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70431bfd82
Change the cifs filesystem to take account of the changes to fscache's
indexing rewrite and reenable caching in cifs.
The following changes have been made:
(1) The fscache_netfs struct is no more, and there's no need to register
the filesystem as a whole.
(2) The session cookie is now an fscache_volume cookie, allocated with
fscache_acquire_volume(). That takes three parameters: a string
representing the "volume" in the index, a string naming the cache to
use (or NULL) and a u64 that conveys coherency metadata for the
volume.
For cifs, I've made it render the volume name string as:
"cifs,<ipaddress>,<sharename>"
where the sharename has '/' characters replaced with ';'.
This probably needs rethinking a bit as the total name could exceed
the maximum filename component length.
Further, the coherency data is currently just set to 0. It needs
something else doing with it - I wonder if it would suffice simply to
sum the resource_id, vol_create_time and vol_serial_number or maybe
hash them.
(3) The fscache_cookie_def is no more and needed information is passed
directly to fscache_acquire_cookie(). The cache no longer calls back
into the filesystem, but rather metadata changes are indicated at
other times.
fscache_acquire_cookie() is passed the same keying and coherency
information as before.
(4) The functions to set/reset cookies are removed and
fscache_use_cookie() and fscache_unuse_cookie() are used instead.
fscache_use_cookie() is passed a flag to indicate if the cookie is
opened for writing. fscache_unuse_cookie() is passed updates for the
metadata if we changed it (ie. if the file was opened for writing).
These are called when the file is opened or closed.
(5) cifs_setattr_*() are made to call fscache_resize() to change the size
of the cache object.
(6) The functions to read and write data are stubbed out pending a
conversion to use netfslib.
Changes
=======
ver #8:
- Abstract cache invalidation into a helper function.
- Fix some checkpatch warnings[3].
ver #7:
- Removed the accidentally added-back call to get the super cookie in
cifs_root_iget().
- Fixed the right call to cifs_fscache_get_super_cookie() to take account
of the "-o fsc" mount flag.
ver #6:
- Moved the change of gfpflags_allow_blocking() to current_is_kswapd() for
cifs here.
- Fixed one of the error paths in cifs_atomic_open() to jump around the
call to use the cookie.
- Fixed an additional successful return in the middle of cifs_open() to
use the cookie on the way out.
- Only get a volume cookie (and thus inode cookies) when "-o fsc" is
supplied to mount.
ver #5:
- Fixed a couple of bits of cookie handling[2]:
- The cookie should be released in cifs_evict_inode(), not
cifsFileInfo_put_final(). The cookie needs to persist beyond file
closure so that writepages will be able to write to it.
- fscache_use_cookie() needs to be called in cifs_atomic_open() as it is
for cifs_open().
ver #4:
- Fixed the use of sizeof with memset.
- tcon->vol_create_time is __le64 so doesn't need cpu_to_le64().
ver #3:
- Canonicalise the cifs coherency data to make the cache portable.
- Set volume coherency data.
ver #2:
- Use gfpflags_allow_blocking() rather than using flag directly.
- Upgraded to -rc4 to allow for upstream changes[1].
- fscache_acquire_volume() now returns errors.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
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://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=23b55d673d7527b093cd97b7c217c82e70cd1af0 [1]
Link: https://lore.kernel.org/r/3419813.1641592362@warthog.procyon.org.uk/ [2]
Link: https://lore.kernel.org/r/CAH2r5muTanw9pJqzAHd01d9A8keeChkzGsCEH6=0rHutVLAF-A@mail.gmail.com/ [3]
Link: https://lore.kernel.org/r/163819671009.215744.11230627184193298714.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906982979.143852.10672081929614953210.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967187187.1823006.247415138444991444.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021579335.640689.2681324337038770579.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/3462849.1641593783@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/1318953.1642024578@warthog.procyon.org.uk/ # v6
Signed-off-by: Steve French <stfrench@microsoft.com>
145 lines
4.1 KiB
C
145 lines
4.1 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/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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extern int cifs_fscache_release_page(struct page *page, gfp_t gfp);
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extern int __cifs_readpage_from_fscache(struct inode *, struct page *);
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extern int __cifs_readpages_from_fscache(struct inode *,
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struct address_space *,
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struct list_head *,
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unsigned *);
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extern void __cifs_readpage_to_fscache(struct inode *, struct page *);
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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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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_I(inode)->fscache)
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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 int cifs_readpages_from_fscache(struct inode *inode,
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struct address_space *mapping,
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struct list_head *pages,
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unsigned *nr_pages)
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{
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if (CIFS_I(inode)->fscache)
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return __cifs_readpages_from_fscache(inode, mapping, pages,
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nr_pages);
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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 (PageFsCache(page))
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__cifs_readpage_to_fscache(inode, page);
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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
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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 int cifs_readpages_from_fscache(struct inode *inode,
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struct address_space *mapping,
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struct list_head *pages,
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unsigned *nr_pages)
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{
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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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#endif /* CONFIG_CIFS_FSCACHE */
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#endif /* _CIFS_FSCACHE_H */
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