diff options
| author | Eric Biggers <ebiggers@google.com> | 2019-04-10 22:21:15 +0200 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2019-04-17 18:43:29 +0200 |
| commit | 2c58d548f5706d085c4b009f6abb945220460632 (patch) | |
| tree | b263f432d3ad778b6970ebbb842bd0a577e88cdc /fs/ext4 | |
| parent | vfs: use READ_ONCE() to access ->i_link (diff) | |
| download | linux-2c58d548f5706d085c4b009f6abb945220460632.tar.xz linux-2c58d548f5706d085c4b009f6abb945220460632.zip | |
fscrypt: cache decrypted symlink target in ->i_link
Path lookups that traverse encrypted symlink(s) are very slow because
each encrypted symlink needs to be decrypted each time it's followed.
This also involves dropping out of rcu-walk mode.
Make encrypted symlinks faster by caching the decrypted symlink target
in ->i_link. The first call to fscrypt_get_symlink() sets it. Then,
the existing VFS path lookup code uses the non-NULL ->i_link to take the
fast path where ->get_link() isn't called, and lookups in rcu-walk mode
remain in rcu-walk mode.
Also set ->i_link immediately when a new encrypted symlink is created.
To safely free the symlink target after an RCU grace period has elapsed,
introduce a new function fscrypt_free_inode(), and make the relevant
filesystems call it just before actually freeing the inode.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/super.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 6ed4eb81e674..5b92054bf8ea 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1110,6 +1110,9 @@ static int ext4_drop_inode(struct inode *inode) static void ext4_i_callback(struct rcu_head *head) { struct inode *inode = container_of(head, struct inode, i_rcu); + + fscrypt_free_inode(inode); + kmem_cache_free(ext4_inode_cachep, EXT4_I(inode)); } |