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2021-09-27fs/netfs: Add folio fscache functionsMatthew Wilcox (Oracle)1-27/+48
Match the page writeback functions by adding folio_start_fscache(), folio_end_fscache(), folio_wait_fscache() and folio_wait_fscache_killable(). Remove set_page_private_2(). Also rewrite the kernel-doc to describe when to use the function rather than what the function does, and include the kernel-doc in the appropriate rst file. Saves 31 bytes of text in netfs_rreq_unlock() due to set_page_fscache() calling page_folio() once instead of three times. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: David Howells <dhowells@redhat.com>
2021-09-27mm/filemap: Add folio private_2 functionsMatthew Wilcox (Oracle)1-3/+3
end_page_private_2() becomes folio_end_private_2(), wait_on_page_private_2() becomes folio_wait_private_2() and wait_on_page_private_2_killable() becomes folio_wait_private_2_killable(). Adjust the fscache equivalents to call page_folio() before calling these functions to avoid adding wrappers. Ends up costing 1 byte of text in ceph & netfs, but the core shrinks by three calls to page_folio(). Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: David Howells <dhowells@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
2021-08-25netfs: Move cookie debug ID to struct netfs_cache_resourcesDavid Howells1-1/+1
Move the cookie debug ID from struct netfs_read_request to struct netfs_cache_resources and drop the 'cookie_' prefix. This makes it available for things that want to use netfs_cache_resources without having a netfs_read_request. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/162431190784.2908479.13386972676539789127.stgit@warthog.procyon.org.uk/
2021-04-23netfs: Define an interface to talk to a cacheDavid Howells1-0/+55
Add an interface to the netfs helper library for reading data from the cache instead of downloading it from the server and support for writing data just downloaded or cleared to the cache. The API passes an iov_iter to the cache read/write routines to indicate the data/buffer to be used. This is done using the ITER_XARRAY type to provide direct access to the netfs inode's pagecache. When the netfs's ->begin_cache_operation() method is called, this must fill in the cache_resources in the netfs_read_request struct, including the netfs_cache_ops used by the helper lib to talk to the cache. The helper lib does not directly access the cache. Changes: v6: - Call trace_netfs_read() after beginning the cache op so that the cookie debug ID can be logged[3]. - Don't record the error from writing to the cache. We don't want to pass it back to the netfs[4]. - Fix copy-to-cache subreq amalgamation to not round up as it goes along otherwise it overcalculates the length of the write[5]. v5: - Use end_page_fscache() rather than unlock_page_fscache()[2]. v4: - Added flag to netfs_subreq_terminated() to indicate that the caller may have been running async and stuff that might sleep needs punting to a workqueue (can't use in_softirq()[1]). - Add missing inc of netfs_n_rh_read stat. - Move initial definition of fscache_begin_read_operation() elsewhere. - Need to call op->begin_cache_operation() from netfs_write_begin(). Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org> Tested-by: Dave Wysochanski <dwysocha@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: Matthew Wilcox <willy@infradead.org> cc: linux-mm@kvack.org cc: linux-cachefs@redhat.com cc: linux-afs@lists.infradead.org cc: linux-nfs@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: ceph-devel@vger.kernel.org cc: v9fs-developer@lists.sourceforge.net cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20210216084230.GA23669@lst.de/ [1] Link: https://lore.kernel.org/r/2499407.1616505440@warthog.procyon.org.uk/ [2] Link: https://lore.kernel.org/r/161781045123.463527.14533348855710902201.stgit@warthog.procyon.org.uk/ [3] Link: https://lore.kernel.org/r/161781046256.463527.18158681600085556192.stgit@warthog.procyon.org.uk/ [4] Link: https://lore.kernel.org/r/161781047695.463527.7463536103593997492.stgit@warthog.procyon.org.uk/ [5] Link: https://lore.kernel.org/r/161118141321.1232039.8296910406755622458.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161036700.2537118.11170748455436854978.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340399569.1303470.1138884774643385730.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539542874.286939.13337898213448136687.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653799826.2770958.9015430297426331950.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789081462.6155.3853904866933313256.stgit@warthog.procyon.org.uk/ # v6
2021-04-23netfs: Add write_begin helperDavid Howells1-0/+8
Add a helper to do the pre-reading work for the netfs write_begin address space op. Changes v6: - Fixed a missing rreq put in netfs_write_begin()[3]. - Use DEFINE_READAHEAD()[4]. v5: - Made the wait for PG_fscache in netfs_write_begin() killable[2]. v4: - Added flag to netfs_subreq_terminated() to indicate that the caller may have been running async and stuff that might sleep needs punting to a workqueue (can't use in_softirq()[1]). Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org> Tested-by: Dave Wysochanski <dwysocha@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: Matthew Wilcox <willy@infradead.org> cc: linux-mm@kvack.org cc: linux-cachefs@redhat.com cc: linux-afs@lists.infradead.org cc: linux-nfs@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: ceph-devel@vger.kernel.org cc: v9fs-developer@lists.sourceforge.net cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20210216084230.GA23669@lst.de/ [1] Link: https://lore.kernel.org/r/2499407.1616505440@warthog.procyon.org.uk/ [2] Link: https://lore.kernel.org/r/161781042127.463527.9154479794406046987.stgit@warthog.procyon.org.uk/ [3] Link: https://lore.kernel.org/r/1234933.1617886271@warthog.procyon.org.uk/ [4] Link: https://lore.kernel.org/r/160588543960.3465195.2792938973035886168.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118140165.1232039.16418853874312234477.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161035539.2537118.15674887534950908530.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340398368.1303470.11242918276563276090.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539541541.286939.1889738674057013729.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653798616.2770958.17213315845968485563.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789080530.6155.1011847312392330491.stgit@warthog.procyon.org.uk/ # v6
2021-04-23netfs: Gather statsDavid Howells1-0/+1
Gather statistics from the netfs interface that can be exported through a seqfile. This is intended to be called by a later patch when viewing /proc/fs/fscache/stats. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org> Tested-by: Dave Wysochanski <dwysocha@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: Matthew Wilcox <willy@infradead.org> cc: linux-mm@kvack.org cc: linux-cachefs@redhat.com cc: linux-afs@lists.infradead.org cc: linux-nfs@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: ceph-devel@vger.kernel.org cc: v9fs-developer@lists.sourceforge.net cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/161118139247.1232039.10556850937548511068.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161034669.2537118.2761232524997091480.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340397101.1303470.17581910581108378458.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539539959.286939.6794352576462965914.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653797700.2770958.5801990354413178228.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789079281.6155.17141344853277186500.stgit@warthog.procyon.org.uk/ # v6
2021-04-23netfs: Add tracepointsDavid Howells1-0/+1
Add three tracepoints to track the activity of the read helpers: (1) netfs/netfs_read This logs entry to the read helpers and also expansion of the range in a readahead request. (2) netfs/netfs_rreq This logs the progress of netfs_read_request objects which track read requests. A read request may be a compound of multiple subrequests. (3) netfs/netfs_sreq This logs the progress of netfs_read_subrequest objects, which track the contributions from various sources to a read request. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org> Tested-by: Dave Wysochanski <dwysocha@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: Matthew Wilcox <willy@infradead.org> cc: linux-mm@kvack.org cc: linux-cachefs@redhat.com cc: linux-afs@lists.infradead.org cc: linux-nfs@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: ceph-devel@vger.kernel.org cc: v9fs-developer@lists.sourceforge.net cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/161118138060.1232039.5353374588021776217.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161033468.2537118.14021843889844001905.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340395843.1303470.7355519662919639648.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539538693.286939.10171713520419106334.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653796447.2770958.1870655382450862155.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789078003.6155.17814844411672989942.stgit@warthog.procyon.org.uk/ # v6
2021-04-23netfs: Provide readahead and readpage netfs helpersDavid Howells1-0/+83
Add a pair of helper functions: (*) netfs_readahead() (*) netfs_readpage() to do the work of handling a readahead or a readpage, where the page(s) that form part of the request may be split between the local cache, the server or just require clearing, and may be single pages and transparent huge pages. This is all handled within the helper. Note that while both will read from the cache if there is data present, only netfs_readahead() will expand the request beyond what it was asked to do, and only netfs_readahead() will write back to the cache. netfs_readpage(), on the other hand, is synchronous and only fetches the page (which might be a THP) it is asked for. The netfs gives the helper parameters from the VM, the cache cookie it wants to use (or NULL) and a table of operations (only one of which is mandatory): (*) expand_readahead() [optional] Called to allow the netfs to request an expansion of a readahead request to meet its own alignment requirements. This is done by changing rreq->start and rreq->len. (*) clamp_length() [optional] Called to allow the netfs to cut down a subrequest to meet its own boundary requirements. If it does this, the helper will generate additional subrequests until the full request is satisfied. (*) is_still_valid() [optional] Called to find out if the data just read from the cache has been invalidated and must be reread from the server. (*) issue_op() [required] Called to ask the netfs to issue a read to the server. The subrequest describes the read. The read request holds information about the file being accessed. The netfs can cache information in rreq->netfs_priv. Upon completion, the netfs should set the error, transferred and can also set FSCACHE_SREQ_CLEAR_TAIL and then call fscache_subreq_terminated(). (*) done() [optional] Called after the pages have been unlocked. The read request is still pinning the file and mapping and may still be pinning pages with PG_fscache. rreq->error indicates any error that has been accumulated. (*) cleanup() [optional] Called when the helper is disposing of a finished read request. This allows the netfs to clear rreq->netfs_priv. Netfs support is enabled with CONFIG_NETFS_SUPPORT=y. It will be built even if CONFIG_FSCACHE=n and in this case much of it should be optimised away, allowing the filesystem to use it even when caching is disabled. Changes: v5: - Comment why netfs_readahead() is putting pages[2]. - Use page_file_mapping() rather than page->mapping[2]. - Use page_index() rather than page->index[2]. - Use set_page_fscache()[3] rather then SetPageFsCache() as this takes an appropriate ref too[4]. v4: - Folded in a kerneldoc comment fix. - Folded in a fix for the error handling in the case that ENOMEM occurs. - Added flag to netfs_subreq_terminated() to indicate that the caller may have been running async and stuff that might sleep needs punting to a workqueue (can't use in_softirq()[1]). Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org> Tested-by: Dave Wysochanski <dwysocha@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: Matthew Wilcox <willy@infradead.org> cc: linux-mm@kvack.org cc: linux-cachefs@redhat.com cc: linux-afs@lists.infradead.org cc: linux-nfs@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: ceph-devel@vger.kernel.org cc: v9fs-developer@lists.sourceforge.net cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20210216084230.GA23669@lst.de/ [1] Link: https://lore.kernel.org/r/20210321014202.GF3420@casper.infradead.org/ [2] Link: https://lore.kernel.org/r/2499407.1616505440@warthog.procyon.org.uk/ [3] Link: https://lore.kernel.org/r/CAHk-=wh+2gbF7XEjYc=HV9w_2uVzVf7vs60BPz0gFA=+pUm3ww@mail.gmail.com/ [4] Link: https://lore.kernel.org/r/160588497406.3465195.18003475695899726222.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118136849.1232039.8923686136144228724.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161032290.2537118.13400578415247339173.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340394873.1303470.6237319335883242536.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539537375.286939.16642940088716990995.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653795430.2770958.4947584573720000554.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789076581.6155.6745849361504760209.stgit@warthog.procyon.org.uk/ # v6
2021-04-23netfs, mm: Add set/end/wait_on_page_fscache() aliasesDavid Howells1-0/+57
Add set/end/wait_on_page_fscache() as aliases of set/end/wait_page_private_2(). These allow a page to marked with PG_fscache, the flag to be removed and waiters woken and waiting for the flag to be cleared. A ref on the page is also taken and dropped. [Linus suggested putting the fscache-themed functions into the caching-specific headers rather than pagemap.h[1]] Changes: v5: - Mirror the changes to the core routines[2]. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Jeff Layton <jlayton@kernel.org> Tested-by: Dave Wysochanski <dwysocha@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: Linus Torvalds <torvalds@linux-foundation.org> cc: Matthew Wilcox <willy@infradead.org> cc: linux-mm@kvack.org cc: linux-cachefs@redhat.com cc: linux-afs@lists.infradead.org cc: linux-nfs@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: ceph-devel@vger.kernel.org cc: v9fs-developer@lists.sourceforge.net cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/1330473.1612974547@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/CAHk-=wjgA-74ddehziVk=XAEMTKswPu1Yw4uaro1R3ibs27ztw@mail.gmail.com/ [1] Link: https://lore.kernel.org/r/161340393568.1303470.4997526899111310530.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539536093.286939.5076448803512118764.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/2499407.1616505440@warthog.procyon.org.uk/ [2] Link: https://lore.kernel.org/r/161653793873.2770958.12157243390965814502.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789075327.6155.7432127924219092385.stgit@warthog.procyon.org.uk/ # v6
2021-04-23netfs, mm: Move PG_fscache helper funcs to linux/netfs.hDavid Howells1-0/+29
Move the PG_fscache related helper funcs (such as SetPageFsCache()) to linux/netfs.h rather than linux/fscache.h as the intention is to move to a model where they're used by the network filesystem and the helper library, but not by fscache/cachefiles itself. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Jeff Layton <jlayton@kernel.org> Tested-by: Dave Wysochanski <dwysocha@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: Matthew Wilcox <willy@infradead.org> cc: linux-mm@kvack.org cc: linux-cachefs@redhat.com cc: linux-afs@lists.infradead.org cc: linux-nfs@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: ceph-devel@vger.kernel.org cc: v9fs-developer@lists.sourceforge.net cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/161340392347.1303470.18065131603507621762.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539534516.286939.6265142985563005000.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653792959.2770958.5386546945273988117.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789073997.6155.18442271115255650614.stgit@warthog.procyon.org.uk/ # v6