From: Matthew Wilcox <willy@infradead.org>
To: David Howells <dhowells@redhat.com>
Cc: linux-cachefs@redhat.com,
Kent Overstreet <kent.overstreet@gmail.com>,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
Trond Myklebust <trondmy@hammerspace.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Steve French <sfrench@samba.org>,
Dominique Martinet <asmadeus@codewreck.org>,
Jeff Layton <jlayton@redhat.com>,
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-kernel@vger.kernel.org
Subject: Re: [PATCH 01/67] mm: Stop filemap_read() from grabbing a superfluous page
Date: Tue, 19 Oct 2021 21:04:51 +0100 [thread overview]
Message-ID: <YW8k4wEpt3Ehz5Hf@casper.infradead.org> (raw)
In-Reply-To: <2971214.1634669295@warthog.procyon.org.uk>
On Tue, Oct 19, 2021 at 07:48:15PM +0100, David Howells wrote:
> Matthew Wilcox <willy@infradead.org> wrote:
>
> > > + isize = i_size_read(inode);
> > > + if (unlikely(iocb->ki_pos >= isize))
> > > + goto put_pages;
> > > +
> >
> > Is there a good reason to assign to isize here? I'd rather not,
> > because it complicates analysis, and a later change might look at
> > the isize read here, not realising it was a racy use. So I'd
> > rather see:
>
> If we don't set isize, the loop will never end. Actually, maybe we can just
> break out at that point rather than going to put_pages.
Umm, yes, of course. Sorry.
It makes more sense to just break because we haven't got any pages,
so putting pages that we haven't got seems unnecessary.
>
next prev parent reply other threads:[~2021-10-19 20:08 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-18 14:50 [PATCH 00/67] fscache: Rewrite index API and management system David Howells
2021-10-18 14:50 ` [PATCH 01/67] mm: Stop filemap_read() from grabbing a superfluous page David Howells
2021-10-19 17:13 ` Jeff Layton
2021-10-19 18:28 ` Matthew Wilcox
2021-10-19 18:48 ` David Howells
2021-10-19 20:04 ` Matthew Wilcox [this message]
2021-10-18 14:50 ` [PATCH 02/67] vfs: Provide S_KERNEL_FILE inode flag David Howells
2021-10-19 18:10 ` Jeff Layton
2021-10-19 19:02 ` David Howells
2021-10-18 14:51 ` [PATCH 03/67] vfs, fscache: Force ->write_inode() to occur if cookie pinned for writeback David Howells
2021-10-19 17:22 ` Jeff Layton
2021-10-20 9:49 ` David Howells
2021-10-18 14:51 ` [PATCH 04/67] afs: Handle len being extending over page end in write_begin/write_end David Howells
2021-10-18 14:51 ` [PATCH 05/67] afs: Fix afs_write_end() to handle len > page size David Howells
2021-10-18 14:51 ` [PATCH 06/67] nfs, cifs, ceph, 9p: Disable use of fscache prior to its rewrite David Howells
2021-10-19 17:50 ` Jeff Layton
2021-10-20 10:57 ` David Howells
2021-10-18 14:52 ` [PATCH 07/67] fscache: Remove the netfs data from the cookie David Howells
2021-10-19 18:05 ` Jeff Layton
2021-10-18 14:52 ` [PATCH 08/67] fscache: Remove struct fscache_cookie_def David Howells
2021-10-18 14:52 ` [PATCH 09/67] fscache: Remove store_limit* from struct fscache_object David Howells
2021-10-18 14:53 ` [PATCH 10/67] fscache: Remove fscache_check_consistency() David Howells
2021-10-18 14:53 ` [PATCH 11/67] fscache: Remove fscache_attr_changed() David Howells
2021-10-18 14:54 ` [PATCH 12/67] fscache: Remove obsolete stats David Howells
2021-10-18 14:54 ` [PATCH 13/67] fscache: Remove old I/O tracepoints David Howells
2021-10-18 14:54 ` [PATCH 14/67] fscache: Temporarily disable fscache_invalidate() David Howells
2021-10-18 14:54 ` [PATCH 15/67] fscache: Disable fscache_begin_operation() David Howells
2021-10-18 14:54 ` [PATCH 16/67] fscache: Remove the I/O operation manager David Howells
2021-10-18 14:55 ` [PATCH 17/67] fscache: Rename fscache_cookie_{get,put,see}() David Howells
2021-10-18 14:55 ` [PATCH 18/67] cachefiles: Remove tree of active files and use S_CACHE_FILE inode flag David Howells
2021-10-18 14:55 ` [PATCH 19/67] cachefiles: Don't set an xattr on the root of the cache David Howells
2021-10-18 14:55 ` [PATCH 20/67] cachefiles: Remove some redundant checks on unsigned values David Howells
2021-10-18 14:56 ` [PATCH 21/67] cachefiles: Prevent inode from going away when burying a dentry David Howells
2021-10-18 14:56 ` [PATCH 22/67] cachefiles: Simplify the pathwalk and save the filename for an object David Howells
2021-10-18 14:56 ` [PATCH 23/67] cachefiles: trace: Improve the lookup tracepoint David Howells
2021-10-18 14:56 ` [PATCH 24/67] cachefiles: Remove separate backer dentry from cachefiles_object David Howells
2021-10-18 14:57 ` [PATCH 25/67] cachefiles: Fold fscache_object into cachefiles_object David Howells
2021-10-18 14:57 ` [PATCH 26/67] cachefiles: Change to storing file* rather than dentry* David Howells
2021-10-18 14:57 ` [PATCH 27/67] cachefiles: trace: Log coherency checks David Howells
2021-10-18 14:57 ` [PATCH 28/67] cachefiles: Trace truncations David Howells
2021-10-18 14:57 ` [PATCH 29/67] cachefiles: Trace read and write operations David Howells
2021-10-18 14:58 ` [PATCH 30/67] cachefiles: Round the cachefile size up to DIO block size David Howells
2021-10-18 14:58 ` [PATCH 31/67] cachefiles: Don't use XATTR_ flags with vfs_setxattr() David Howells
2021-10-18 14:59 ` [PATCH 33/67] cachefiles: Trace decisions in cachefiles_prepare_read() David Howells
2021-10-18 14:59 ` [PATCH 34/67] cachefiles: Make cachefiles_write_prepare() check for space David Howells
2021-10-18 14:59 ` [PATCH 35/67] fscache: Automatically close a file that's been unused for a while David Howells
2021-10-18 15:00 ` [PATCH 36/67] fscache: Add stats for the cookie commit LRU David Howells
2021-10-18 15:00 ` [PATCH 37/67] fscache: Move fscache_update_cookie() complete inline David Howells
2021-10-18 15:00 ` [PATCH 38/67] fscache: Remove more obsolete stats David Howells
2021-10-18 15:00 ` [PATCH 39/67] fscache: Note the object size during invalidation David Howells
2021-10-18 15:00 ` [PATCH 40/67] vfs, fscache: Force ->write_inode() to occur if cookie pinned for writeback David Howells
2021-10-18 15:00 ` [PATCH 41/67] afs: Render cache cookie key as big endian David Howells
2021-10-18 15:01 ` [PATCH 42/67] cachefiles: Use tmpfile/link David Howells
2021-10-18 15:01 ` [PATCH 43/67] fscache: Rewrite invalidation David Howells
2021-10-18 15:01 ` [PATCH 44/67] fscache: disable cookie when doing an invalidation for DIO write David Howells
2021-10-18 15:01 ` [PATCH 45/67] cachefiles: Simplify the file lookup/creation/check code David Howells
2021-10-18 15:01 ` [PATCH 46/67] fscache: Provide resize operation David Howells
2021-10-18 15:02 ` [PATCH 47/67] cachefiles: Put more information in the xattr attached to the cache file David Howells
2021-10-18 15:02 ` [PATCH 48/67] fscache: Implement "will_modify" parameter on fscache_use_cookie() David Howells
2021-10-18 15:02 ` [PATCH 49/67] fscache: Add support for writing to the cache David Howells
2021-10-18 15:03 ` [PATCH 50/67] fscache: Make fscache_clear_page_bits() conditional on cookie David Howells
2021-10-18 15:03 ` [PATCH 51/67] fscache: Make fscache_write_to_cache() " David Howells
2021-10-18 15:03 ` [PATCH 52/67] afs: Copy local writes to the cache when writing to the server David Howells
2021-10-18 15:04 ` [PATCH 53/67] afs: Invoke fscache_resize_cookie() when handling ATTR_SIZE for setattr David Howells
2021-10-18 15:04 ` [PATCH 54/67] afs: Add O_DIRECT read support David Howells
2021-10-18 15:05 ` [PATCH 55/67] afs: Skip truncation on the server of data we haven't written yet David Howells
2021-10-18 15:05 ` [PATCH 56/67] afs: Make afs_write_begin() return the THP subpage David Howells
2021-10-18 15:05 ` [PATCH 57/67] cachefiles, afs: Drive FSCACHE_COOKIE_NO_DATA_TO_READ David Howells
2021-10-18 15:06 ` [PATCH 58/67] NFS: Convert fscache_acquire_cookie and fscache_relinquish_cookie David Howells
2021-10-18 15:06 ` [PATCH 59/67] NFS: Convert fscache_enable_cookie and fscache_disable_cookie David Howells
2021-10-18 15:07 ` [PATCH 60/67] NFS: Convert fscache invalidation and update aux_data and i_size David Howells
2021-10-18 15:08 ` [PATCH 61/67] nfs: Convert to new fscache volume/cookie API David Howells
2021-10-18 15:08 ` [PATCH 62/67] 9p: Use fscache indexing rewrite and reenable caching David Howells
2021-10-18 15:08 ` [PATCH 63/67] 9p: Copy local writes to the cache when writing to the server David Howells
2021-10-18 15:08 ` [PATCH 64/67] netfs: Display the netfs inode number in the netfs_read tracepoint David Howells
2021-10-18 15:08 ` [PATCH 65/67] cachefiles: Add tracepoints to log errors from ops on the backing fs David Howells
2021-10-18 15:08 ` [PATCH 66/67] cachefiles: Add error injection support David Howells
2021-10-18 15:09 ` [PATCH 67/67] cifs: Support fscache indexing rewrite (untested) David Howells
2021-10-19 13:29 ` [Linux-cachefs] [PATCH 00/67] fscache: Rewrite index API and management system Marc Dionne
2021-10-19 18:08 ` Jeff Layton
2021-10-19 19:00 ` David Howells
2021-10-21 22:20 ` Omar Sandoval
2021-10-21 23:15 ` Steve French
2021-10-21 23:23 ` Dominique Martinet
2021-10-21 23:43 ` Jeff Layton
2021-10-22 18:52 ` David Howells
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