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0174ee9947
Move cifs to using fscache DIO API instead of the old upstream I/O API as that has been removed. This is a stopgap solution as the intention is that at sometime in the future, the cache will move to using larger blocks and won't be able to store individual pages in order to deal with the potential for data corruption due to the backing filesystem being able insert/remove bridging blocks of zeros into its extent list[1]. cifs then reads and writes cache pages synchronously and one page at a time. The preferred change would be to use the netfs lib, but the new I/O API can be used directly. It's just that as the cache now needs to track data for itself, caching blocks may exceed page size... This code is somewhat borrowed from my "fallback I/O" patchset[2]. Signed-off-by: David Howells <dhowells@redhat.com> cc: Steve French <smfrench@gmail.com> cc: Shyam Prasad N <nspmangalore@gmail.com> cc: linux-cifs@vger.kernel.org cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/YO17ZNOcq+9PajfQ@mit.edu [1] Link: https://lore.kernel.org/r/202112100957.2oEDT20W-lkp@intel.com/ [2] Acked-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
164 lines
4.7 KiB
C
164 lines
4.7 KiB
C
/* SPDX-License-Identifier: LGPL-2.1 */
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/*
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* CIFS filesystem cache interface definitions
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*
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* Copyright (c) 2010 Novell, Inc.
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* Authors(s): Suresh Jayaraman (sjayaraman@suse.de>
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*
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*/
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#ifndef _CIFS_FSCACHE_H
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#define _CIFS_FSCACHE_H
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#include <linux/swap.h>
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#include <linux/fscache.h>
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#include "cifsglob.h"
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/*
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* Coherency data attached to CIFS volume within the cache
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*/
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struct cifs_fscache_volume_coherency_data {
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__le64 resource_id; /* unique server resource id */
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__le64 vol_create_time;
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__le32 vol_serial_number;
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} __packed;
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/*
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* Coherency data attached to CIFS inode within the cache.
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*/
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struct cifs_fscache_inode_coherency_data {
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__le64 last_write_time_sec;
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__le64 last_change_time_sec;
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__le32 last_write_time_nsec;
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__le32 last_change_time_nsec;
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};
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#ifdef CONFIG_CIFS_FSCACHE
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/*
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* fscache.c
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*/
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extern int cifs_fscache_get_super_cookie(struct cifs_tcon *);
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extern void cifs_fscache_release_super_cookie(struct cifs_tcon *);
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extern void cifs_fscache_get_inode_cookie(struct inode *inode);
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extern void cifs_fscache_release_inode_cookie(struct inode *);
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extern void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update);
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static inline
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void cifs_fscache_fill_coherency(struct inode *inode,
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struct cifs_fscache_inode_coherency_data *cd)
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{
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struct cifsInodeInfo *cifsi = CIFS_I(inode);
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memset(cd, 0, sizeof(*cd));
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cd->last_write_time_sec = cpu_to_le64(cifsi->vfs_inode.i_mtime.tv_sec);
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cd->last_write_time_nsec = cpu_to_le32(cifsi->vfs_inode.i_mtime.tv_nsec);
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cd->last_change_time_sec = cpu_to_le64(cifsi->vfs_inode.i_ctime.tv_sec);
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cd->last_change_time_nsec = cpu_to_le32(cifsi->vfs_inode.i_ctime.tv_nsec);
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}
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static inline struct fscache_cookie *cifs_inode_cookie(struct inode *inode)
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{
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return CIFS_I(inode)->fscache;
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}
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static inline void cifs_invalidate_cache(struct inode *inode, unsigned int flags)
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{
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struct cifs_fscache_inode_coherency_data cd;
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cifs_fscache_fill_coherency(inode, &cd);
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fscache_invalidate(cifs_inode_cookie(inode), &cd,
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i_size_read(inode), flags);
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}
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extern int __cifs_fscache_query_occupancy(struct inode *inode,
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pgoff_t first, unsigned int nr_pages,
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pgoff_t *_data_first,
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unsigned int *_data_nr_pages);
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static inline int cifs_fscache_query_occupancy(struct inode *inode,
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pgoff_t first, unsigned int nr_pages,
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pgoff_t *_data_first,
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unsigned int *_data_nr_pages)
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{
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if (!cifs_inode_cookie(inode))
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return -ENOBUFS;
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return __cifs_fscache_query_occupancy(inode, first, nr_pages,
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_data_first, _data_nr_pages);
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}
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extern int __cifs_readpage_from_fscache(struct inode *pinode, struct page *ppage);
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extern void __cifs_readpage_to_fscache(struct inode *pinode, struct page *ppage);
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static inline int cifs_readpage_from_fscache(struct inode *inode,
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struct page *page)
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{
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if (cifs_inode_cookie(inode))
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return __cifs_readpage_from_fscache(inode, page);
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return -ENOBUFS;
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}
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static inline void cifs_readpage_to_fscache(struct inode *inode,
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struct page *page)
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{
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if (cifs_inode_cookie(inode))
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__cifs_readpage_to_fscache(inode, page);
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}
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static inline int cifs_fscache_release_page(struct page *page, gfp_t gfp)
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{
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if (PageFsCache(page)) {
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if (current_is_kswapd() || !(gfp & __GFP_FS))
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return false;
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wait_on_page_fscache(page);
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fscache_note_page_release(cifs_inode_cookie(page->mapping->host));
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}
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return true;
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}
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#else /* CONFIG_CIFS_FSCACHE */
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static inline
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void cifs_fscache_fill_coherency(struct inode *inode,
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struct cifs_fscache_inode_coherency_data *cd)
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{
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}
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static inline int cifs_fscache_get_super_cookie(struct cifs_tcon *tcon) { return 0; }
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static inline void cifs_fscache_release_super_cookie(struct cifs_tcon *tcon) {}
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static inline void cifs_fscache_get_inode_cookie(struct inode *inode) {}
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static inline void cifs_fscache_release_inode_cookie(struct inode *inode) {}
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static inline void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update) {}
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static inline struct fscache_cookie *cifs_inode_cookie(struct inode *inode) { return NULL; }
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static inline void cifs_invalidate_cache(struct inode *inode, unsigned int flags) {}
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static inline int cifs_fscache_query_occupancy(struct inode *inode,
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pgoff_t first, unsigned int nr_pages,
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pgoff_t *_data_first,
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unsigned int *_data_nr_pages)
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{
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*_data_first = ULONG_MAX;
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*_data_nr_pages = 0;
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return -ENOBUFS;
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}
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static inline int
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cifs_readpage_from_fscache(struct inode *inode, struct page *page)
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{
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return -ENOBUFS;
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}
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static inline
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void cifs_readpage_to_fscache(struct inode *inode, struct page *page) {}
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static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
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{
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return true; /* May release page */
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}
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#endif /* CONFIG_CIFS_FSCACHE */
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#endif /* _CIFS_FSCACHE_H */
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