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Commit cac45b06 authored by Al Viro's avatar Al Viro
Browse files

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: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 2e32cf5e

fs/fat/fat.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */

fs/fat/inode.c

+11 −8
Original line number Diff line number Diff line
@@ -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;