diff options
Diffstat (limited to 'fs/nfs/fscache.c')
| -rw-r--r-- | fs/nfs/fscache.c | 523 |
1 files changed, 523 insertions, 0 deletions
diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c new file mode 100644 index 000000000000..379be678cb7e --- /dev/null +++ b/fs/nfs/fscache.c @@ -0,0 +1,523 @@ +/* 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 "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); + 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. + */ +void nfs_fscache_get_super_cookie(struct super_block *sb, + struct nfs_parsed_mount_data *data) +{ + struct nfs_fscache_key *key, *xkey; + struct nfs_server *nfss = NFS_SB(sb); + struct rb_node **p, *parent; + const char *uniq = data->fscache_uniq ?: ""; + int diff, ulen; + + ulen = strlen(uniq); + 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); + 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); + + 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 invalidate any mapped pages that were read in before + * turning off the cache. + */ + if (inode->i_mapping && inode->i_mapping->nrpages) + invalidate_inode_pages2(inode->i_mapping); + + 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); + } +} + +/* + * 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); + 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); + + 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) +{ + struct nfs_inode *nfsi = NFS_I(page->mapping->host); + struct fscache_cookie *cookie = nfsi->fscache; + + BUG_ON(!cookie); + + if (fscache_check_page_write(cookie, page)) { + if (!(gfp & __GFP_WAIT)) + return 0; + fscache_wait_on_page_write(cookie, page); + } + + if (PageFsCache(page)) { + dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n", + cookie, page, nfsi); + + fscache_uncache_page(cookie, page); + 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) +{ + int ret, npages = *nr_pages; + + 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); + } +} |