377 lines
10 KiB
C
377 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* NFS filesystem cache interface
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*
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* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/nfs_fs.h>
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#include <linux/nfs_fs_sb.h>
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#include <linux/in6.h>
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#include <linux/seq_file.h>
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#include <linux/slab.h>
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#include <linux/iversion.h>
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#include "internal.h"
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#include "iostat.h"
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#include "fscache.h"
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#define NFSDBG_FACILITY NFSDBG_FSCACHE
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#define NFS_MAX_KEY_LEN 1000
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static bool nfs_append_int(char *key, int *_len, unsigned long long x)
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{
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if (*_len > NFS_MAX_KEY_LEN)
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return false;
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if (x == 0)
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key[(*_len)++] = ',';
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else
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*_len += sprintf(key + *_len, ",%llx", x);
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return true;
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}
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/*
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* Get the per-client index cookie for an NFS client if the appropriate mount
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* flag was set
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* - We always try and get an index cookie for the client, but get filehandle
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* cookies on a per-superblock basis, depending on the mount flags
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*/
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static bool nfs_fscache_get_client_key(struct nfs_client *clp,
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char *key, int *_len)
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{
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const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr;
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const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr;
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*_len += snprintf(key + *_len, NFS_MAX_KEY_LEN - *_len,
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",%u.%u,%x",
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clp->rpc_ops->version,
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clp->cl_minorversion,
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clp->cl_addr.ss_family);
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switch (clp->cl_addr.ss_family) {
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case AF_INET:
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if (!nfs_append_int(key, _len, sin->sin_port) ||
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!nfs_append_int(key, _len, sin->sin_addr.s_addr))
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return false;
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return true;
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case AF_INET6:
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if (!nfs_append_int(key, _len, sin6->sin6_port) ||
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!nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[0]) ||
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!nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[1]) ||
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!nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[2]) ||
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!nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[3]))
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return false;
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return true;
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default:
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printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
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clp->cl_addr.ss_family);
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return false;
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}
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}
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/*
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* Get the cache cookie for an NFS superblock.
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*
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* The default uniquifier is just an empty string, but it may be overridden
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* either by the 'fsc=xxx' option to mount, or by inheriting it from the parent
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* superblock across an automount point of some nature.
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*/
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int nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen)
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{
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struct fscache_volume *vcookie;
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struct nfs_server *nfss = NFS_SB(sb);
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unsigned int len = 3;
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char *key;
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if (uniq) {
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nfss->fscache_uniq = kmemdup_nul(uniq, ulen, GFP_KERNEL);
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if (!nfss->fscache_uniq)
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return -ENOMEM;
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}
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key = kmalloc(NFS_MAX_KEY_LEN + 24, GFP_KERNEL);
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if (!key)
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return -ENOMEM;
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memcpy(key, "nfs", 3);
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if (!nfs_fscache_get_client_key(nfss->nfs_client, key, &len) ||
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!nfs_append_int(key, &len, nfss->fsid.major) ||
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!nfs_append_int(key, &len, nfss->fsid.minor) ||
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!nfs_append_int(key, &len, sb->s_flags & NFS_SB_MASK) ||
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!nfs_append_int(key, &len, nfss->flags) ||
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!nfs_append_int(key, &len, nfss->rsize) ||
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!nfs_append_int(key, &len, nfss->wsize) ||
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!nfs_append_int(key, &len, nfss->acregmin) ||
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!nfs_append_int(key, &len, nfss->acregmax) ||
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!nfs_append_int(key, &len, nfss->acdirmin) ||
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!nfs_append_int(key, &len, nfss->acdirmax) ||
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!nfs_append_int(key, &len, nfss->client->cl_auth->au_flavor))
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goto out;
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if (ulen > 0) {
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if (ulen > NFS_MAX_KEY_LEN - len)
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goto out;
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key[len++] = ',';
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memcpy(key + len, uniq, ulen);
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len += ulen;
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}
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key[len] = 0;
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/* create a cache index for looking up filehandles */
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vcookie = fscache_acquire_volume(key,
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NULL, /* preferred_cache */
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NULL, 0 /* coherency_data */);
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dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
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nfss, vcookie);
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if (IS_ERR(vcookie)) {
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if (vcookie != ERR_PTR(-EBUSY)) {
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kfree(key);
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return PTR_ERR(vcookie);
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}
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pr_err("NFS: Cache volume key already in use (%s)\n", key);
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vcookie = NULL;
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}
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nfss->fscache = vcookie;
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out:
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kfree(key);
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return 0;
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}
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/*
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* release a per-superblock cookie
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*/
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void nfs_fscache_release_super_cookie(struct super_block *sb)
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{
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struct nfs_server *nfss = NFS_SB(sb);
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dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
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nfss, nfss->fscache);
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fscache_relinquish_volume(nfss->fscache, NULL, false);
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nfss->fscache = NULL;
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kfree(nfss->fscache_uniq);
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}
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/*
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* Initialise the per-inode cache cookie pointer for an NFS inode.
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*/
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void nfs_fscache_init_inode(struct inode *inode)
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{
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struct nfs_fscache_inode_auxdata auxdata;
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struct nfs_server *nfss = NFS_SERVER(inode);
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struct nfs_inode *nfsi = NFS_I(inode);
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nfsi->fscache = NULL;
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if (!(nfss->fscache && S_ISREG(inode->i_mode)))
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return;
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nfs_fscache_update_auxdata(&auxdata, nfsi);
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nfsi->fscache = fscache_acquire_cookie(NFS_SB(inode->i_sb)->fscache,
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0,
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nfsi->fh.data, /* index_key */
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nfsi->fh.size,
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&auxdata, /* aux_data */
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sizeof(auxdata),
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i_size_read(&nfsi->vfs_inode));
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}
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/*
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* Release a per-inode cookie.
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*/
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void nfs_fscache_clear_inode(struct inode *inode)
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{
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struct nfs_inode *nfsi = NFS_I(inode);
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struct fscache_cookie *cookie = nfs_i_fscache(inode);
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dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n", nfsi, cookie);
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fscache_relinquish_cookie(cookie, false);
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nfsi->fscache = NULL;
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}
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/*
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* Enable or disable caching for a file that is being opened as appropriate.
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* The cookie is allocated when the inode is initialised, but is not enabled at
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* that time. Enablement is deferred to file-open time to avoid stat() and
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* access() thrashing the cache.
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*
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* For now, with NFS, only regular files that are open read-only will be able
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* to use the cache.
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*
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* We enable the cache for an inode if we open it read-only and it isn't
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* currently open for writing. We disable the cache if the inode is open
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* write-only.
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*
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* The caller uses the file struct to pin i_writecount on the inode before
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* calling us when a file is opened for writing, so we can make use of that.
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*
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* Note that this may be invoked multiple times in parallel by parallel
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* nfs_open() functions.
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*/
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void nfs_fscache_open_file(struct inode *inode, struct file *filp)
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{
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struct nfs_fscache_inode_auxdata auxdata;
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struct nfs_inode *nfsi = NFS_I(inode);
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struct fscache_cookie *cookie = nfs_i_fscache(inode);
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bool open_for_write = inode_is_open_for_write(inode);
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if (!fscache_cookie_valid(cookie))
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return;
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fscache_use_cookie(cookie, open_for_write);
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if (open_for_write) {
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dfprintk(FSCACHE, "NFS: nfsi 0x%p disabling cache\n", nfsi);
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nfs_fscache_update_auxdata(&auxdata, nfsi);
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fscache_invalidate(cookie, &auxdata, i_size_read(inode),
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FSCACHE_INVAL_DIO_WRITE);
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}
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}
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EXPORT_SYMBOL_GPL(nfs_fscache_open_file);
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void nfs_fscache_release_file(struct inode *inode, struct file *filp)
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{
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struct nfs_fscache_inode_auxdata auxdata;
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struct nfs_inode *nfsi = NFS_I(inode);
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struct fscache_cookie *cookie = nfs_i_fscache(inode);
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if (fscache_cookie_valid(cookie)) {
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nfs_fscache_update_auxdata(&auxdata, nfsi);
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fscache_unuse_cookie(cookie, &auxdata, NULL);
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}
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}
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static inline void fscache_end_operation(struct netfs_cache_resources *cres)
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{
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const struct netfs_cache_ops *ops = fscache_operation_valid(cres);
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if (ops)
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ops->end_operation(cres);
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}
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/*
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* Fallback page reading interface.
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*/
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static int fscache_fallback_read_page(struct inode *inode, struct page *page)
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{
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struct netfs_cache_resources cres;
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struct fscache_cookie *cookie = nfs_i_fscache(inode);
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struct iov_iter iter;
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struct bio_vec bvec[1];
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int ret;
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memset(&cres, 0, sizeof(cres));
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bvec[0].bv_page = page;
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bvec[0].bv_offset = 0;
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bvec[0].bv_len = PAGE_SIZE;
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iov_iter_bvec(&iter, READ, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
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ret = fscache_begin_read_operation(&cres, cookie);
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if (ret < 0)
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return ret;
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ret = fscache_read(&cres, page_offset(page), &iter, NETFS_READ_HOLE_FAIL,
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NULL, NULL);
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fscache_end_operation(&cres);
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return ret;
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}
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/*
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* Fallback page writing interface.
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*/
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static int fscache_fallback_write_page(struct inode *inode, struct page *page,
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bool no_space_allocated_yet)
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{
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struct netfs_cache_resources cres;
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struct fscache_cookie *cookie = nfs_i_fscache(inode);
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struct iov_iter iter;
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struct bio_vec bvec[1];
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loff_t start = page_offset(page);
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size_t len = PAGE_SIZE;
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int ret;
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memset(&cres, 0, sizeof(cres));
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bvec[0].bv_page = page;
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bvec[0].bv_offset = 0;
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bvec[0].bv_len = PAGE_SIZE;
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iov_iter_bvec(&iter, WRITE, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
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ret = fscache_begin_write_operation(&cres, cookie);
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if (ret < 0)
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return ret;
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ret = cres.ops->prepare_write(&cres, &start, &len, i_size_read(inode),
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no_space_allocated_yet);
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if (ret == 0)
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ret = fscache_write(&cres, page_offset(page), &iter, NULL, NULL);
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fscache_end_operation(&cres);
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return ret;
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}
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/*
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* Retrieve a page from fscache
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*/
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int __nfs_readpage_from_fscache(struct inode *inode, struct page *page)
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{
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int ret;
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dfprintk(FSCACHE,
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"NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n",
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nfs_i_fscache(inode), page, page->index, page->flags, inode);
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if (PageChecked(page)) {
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dfprintk(FSCACHE, "NFS: readpage_from_fscache: PageChecked\n");
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ClearPageChecked(page);
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return 1;
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}
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ret = fscache_fallback_read_page(inode, page);
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if (ret < 0) {
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nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
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dfprintk(FSCACHE,
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"NFS: readpage_from_fscache failed %d\n", ret);
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SetPageChecked(page);
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return ret;
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}
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/* Read completed synchronously */
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dfprintk(FSCACHE, "NFS: readpage_from_fscache: read successful\n");
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nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK);
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SetPageUptodate(page);
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return 0;
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}
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/*
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* Store a newly fetched page in fscache. We can be certain there's no page
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* stored in the cache as yet otherwise we would've read it from there.
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*/
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void __nfs_readpage_to_fscache(struct inode *inode, struct page *page)
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{
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int ret;
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dfprintk(FSCACHE,
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"NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx))\n",
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nfs_i_fscache(inode), page, page->index, page->flags);
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ret = fscache_fallback_write_page(inode, page, true);
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dfprintk(FSCACHE,
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"NFS: readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n",
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page, page->index, page->flags, ret);
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if (ret != 0) {
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nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL);
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nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED);
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} else {
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nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_WRITTEN_OK);
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}
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}
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