[PATCH 13/14] fs/ntfs3: Improve checking of bad clusters

[Konstantin Komarov]

Added new function wnd_set_used_safe.
Load $BadClus before $AttrDef instead of before $Bitmap.

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@xxxxxxxxxxxxxxxxxxxx>
---
 fs/ntfs3/bitmap.c  | 38 +++++++++++++++++++++++++++
 fs/ntfs3/ntfs_fs.h |  2 ++
 fs/ntfs3/run.c     | 21 ++-------------
 fs/ntfs3/super.c   | 64 ++++++++++++++++++++++++++++------------------
 4 files changed, 81 insertions(+), 44 deletions(-)

diff --git a/fs/ntfs3/bitmap.c b/fs/ntfs3/bitmap.c
index 6e68887597ac..c86a76dd44b9 100644
--- a/fs/ntfs3/bitmap.c
+++ b/fs/ntfs3/bitmap.c
@@ -800,6 +800,44 @@ int wnd_set_used(struct wnd_bitmap *wnd, size_t bit, size_t bits)
 	return err;
 }
 
+/*
+ * wnd_set_used_safe - Mark the bits range from bit to bit + bits as used.
+ *
+ * Unlikely wnd_set_used/wnd_set_free this function is not full trusted.
+ * It scans every bit in bitmap and marks free bit as used.
+ * @done - how many bits were marked as used.
+ *
+ * NOTE: normally *done should be 0.
+ */
+int wnd_set_used_safe(struct wnd_bitmap *wnd, size_t bit, size_t bits,
+		      size_t *done)
+{
+	size_t i, from = 0, len = 0;
+	int err = 0;
+
+	*done = 0;
+	for (i = 0; i < bits; i++) {
+		if (wnd_is_free(wnd, bit + i, 1)) {
+			if (!len)
+				from = bit + i;
+			len += 1;
+		} else if (len) {
+			err = wnd_set_used(wnd, from, len);
+			*done += len;
+			len = 0;
+			if (err)
+				break;
+		}
+	}
+
+	if (len) {
+		/* last fragment. */
+		err = wnd_set_used(wnd, from, len);
+		*done += len;
+	}
+	return err;
+}
+
 /*
  * wnd_is_free_hlp
  *
diff --git a/fs/ntfs3/ntfs_fs.h b/fs/ntfs3/ntfs_fs.h
index bc02cfb344f9..2f55993a716c 100644
--- a/fs/ntfs3/ntfs_fs.h
+++ b/fs/ntfs3/ntfs_fs.h
@@ -826,6 +826,8 @@ static inline size_t wnd_zeroes(const struct wnd_bitmap *wnd)
 int wnd_init(struct wnd_bitmap *wnd, struct super_block *sb, size_t nbits);
 int wnd_set_free(struct wnd_bitmap *wnd, size_t bit, size_t bits);
 int wnd_set_used(struct wnd_bitmap *wnd, size_t bit, size_t bits);
+int wnd_set_used_safe(struct wnd_bitmap *wnd, size_t bit, size_t bits,
+		      size_t *done);
 bool wnd_is_free(struct wnd_bitmap *wnd, size_t bit, size_t bits);
 bool wnd_is_used(struct wnd_bitmap *wnd, size_t bit, size_t bits);
 
diff --git a/fs/ntfs3/run.c b/fs/ntfs3/run.c
index 12d8682f33b5..a5af71cd8d14 100644
--- a/fs/ntfs3/run.c
+++ b/fs/ntfs3/run.c
@@ -1096,25 +1096,8 @@ int run_unpack_ex(struct runs_tree *run, struct ntfs_sb_info *sbi, CLST ino,
 
 		if (down_write_trylock(&wnd->rw_lock)) {
 			/* Mark all zero bits as used in range [lcn, lcn+len). */
-			CLST i, lcn_f = 0, len_f = 0;
-
-			err = 0;
-			for (i = 0; i < len; i++) {
-				if (wnd_is_free(wnd, lcn + i, 1)) {
-					if (!len_f)
-						lcn_f = lcn + i;
-					len_f += 1;
-				} else if (len_f) {
-					err = wnd_set_used(wnd, lcn_f, len_f);
-					len_f = 0;
-					if (err)
-						break;
-				}
-			}
-
-			if (len_f)
-				err = wnd_set_used(wnd, lcn_f, len_f);
-
+			size_t done;
+			err = wnd_set_used_safe(wnd, lcn, len, &done);
 			up_write(&wnd->rw_lock);
 			if (err)
 				return err;
diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
index 1e2c04e48f98..d8ba6724adf1 100644
--- a/fs/ntfs3/super.c
+++ b/fs/ntfs3/super.c
@@ -921,7 +921,7 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
 	struct block_device *bdev = sb->s_bdev;
 	struct inode *inode;
 	struct ntfs_inode *ni;
-	size_t i, tt;
+	size_t i, tt, bad_len, bad_frags;
 	CLST vcn, lcn, len;
 	struct ATTRIB *attr;
 	const struct VOLUME_INFO *info;
@@ -1091,30 +1091,6 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
 
 	sbi->mft.ni = ni;
 
-	/* Load $BadClus. */
-	ref.low = cpu_to_le32(MFT_REC_BADCLUST);
-	ref.seq = cpu_to_le16(MFT_REC_BADCLUST);
-	inode = ntfs_iget5(sb, &ref, &NAME_BADCLUS);
-	if (IS_ERR(inode)) {
-		ntfs_err(sb, "Failed to load $BadClus.");
-		err = PTR_ERR(inode);
-		goto out;
-	}
-
-	ni = ntfs_i(inode);
-
-	for (i = 0; run_get_entry(&ni->file.run, i, &vcn, &lcn, &len); i++) {
-		if (lcn == SPARSE_LCN)
-			continue;
-
-		if (!sbi->bad_clusters)
-			ntfs_notice(sb, "Volume contains bad blocks");
-
-		sbi->bad_clusters += len;
-	}
-
-	iput(inode);
-
 	/* Load $Bitmap. */
 	ref.low = cpu_to_le32(MFT_REC_BITMAP);
 	ref.seq = cpu_to_le16(MFT_REC_BITMAP);
@@ -1152,6 +1128,44 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
 	if (err)
 		goto out;
 
+	/* Load $BadClus. */
+	ref.low = cpu_to_le32(MFT_REC_BADCLUST);
+	ref.seq = cpu_to_le16(MFT_REC_BADCLUST);
+	inode = ntfs_iget5(sb, &ref, &NAME_BADCLUS);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		ntfs_err(sb, "Failed to load $BadClus (%d).", err);
+		goto out;
+	}
+
+	ni = ntfs_i(inode);
+	bad_len = bad_frags = 0;
+	for (i = 0; run_get_entry(&ni->file.run, i, &vcn, &lcn, &len); i++) {
+		if (lcn == SPARSE_LCN)
+			continue;
+
+		bad_len += len;
+		bad_frags += 1;
+		if (sb_rdonly(sb))
+			continue;
+
+		if (wnd_set_used_safe(&sbi->used.bitmap, lcn, len, &tt) || tt) {
+			/* Bad blocks marked as free in bitmap. */
+			ntfs_set_state(sbi, NTFS_DIRTY_ERROR);
+		}
+	}
+	if (bad_len) {
+		/*
+		 * Notice about bad blocks.
+		 * In normal cases these blocks are marked as used in bitmap.
+		 * And we never allocate space in it.
+		 */
+		ntfs_notice(sb,
+			    "Volume contains %zu bad blocks in %zu fragments.",
+			    bad_len, bad_frags);
+	}
+	iput(inode);
+
 	/* Load $AttrDef. */
 	ref.low = cpu_to_le32(MFT_REC_ATTR);
 	ref.seq = cpu_to_le16(MFT_REC_ATTR);
--
2.37.0