1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* NFS filesystem cache interface definitions 3 * 4 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 */ 7 8 #ifndef _NFS_FSCACHE_H 9 #define _NFS_FSCACHE_H 10 11 #include <linux/swap.h> 12 #include <linux/nfs_fs.h> 13 #include <linux/nfs_mount.h> 14 #include <linux/nfs4_mount.h> 15 #include <linux/fscache.h> 16 #include <linux/iversion.h> 17 18 #ifdef CONFIG_NFS_FSCACHE 19 20 /* 21 * Definition of the auxiliary data attached to NFS inode storage objects 22 * within the cache. 23 * 24 * The contents of this struct are recorded in the on-disk local cache in the 25 * auxiliary data attached to the data storage object backing an inode. This 26 * permits coherency to be managed when a new inode binds to an already extant 27 * cache object. 28 */ 29 struct nfs_fscache_inode_auxdata { 30 s64 mtime_sec; 31 s64 mtime_nsec; 32 s64 ctime_sec; 33 s64 ctime_nsec; 34 u64 change_attr; 35 }; 36 37 /* 38 * fscache.c 39 */ 40 extern int nfs_fscache_get_super_cookie(struct super_block *, const char *, int); 41 extern void nfs_fscache_release_super_cookie(struct super_block *); 42 43 extern void nfs_fscache_init_inode(struct inode *); 44 extern void nfs_fscache_clear_inode(struct inode *); 45 extern void nfs_fscache_open_file(struct inode *, struct file *); 46 extern void nfs_fscache_release_file(struct inode *, struct file *); 47 48 extern int __nfs_fscache_read_page(struct inode *, struct page *); 49 extern void __nfs_fscache_write_page(struct inode *, struct page *); 50 51 static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp) 52 { 53 if (PageFsCache(page)) { 54 if (current_is_kswapd() || !(gfp & __GFP_FS)) 55 return false; 56 wait_on_page_fscache(page); 57 fscache_note_page_release(nfs_i_fscache(page->mapping->host)); 58 nfs_inc_fscache_stats(page->mapping->host, 59 NFSIOS_FSCACHE_PAGES_UNCACHED); 60 } 61 return true; 62 } 63 64 /* 65 * Retrieve a page from an inode data storage object. 66 */ 67 static inline int nfs_fscache_read_page(struct inode *inode, struct page *page) 68 { 69 if (nfs_i_fscache(inode)) 70 return __nfs_fscache_read_page(inode, page); 71 return -ENOBUFS; 72 } 73 74 /* 75 * Store a page newly fetched from the server in an inode data storage object 76 * in the cache. 77 */ 78 static inline void nfs_fscache_write_page(struct inode *inode, 79 struct page *page) 80 { 81 if (nfs_i_fscache(inode)) 82 __nfs_fscache_write_page(inode, page); 83 } 84 85 static inline void nfs_fscache_update_auxdata(struct nfs_fscache_inode_auxdata *auxdata, 86 struct inode *inode) 87 { 88 memset(auxdata, 0, sizeof(*auxdata)); 89 auxdata->mtime_sec = inode->i_mtime.tv_sec; 90 auxdata->mtime_nsec = inode->i_mtime.tv_nsec; 91 auxdata->ctime_sec = inode->i_ctime.tv_sec; 92 auxdata->ctime_nsec = inode->i_ctime.tv_nsec; 93 94 if (NFS_SERVER(inode)->nfs_client->rpc_ops->version == 4) 95 auxdata->change_attr = inode_peek_iversion_raw(inode); 96 } 97 98 /* 99 * Invalidate the contents of fscache for this inode. This will not sleep. 100 */ 101 static inline void nfs_fscache_invalidate(struct inode *inode, int flags) 102 { 103 struct nfs_fscache_inode_auxdata auxdata; 104 struct nfs_inode *nfsi = NFS_I(inode); 105 106 if (nfsi->fscache) { 107 nfs_fscache_update_auxdata(&auxdata, inode); 108 fscache_invalidate(nfsi->fscache, &auxdata, 109 i_size_read(inode), flags); 110 } 111 } 112 113 /* 114 * indicate the client caching state as readable text 115 */ 116 static inline const char *nfs_server_fscache_state(struct nfs_server *server) 117 { 118 if (server->fscache) 119 return "yes"; 120 return "no "; 121 } 122 123 #else /* CONFIG_NFS_FSCACHE */ 124 static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {} 125 126 static inline void nfs_fscache_init_inode(struct inode *inode) {} 127 static inline void nfs_fscache_clear_inode(struct inode *inode) {} 128 static inline void nfs_fscache_open_file(struct inode *inode, 129 struct file *filp) {} 130 static inline void nfs_fscache_release_file(struct inode *inode, struct file *file) {} 131 132 static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp) 133 { 134 return 1; /* True: may release page */ 135 } 136 static inline int nfs_fscache_read_page(struct inode *inode, struct page *page) 137 { 138 return -ENOBUFS; 139 } 140 static inline void nfs_fscache_write_page(struct inode *inode, struct page *page) {} 141 static inline void nfs_fscache_invalidate(struct inode *inode, int flags) {} 142 143 static inline const char *nfs_server_fscache_state(struct nfs_server *server) 144 { 145 return "no "; 146 } 147 148 #endif /* CONFIG_NFS_FSCACHE */ 149 #endif /* _NFS_FSCACHE_H */ 150