fs/nfs/fscache.h

   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 */