From cac45b062c67f86dc1d91d675128838773523243 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 3 Oct 2013 13:16:50 -0400 Subject: [PATCH] fat: rcu-delay unloading nls and freeing sbi makes ->d_hash() and ->d_compare() safety in RCU mode independent from vfsmount_lock. Signed-off-by: Al Viro --- fs/fat/fat.h | 1 + fs/fat/inode.c | 19 +++++++++++-------- 2 files changed, 12 insertions(+), 8 deletions(-) diff --git a/fs/fat/fat.h b/fs/fat/fat.h index 4241e6f39e8..7c31f4bc74a 100644 --- a/fs/fat/fat.h +++ b/fs/fat/fat.h @@ -102,6 +102,7 @@ struct msdos_sb_info { struct hlist_head dir_hashtable[FAT_HASH_SIZE]; unsigned int dirty; /* fs state before mount */ + struct rcu_head rcu; }; #define FAT_CACHE_VALID 0 /* special case for valid cache */ diff --git a/fs/fat/inode.c b/fs/fat/inode.c index 0062da21dd8..854b578f669 100644 --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -548,6 +548,16 @@ static void fat_set_state(struct super_block *sb, brelse(bh); } +static void delayed_free(struct rcu_head *p) +{ + struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu); + unload_nls(sbi->nls_disk); + unload_nls(sbi->nls_io); + if (sbi->options.iocharset != fat_default_iocharset) + kfree(sbi->options.iocharset); + kfree(sbi); +} + static void fat_put_super(struct super_block *sb) { struct msdos_sb_info *sbi = MSDOS_SB(sb); @@ -557,14 +567,7 @@ static void fat_put_super(struct super_block *sb) iput(sbi->fsinfo_inode); iput(sbi->fat_inode); - unload_nls(sbi->nls_disk); - unload_nls(sbi->nls_io); - - if (sbi->options.iocharset != fat_default_iocharset) - kfree(sbi->options.iocharset); - - sb->s_fs_info = NULL; - kfree(sbi); + call_rcu(&sbi->rcu, delayed_free); } static struct kmem_cache *fat_inode_cachep; -- 2.43.2