| /* 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 "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); |
| |
| /* |
| * 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) |
| { |
| /* create a cache index for looking up filehandles */ |
| clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index, |
| &nfs_fscache_server_index_def, |
| clp, 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, 0); |
| 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, |
| nfss, 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, 0); |
| 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_cookie(struct inode *inode) |
| { |
| NFS_I(inode)->fscache = NULL; |
| if (S_ISREG(inode->i_mode)) |
| set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags); |
| } |
| |
| /* |
| * Get the per-inode cache cookie for an NFS inode. |
| */ |
| static void nfs_fscache_enable_inode_cookie(struct inode *inode) |
| { |
| struct super_block *sb = inode->i_sb; |
| struct nfs_inode *nfsi = NFS_I(inode); |
| |
| if (nfsi->fscache || !NFS_FSCACHE(inode)) |
| return; |
| |
| if ((NFS_SB(sb)->options & NFS_OPTION_FSCACHE)) { |
| nfsi->fscache = fscache_acquire_cookie( |
| NFS_SB(sb)->fscache, |
| &nfs_fscache_inode_object_def, |
| nfsi, true); |
| |
| dfprintk(FSCACHE, "NFS: get FH cookie (0x%p/0x%p/0x%p)\n", |
| sb, nfsi, nfsi->fscache); |
| } |
| } |
| |
| /* |
| * Release a per-inode cookie. |
| */ |
| void nfs_fscache_release_inode_cookie(struct inode *inode) |
| { |
| struct nfs_inode *nfsi = NFS_I(inode); |
| |
| dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n", |
| nfsi, nfsi->fscache); |
| |
| fscache_relinquish_cookie(nfsi->fscache, 0); |
| nfsi->fscache = NULL; |
| } |
| |
| /* |
| * Retire a per-inode cookie, destroying the data attached to it. |
| */ |
| void nfs_fscache_zap_inode_cookie(struct inode *inode) |
| { |
| struct nfs_inode *nfsi = NFS_I(inode); |
| |
| dfprintk(FSCACHE, "NFS: zapping cookie (0x%p/0x%p)\n", |
| nfsi, nfsi->fscache); |
| |
| fscache_relinquish_cookie(nfsi->fscache, 1); |
| nfsi->fscache = NULL; |
| } |
| |
| /* |
| * Turn off the cache with regard to a per-inode cookie if opened for writing, |
| * invalidating all the pages in the page cache relating to the associated |
| * inode to clear the per-page caching. |
| */ |
| static void nfs_fscache_disable_inode_cookie(struct inode *inode) |
| { |
| clear_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags); |
| |
| if (NFS_I(inode)->fscache) { |
| dfprintk(FSCACHE, |
| "NFS: nfsi 0x%p turning cache off\n", NFS_I(inode)); |
| |
| /* Need to uncache any pages attached to this inode that |
| * fscache knows about before turning off the cache. |
| */ |
| fscache_uncache_all_inode_pages(NFS_I(inode)->fscache, inode); |
| nfs_fscache_zap_inode_cookie(inode); |
| } |
| } |
| |
| /* |
| * wait_on_bit() sleep function for uninterruptible waiting |
| */ |
| static int nfs_fscache_wait_bit(void *flags) |
| { |
| schedule(); |
| return 0; |
| } |
| |
| /* |
| * Lock against someone else trying to also acquire or relinquish a cookie |
| */ |
| static inline void nfs_fscache_inode_lock(struct inode *inode) |
| { |
| struct nfs_inode *nfsi = NFS_I(inode); |
| |
| while (test_and_set_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags)) |
| wait_on_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK, |
| nfs_fscache_wait_bit, TASK_UNINTERRUPTIBLE); |
| } |
| |
| /* |
| * Unlock cookie management lock |
| */ |
| static inline void nfs_fscache_inode_unlock(struct inode *inode) |
| { |
| struct nfs_inode *nfsi = NFS_I(inode); |
| |
| smp_mb__before_clear_bit(); |
| clear_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags); |
| smp_mb__after_clear_bit(); |
| wake_up_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK); |
| } |
| |
| /* |
| * Decide if we should enable or disable local caching for this inode. |
| * - For now, with NFS, only regular files that are open read-only will be able |
| * to use the cache. |
| * - May be invoked multiple times in parallel by parallel nfs_open() functions. |
| */ |
| void nfs_fscache_set_inode_cookie(struct inode *inode, struct file *filp) |
| { |
| if (NFS_FSCACHE(inode)) { |
| nfs_fscache_inode_lock(inode); |
| if ((filp->f_flags & O_ACCMODE) != O_RDONLY) |
| nfs_fscache_disable_inode_cookie(inode); |
| else |
| nfs_fscache_enable_inode_cookie(inode); |
| nfs_fscache_inode_unlock(inode); |
| } |
| } |
| EXPORT_SYMBOL_GPL(nfs_fscache_set_inode_cookie); |
| |
| /* |
| * Replace a per-inode cookie due to revalidation detecting a file having |
| * changed on the server. |
| */ |
| void nfs_fscache_reset_inode_cookie(struct inode *inode) |
| { |
| struct nfs_inode *nfsi = NFS_I(inode); |
| struct nfs_server *nfss = NFS_SERVER(inode); |
| NFS_IFDEBUG(struct fscache_cookie *old = nfsi->fscache); |
| |
| nfs_fscache_inode_lock(inode); |
| if (nfsi->fscache) { |
| /* retire the current fscache cache and get a new one */ |
| fscache_relinquish_cookie(nfsi->fscache, 1); |
| |
| nfsi->fscache = fscache_acquire_cookie( |
| nfss->nfs_client->fscache, |
| &nfs_fscache_inode_object_def, |
| nfsi, true); |
| |
| dfprintk(FSCACHE, |
| "NFS: revalidation new cookie (0x%p/0x%p/0x%p/0x%p)\n", |
| nfss, nfsi, old, nfsi->fscache); |
| } |
| nfs_fscache_inode_unlock(inode); |
| } |
| |
| /* |
| * 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 nfs_inode *nfsi = NFS_I(page->mapping->host); |
| struct fscache_cookie *cookie = nfsi->fscache; |
| |
| BUG_ON(!cookie); |
| dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n", |
| cookie, page, nfsi); |
| |
| if (!fscache_maybe_release_page(cookie, page, gfp)) |
| return 0; |
| |
| nfs_add_fscache_stats(page->mapping->host, |
| NFSIOS_FSCACHE_PAGES_UNCACHED, 1); |
| } |
| |
| 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 nfs_inode *nfsi = NFS_I(inode); |
| struct fscache_cookie *cookie = nfsi->fscache; |
| |
| BUG_ON(!cookie); |
| |
| dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n", |
| cookie, page, nfsi); |
| |
| fscache_wait_on_page_write(cookie, page); |
| |
| BUG_ON(!PageLocked(page)); |
| fscache_uncache_page(cookie, page); |
| nfs_add_fscache_stats(page->mapping->host, |
| NFSIOS_FSCACHE_PAGES_UNCACHED, 1); |
| } |
| |
| /* |
| * 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(inode)->fscache, page, page->index, page->flags, inode); |
| |
| ret = fscache_read_or_alloc_page(NFS_I(inode)->fscache, |
| 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_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK, 1); |
| return ret; |
| |
| case -ENOBUFS: /* inode not in cache */ |
| case -ENODATA: /* page not in cache */ |
| nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 1); |
| dfprintk(FSCACHE, |
| "NFS: readpage_from_fscache %d\n", ret); |
| return 1; |
| |
| default: |
| dfprintk(FSCACHE, "NFS: readpage_from_fscache %d\n", ret); |
| nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 1); |
| } |
| 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(inode)->fscache, npages, inode); |
| |
| ret = fscache_read_or_alloc_pages(NFS_I(inode)->fscache, |
| 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(inode)->fscache, page, page->index, page->flags, sync); |
| |
| ret = fscache_write_page(NFS_I(inode)->fscache, page, 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(inode)->fscache, page); |
| nfs_add_fscache_stats(inode, |
| NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL, 1); |
| nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED, 1); |
| } else { |
| nfs_add_fscache_stats(inode, |
| NFSIOS_FSCACHE_PAGES_WRITTEN_OK, 1); |
| } |
| } |