diff options
author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-03-11 17:10:07 +1100 |
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committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-03-11 17:10:07 +1100 |
commit | e14eee56c2280953c6e3d24d5dce42bd90836b81 (patch) | |
tree | 21ab792d9ad6fbbab460058f352a0158f995644e /fs/super.c | |
parent | d6ee6f7e4c74d9a0fed7544f4d389bde004651d3 (diff) | |
parent | 99adcd9d67aaf04e28f5ae96df280f236bde4b66 (diff) |
Merge commit 'origin/master' into next
Diffstat (limited to 'fs/super.c')
-rw-r--r-- | fs/super.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/fs/super.c b/fs/super.c index 61dce001dd57..8349ed6b1412 100644 --- a/fs/super.c +++ b/fs/super.c @@ -82,7 +82,22 @@ static struct super_block *alloc_super(struct file_system_type *type) * lock ordering than usbfs: */ lockdep_set_class(&s->s_lock, &type->s_lock_key); - down_write(&s->s_umount); + /* + * sget() can have s_umount recursion. + * + * When it cannot find a suitable sb, it allocates a new + * one (this one), and tries again to find a suitable old + * one. + * + * In case that succeeds, it will acquire the s_umount + * lock of the old one. Since these are clearly distrinct + * locks, and this object isn't exposed yet, there's no + * risk of deadlocks. + * + * Annotate this by putting this lock in a different + * subclass. + */ + down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING); s->s_count = S_BIAS; atomic_set(&s->s_active, 1); mutex_init(&s->s_vfs_rename_mutex); |