From: JeffleXu <jefflexu@linux.alibaba.com> To: David Howells <dhowells@redhat.com>, linux-cachefs@redhat.com Cc: Trond Myklebust <trondmy@hammerspace.com>, Anna Schumaker <anna.schumaker@netapp.com>, Steve French <sfrench@samba.org>, Dominique Martinet <asmadeus@codewreck.org>, Jeff Layton <jlayton@kernel.org>, Matthew Wilcox <willy@infradead.org>, Alexander Viro <viro@zeniv.linux.org.uk>, Omar Sandoval <osandov@osandov.com>, Linus Torvalds <torvalds@linux-foundation.org>, linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 24/64] netfs: Pass more information on how to deal with a hole in the cache Date: Mon, 6 Dec 2021 19:42:18 +0800 [thread overview] Message-ID: <d4167c15-b3ce-73b2-1d66-97d651723305@linux.alibaba.com> (raw) In-Reply-To: <163819612321.215744.9738308885948264476.stgit@warthog.procyon.org.uk> On 11/29/21 10:28 PM, David Howells wrote: > Pass more information to the cache on how to deal with a hole if it > encounters one when trying to read from the cache. Three options are > provided: > > (1) NETFS_READ_HOLE_IGNORE. Read the hole along with the data, assuming > it to be a punched-out extent by the backing filesystem. > > (2) NETFS_READ_HOLE_CLEAR. If there's a hole, erase the requested region > of the cache and clear the read buffer. > > (3) NETFS_READ_HOLE_FAIL. Fail the read if a hole is detected. > > Signed-off-by: David Howells <dhowells@redhat.com> > cc: linux-cachefs@redhat.com > --- > > fs/netfs/read_helper.c | 8 ++++---- > include/linux/netfs.h | 11 ++++++++++- > 2 files changed, 14 insertions(+), 5 deletions(-) > > diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c > index 7dc79fa8a1f3..08df413efdf3 100644 > --- a/fs/netfs/read_helper.c > +++ b/fs/netfs/read_helper.c > @@ -170,7 +170,7 @@ static void netfs_cache_read_terminated(void *priv, ssize_t transferred_or_error > */ > static void netfs_read_from_cache(struct netfs_read_request *rreq, > struct netfs_read_subrequest *subreq, > - bool seek_data) > + enum netfs_read_from_hole read_hole) > { > struct netfs_cache_resources *cres = &rreq->cache_resources; > struct iov_iter iter; > @@ -180,7 +180,7 @@ static void netfs_read_from_cache(struct netfs_read_request *rreq, > subreq->start + subreq->transferred, > subreq->len - subreq->transferred); > > - cres->ops->read(cres, subreq->start, &iter, seek_data, > + cres->ops->read(cres, subreq->start, &iter, read_hole, > netfs_cache_read_terminated, subreq); > } > > @@ -466,7 +466,7 @@ static void netfs_rreq_short_read(struct netfs_read_request *rreq, > netfs_get_read_subrequest(subreq); > atomic_inc(&rreq->nr_rd_ops); > if (subreq->source == NETFS_READ_FROM_CACHE) > - netfs_read_from_cache(rreq, subreq, true); > + netfs_read_from_cache(rreq, subreq, NETFS_READ_HOLE_CLEAR); Hi I'm not sure why NETFS_READ_HOLE_CLEAR style should be used in 'short read' case. Besides, ``` static void netfs_read_from_cache(struct netfs_read_request *rreq, struct netfs_read_subrequest *subreq, enum netfs_read_from_hole read_hole) { struct netfs_cache_resources *cres = &rreq->cache_resources; struct iov_iter iter; netfs_stat(&netfs_n_rh_read); iov_iter_xarray(&iter, READ, &rreq->mapping->i_pages, subreq->start + subreq->transferred, subreq->len - subreq->transferred); cres->ops->read(cres, subreq->start, &iter, read_hole, netfs_cache_read_terminated, subreq); } ``` I'm not sure why 'subreq->start' is not incremented with 'subreq->transferred' when calling cres->ops->read() in 'short read' case. > else > netfs_read_from_server(rreq, subreq); > } > @@ -794,7 +794,7 @@ static bool netfs_rreq_submit_slice(struct netfs_read_request *rreq, > netfs_read_from_server(rreq, subreq); > break; > case NETFS_READ_FROM_CACHE: > - netfs_read_from_cache(rreq, subreq, false); > + netfs_read_from_cache(rreq, subreq, NETFS_READ_HOLE_IGNORE); > break; > default: > BUG(); > diff --git a/include/linux/netfs.h b/include/linux/netfs.h > index 5a46fde65759..b46c39d98bbd 100644 > --- a/include/linux/netfs.h > +++ b/include/linux/netfs.h > @@ -196,6 +196,15 @@ struct netfs_read_request_ops { > void (*cleanup)(struct address_space *mapping, void *netfs_priv); > }; > > +/* > + * How to handle reading from a hole. > + */ > +enum netfs_read_from_hole { > + NETFS_READ_HOLE_IGNORE, > + NETFS_READ_HOLE_CLEAR, > + NETFS_READ_HOLE_FAIL, > +}; > + > /* > * Table of operations for access to a cache. This is obtained by > * rreq->ops->begin_cache_operation(). > @@ -208,7 +217,7 @@ struct netfs_cache_ops { > int (*read)(struct netfs_cache_resources *cres, > loff_t start_pos, > struct iov_iter *iter, > - bool seek_data, > + enum netfs_read_from_hole read_hole, > netfs_io_terminated_t term_func, > void *term_func_priv); > > -- Thanks, Jeffle
next prev parent reply other threads:[~2021-12-06 11:42 UTC|newest] Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-11-29 14:22 [PATCH 00/64] fscache, cachefiles: Rewrite David Howells 2021-11-29 14:22 ` [PATCH 01/64] fscache, cachefiles: Disable configuration David Howells 2021-11-29 14:22 ` [PATCH 02/64] cachefiles: Delete the cachefiles driver pending rewrite David Howells 2021-11-29 14:23 ` [PATCH 03/64] fscache: Remove the contents of the fscache driver, " David Howells 2021-11-29 14:23 ` [PATCH 04/64] netfs: Display the netfs inode number in the netfs_read tracepoint David Howells 2021-11-29 14:23 ` [PATCH 05/64] netfs: Pass a flag to ->prepare_write() to say if there's no alloc'd space David Howells 2021-11-29 14:24 ` [PATCH 06/64] fscache: Introduce new driver David Howells 2021-11-29 14:24 ` [PATCH 07/64] fscache: Implement a hash function David Howells 2021-11-29 14:24 ` [PATCH 08/64] fscache: Implement cache registration David Howells 2021-11-29 14:24 ` [PATCH 09/64] fscache: Implement volume registration David Howells 2021-11-29 14:25 ` [PATCH 10/64] fscache: Implement cookie registration David Howells 2021-11-29 14:25 ` [PATCH 11/64] fscache: Implement cache-level access helpers David Howells 2021-11-29 14:25 ` [PATCH 12/64] fscache: Implement volume-level " David Howells 2021-11-29 14:25 ` [PATCH 13/64] fscache: Implement cookie-level " David Howells 2021-11-29 14:26 ` [PATCH 14/64] fscache: Implement functions add/remove a cache David Howells 2021-11-29 14:26 ` [PATCH 15/64] fscache: Provide and use cache methods to lookup/create/free a volume David Howells 2021-11-29 14:26 ` [PATCH 16/64] fscache: Add a function for a cache backend to note an I/O error David Howells 2021-11-29 14:26 ` [PATCH 17/64] fscache: Implement simple cookie state machine David Howells 2021-11-29 14:26 ` [PATCH 18/64] fscache: Implement cookie user counting and resource pinning David Howells 2021-11-29 14:27 ` [PATCH 19/64] fscache: Implement cookie invalidation David Howells 2021-11-29 14:27 ` [PATCH 20/64] fscache: Provide a means to begin an operation David Howells 2021-11-29 14:28 ` [PATCH 21/64] fscache: Count data storage objects in a cache David Howells 2021-11-29 14:28 ` [PATCH 22/64] fscache: Provide read/write stat counters for the cache David Howells 2021-11-29 14:28 ` [PATCH 23/64] fscache: Provide a function to let the netfs update its coherency data David Howells 2021-11-29 14:28 ` [PATCH 24/64] netfs: Pass more information on how to deal with a hole in the cache David Howells 2021-12-06 11:42 ` JeffleXu [this message] 2021-12-09 16:49 ` David Howells 2021-11-29 14:28 ` [PATCH 25/64] fscache: Implement raw I/O interface David Howells 2021-11-29 14:29 ` [PATCH 26/64] fscache: Implement higher-level write " David Howells 2021-11-29 14:29 ` [PATCH 27/64] vfs, fscache: Implement pinning of cache usage for writeback David Howells 2021-11-29 14:29 ` [PATCH 28/64] fscache: Provide a function to note the release of a page David Howells 2021-11-29 14:30 ` [PATCH 29/64] fscache: Provide a function to resize a cookie David Howells 2021-11-29 14:30 ` [PATCH 30/64] cachefiles: Introduce rewritten driver David Howells 2021-11-29 14:30 ` [PATCH 31/64] cachefiles: Define structs David Howells 2021-11-29 14:30 ` [PATCH 32/64] cachefiles: Add some error injection support David Howells 2021-11-29 14:30 ` [PATCH 33/64] cachefiles: Add a couple of tracepoints for logging errors David Howells 2021-11-29 14:31 ` [PATCH 34/64] cachefiles: Add cache error reporting macro David Howells 2021-11-29 14:31 ` [PATCH 35/64] cachefiles: Add security derivation David Howells 2021-11-29 14:31 ` [PATCH 36/64] cachefiles: Register a miscdev and parse commands over it David Howells 2021-11-29 14:31 ` [PATCH 37/64] cachefiles: Provide a function to check how much space there is David Howells 2021-11-29 14:31 ` [PATCH 38/64] vfs, cachefiles: Mark a backing file in use with an inode flag David Howells 2021-11-29 14:31 ` [PATCH 39/64] cachefiles: Implement a function to get/create a directory in the cache David Howells 2021-11-29 14:32 ` [PATCH 40/64] cachefiles: Implement cache registration and withdrawal David Howells 2021-11-29 14:32 ` [PATCH 41/64] cachefiles: Implement volume support David Howells 2021-11-29 14:33 ` [PATCH 42/64] cachefiles: Add tracepoints for calls to the VFS David Howells 2021-11-29 14:33 ` [PATCH 43/64] cachefiles: Implement object lifecycle funcs David Howells 2021-11-29 14:33 ` [PATCH 44/64] cachefiles: Implement key to filename encoding David Howells 2021-12-01 5:46 ` JeffleXu 2021-12-01 8:29 ` David Howells 2021-11-29 14:33 ` [PATCH 45/64] cachefiles: Implement metadata/coherency data storage in xattrs David Howells 2021-11-29 14:33 ` [PATCH 46/64] cachefiles: Mark a backing file in use with an inode flag David Howells 2021-11-29 14:33 ` [PATCH 47/64] cachefiles: Implement culling daemon commands David Howells 2021-11-29 14:34 ` [PATCH 48/64] cachefiles: Implement backing file wrangling David Howells 2021-11-29 14:34 ` [PATCH 49/64] cachefiles: Implement begin and end I/O operation David Howells 2021-11-29 14:34 ` [PATCH 50/64] cachefiles: Implement cookie resize for truncate David Howells 2021-11-29 14:34 ` [PATCH 51/64] cachefiles: Implement the I/O routines David Howells 2021-11-30 16:15 ` Nathan Chancellor 2021-11-30 21:05 ` David Howells 2021-11-29 14:34 ` [PATCH 52/64] cachefiles: Allow cachefiles to actually function David Howells 2021-11-29 14:35 ` [PATCH 53/64] fscache, cachefiles: Display stats of no-space events David Howells 2021-11-29 14:35 ` [PATCH 54/64] fscache, cachefiles: Display stat of culling events David Howells 2021-11-29 14:36 ` [PATCH 55/64] afs: Handle len being extending over page end in write_begin/write_end David Howells 2021-11-29 14:36 ` [PATCH 56/64] afs: Fix afs_write_end() to handle len > page size David Howells 2021-11-29 14:36 ` [PATCH 57/64] afs: Convert afs to use the new fscache API David Howells 2021-11-29 14:37 ` [PATCH 58/64] afs: Copy local writes to the cache when writing to the server David Howells 2021-11-29 14:37 ` [PATCH 59/64] afs: Skip truncation on the server of data we haven't written yet David Howells 2021-11-29 14:37 ` [PATCH 60/64] 9p: Use fscache indexing rewrite and reenable caching David Howells 2021-11-29 14:37 ` [PATCH 61/64] 9p: Copy local writes to the cache when writing to the server David Howells 2021-11-29 14:38 ` [PATCH 62/64] nfs: Convert to new fscache volume/cookie API David Howells 2021-11-29 14:38 ` [PATCH 63/64] cifs: Support fscache indexing rewrite (untested) David Howells 2021-11-29 14:38 ` [PATCH 64/64] fscache: Rewrite documentation David Howells 2021-11-29 18:12 ` [PATCH 00/64] fscache, cachefiles: Rewrite Linus Torvalds 2021-11-29 21:40 ` [PATCH 35/64] cachefiles: Add security derivation David Howells
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