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 ssize_t final_len; 64 65 /* Only the last RPC completion should call netfs_subreq_terminated() */ 66 if (!refcount_dec_and_test(&netfs->refcount)) 67 return; 68 69 /* 70 * The NFS pageio interface may read a complete page, even when netfs 71 * only asked for a partial page. Specifically, this may be seen when 72 * one thread is truncating a file while another one is reading the last 73 * page of the file. 74 * Correct the final length here to be no larger than the netfs subrequest 75 * length, and thus avoid netfs's "Subreq overread" warning message. 76 */ 77 final_len = min_t(s64, netfs->sreq->len, atomic64_read(&netfs->transferred)); 78 netfs_subreq_terminated(netfs->sreq, netfs->error ?: final_len, false); 79 kfree(netfs); 80 } 81 static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi) 82 { 83 netfs_inode_init(&nfsi->netfs, &nfs_netfs_ops); 84 } 85 extern void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr); 86 extern void nfs_netfs_read_completion(struct nfs_pgio_header *hdr); 87 extern int nfs_netfs_folio_unlock(struct folio *folio); 88 89 /* 90 * fscache.c 91 */ 92 extern int nfs_fscache_get_super_cookie(struct super_block *, const char *, int); 93 extern void nfs_fscache_release_super_cookie(struct super_block *); 94 95 extern void nfs_fscache_init_inode(struct inode *); 96 extern void nfs_fscache_clear_inode(struct inode *); 97 extern void nfs_fscache_open_file(struct inode *, struct file *); 98 extern void nfs_fscache_release_file(struct inode *, struct file *); 99 extern int nfs_netfs_readahead(struct readahead_control *ractl); 100 extern int nfs_netfs_read_folio(struct file *file, struct folio *folio); 101 102 static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp) 103 { 104 if (folio_test_fscache(folio)) { 105 if (current_is_kswapd() || !(gfp & __GFP_FS)) 106 return false; 107 folio_wait_fscache(folio); 108 } 109 fscache_note_page_release(netfs_i_cookie(netfs_inode(folio->mapping->host))); 110 return true; 111 } 112 113 static inline void nfs_fscache_update_auxdata(struct nfs_fscache_inode_auxdata *auxdata, 114 struct inode *inode) 115 { 116 memset(auxdata, 0, sizeof(*auxdata)); 117 auxdata->mtime_sec = inode->i_mtime.tv_sec; 118 auxdata->mtime_nsec = inode->i_mtime.tv_nsec; 119 auxdata->ctime_sec = inode_get_ctime(inode).tv_sec; 120 auxdata->ctime_nsec = inode_get_ctime(inode).tv_nsec; 121 122 if (NFS_SERVER(inode)->nfs_client->rpc_ops->version == 4) 123 auxdata->change_attr = inode_peek_iversion_raw(inode); 124 } 125 126 /* 127 * Invalidate the contents of fscache for this inode. This will not sleep. 128 */ 129 static inline void nfs_fscache_invalidate(struct inode *inode, int flags) 130 { 131 struct nfs_fscache_inode_auxdata auxdata; 132 struct fscache_cookie *cookie = netfs_i_cookie(&NFS_I(inode)->netfs); 133 134 nfs_fscache_update_auxdata(&auxdata, inode); 135 fscache_invalidate(cookie, &auxdata, i_size_read(inode), flags); 136 } 137 138 /* 139 * indicate the client caching state as readable text 140 */ 141 static inline const char *nfs_server_fscache_state(struct nfs_server *server) 142 { 143 if (server->fscache) 144 return "yes"; 145 return "no "; 146 } 147 148 static inline void nfs_netfs_set_pgio_header(struct nfs_pgio_header *hdr, 149 struct nfs_pageio_descriptor *desc) 150 { 151 hdr->netfs = desc->pg_netfs; 152 } 153 static inline void nfs_netfs_set_pageio_descriptor(struct nfs_pageio_descriptor *desc, 154 struct nfs_pgio_header *hdr) 155 { 156 desc->pg_netfs = hdr->netfs; 157 } 158 static inline void nfs_netfs_reset_pageio_descriptor(struct nfs_pageio_descriptor *desc) 159 { 160 desc->pg_netfs = NULL; 161 } 162 #else /* CONFIG_NFS_FSCACHE */ 163 static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi) {} 164 static inline void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr) {} 165 static inline void nfs_netfs_read_completion(struct nfs_pgio_header *hdr) {} 166 static inline int nfs_netfs_folio_unlock(struct folio *folio) 167 { 168 return 1; 169 } 170 static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {} 171 172 static inline void nfs_fscache_init_inode(struct inode *inode) {} 173 static inline void nfs_fscache_clear_inode(struct inode *inode) {} 174 static inline void nfs_fscache_open_file(struct inode *inode, 175 struct file *filp) {} 176 static inline void nfs_fscache_release_file(struct inode *inode, struct file *file) {} 177 static inline int nfs_netfs_readahead(struct readahead_control *ractl) 178 { 179 return -ENOBUFS; 180 } 181 static inline int nfs_netfs_read_folio(struct file *file, struct folio *folio) 182 { 183 return -ENOBUFS; 184 } 185 186 static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp) 187 { 188 return true; /* may release folio */ 189 } 190 static inline void nfs_fscache_invalidate(struct inode *inode, int flags) {} 191 192 static inline const char *nfs_server_fscache_state(struct nfs_server *server) 193 { 194 return "no "; 195 } 196 static inline void nfs_netfs_set_pgio_header(struct nfs_pgio_header *hdr, 197 struct nfs_pageio_descriptor *desc) {} 198 static inline void nfs_netfs_set_pageio_descriptor(struct nfs_pageio_descriptor *desc, 199 struct nfs_pgio_header *hdr) {} 200 static inline void nfs_netfs_reset_pageio_descriptor(struct nfs_pageio_descriptor *desc) {} 201 #endif /* CONFIG_NFS_FSCACHE */ 202 #endif /* _NFS_FSCACHE_H */ 203