode_object_def, |
| nfsi->fh.data, nfsi->fh.size, |
| &auxdata, sizeof(auxdata), |
| nfsi, nfsi->vfs_inode.i_size, false); |
| } |
| |
| /* |
| * Release a per-inode cookie. |
| */ |
| void nfs_fscache_clear_inode(struct inode *inode) |
| { |
| struct nfs_fscache_inode_auxdata auxdata; |
| struct nfs_inode *nfsi = NFS_I(inode); |
| struct fscache_cookie *cookie = nfs_i_fscache(inode); |
| |
| dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n", nfsi, cookie); |
| |
| memset(&auxdata, 0, sizeof(auxdata)); |
| auxdata.mtime = nfsi->vfs_inode.i_mtime; |
| auxdata.ctime = nfsi->vfs_inode.i_ctime; |
| fscache_relinquish_cookie(cookie, &auxdata, false); |
| nfsi->fscache = NULL; |
| } |
| |
| static bool nfs_fscache_can_enable(void *data) |
| { |
| struct inode *inode = data; |
| |
| return !inode_is_open_for_write(inode); |
| } |
| |
| /* |
| * Enable or disable caching for a file that is being opened as appropriate. |
| * The cookie is allocated when the inode is initialised, but is not enabled at |
| * that time. Enablement is deferred to file-open time to avoid stat() and |
| * access() thrashing the cache. |
| * |
| * For now, with NFS, only regular files that are open read-only will be able |
| * to use the cache. |
| * |
| * We enable the cache for an inode if we open it read-only and it isn't |
| * currently open for writing. We disable the cache if the inode is open |
| * write-only. |
| * |
| * The caller uses the file struct to pin i_writecount on the inode before |
| * calling us when a file is opened for writing, so we can make use of that. |
| * |
| * Note that this may be invoked multiple times in parallel by parallel |
| * nfs_open() functions. |
| */ |
| void nfs_fscache_open_file(struct inode *inode, struct file *filp) |
| { |
| struct nfs_fscache_inode_auxdata auxdata; |
| struct nfs_inode *nfsi = NFS_I(inode); |
| struct fscache_cookie *cookie = nfs_i_fscache(inode); |
| |
| if (!fscache_cookie_valid(cookie)) |
| return; |
| |
| memset(&auxdata, 0, sizeof(auxdata)); |
| auxdata.mtime = nfsi->vfs_inode.i_mtime; |
| auxdata.ctime = nfsi->vfs_inode.i_ctime; |
| |
| if (inode_is_open_for_write(inode)) { |
| dfprintk(FSCACHE, "NFS: nfsi 0x%p disabling cache\n", nfsi); |
| clear_bit(NFS_INO_FSCACHE, &nfsi->flags); |
| fscache_disable_cookie(cookie, &auxdata, true); |
| fscache_uncache_all_inode_pages(cookie, inode); |
| } else { |
| dfprintk(FSCACHE, "NFS: nfsi 0x%p enabling cache\n", nfsi); |
| fscache_enable_cookie(cookie, &auxdata, nfsi->vfs_inode.i_size, |
| nfs_fscache_can_enable, inode); |
| if (fscache_cookie_enabled(cookie)) |
| set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags); |
| } |
| } |
| EXPORT_SYMBOL_GPL(nfs_fscache_open_file); |
| |
| /* |
| * Release the caching state associated with a page, if the page isn't busy |
| * interacting with the cache. |
| * - Returns true (can release page) or false (page busy). |
| */ |
| int nfs_fscache_release_page(struct page *page, gfp_t gfp) |
| { |
| if (PageFsCache(page)) { |
| struct fscache_cookie *cookie = nfs_i_fscache(page->mapping->host); |
| |
| BUG_ON(!cookie); |
| dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n", |
| cookie, page, NFS_I(page->mapping->host)); |
| |
| if (!fscache_maybe_release_page(cookie, page, gfp)) |
| return 0; |
| |
| nfs_inc_fscache_stats(page->mapping->host, |
| NFSIOS_FSCACHE_PAGES_UNCACHED); |
| } |
| |
| return 1; |
| } |
| |
| /* |
| * Release the caching state associated with a page if undergoing complete page |
| * invalidation. |
| */ |
| void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode) |
| { |
| struct fscache_cookie *cookie = nfs_i_fscache(inode); |
| |
| BUG_ON(!cookie); |
| |
| dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n", |
| cookie, page, NFS_I(inode)); |
| |
| fscache_wait_on_page_write(cookie, page); |
| |
| BUG_ON(!PageLocked(page)); |
| fscache_uncache_page(cookie, page); |
| nfs_inc_fscache_stats(page->mapping->host, |
| NFSIOS_FSCACHE_PAGES_UNCACHED); |
| } |
| |
| /* |
| * Handle completion of a page being read from the cache. |
| * - Called in process (keventd) context. |
| */ |
| static void nfs_readpage_from_fscache_complete(struct page *page, |
| void *context, |
| int error) |
| { |
| dfprintk(FSCACHE, |
| "NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n", |
| page, context, error); |
| |
| /* if the read completes with an error, we just unlock the page and let |
| * the VM reissue the readpage */ |
| if (!error) { |
| SetPageUptodate(page); |
| unlock_page(page); |
| } else { |
| error = nfs_readpage_async(context, page->mapping->host, page); |
| if (error) |
| unlock_page(page); |
| } |
| } |
| |
| /* |
| * Retrieve a page from fscache |
| */ |
| int __nfs_readpage_from_fscache(struct nfs_open_context *ctx, |
| struct inode *inode, struct page *page) |
| { |
| int ret; |
| |
| dfprintk(FSCACHE, |
| "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n", |
| nfs_i_fscache(inode), page, page->index, page->flags, inode); |
| |
| ret = fscache_read_or_alloc_page(nfs_i_fscache(inode), |
| page, |
| nfs_readpage_from_fscache_complete, |
| ctx, |
| GFP_KERNEL); |
| |
| switch (ret) { |
| case 0: /* read BIO submitted (page in fscache) */ |
| dfprintk(FSCACHE, |
| "NFS: readpage_from_fscache: BIO submitted\n"); |
| nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK); |
| return ret; |
| |
| case -ENOBUFS: /* inode not in cache */ |
| case -ENODATA: /* page not in cache */ |
| nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL); |
| dfprintk(FSCACHE, |
| "NFS: readpage_from_fscache %d\n", ret); |
| return 1; |
| |
| default: |
| dfprintk(FSCACHE, "NFS: readpage_from_fscache %d\n", ret); |
| nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL); |
| } |
| return ret; |
| } |
| |
| /* |
| * Retrieve a set of pages from fscache |
| */ |
| int __nfs_readpages_from_fscache(struct nfs_open_context *ctx, |
| struct inode *inode, |
| struct address_space *mapping, |
| struct list_head *pages, |
| unsigned *nr_pages) |
| { |
| unsigned npages = *nr_pages; |
| int ret; |
| |
| dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n", |
| nfs_i_fscache(inode), npages, inode); |
| |
| ret = fscache_read_or_alloc_pages(nfs_i_fscache(inode), |
| mapping, pages, nr_pages, |
| nfs_readpage_from_fscache_complete, |
| ctx, |
| mapping_gfp_mask(mapping)); |
| if (*nr_pages < npages) |
| nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK, |
| npages); |
| if (*nr_pages > 0) |
| nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, |
| *nr_pages); |
| |
| switch (ret) { |
| case 0: /* read submitted to the cache for all pages */ |
| BUG_ON(!list_empty(pages)); |
| BUG_ON(*nr_pages != 0); |
| dfprintk(FSCACHE, |
| "NFS: nfs_getpages_from_fscache: submitted\n"); |
| |
| return ret; |
| |
| case -ENOBUFS: /* some pages aren't cached and can't be */ |
| case -ENODATA: /* some pages aren't cached */ |
| dfprintk(FSCACHE, |
| "NFS: nfs_getpages_from_fscache: no page: %d\n", ret); |
| return 1; |
| |
| default: |
| dfprintk(FSCACHE, |
| "NFS: nfs_getpages_from_fscache: ret %d\n", ret); |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * Store a newly fetched page in fscache |
| * - PG_fscache must be set on the page |
| */ |
| void __nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync) |
| { |
| int ret; |
| |
| dfprintk(FSCACHE, |
| "NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx)/%d)\n", |
| nfs_i_fscache(inode), page, page->index, page->flags, sync); |
| |
| ret = fscache_write_page(nfs_i_fscache(inode), page, |
| inode->i_size, GFP_KERNEL); |
| dfprintk(FSCACHE, |
| "NFS: readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n", |
| page, page->index, page->flags, ret); |
| |
| if (ret != 0) { |
| fscache_uncache_page(nfs_i_fscache(inode), page); |
| nfs_inc_fscache_stats(inode, |
| NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL); |
| nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED); |
| } else { |
| nfs_inc_fscache_stats(inode, |
| NFSIOS_FSCACHE_PAGES_WRITTEN_OK); |
| } |
| } |