kernel.git/fs/netfs/fscache_volume.c, branch linux-rolling-stable

netfs/fscache: Add a memory barrier for FSCACHE_VOLUME_CREATING

2024-12-05T12:52:47Z

[ Upstream commit 22f9400a6f3560629478e0a64247b8fcc811a24d ] In fscache_create_volume(), there is a missing memory barrier between the bit-clearing operation and the wake-up operation. This may cause a situation where, after a wake-up, the bit-clearing operation hasn't been detected yet, leading to an indefinite wait. The triggering process is as follows: [cookie1] [cookie2] [volume_work] fscache_perform_lookup fscache_create_volume fscache_perform_lookup fscache_create_volume fscache_create_volume_work cachefiles_acquire_volume clear_and_wake_up_bit test_and_set_bit test_and_set_bit goto maybe_wait goto no_wait In the above process, cookie1 and cookie2 has the same volume. When cookie1 enters the -no_wait- process, it will clear the bit and wake up the waiting process. If a barrier is missing, it may cause cookie2 to remain in the -wait- process indefinitely. In commit 3288666c7256 ("fscache: Use clear_and_wake_up_bit() in fscache_create_volume_work()"), barriers were added to similar operations in fscache_create_volume_work(), but fscache_create_volume() was missed. By combining the clear and wake operations into clear_and_wake_up_bit() to fix this issue. Fixes: bfa22da3ed65 ("fscache: Provide and use cache methods to lookup/create/free a volume") Signed-off-by: Zizhi Wo Link: https://lore.kernel.org/r/20241107110649.3980193-6-wozizhi@huawei.com Acked-by: David Howells Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin

netfs: Revert "netfs: Switch debug logging to pr_debug()"

2024-07-24T08:15:37Z

Revert commit 163eae0fb0d4c610c59a8de38040f8e12f89fd43 to get back the original operation of the debugging macros. Signed-off-by: David Howells Link: https://lore.kernel.org/r/20240608151352.22860-2-ukleinek@kernel.org Link: https://lore.kernel.org/r/1410685.1721333252@warthog.procyon.org.uk cc: Uwe Kleine-König cc: Christian Brauner cc: Jeff Layton cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner

netfs, fscache: export fscache_put_volume() and add fscache_try_get_volume()

2024-07-03T08:36:14Z

Export fscache_put_volume() and add fscache_try_get_volume() helper function to allow cachefiles to get/put fscache_volume via linux/fscache-cache.h. Signed-off-by: Baokun Li Link: https://lore.kernel.org/r/20240628062930.2467993-2-libaokun@huaweicloud.com Signed-off-by: Christian Brauner

netfs: Switch debug logging to pr_debug()

2024-06-12T12:25:41Z

Instead of inventing a custom way to conditionally enable debugging, just make use of pr_debug(), which also has dynamic debugging facilities and is more likely known to someone who hunts a problem in the netfs code. Also drop the module parameter netfs_debug which didn't have any effect without further source changes. (The variable netfs_debug was only used in #ifdef blocks for cpp vars that don't exist; Note that CONFIG_NETFS_DEBUG isn't settable via kconfig, a variable with that name never existed in the mainline and is probably just taken over (and renamed) from similar custom debug logging implementations.) Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20240608151352.22860-2-ukleinek@kernel.org Signed-off-by: Christian Brauner

netfs, fscache: Move fs/fscache/* into fs/netfs/

2023-12-24T11:36:00Z

There's a problem with dependencies between netfslib and fscache as each wants to access some functions of the other. Deal with this by moving fs/fscache/* into fs/netfs/ and renaming those files to begin with "fscache-". For the moment, the moved files are changed as little as possible and an fscache module is still built. A subsequent patch will integrate them. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: Christian Brauner cc: linux-fsdevel@vger.kernel.org cc: linux-cachefs@redhat.com