user/sven/linux.git/fs/mbcache.c, branch v4.9.329

mbcache: initialize entry->e_referenced in mb_cache_entry_create()

2018-02-22T14:43:48Z

commit 3876bbe27d04b848750d5310a37d6b76b593f648 upstream. KMSAN reported use of uninitialized |entry->e_referenced| in a condition in mb_cache_shrink(): ================================================================== BUG: KMSAN: use of uninitialized memory in mb_cache_shrink+0x3b4/0xc50 fs/mbcache.c:287 CPU: 2 PID: 816 Comm: kswapd1 Not tainted 4.11.0-rc5+ #2877 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x172/0x1c0 lib/dump_stack.c:52 kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:927 __msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:469 mb_cache_shrink+0x3b4/0xc50 fs/mbcache.c:287 mb_cache_scan+0x67/0x80 fs/mbcache.c:321 do_shrink_slab mm/vmscan.c:397 [inline] shrink_slab+0xc3d/0x12d0 mm/vmscan.c:500 shrink_node+0x208f/0x2fd0 mm/vmscan.c:2603 kswapd_shrink_node mm/vmscan.c:3172 [inline] balance_pgdat mm/vmscan.c:3289 [inline] kswapd+0x160f/0x2850 mm/vmscan.c:3478 kthread+0x46c/0x5f0 kernel/kthread.c:230 ret_from_fork+0x29/0x40 arch/x86/entry/entry_64.S:430 chained origin: save_stack_trace+0x37/0x40 arch/x86/kernel/stacktrace.c:59 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:302 [inline] kmsan_save_stack mm/kmsan/kmsan.c:317 [inline] kmsan_internal_chain_origin+0x12a/0x1f0 mm/kmsan/kmsan.c:547 __msan_store_shadow_origin_1+0xac/0x110 mm/kmsan/kmsan_instr.c:257 mb_cache_entry_create+0x3b3/0xc60 fs/mbcache.c:95 ext4_xattr_cache_insert fs/ext4/xattr.c:1647 [inline] ext4_xattr_block_set+0x4c82/0x5530 fs/ext4/xattr.c:1022 ext4_xattr_set_handle+0x1332/0x20a0 fs/ext4/xattr.c:1252 ext4_xattr_set+0x4d2/0x680 fs/ext4/xattr.c:1306 ext4_xattr_trusted_set+0x8d/0xa0 fs/ext4/xattr_trusted.c:36 __vfs_setxattr+0x703/0x790 fs/xattr.c:149 __vfs_setxattr_noperm+0x27a/0x6f0 fs/xattr.c:180 vfs_setxattr fs/xattr.c:223 [inline] setxattr+0x6ae/0x790 fs/xattr.c:449 path_setxattr+0x1eb/0x380 fs/xattr.c:468 SYSC_lsetxattr+0x8d/0xb0 fs/xattr.c:490 SyS_lsetxattr+0x77/0xa0 fs/xattr.c:486 entry_SYSCALL_64_fastpath+0x13/0x94 origin: save_stack_trace+0x37/0x40 arch/x86/kernel/stacktrace.c:59 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:302 [inline] kmsan_internal_poison_shadow+0xb1/0x1a0 mm/kmsan/kmsan.c:198 kmsan_kmalloc+0x7f/0xe0 mm/kmsan/kmsan.c:337 kmem_cache_alloc+0x1c2/0x1e0 mm/slub.c:2766 mb_cache_entry_create+0x283/0xc60 fs/mbcache.c:86 ext4_xattr_cache_insert fs/ext4/xattr.c:1647 [inline] ext4_xattr_block_set+0x4c82/0x5530 fs/ext4/xattr.c:1022 ext4_xattr_set_handle+0x1332/0x20a0 fs/ext4/xattr.c:1252 ext4_xattr_set+0x4d2/0x680 fs/ext4/xattr.c:1306 ext4_xattr_trusted_set+0x8d/0xa0 fs/ext4/xattr_trusted.c:36 __vfs_setxattr+0x703/0x790 fs/xattr.c:149 __vfs_setxattr_noperm+0x27a/0x6f0 fs/xattr.c:180 vfs_setxattr fs/xattr.c:223 [inline] setxattr+0x6ae/0x790 fs/xattr.c:449 path_setxattr+0x1eb/0x380 fs/xattr.c:468 SYSC_lsetxattr+0x8d/0xb0 fs/xattr.c:490 SyS_lsetxattr+0x77/0xa0 fs/xattr.c:486 entry_SYSCALL_64_fastpath+0x13/0x94 ================================================================== Signed-off-by: Alexander Potapenko Signed-off-by: Eric Biggers Cc: stable@vger.kernel.org # v4.6 Signed-off-by: Greg Kroah-Hartman

mbcache: fix to detect failure of register_shrinker

2016-08-31T15:44:36Z

register_shrinker in mb_cache_create may fail due to no memory. This patch fixes to do the check of return value of register_shrinker and handle the error case, otherwise mb_cache_create may return with no error, but losing the inner shrinker. Signed-off-by: Chao Yu Reviewed-by: Jan Kara Signed-off-by: Theodore Ts'o

mbcache: add reusable flag to cache entries

2016-02-23T03:44:04Z

To reduce amount of damage caused by single bad block, we limit number of inodes sharing an xattr block to 1024. Thus there can be more xattr blocks with the same contents when there are lots of files with the same extended attributes. These xattr blocks naturally result in hash collisions and can form long hash chains and we unnecessarily check each such block only to find out we cannot use it because it is already shared by too many inodes. Add a reusable flag to cache entries which is cleared when a cache entry has reached its maximum refcount. Cache entries which are not marked reusable are skipped by mb_cache_entry_find_{first,next}. This significantly speeds up mbcache when there are many same xattr blocks. For example for xattr-bench with 5 values and each process handling 20000 files, the run for 64 processes is 25x faster with this patch. Even for 8 processes the speedup is almost 3x. We have also verified that for situations where there is only one xattr block of each kind, the patch doesn't have a measurable cost. [JK: Remove handling of setting the same value since it is not needed anymore, check for races in e_reusable setting, improve changelog, add measurements] Signed-off-by: Andreas Gruenbacher Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o

mbcache: get rid of _e_hash_list_head

2016-02-23T03:42:05Z

Get rid of field _e_hash_list_head in cache entries and add bit field e_referenced instead. Signed-off-by: Andreas Gruenbacher Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o

mbcache2: rename to mbcache

2016-02-23T03:35:22Z

Since old mbcache code is gone, let's rename new code to mbcache since number 2 is now meaningless. This is just a mechanical replacement. Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o

mbcache: remove mbcache

2016-02-22T17:21:14Z

Both ext2 and ext4 are now converted to mbcache2. Remove the old mbcache code. Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o

fs/mbcache: replace __builtin_log2() with ilog2()

2014-06-26T02:08:29Z

Fix compiler error with some gcc version(s) that do not support __builtin_log2() by replacing __builtin_log2() with ilog2(). Signed-off-by: T. Makphaibulchoke Signed-off-by: Theodore Ts'o Reviewed-by: Maciej W. Rozycki

ext4: each filesystem creates and uses its own mb_cache

2014-03-18T23:24:49Z

This patch adds new interfaces to create and destory cache, ext4_xattr_create_cache() and ext4_xattr_destroy_cache(), and remove the cache creation and destory calls from ex4_init_xattr() and ext4_exitxattr() in fs/ext4/xattr.c. fs/ext4/super.c has been changed so that when a filesystem is mounted a cache is allocated and attched to its ext4_sb_info structure. fs/mbcache.c has been changed so that only one slab allocator is allocated and used by all mbcache structures. Signed-off-by: T. Makphaibulchoke

fs/mbcache.c: doucple the locking of local from global data

2014-03-18T23:23:20Z

The patch increases the parallelism of mbcache by using the built-in lock in the hlist_bl_node to protect the mb_cache's local block and index hash chains. The global data mb_cache_lru_list and mb_cache_list continue to be protected by the global mb_cache_spinlock. New block group spinlock, mb_cache_bg_lock is also added to serialize accesses to mb_cache_entry's local data. A new member e_refcnt is added to the mb_cache_entry structure to help preventing an mb_cache_entry from being deallocated by a free while it is being referenced by either mb_cache_entry_get() or mb_cache_entry_find(). Signed-off-by: T. Makphaibulchoke Signed-off-by: "Theodore Ts'o"

fs/mbcache.c: change block and index hash chain to hlist_bl_node

2014-03-18T23:19:41Z

This patch changes each mb_cache's both block and index hash chains to use a hlist_bl_node, which contains a built-in lock. This is the first step in decoupling of locks serializing accesses to mb_cache global data and each mb_cache_entry local data. Signed-off-by: T. Makphaibulchoke Signed-off-by: "Theodore Ts'o"