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Diffstat (limited to 'fs/nfs/fscache.h')
| -rw-r--r-- | fs/nfs/fscache.h | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h new file mode 100644 index 000000000..2dc644544 --- /dev/null +++ b/fs/nfs/fscache.h @@ -0,0 +1,202 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* NFS filesystem cache interface definitions + * + * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#ifndef _NFS_FSCACHE_H +#define _NFS_FSCACHE_H + +#include <linux/swap.h> +#include <linux/nfs_fs.h> +#include <linux/nfs_mount.h> +#include <linux/nfs4_mount.h> +#include <linux/fscache.h> +#include <linux/iversion.h> + +#ifdef CONFIG_NFS_FSCACHE + +/* + * Definition of the auxiliary data attached to NFS inode storage objects + * within the cache. + * + * The contents of this struct are recorded in the on-disk local cache in the + * auxiliary data attached to the data storage object backing an inode. This + * permits coherency to be managed when a new inode binds to an already extant + * cache object. + */ +struct nfs_fscache_inode_auxdata { + s64 mtime_sec; + s64 mtime_nsec; + s64 ctime_sec; + s64 ctime_nsec; + u64 change_attr; +}; + +struct nfs_netfs_io_data { + /* + * NFS may split a netfs_io_subrequest into multiple RPCs, each + * with their own read completion. In netfs, we can only call + * netfs_subreq_terminated() once for each subrequest. Use the + * refcount here to double as a marker of the last RPC completion, + * and only call netfs via netfs_subreq_terminated() once. + */ + refcount_t refcount; + struct netfs_io_subrequest *sreq; + + /* + * Final disposition of the netfs_io_subrequest, sent in + * netfs_subreq_terminated() + */ + atomic64_t transferred; + int error; +}; + +static inline void nfs_netfs_get(struct nfs_netfs_io_data *netfs) +{ + refcount_inc(&netfs->refcount); +} + +static inline void nfs_netfs_put(struct nfs_netfs_io_data *netfs) +{ + ssize_t final_len; + + /* Only the last RPC completion should call netfs_subreq_terminated() */ + if (!refcount_dec_and_test(&netfs->refcount)) + return; + + /* + * The NFS pageio interface may read a complete page, even when netfs + * only asked for a partial page. Specifically, this may be seen when + * one thread is truncating a file while another one is reading the last + * page of the file. + * Correct the final length here to be no larger than the netfs subrequest + * length, and thus avoid netfs's "Subreq overread" warning message. + */ + final_len = min_t(s64, netfs->sreq->len, atomic64_read(&netfs->transferred)); + netfs_subreq_terminated(netfs->sreq, netfs->error ?: final_len, false); + kfree(netfs); +} +static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi) +{ + netfs_inode_init(&nfsi->netfs, &nfs_netfs_ops); +} +extern void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr); +extern void nfs_netfs_read_completion(struct nfs_pgio_header *hdr); +extern int nfs_netfs_folio_unlock(struct folio *folio); + +/* + * fscache.c + */ +extern int nfs_fscache_get_super_cookie(struct super_block *, const char *, int); +extern void nfs_fscache_release_super_cookie(struct super_block *); + +extern void nfs_fscache_init_inode(struct inode *); +extern void nfs_fscache_clear_inode(struct inode *); +extern void nfs_fscache_open_file(struct inode *, struct file *); +extern void nfs_fscache_release_file(struct inode *, struct file *); +extern int nfs_netfs_readahead(struct readahead_control *ractl); +extern int nfs_netfs_read_folio(struct file *file, struct folio *folio); + +static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp) +{ + if (folio_test_fscache(folio)) { + if (current_is_kswapd() || !(gfp & __GFP_FS)) + return false; + folio_wait_fscache(folio); + } + fscache_note_page_release(netfs_i_cookie(netfs_inode(folio->mapping->host))); + return true; +} + +static inline void nfs_fscache_update_auxdata(struct nfs_fscache_inode_auxdata *auxdata, + struct inode *inode) +{ + memset(auxdata, 0, sizeof(*auxdata)); + auxdata->mtime_sec = inode->i_mtime.tv_sec; + auxdata->mtime_nsec = inode->i_mtime.tv_nsec; + auxdata->ctime_sec = inode_get_ctime(inode).tv_sec; + auxdata->ctime_nsec = inode_get_ctime(inode).tv_nsec; + + if (NFS_SERVER(inode)->nfs_client->rpc_ops->version == 4) + auxdata->change_attr = inode_peek_iversion_raw(inode); +} + +/* + * Invalidate the contents of fscache for this inode. This will not sleep. + */ +static inline void nfs_fscache_invalidate(struct inode *inode, int flags) +{ + struct nfs_fscache_inode_auxdata auxdata; + struct fscache_cookie *cookie = netfs_i_cookie(&NFS_I(inode)->netfs); + + nfs_fscache_update_auxdata(&auxdata, inode); + fscache_invalidate(cookie, &auxdata, i_size_read(inode), flags); +} + +/* + * indicate the client caching state as readable text + */ +static inline const char *nfs_server_fscache_state(struct nfs_server *server) +{ + if (server->fscache) + return "yes"; + return "no "; +} + +static inline void nfs_netfs_set_pgio_header(struct nfs_pgio_header *hdr, + struct nfs_pageio_descriptor *desc) +{ + hdr->netfs = desc->pg_netfs; +} +static inline void nfs_netfs_set_pageio_descriptor(struct nfs_pageio_descriptor *desc, + struct nfs_pgio_header *hdr) +{ + desc->pg_netfs = hdr->netfs; +} +static inline void nfs_netfs_reset_pageio_descriptor(struct nfs_pageio_descriptor *desc) +{ + desc->pg_netfs = NULL; +} +#else /* CONFIG_NFS_FSCACHE */ +static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi) {} +static inline void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr) {} +static inline void nfs_netfs_read_completion(struct nfs_pgio_header *hdr) {} +static inline int nfs_netfs_folio_unlock(struct folio *folio) +{ + return 1; +} +static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {} + +static inline void nfs_fscache_init_inode(struct inode *inode) {} +static inline void nfs_fscache_clear_inode(struct inode *inode) {} +static inline void nfs_fscache_open_file(struct inode *inode, + struct file *filp) {} +static inline void nfs_fscache_release_file(struct inode *inode, struct file *file) {} +static inline int nfs_netfs_readahead(struct readahead_control *ractl) +{ + return -ENOBUFS; +} +static inline int nfs_netfs_read_folio(struct file *file, struct folio *folio) +{ + return -ENOBUFS; +} + +static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp) +{ + return true; /* may release folio */ +} +static inline void nfs_fscache_invalidate(struct inode *inode, int flags) {} + +static inline const char *nfs_server_fscache_state(struct nfs_server *server) +{ + return "no "; +} +static inline void nfs_netfs_set_pgio_header(struct nfs_pgio_header *hdr, + struct nfs_pageio_descriptor *desc) {} +static inline void nfs_netfs_set_pageio_descriptor(struct nfs_pageio_descriptor *desc, + struct nfs_pgio_header *hdr) {} +static inline void nfs_netfs_reset_pageio_descriptor(struct nfs_pageio_descriptor *desc) {} +#endif /* CONFIG_NFS_FSCACHE */ +#endif /* _NFS_FSCACHE_H */ |