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 struct nfs_netfs_io_data { 38 /* 39 * NFS may split a netfs_io_subrequest into multiple RPCs, each 40 * with their own read completion. In netfs, we can only call 41 * netfs_subreq_terminated() once for each subrequest. Use the 42 * refcount here to double as a marker of the last RPC completion, 43 * and only call netfs via netfs_subreq_terminated() once. 44 */ 45 refcount_t refcount; 46 struct netfs_io_subrequest *sreq; 47 48 /* 49 * Final disposition of the netfs_io_subrequest, sent in 50 * netfs_subreq_terminated() 51 */ 52 atomic64_t transferred; 53 int error; 54 }; 55 56 static inline void nfs_netfs_get(struct nfs_netfs_io_data *netfs) 57 { 58 refcount_inc(&netfs->refcount); 59 } 60 61 static inline void nfs_netfs_put(struct nfs_netfs_io_data *netfs) 62 { 63 /* Only the last RPC completion should call netfs_subreq_terminated() */ 64 if (!refcount_dec_and_test(&netfs->refcount)) 65 return; 66 67 /* 68 * The NFS pageio interface may read a complete page, even when netfs 69 * only asked for a partial page. Specifically, this may be seen when 70 * one thread is truncating a file while another one is reading the last 71 * page of the file. 72 * Correct the final length here to be no larger than the netfs subrequest 73 * length, and thus avoid netfs's "Subreq overread" warning message. 74 */ 75 netfs->sreq->transferred = min_t(s64, netfs->sreq->len, 76 atomic64_read(&netfs->transferred)); 77 netfs_read_subreq_terminated(netfs->sreq, netfs->error, false); 78 kfree(netfs); 79 } 80 static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi) 81 { 82 netfs_inode_init(&nfsi->netfs, &nfs_netfs_ops, false); 83 } 84 extern void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr); 85 extern void nfs_netfs_read_completion(struct nfs_pgio_header *hdr); 86 extern int nfs_netfs_folio_unlock(struct folio *folio); 87 88 /* 89 * fscache.c 90 */ 91 extern int nfs_fscache_get_super_cookie(struct super_block *, const char *, int); 92 extern void nfs_fscache_release_super_cookie(struct super_block *); 93 94 extern void nfs_fscache_init_inode(struct inode *); 95 extern void nfs_fscache_clear_inode(struct inode *); 96 extern void nfs_fscache_open_file(struct inode *, struct file *); 97 extern void nfs_fscache_release_file(struct inode *, struct file *); 98 extern int nfs_netfs_readahead(struct readahead_control *ractl); 99 extern int nfs_netfs_read_folio(struct file *file, struct folio *folio); 100 101 static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp) 102 { 103 if (folio_test_private_2(folio)) { /* [DEPRECATED] */ 104 if (current_is_kswapd() || !(gfp & __GFP_FS)) 105 return false; 106 folio_wait_private_2(folio); 107 } 108 fscache_note_page_release(netfs_i_cookie(netfs_inode(folio->mapping->host))); 109 return true; 110 } 111 112 static inline void nfs_fscache_update_auxdata(struct nfs_fscache_inode_auxdata *auxdata, 113 struct inode *inode) 114 { 115 memset(auxdata, 0, sizeof(*auxdata)); 116 auxdata->mtime_sec = inode_get_mtime(inode).tv_sec; 117 auxdata->mtime_nsec = inode_get_mtime(inode).tv_nsec; 118 auxdata->ctime_sec = inode_get_ctime(inode).tv_sec; 119 auxdata->ctime_nsec = inode_get_ctime(inode).tv_nsec; 120 121 if (NFS_SERVER(inode)->nfs_client->rpc_ops->version == 4) 122 auxdata->change_attr = inode_peek_iversion_raw(inode); 123 } 124 125 /* 126 * Invalidate the contents of fscache for this inode. This will not sleep. 127 */ 128 static inline void nfs_fscache_invalidate(struct inode *inode, int flags) 129 { 130 struct nfs_fscache_inode_auxdata auxdata; 131 struct fscache_cookie *cookie = netfs_i_cookie(&NFS_I(inode)->netfs); 132 133 nfs_fscache_update_auxdata(&auxdata, inode); 134 fscache_invalidate(cookie, &auxdata, i_size_read(inode), flags); 135 } 136 137 /* 138 * indicate the client caching state as readable text 139 */ 140 static inline const char *nfs_server_fscache_state(struct nfs_server *server) 141 { 142 if (server->fscache) 143 return "yes"; 144 return "no "; 145 } 146 147 static inline void nfs_netfs_set_pgio_header(struct nfs_pgio_header *hdr, 148 struct nfs_pageio_descriptor *desc) 149 { 150 hdr->netfs = desc->pg_netfs; 151 } 152 static inline void nfs_netfs_set_pageio_descriptor(struct nfs_pageio_descriptor *desc, 153 struct nfs_pgio_header *hdr) 154 { 155 desc->pg_netfs = hdr->netfs; 156 } 157 static inline void nfs_netfs_reset_pageio_descriptor(struct nfs_pageio_descriptor *desc) 158 { 159 desc->pg_netfs = NULL; 160 } 161 #else /* CONFIG_NFS_FSCACHE */ 162 static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi) {} 163 static inline void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr) {} 164 static inline void nfs_netfs_read_completion(struct nfs_pgio_header *hdr) {} 165 static inline int nfs_netfs_folio_unlock(struct folio *folio) 166 { 167 return 1; 168 } 169 static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {} 170 171 static inline void nfs_fscache_init_inode(struct inode *inode) {} 172 static inline void nfs_fscache_clear_inode(struct inode *inode) {} 173 static inline void nfs_fscache_open_file(struct inode *inode, 174 struct file *filp) {} 175 static inline void nfs_fscache_release_file(struct inode *inode, struct file *file) {} 176 static inline int nfs_netfs_readahead(struct readahead_control *ractl) 177 { 178 return -ENOBUFS; 179 } 180 static inline int nfs_netfs_read_folio(struct file *file, struct folio *folio) 181 { 182 return -ENOBUFS; 183 } 184 185 static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp) 186 { 187 return true; /* may release folio */ 188 } 189 static inline void nfs_fscache_invalidate(struct inode *inode, int flags) {} 190 191 static inline const char *nfs_server_fscache_state(struct nfs_server *server) 192 { 193 return "no "; 194 } 195 static inline void nfs_netfs_set_pgio_header(struct nfs_pgio_header *hdr, 196 struct nfs_pageio_descriptor *desc) {} 197 static inline void nfs_netfs_set_pageio_descriptor(struct nfs_pageio_descriptor *desc, 198 struct nfs_pgio_header *hdr) {} 199 static inline void nfs_netfs_reset_pageio_descriptor(struct nfs_pageio_descriptor *desc) {} 200 #endif /* CONFIG_NFS_FSCACHE */ 201 #endif /* _NFS_FSCACHE_H */ 202