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| author | Shaohua Li <shli@fb.com> | 2017-07-12 11:49:48 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2017-07-29 09:00:03 -0600 |
| commit | ba16b2846a8c6965d0d35be3968bc10f6277812d (patch) | |
| tree | 332d1796149f4e5eb713fcf95b44cc6177965158 /fs/kernfs/mount.c | |
| parent | 4a3ef68acacf31570066e69593de5cc49cc91638 (diff) | |
| download | lwn-ba16b2846a8c6965d0d35be3968bc10f6277812d.tar.gz lwn-ba16b2846a8c6965d0d35be3968bc10f6277812d.zip | |
kernfs: add an API to get kernfs node from inode number
Add an API to get kernfs node from inode number. We will need this to
implement exportfs operations.
This API will be used in blktrace too later, so it should be as fast as
possible. To make the API lock free, kernfs node is freed in RCU
context. And we depend on kernfs_node count/ino number to filter out
stale kernfs nodes.
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/kernfs/mount.c')
| -rw-r--r-- | fs/kernfs/mount.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c index d5b149a45be1..69c48bec8a63 100644 --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -330,7 +330,16 @@ struct super_block *kernfs_pin_sb(struct kernfs_root *root, const void *ns) void __init kernfs_init(void) { + + /* + * the slab is freed in RCU context, so kernfs_find_and_get_node_by_ino + * can access the slab lock free. This could introduce stale nodes, + * please see how kernfs_find_and_get_node_by_ino filters out stale + * nodes. + */ kernfs_node_cache = kmem_cache_create("kernfs_node_cache", sizeof(struct kernfs_node), - 0, SLAB_PANIC, NULL); + 0, + SLAB_PANIC | SLAB_TYPESAFE_BY_RCU, + NULL); } |