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348 lines
9.4 KiB
348 lines
9.4 KiB
// 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 ([email protected]) |
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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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#include "nfstrace.h" |
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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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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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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, inode); |
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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(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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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 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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nfs_fscache_update_auxdata(&auxdata, inode); |
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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 fscache_cookie *cookie = nfs_i_fscache(inode); |
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loff_t i_size = i_size_read(inode); |
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nfs_fscache_update_auxdata(&auxdata, inode); |
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fscache_unuse_cookie(cookie, &auxdata, &i_size); |
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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_fscache_read_page(struct inode *inode, struct page *page) |
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{ |
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int ret; |
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trace_nfs_fscache_read_page(inode, page); |
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if (PageChecked(page)) { |
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ClearPageChecked(page); |
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ret = 1; |
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goto out; |
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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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SetPageChecked(page); |
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goto out; |
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} |
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/* Read completed synchronously */ |
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nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK); |
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SetPageUptodate(page); |
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ret = 0; |
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out: |
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trace_nfs_fscache_read_page_exit(inode, page, ret); |
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return ret; |
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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_fscache_write_page(struct inode *inode, struct page *page) |
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{ |
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int ret; |
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trace_nfs_fscache_write_page(inode, page); |
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ret = fscache_fallback_write_page(inode, page, true); |
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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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trace_nfs_fscache_write_page_exit(inode, page, ret); |
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}
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