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authorEric Biggers <ebiggers@google.com>2019-04-10 13:21:15 -0700
committerTheodore Ts'o <tytso@mit.edu>2019-04-17 12:43:29 -0400
commit2c58d548f5706d085c4b009f6abb945220460632 (patch)
treeb263f432d3ad778b6970ebbb842bd0a577e88cdc /fs/ext4/super.c
parent4c4f7c19b3c721aed418bc97907b411608c5c6a0 (diff)
downloadlinux-2c58d548f5706d085c4b009f6abb945220460632.tar.bz2
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/super.c')
-rw-r--r--fs/ext4/super.c3
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));
}