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authorKent Overstreet <kmo@daterainc.com>2013-12-16 17:12:09 -0500
committerKent Overstreet <kmo@daterainc.com>2013-12-16 17:22:58 -0500
commit6d3d1a9c542b19dff1c7d7c8354d0869e4655287 (patch)
tree92afafc81797f8ad6ed2548e25f9818f7f67a8d4 /drivers/md/bcache/movinggc.c
parentbf0a628a95dba7f983b6047cea695fb066fb2512 (diff)
bcache: bugfix for race between moving_gc and bucket_invalidate
There is a possibility for a bucket to be invalidated by the allocator while moving_gc was copying it's contents to another bucket, if the bucket only held cached data. To prevent this moving checks for a stale ptr (to an invalidated bucket), before and after reads. It it finds one, it simply ignores moving that data. This only affects bcache if the moving_gc was turned on, note that it's off by default. Signed-off-by: Nicholas Swenson <nks@daterainc.com> Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Diffstat (limited to 'drivers/md/bcache/movinggc.c')
-rw-r--r--drivers/md/bcache/movinggc.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/md/bcache/movinggc.c b/drivers/md/bcache/movinggc.c
index 30f347d4e609..f2f0998c4a91 100644
--- a/drivers/md/bcache/movinggc.c
+++ b/drivers/md/bcache/movinggc.c
@@ -64,11 +64,16 @@ static void write_moving_finish(struct closure *cl)
64 64
65static void read_moving_endio(struct bio *bio, int error) 65static void read_moving_endio(struct bio *bio, int error)
66{ 66{
67 struct bbio *b = container_of(bio, struct bbio, bio);
67 struct moving_io *io = container_of(bio->bi_private, 68 struct moving_io *io = container_of(bio->bi_private,
68 struct moving_io, cl); 69 struct moving_io, cl);
69 70
70 if (error) 71 if (error)
71 io->op.error = error; 72 io->op.error = error;
73 else if (!KEY_DIRTY(&b->key) &&
74 ptr_stale(io->op.c, &b->key, 0)) {
75 io->op.error = -EINTR;
76 }
72 77
73 bch_bbio_endio(io->op.c, bio, error, "reading data to move"); 78 bch_bbio_endio(io->op.c, bio, error, "reading data to move");
74} 79}
@@ -140,6 +145,11 @@ static void read_moving(struct cache_set *c)
140 if (!w) 145 if (!w)
141 break; 146 break;
142 147
148 if (ptr_stale(c, &w->key, 0)) {
149 bch_keybuf_del(&c->moving_gc_keys, w);
150 continue;
151 }
152
143 io = kzalloc(sizeof(struct moving_io) + sizeof(struct bio_vec) 153 io = kzalloc(sizeof(struct moving_io) + sizeof(struct bio_vec)
144 * DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS), 154 * DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS),
145 GFP_KERNEL); 155 GFP_KERNEL);