David Howells d6a77668a7 netfs: Downgrade i_rwsem for a buffered write ...

In the I/O locking code borrowed from NFS into netfslib, i_rwsem is held
locked across a buffered write - but this causes a performance regression
in cifs as it excludes buffered reads for the duration (cifs didn't use any
locking for buffered reads).

Mitigate this somewhat by downgrading the i_rwsem to a read lock across the
buffered write.  This at least allows parallel reads to occur whilst
excluding other writes, DIO, truncate and setattr.

Note that this shouldn't be a problem for a buffered write as a read
through an mmap can circumvent i_rwsem anyway.

Also note that we might want to make this change in NFS also.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/1317958.1729096113@warthog.procyon.org.uk
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.com>
cc: Trond Myklebust <trondmy@kernel.org>
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-cifs@vger.kernel.org
cc: linux-nfs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

2024-10-17 15:33:42 +02:00

..

buffered_read.c

netfs: In readahead, put the folio refs as soon extracted

2024-10-07 13:48:22 +02:00

buffered_write.c

netfs, cifs: Fix mtime/ctime update for mmapped writes

2024-09-24 21:57:00 -05:00

direct_read.c

netfs: Speed up buffered reading

2024-09-12 12:20:41 +02:00

direct_write.c

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

2024-07-24 10:15:37 +02:00

fscache_cache.c

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

2024-07-24 10:15:37 +02:00

fscache_cookie.c

fs/netfs/fscache_cookie: add missing "n_accesses" check

2024-08-12 22:03:26 +02:00

fscache_internal.h

netfs, fscache: Combine fscache with netfs

2023-12-24 15:08:46 +00:00

fscache_io.c

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

2024-07-24 10:15:37 +02:00

fscache_main.c

fscache: delete fscache_cookie_lru_timer when fscache exits to avoid UAF

2024-09-01 10:30:25 +02:00

fscache_proc.c

netfs: Fix proc/fs/fscache symlink to point to "netfs" not "../netfs"

2024-01-04 13:15:32 +00:00

fscache_stats.c

netfs: Fix interaction between write-streaming and cachefiles culling

2024-01-05 15:42:25 +00:00

fscache_volume.c

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

2024-07-24 10:15:37 +02:00

internal.h

netfs: Fix write oops in generic/346 (9p) and generic/074 (cifs)

2024-09-26 17:45:20 -05:00

iterator.c

netfs: Speed up buffered reading

2024-09-12 12:20:41 +02:00

Kconfig

netfs: clean up after renaming FSCACHE_DEBUG config

2024-08-12 22:03:26 +02:00

locking.c

netfs: Downgrade i_rwsem for a buffered write

2024-10-17 15:33:42 +02:00

main.c

Merge tag 'vfs-6.12.netfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2024-09-16 12:13:31 +02:00

Makefile

netfs: Speed up buffered reading

2024-09-12 12:20:41 +02:00

misc.c

netfs: Fix a KMSAN uninit-value error in netfs_clear_buffer

2024-10-01 16:02:42 +02:00

objects.c

netfs: Speed up buffered reading

2024-09-12 12:20:41 +02:00

read_collect.c

netfs: In readahead, put the folio refs as soon extracted

2024-10-07 13:48:22 +02:00

read_pgpriv2.c

cachefiles, netfs: Fix write to partial block at EOF

2024-09-12 12:20:41 +02:00

read_retry.c

netfs: Speed up buffered reading

2024-09-12 12:20:41 +02:00

stats.c

netfs: Speed up buffered reading

2024-09-12 12:20:41 +02:00

write_collect.c

netfs: Speed up buffered reading

2024-09-12 12:20:41 +02:00

write_issue.c

netfs: Fix missing wakeup after issuing writes

2024-10-02 16:56:15 +02:00