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From: Nathan Chancellor <nathan@kernel.org>
To: David Howells <dhowells@redhat.com>
Cc: linux-cachefs@redhat.com,
	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,
	llvm@lists.linux.dev
Subject: Re: [PATCH 51/64] cachefiles: Implement the I/O routines
Date: Tue, 30 Nov 2021 09:15:06 -0700	[thread overview]
Message-ID: <YaZOCk9zxApPattb@archlinux-ax161> (raw)
In-Reply-To: <163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk>

On Mon, Nov 29, 2021 at 02:34:39PM +0000, David Howells wrote:
> Implement the I/O routines for cachefiles.  There are two sets of routines
> here: preparation and actual I/O.
> 
> Preparation for read involves looking to see whether there is data present,
> and how much.  Netfslib tells us what it wants us to do and we have the
> option of adjusting shrinking and telling it whether to read from the
> cache, download from the server or simply clear a region.
> 
> Preparation for write involves checking for space and defending against
> possibly running short of space, if necessary punching out a hole in the
> file so that we don't leave old data in the cache if we update the
> coherency information.
> 
> Then there's a read routine and a write routine.  They wait for the cookie
> state to move to something appropriate and then start a potentially
> asynchronous direct I/O operation upon it.
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: linux-cachefs@redhat.com

This patch as commit 0443b01eccbb ("cachefiles: Implement the I/O
routines") in -next causes the following clang warning/error:

fs/cachefiles/io.c:489:6: error: variable 'ret' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
        if (pos == 0)
            ^~~~~~~~
fs/cachefiles/io.c:492:6: note: uninitialized use occurs here
        if (ret < 0) {
            ^~~
fs/cachefiles/io.c:489:2: note: remove the 'if' if its condition is always true
        if (pos == 0)
        ^~~~~~~~~~~~~
fs/cachefiles/io.c:440:9: note: initialize the variable 'ret' to silence this warning
        int ret;
               ^
                = 0
1 error generated.

It is the same one that has been reported two other times over the past
two months:

https://lore.kernel.org/r/202110150048.HPNa2Mn7-lkp@intel.com/
https://lore.kernel.org/r/202111070451.bsfAyznx-lkp@intel.com/

Should ret just be initialized to zero or does it need to be set to
something else if pos is not equal to zero at the end?

Cheers,
Nathan

  reply	other threads:[~2021-11-30 16:15 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
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 [this message]
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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