diff options
| author | Jan Kara <jack@suse.cz> | 2022-07-12 12:54:20 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-01-14 10:16:43 +0100 |
| commit | fb59d12ae7f9f7584e6702d4c2e26ce10210af3d (patch) | |
| tree | 81abcae2c9004fab918d266e3e9a09533cbb7ad2 /fs | |
| parent | 4c363e2961cd80389c5581e5679332aafb9cbfc0 (diff) | |
mbcache: don't reclaim used entries
[ Upstream commit 58318914186c157477b978b1739dfe2f1b9dc0fe ]
Do not reclaim entries that are currently used by somebody from a
shrinker. Firstly, these entries are likely useful. Secondly, we will
need to keep such entries to protect pending increment of xattr block
refcount.
CC: stable@vger.kernel.org
Fixes: 82939d7999df ("ext4: convert to mbcache2")
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220712105436.32204-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Stable-dep-of: a44e84a9b776 ("ext4: fix deadlock due to mbcache entry corruption")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/mbcache.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/fs/mbcache.c b/fs/mbcache.c index 97c54d3a2227..cfc28129fb6f 100644 --- a/fs/mbcache.c +++ b/fs/mbcache.c @@ -288,7 +288,7 @@ static unsigned long mb_cache_shrink(struct mb_cache *cache, while (nr_to_scan-- && !list_empty(&cache->c_list)) { entry = list_first_entry(&cache->c_list, struct mb_cache_entry, e_list); - if (entry->e_referenced) { + if (entry->e_referenced || atomic_read(&entry->e_refcnt) > 2) { entry->e_referenced = 0; list_move_tail(&entry->e_list, &cache->c_list); continue; @@ -302,6 +302,14 @@ static unsigned long mb_cache_shrink(struct mb_cache *cache, spin_unlock(&cache->c_list_lock); head = mb_cache_entry_head(cache, entry->e_key); hlist_bl_lock(head); + /* Now a reliable check if the entry didn't get used... */ + if (atomic_read(&entry->e_refcnt) > 2) { + hlist_bl_unlock(head); + spin_lock(&cache->c_list_lock); + list_add_tail(&entry->e_list, &cache->c_list); + cache->c_entry_count++; + continue; + } if (!hlist_bl_unhashed(&entry->e_hash_list)) { hlist_bl_del_init(&entry->e_hash_list); atomic_dec(&entry->e_refcnt); |