[PATCH] lockdep: annotate NTFS locking rules
NTFS uses lots of type-opaque objects which acquire their true identity
runtime - so the lock validator needs to be helped in a couple of places to
figure out object types.
Many thanks to Anton Altaparmakov for giving lots of explanations about NTFS
locking rules.
Has no effect on non-lockdep kernels.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
index 4c86b7e..d313f35 100644
--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -367,6 +367,12 @@
kmem_cache_free(ntfs_inode_cache, ni);
}
+/*
+ * The attribute runlist lock has separate locking rules from the
+ * normal runlist lock, so split the two lock-classes:
+ */
+static struct lock_class_key attr_list_rl_lock_class;
+
/**
* __ntfs_init_inode - initialize ntfs specific part of an inode
* @sb: super block of mounted volume
@@ -394,6 +400,8 @@
ni->attr_list_size = 0;
ni->attr_list = NULL;
ntfs_init_runlist(&ni->attr_list_rl);
+ lockdep_set_class(&ni->attr_list_rl.lock,
+ &attr_list_rl_lock_class);
ni->itype.index.bmp_ino = NULL;
ni->itype.index.block_size = 0;
ni->itype.index.vcn_size = 0;
@@ -405,6 +413,13 @@
ni->ext.base_ntfs_ino = NULL;
}
+/*
+ * Extent inodes get MFT-mapped in a nested way, while the base inode
+ * is still mapped. Teach this nesting to the lock validator by creating
+ * a separate class for nested inode's mrec_lock's:
+ */
+static struct lock_class_key extent_inode_mrec_lock_key;
+
inline ntfs_inode *ntfs_new_extent_inode(struct super_block *sb,
unsigned long mft_no)
{
@@ -413,6 +428,7 @@
ntfs_debug("Entering.");
if (likely(ni != NULL)) {
__ntfs_init_inode(sb, ni);
+ lockdep_set_class(&ni->mrec_lock, &extent_inode_mrec_lock_key);
ni->mft_no = mft_no;
ni->type = AT_UNUSED;
ni->name = NULL;
@@ -1722,6 +1738,15 @@
return err;
}
+/*
+ * The MFT inode has special locking, so teach the lock validator
+ * about this by splitting off the locking rules of the MFT from
+ * the locking rules of other inodes. The MFT inode can never be
+ * accessed from the VFS side (or even internally), only by the
+ * map_mft functions.
+ */
+static struct lock_class_key mft_ni_runlist_lock_key, mft_ni_mrec_lock_key;
+
/**
* ntfs_read_inode_mount - special read_inode for mount time use only
* @vi: inode to read
@@ -2148,6 +2173,14 @@
ntfs_attr_put_search_ctx(ctx);
ntfs_debug("Done.");
ntfs_free(m);
+
+ /*
+ * Split the locking rules of the MFT inode from the
+ * locking rules of other inodes:
+ */
+ lockdep_set_class(&ni->runlist.lock, &mft_ni_runlist_lock_key);
+ lockdep_set_class(&ni->mrec_lock, &mft_ni_mrec_lock_key);
+
return 0;
em_put_err_out: