[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>

1 files changed, 31 insertions, 0 deletions

diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
index 0e14acea3f8b..74e0ee8fce72 100644
--- a/fs/ntfs/super.c
+++ b/fs/ntfs/super.c
@@ -1724,6 +1724,14 @@ upcase_failed:
         return FALSE;
 }
 
+/*
+ * The lcn and mft bitmap inodes are NTFS-internal inodes with
+ * their own special locking rules:
+ */
+static struct lock_class_key
+        lcnbmp_runlist_lock_key, lcnbmp_mrec_lock_key,
+        mftbmp_runlist_lock_key, mftbmp_mrec_lock_key;
+
 /**
  * load_system_files - open the system files using normal functions
  * @vol:        ntfs super block describing device whose system files to load
@@ -1780,6 +1788,10 @@ static BOOL load_system_files(ntfs_volume *vol)
                 ntfs_error(sb, "Failed to load $MFT/$BITMAP attribute.");
                 goto iput_mirr_err_out;
         }
+        lockdep_set_class(&NTFS_I(vol->mftbmp_ino)->runlist.lock,
+                           &mftbmp_runlist_lock_key);
+        lockdep_set_class(&NTFS_I(vol->mftbmp_ino)->mrec_lock,
+                           &mftbmp_mrec_lock_key);
         /* Read upcase table and setup @vol->upcase and @vol->upcase_len. */
         if (!load_and_init_upcase(vol))
                 goto iput_mftbmp_err_out;
@@ -1802,6 +1814,11 @@ static BOOL load_system_files(ntfs_volume *vol)
                         iput(vol->lcnbmp_ino);
                 goto bitmap_failed;
         }
+        lockdep_set_class(&NTFS_I(vol->lcnbmp_ino)->runlist.lock,
+                           &lcnbmp_runlist_lock_key);
+        lockdep_set_class(&NTFS_I(vol->lcnbmp_ino)->mrec_lock,
+                           &lcnbmp_mrec_lock_key);
+
         NInoSetSparseDisabled(NTFS_I(vol->lcnbmp_ino));
         if ((vol->nr_clusters + 7) >> 3 > i_size_read(vol->lcnbmp_ino)) {
                 iput(vol->lcnbmp_ino);
@@ -2743,6 +2760,17 @@ static int ntfs_fill_super(struct super_block *sb, void *opt, const int silent)
         struct inode *tmp_ino;
         int blocksize, result;
 
+        /*
+         * We do a pretty difficult piece of bootstrap by reading the
+         * MFT (and other metadata) from disk into memory. We'll only
+         * release this metadata during umount, so the locking patterns
+         * observed during bootstrap do not count. So turn off the
+         * observation of locking patterns (strictly for this context
+         * only) while mounting NTFS. [The validator is still active
+         * otherwise, even for this context: it will for example record
+         * lock class registrations.]
+         */
+        lockdep_off();
         ntfs_debug("Entering.");
 #ifndef NTFS_RW
         sb->s_flags |= MS_RDONLY;
@@ -2754,6 +2782,7 @@ static int ntfs_fill_super(struct super_block *sb, void *opt, const int silent)
                 if (!silent)
                         ntfs_error(sb, "Allocation of NTFS volume structure "
                                         "failed. Aborting mount...");
+                lockdep_on();
                 return -ENOMEM;
         }
         /* Initialize ntfs_volume structure. */
@@ -2940,6 +2969,7 @@ static int ntfs_fill_super(struct super_block *sb, void *opt, const int silent)
                 mutex_unlock(&ntfs_lock);
                 sb->s_export_op = &ntfs_export_ops;
                 lock_kernel();
+                lockdep_on();
                 return 0;
         }
         ntfs_error(sb, "Failed to allocate root directory.");
@@ -3059,6 +3089,7 @@ err_out_now:
         sb->s_fs_info = NULL;
         kfree(vol);
         ntfs_debug("Failed, returning -EINVAL.");
+        lockdep_on();
         return -EINVAL;
 }