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authorFabian Frederick <fabf@skynet.be>2015-02-17 13:45:31 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-17 14:34:51 -0800
commited3ad79f87f31beed64778af0b29aff3074f700e (patch)
tree6bf46242e32c441b0e16ff95295507c0323ee833
parentfs/ufs/super.c: remove unnecessary casting (diff)
downloadlinux-dev-ed3ad79f87f31beed64778af0b29aff3074f700e.tar.xz
linux-dev-ed3ad79f87f31beed64778af0b29aff3074f700e.zip
fs/ufs/super.c: fix potential race condition
Let locking subsystem decide on mutex management. As reported by Andrew Morton this patch fixes a bug: : lock_ufs() is assuming that on non-preempt uniprocessor, the calling : code will run atomically up to the matching unlock_ufs(). : : But that isn't true. The very first site I looked at (ufs_frag_map) : does sb_bread() under lock_ufs(). And sb_bread() will call schedule(), : very commonly. : : The ->mutex_owner stuff is a bit hacky but should work OK. Signed-off-by: Fabian Frederick <fabf@skynet.be> Cc: Evgeniy Dushistov <dushistov@mail.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/ufs/super.c4
1 files changed, 0 insertions, 4 deletions
diff --git a/fs/ufs/super.c b/fs/ufs/super.c
index e515e99a02f9..8092d3759a5e 100644
--- a/fs/ufs/super.c
+++ b/fs/ufs/super.c
@@ -95,22 +95,18 @@
void lock_ufs(struct super_block *sb)
{
-#if defined(CONFIG_SMP) || defined (CONFIG_PREEMPT)
struct ufs_sb_info *sbi = UFS_SB(sb);
mutex_lock(&sbi->mutex);
sbi->mutex_owner = current;
-#endif
}
void unlock_ufs(struct super_block *sb)
{
-#if defined(CONFIG_SMP) || defined (CONFIG_PREEMPT)
struct ufs_sb_info *sbi = UFS_SB(sb);
sbi->mutex_owner = NULL;
mutex_unlock(&sbi->mutex);
-#endif
}
static struct inode *ufs_nfs_get_inode(struct super_block *sb, u64 ino, u32 generation)