From 814525f4df50a196464ce2c7abe91f693203060f Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@us.ibm.com>
Date: Sun, 29 Apr 2012 18:31:10 -0400
Subject: ext4: calculate and verify inode checksums

This patch introduces to ext4 the ability to calculate and verify
inode checksums.  This requires the use of a new ro compatibility flag
and some accompanying e2fsprogs patches to provide the relevant
features in tune2fs and e2fsck.  The inode generation changes have
been integrated into this patch.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/ext4/ialloc.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

(limited to 'fs/ext4/ialloc.c')

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 409c2ee7750a..8207dfab2682 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -850,6 +850,19 @@ got:
 	inode->i_generation = sbi->s_next_generation++;
 	spin_unlock(&sbi->s_next_gen_lock);
 
+	/* Precompute checksum seed for inode metadata */
+	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+			EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
+		__u32 csum;
+		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+		__le32 inum = cpu_to_le32(inode->i_ino);
+		__le32 gen = cpu_to_le32(inode->i_generation);
+		csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
+				   sizeof(inum));
+		ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
+					      sizeof(gen));
+	}
+
 	ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
 	ext4_set_inode_state(inode, EXT4_STATE_NEW);
 
-- 
cgit v1.2.3-70-g09d2


From 41a246d1ff75a95d2be3191ca6e6db139dc0f430 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@us.ibm.com>
Date: Sun, 29 Apr 2012 18:33:10 -0400
Subject: ext4: calculate and verify checksums for inode bitmaps

Compute and verify the checksum of the inode bitmap; the checkum is
stored in the block group descriptor.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/ext4/bitmap.c | 39 +++++++++++++++++++++++++++++++++++++++
 fs/ext4/ext4.h   | 20 ++++++++++++++++++++
 fs/ext4/ialloc.c | 34 +++++++++++++++++++++++++++++-----
 fs/ext4/resize.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 135 insertions(+), 5 deletions(-)

(limited to 'fs/ext4/ialloc.c')

diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c
index fa3af81ac565..5813e7f2e2c6 100644
--- a/fs/ext4/bitmap.c
+++ b/fs/ext4/bitmap.c
@@ -29,3 +29,42 @@ unsigned int ext4_count_free(struct buffer_head *map, unsigned int numchars)
 
 #endif  /*  EXT4FS_DEBUG  */
 
+int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
+				  struct ext4_group_desc *gdp,
+				  struct buffer_head *bh, int sz)
+{
+	__u32 hi;
+	__u32 provided, calculated;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
+					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+		return 1;
+
+	provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo);
+	calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) {
+		hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi);
+		provided |= (hi << 16);
+	} else
+		calculated &= 0xFFFF;
+
+	return provided == calculated;
+}
+
+void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
+				struct ext4_group_desc *gdp,
+				struct buffer_head *bh, int sz)
+{
+	__u32 csum;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
+					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+		return;
+
+	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+	gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
+	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
+		gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16);
+}
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index ca96401b4b81..7f0ff88f32ba 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -317,6 +317,13 @@ struct ext4_group_desc
 	__u32   bg_reserved;
 };
 
+#define EXT4_BG_INODE_BITMAP_CSUM_HI_END	\
+	(offsetof(struct ext4_group_desc, bg_inode_bitmap_csum_hi) + \
+	 sizeof(__le16))
+#define EXT4_BG_BLOCK_BITMAP_CSUM_HI_END	\
+	(offsetof(struct ext4_group_desc, bg_block_bitmap_csum_hi) + \
+	 sizeof(__le16))
+
 /*
  * Structure of a flex block group info
  */
@@ -1844,6 +1851,12 @@ struct mmpd_data {
 
 /* bitmap.c */
 extern unsigned int ext4_count_free(struct buffer_head *, unsigned);
+void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
+				struct ext4_group_desc *gdp,
+				struct buffer_head *bh, int sz);
+int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
+				  struct ext4_group_desc *gdp,
+				  struct buffer_head *bh, int sz);
 
 /* balloc.c */
 extern unsigned int ext4_block_group(struct super_block *sb,
@@ -2094,6 +2107,13 @@ extern __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 group,
 extern int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 group,
 				       struct ext4_group_desc *gdp);
 
+static inline int ext4_has_group_desc_csum(struct super_block *sb)
+{
+	return EXT4_HAS_RO_COMPAT_FEATURE(sb,
+					  EXT4_FEATURE_RO_COMPAT_GDT_CSUM |
+					  EXT4_FEATURE_RO_COMPAT_METADATA_CSUM);
+}
+
 static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es)
 {
 	return ((ext4_fsblk_t)le32_to_cpu(es->s_blocks_count_hi) << 32) |
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 8207dfab2682..fb897ec183c8 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -82,12 +82,17 @@ static unsigned ext4_init_inode_bitmap(struct super_block *sb,
 		ext4_free_inodes_set(sb, gdp, 0);
 		ext4_itable_unused_set(sb, gdp, 0);
 		memset(bh->b_data, 0xff, sb->s_blocksize);
+		ext4_inode_bitmap_csum_set(sb, block_group, gdp, bh,
+					   EXT4_INODES_PER_GROUP(sb) / 8);
 		return 0;
 	}
 
 	memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
 	ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
 			bh->b_data);
+	ext4_inode_bitmap_csum_set(sb, block_group, gdp, bh,
+				   EXT4_INODES_PER_GROUP(sb) / 8);
+	gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
 
 	return EXT4_INODES_PER_GROUP(sb);
 }
@@ -128,12 +133,12 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 		return NULL;
 	}
 	if (bitmap_uptodate(bh))
-		return bh;
+		goto verify;
 
 	lock_buffer(bh);
 	if (bitmap_uptodate(bh)) {
 		unlock_buffer(bh);
-		return bh;
+		goto verify;
 	}
 
 	ext4_lock_group(sb, block_group);
@@ -141,6 +146,7 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 		ext4_init_inode_bitmap(sb, bh, block_group, desc);
 		set_bitmap_uptodate(bh);
 		set_buffer_uptodate(bh);
+		set_buffer_verified(bh);
 		ext4_unlock_group(sb, block_group);
 		unlock_buffer(bh);
 		return bh;
@@ -154,7 +160,7 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 		 */
 		set_bitmap_uptodate(bh);
 		unlock_buffer(bh);
-		return bh;
+		goto verify;
 	}
 	/*
 	 * submit the buffer_head for reading
@@ -171,6 +177,20 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 			   block_group, bitmap_blk);
 		return NULL;
 	}
+
+verify:
+	ext4_lock_group(sb, block_group);
+	if (!buffer_verified(bh) &&
+	    !ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
+					   EXT4_INODES_PER_GROUP(sb) / 8)) {
+		ext4_unlock_group(sb, block_group);
+		put_bh(bh);
+		ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
+			   "inode_bitmap = %llu", block_group, bitmap_blk);
+		return NULL;
+	}
+	ext4_unlock_group(sb, block_group);
+	set_buffer_verified(bh);
 	return bh;
 }
 
@@ -276,6 +296,8 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
 		ext4_used_dirs_set(sb, gdp, count);
 		percpu_counter_dec(&sbi->s_dirs_counter);
 	}
+	ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
+				   EXT4_INODES_PER_GROUP(sb) / 8);
 	gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
 	ext4_unlock_group(sb, block_group);
 
@@ -751,7 +773,7 @@ got:
 		goto fail;
 
 	/* Update the relevant bg descriptor fields */
-	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
+	if (ext4_has_group_desc_csum(sb)) {
 		int free;
 		struct ext4_group_info *grp = ext4_get_group_info(sb, group);
 
@@ -782,7 +804,9 @@ got:
 			atomic_inc(&sbi->s_flex_groups[f].used_dirs);
 		}
 	}
-	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
+	if (ext4_has_group_desc_csum(sb)) {
+		ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
+					   EXT4_INODES_PER_GROUP(sb) / 8);
 		gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
 		ext4_unlock_group(sb, group);
 	}
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index e0374757a94b..7810cac241e1 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1069,6 +1069,47 @@ static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
 	return err;
 }
 
+static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
+{
+	struct buffer_head *bh = sb_getblk(sb, block);
+	if (!bh)
+		return NULL;
+
+	if (bitmap_uptodate(bh))
+		return bh;
+
+	lock_buffer(bh);
+	if (bh_submit_read(bh) < 0) {
+		unlock_buffer(bh);
+		brelse(bh);
+		return NULL;
+	}
+	unlock_buffer(bh);
+
+	return bh;
+}
+
+static int ext4_set_bitmap_checksums(struct super_block *sb,
+				     ext4_group_t group,
+				     struct ext4_group_desc *gdp,
+				     struct ext4_new_group_data *group_data)
+{
+	struct buffer_head *bh;
+
+	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
+					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+		return 0;
+
+	bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
+	if (!bh)
+		return -EIO;
+	ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
+				   EXT4_INODES_PER_GROUP(sb) / 8);
+	brelse(bh);
+
+	return 0;
+}
+
 /*
  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
  */
@@ -1101,6 +1142,12 @@ static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
 		memset(gdp, 0, EXT4_DESC_SIZE(sb));
 		ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
 		ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
+		err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
+		if (err) {
+			ext4_std_error(sb, err);
+			break;
+		}
+
 		ext4_inode_table_set(sb, gdp, group_data->inode_table);
 		ext4_free_group_clusters_set(sb, gdp,
 					     EXT4_B2C(sbi, group_data->free_blocks_count));
-- 
cgit v1.2.3-70-g09d2


From fa77dcfafeaa6bc73293c646bfc3d5192dcf0be2 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@us.ibm.com>
Date: Sun, 29 Apr 2012 18:35:10 -0400
Subject: ext4: calculate and verify block bitmap checksum

Compute and verify the checksum of the block bitmap; this checksum is
stored in the block group descriptor.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/ext4/balloc.c  | 39 ++++++++++++++++++++++++++++++++-------
 fs/ext4/bitmap.c  | 44 ++++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/ext4.h    | 10 ++++++++++
 fs/ext4/ialloc.c  |  4 ++++
 fs/ext4/mballoc.c |  8 +++++++-
 fs/ext4/resize.c  |  7 +++++++
 6 files changed, 104 insertions(+), 8 deletions(-)

(limited to 'fs/ext4/ialloc.c')

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 4bbd07a6fa18..0a64e4d5dbad 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -174,6 +174,8 @@ void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
 		ext4_free_inodes_set(sb, gdp, 0);
 		ext4_itable_unused_set(sb, gdp, 0);
 		memset(bh->b_data, 0xff, sb->s_blocksize);
+		ext4_block_bitmap_csum_set(sb, block_group, gdp, bh,
+					   EXT4_BLOCKS_PER_GROUP(sb) / 8);
 		return;
 	}
 	memset(bh->b_data, 0, sb->s_blocksize);
@@ -210,6 +212,9 @@ void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
 	 */
 	ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group),
 			     sb->s_blocksize * 8, bh->b_data);
+	ext4_block_bitmap_csum_set(sb, block_group, gdp, bh,
+				   EXT4_BLOCKS_PER_GROUP(sb) / 8);
+	gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
 }
 
 /* Return the number of free blocks in a block group.  It is used when
@@ -276,9 +281,9 @@ struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
 }
 
 static int ext4_valid_block_bitmap(struct super_block *sb,
-					struct ext4_group_desc *desc,
-					unsigned int block_group,
-					struct buffer_head *bh)
+				   struct ext4_group_desc *desc,
+				   unsigned int block_group,
+				   struct buffer_head *bh)
 {
 	ext4_grpblk_t offset;
 	ext4_grpblk_t next_zero_bit;
@@ -325,6 +330,23 @@ err_out:
 			block_group, bitmap_blk);
 	return 0;
 }
+
+void ext4_validate_block_bitmap(struct super_block *sb,
+			       struct ext4_group_desc *desc,
+			       unsigned int block_group,
+			       struct buffer_head *bh)
+{
+	if (buffer_verified(bh))
+		return;
+
+	ext4_lock_group(sb, block_group);
+	if (ext4_valid_block_bitmap(sb, desc, block_group, bh) &&
+	    ext4_block_bitmap_csum_verify(sb, block_group, desc, bh,
+					  EXT4_BLOCKS_PER_GROUP(sb) / 8))
+		set_buffer_verified(bh);
+	ext4_unlock_group(sb, block_group);
+}
+
 /**
  * ext4_read_block_bitmap()
  * @sb:			super block
@@ -355,12 +377,12 @@ ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
 	}
 
 	if (bitmap_uptodate(bh))
-		return bh;
+		goto verify;
 
 	lock_buffer(bh);
 	if (bitmap_uptodate(bh)) {
 		unlock_buffer(bh);
-		return bh;
+		goto verify;
 	}
 	ext4_lock_group(sb, block_group);
 	if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
@@ -379,7 +401,7 @@ ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
 		 */
 		set_bitmap_uptodate(bh);
 		unlock_buffer(bh);
-		return bh;
+		goto verify;
 	}
 	/*
 	 * submit the buffer_head for reading
@@ -390,6 +412,9 @@ ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
 	get_bh(bh);
 	submit_bh(READ, bh);
 	return bh;
+verify:
+	ext4_validate_block_bitmap(sb, desc, block_group, bh);
+	return bh;
 }
 
 /* Returns 0 on success, 1 on error */
@@ -412,7 +437,7 @@ int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group,
 	}
 	clear_buffer_new(bh);
 	/* Panic or remount fs read-only if block bitmap is invalid */
-	ext4_valid_block_bitmap(sb, desc, block_group, bh);
+	ext4_validate_block_bitmap(sb, desc, block_group, bh);
 	return 0;
 }
 
diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c
index 5813e7f2e2c6..b319721da26a 100644
--- a/fs/ext4/bitmap.c
+++ b/fs/ext4/bitmap.c
@@ -68,3 +68,47 @@ void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
 	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
 		gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16);
 }
+
+int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
+				  struct ext4_group_desc *gdp,
+				  struct buffer_head *bh, int sz)
+{
+	__u32 hi;
+	__u32 provided, calculated;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
+					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+		return 1;
+
+	provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo);
+	calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) {
+		hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi);
+		provided |= (hi << 16);
+	} else
+		calculated &= 0xFFFF;
+
+	if (provided == calculated)
+		return 1;
+
+	ext4_error(sb, "Bad block bitmap checksum: block_group = %u", group);
+	return 0;
+}
+
+void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
+				struct ext4_group_desc *gdp,
+				struct buffer_head *bh, int sz)
+{
+	__u32 csum;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
+			EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+		return;
+
+	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+	gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
+	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END)
+		gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16);
+}
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 7f0ff88f32ba..7a4f16075257 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1857,8 +1857,18 @@ void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
 int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
 				  struct ext4_group_desc *gdp,
 				  struct buffer_head *bh, int sz);
+void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
+				struct ext4_group_desc *gdp,
+				struct buffer_head *bh, int sz);
+int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
+				  struct ext4_group_desc *gdp,
+				  struct buffer_head *bh, int sz);
 
 /* balloc.c */
+extern void ext4_validate_block_bitmap(struct super_block *sb,
+				       struct ext4_group_desc *desc,
+				       unsigned int block_group,
+				       struct buffer_head *bh);
 extern unsigned int ext4_block_group(struct super_block *sb,
 			ext4_fsblk_t blocknr);
 extern ext4_grpblk_t ext4_block_group_offset(struct super_block *sb,
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index fb897ec183c8..a6383fcb714b 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -753,6 +753,10 @@ got:
 			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
 			ext4_free_group_clusters_set(sb, gdp,
 				ext4_free_clusters_after_init(sb, group, gdp));
+			ext4_block_bitmap_csum_set(sb, group, gdp,
+						   block_bitmap_bh,
+						   EXT4_BLOCKS_PER_GROUP(sb) /
+						   8);
 			gdp->bg_checksum = ext4_group_desc_csum(sbi, group,
 								gdp);
 		}
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 99ab428bcfa0..95a388fef397 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -788,7 +788,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
 	int first_block;
 	struct super_block *sb;
 	struct buffer_head *bhs;
-	struct buffer_head **bh;
+	struct buffer_head **bh = NULL;
 	struct inode *inode;
 	char *data;
 	char *bitmap;
@@ -2797,6 +2797,8 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
 	}
 	len = ext4_free_group_clusters(sb, gdp) - ac->ac_b_ex.fe_len;
 	ext4_free_group_clusters_set(sb, gdp, len);
+	ext4_block_bitmap_csum_set(sb, ac->ac_b_ex.fe_group, gdp, bitmap_bh,
+				   EXT4_BLOCKS_PER_GROUP(sb) / 8);
 	gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp);
 
 	ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
@@ -4659,6 +4661,8 @@ do_more:
 
 	ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
 	ext4_free_group_clusters_set(sb, gdp, ret);
+	ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
+				   EXT4_BLOCKS_PER_GROUP(sb) / 8);
 	gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
 	ext4_unlock_group(sb, block_group);
 	percpu_counter_add(&sbi->s_freeclusters_counter, count_clusters);
@@ -4803,6 +4807,8 @@ int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
 	mb_free_blocks(NULL, &e4b, bit, count);
 	blk_free_count = blocks_freed + ext4_free_group_clusters(sb, desc);
 	ext4_free_group_clusters_set(sb, desc, blk_free_count);
+	ext4_block_bitmap_csum_set(sb, block_group, desc, bitmap_bh,
+				   EXT4_BLOCKS_PER_GROUP(sb) / 8);
 	desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc);
 	ext4_unlock_group(sb, block_group);
 	percpu_counter_add(&sbi->s_freeclusters_counter,
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 7810cac241e1..dc597e066308 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1107,6 +1107,13 @@ static int ext4_set_bitmap_checksums(struct super_block *sb,
 				   EXT4_INODES_PER_GROUP(sb) / 8);
 	brelse(bh);
 
+	bh = ext4_get_bitmap(sb, group_data->block_bitmap);
+	if (!bh)
+		return -EIO;
+	ext4_block_bitmap_csum_set(sb, group, gdp, bh,
+				   EXT4_BLOCKS_PER_GROUP(sb) / 8);
+	brelse(bh);
+
 	return 0;
 }
 
-- 
cgit v1.2.3-70-g09d2


From feb0ab32a57e4e6c8b24f6fb68f0ce08efe4603c Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@us.ibm.com>
Date: Sun, 29 Apr 2012 18:45:10 -0400
Subject: ext4: make block group checksums use metadata_csum algorithm

metadata_csum supersedes uninit_bg.  Convert the ROCOMPAT uninit_bg
flag check to a helper function that covers both, and make the
checksum calculation algorithm use either crc16 or the metadata_csum
chosen algorithm depending on which flag is set.  Print a warning if
we try to mount a filesystem with both feature flags set.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/ext4/balloc.c  |  4 +--
 fs/ext4/ext4.h    |  6 ++---
 fs/ext4/ialloc.c  | 17 +++++-------
 fs/ext4/inode.c   |  3 +--
 fs/ext4/mballoc.c |  6 ++---
 fs/ext4/resize.c  |  9 +++----
 fs/ext4/super.c   | 81 ++++++++++++++++++++++++++++++++++++++-----------------
 7 files changed, 76 insertions(+), 50 deletions(-)

(limited to 'fs/ext4/ialloc.c')

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 0a64e4d5dbad..5745d53c67e8 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -168,7 +168,7 @@ void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
 
 	/* If checksum is bad mark all blocks used to prevent allocation
 	 * essentially implementing a per-group read-only flag. */
-	if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
+	if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
 		ext4_error(sb, "Checksum bad for group %u", block_group);
 		ext4_free_group_clusters_set(sb, gdp, 0);
 		ext4_free_inodes_set(sb, gdp, 0);
@@ -214,7 +214,7 @@ void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
 			     sb->s_blocksize * 8, bh->b_data);
 	ext4_block_bitmap_csum_set(sb, block_group, gdp, bh,
 				   EXT4_BLOCKS_PER_GROUP(sb) / 8);
-	gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
+	ext4_group_desc_csum_set(sb, block_group, gdp);
 }
 
 /* Return the number of free blocks in a block group.  It is used when
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 57d7c356eaab..84e76bb96070 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2114,10 +2114,10 @@ extern void ext4_used_dirs_set(struct super_block *sb,
 				struct ext4_group_desc *bg, __u32 count);
 extern void ext4_itable_unused_set(struct super_block *sb,
 				   struct ext4_group_desc *bg, __u32 count);
-extern __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 group,
-				   struct ext4_group_desc *gdp);
-extern int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 group,
+extern int ext4_group_desc_csum_verify(struct super_block *sb, __u32 group,
 				       struct ext4_group_desc *gdp);
+extern void ext4_group_desc_csum_set(struct super_block *sb, __u32 group,
+				     struct ext4_group_desc *gdp);
 
 static inline int ext4_has_group_desc_csum(struct super_block *sb)
 {
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index a6383fcb714b..a044a9b77491 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -70,13 +70,11 @@ static unsigned ext4_init_inode_bitmap(struct super_block *sb,
 				       ext4_group_t block_group,
 				       struct ext4_group_desc *gdp)
 {
-	struct ext4_sb_info *sbi = EXT4_SB(sb);
-
 	J_ASSERT_BH(bh, buffer_locked(bh));
 
 	/* If checksum is bad mark all blocks and inodes use to prevent
 	 * allocation, essentially implementing a per-group read-only flag. */
-	if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
+	if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
 		ext4_error(sb, "Checksum bad for group %u", block_group);
 		ext4_free_group_clusters_set(sb, gdp, 0);
 		ext4_free_inodes_set(sb, gdp, 0);
@@ -92,7 +90,7 @@ static unsigned ext4_init_inode_bitmap(struct super_block *sb,
 			bh->b_data);
 	ext4_inode_bitmap_csum_set(sb, block_group, gdp, bh,
 				   EXT4_INODES_PER_GROUP(sb) / 8);
-	gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
+	ext4_group_desc_csum_set(sb, block_group, gdp);
 
 	return EXT4_INODES_PER_GROUP(sb);
 }
@@ -298,7 +296,7 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
 	}
 	ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
 				   EXT4_INODES_PER_GROUP(sb) / 8);
-	gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
+	ext4_group_desc_csum_set(sb, block_group, gdp);
 	ext4_unlock_group(sb, block_group);
 
 	percpu_counter_inc(&sbi->s_freeinodes_counter);
@@ -731,7 +729,7 @@ repeat_in_this_group:
 
 got:
 	/* We may have to initialize the block bitmap if it isn't already */
-	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
+	if (ext4_has_group_desc_csum(sb) &&
 	    gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 		struct buffer_head *block_bitmap_bh;
 
@@ -757,8 +755,7 @@ got:
 						   block_bitmap_bh,
 						   EXT4_BLOCKS_PER_GROUP(sb) /
 						   8);
-			gdp->bg_checksum = ext4_group_desc_csum(sbi, group,
-								gdp);
+			ext4_group_desc_csum_set(sb, group, gdp);
 		}
 		ext4_unlock_group(sb, group);
 
@@ -811,7 +808,7 @@ got:
 	if (ext4_has_group_desc_csum(sb)) {
 		ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
 					   EXT4_INODES_PER_GROUP(sb) / 8);
-		gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
+		ext4_group_desc_csum_set(sb, group, gdp);
 		ext4_unlock_group(sb, group);
 	}
 
@@ -1181,7 +1178,7 @@ int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
 skip_zeroout:
 	ext4_lock_group(sb, group);
 	gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
-	gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
+	ext4_group_desc_csum_set(sb, group, gdp);
 	ext4_unlock_group(sb, group);
 
 	BUFFER_TRACE(group_desc_bh,
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 16a67359b4c7..7bccdf32a32c 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3584,8 +3584,7 @@ make_io:
 				b = table;
 			end = b + EXT4_SB(sb)->s_inode_readahead_blks;
 			num = EXT4_INODES_PER_GROUP(sb);
-			if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
-				       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+			if (ext4_has_group_desc_csum(sb))
 				num -= ext4_itable_unused_count(sb, gdp);
 			table += num / inodes_per_block;
 			if (end > table)
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 95a388fef397..ccb9c2f527d5 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2799,7 +2799,7 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
 	ext4_free_group_clusters_set(sb, gdp, len);
 	ext4_block_bitmap_csum_set(sb, ac->ac_b_ex.fe_group, gdp, bitmap_bh,
 				   EXT4_BLOCKS_PER_GROUP(sb) / 8);
-	gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp);
+	ext4_group_desc_csum_set(sb, ac->ac_b_ex.fe_group, gdp);
 
 	ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
 	percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len);
@@ -4663,7 +4663,7 @@ do_more:
 	ext4_free_group_clusters_set(sb, gdp, ret);
 	ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
 				   EXT4_BLOCKS_PER_GROUP(sb) / 8);
-	gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
+	ext4_group_desc_csum_set(sb, block_group, gdp);
 	ext4_unlock_group(sb, block_group);
 	percpu_counter_add(&sbi->s_freeclusters_counter, count_clusters);
 
@@ -4809,7 +4809,7 @@ int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
 	ext4_free_group_clusters_set(sb, desc, blk_free_count);
 	ext4_block_bitmap_csum_set(sb, block_group, desc, bitmap_bh,
 				   EXT4_BLOCKS_PER_GROUP(sb) / 8);
-	desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc);
+	ext4_group_desc_csum_set(sb, block_group, desc);
 	ext4_unlock_group(sb, block_group);
 	percpu_counter_add(&sbi->s_freeclusters_counter,
 			   EXT4_B2C(sbi, blocks_freed));
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index dc597e066308..a58ce7c507ae 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1160,7 +1160,7 @@ static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
 					     EXT4_B2C(sbi, group_data->free_blocks_count));
 		ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
 		gdp->bg_flags = cpu_to_le16(*bg_flags);
-		gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
+		ext4_group_desc_csum_set(sb, group, gdp);
 
 		err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 		if (unlikely(err)) {
@@ -1399,17 +1399,14 @@ static int ext4_setup_next_flex_gd(struct super_block *sb,
 			   (1 + ext4_bg_num_gdb(sb, group + i) +
 			    le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
 		group_data[i].free_blocks_count = blocks_per_group - overhead;
-		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
-					       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+		if (ext4_has_group_desc_csum(sb))
 			flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
 					       EXT4_BG_INODE_UNINIT;
 		else
 			flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
 	}
 
-	if (last_group == n_group &&
-	    EXT4_HAS_RO_COMPAT_FEATURE(sb,
-				       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+	if (last_group == n_group && ext4_has_group_desc_csum(sb))
 		/* We need to initialize block bitmap of last group. */
 		flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
 
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index f80c7e612829..c18c5968cd96 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1952,43 +1952,69 @@ failed:
 	return 0;
 }
 
-__le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
-			    struct ext4_group_desc *gdp)
+static __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
+				   struct ext4_group_desc *gdp)
 {
+	int offset;
 	__u16 crc = 0;
+	__le32 le_group = cpu_to_le32(block_group);
 
-	if (sbi->s_es->s_feature_ro_compat &
-	    cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
-		int offset = offsetof(struct ext4_group_desc, bg_checksum);
-		__le32 le_group = cpu_to_le32(block_group);
-
-		crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
-		crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
-		crc = crc16(crc, (__u8 *)gdp, offset);
-		offset += sizeof(gdp->bg_checksum); /* skip checksum */
-		/* for checksum of struct ext4_group_desc do the rest...*/
-		if ((sbi->s_es->s_feature_incompat &
-		     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
-		    offset < le16_to_cpu(sbi->s_es->s_desc_size))
-			crc = crc16(crc, (__u8 *)gdp + offset,
-				    le16_to_cpu(sbi->s_es->s_desc_size) -
-					offset);
+	if ((sbi->s_es->s_feature_ro_compat &
+	     cpu_to_le32(EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))) {
+		/* Use new metadata_csum algorithm */
+		__u16 old_csum;
+		__u32 csum32;
+
+		old_csum = gdp->bg_checksum;
+		gdp->bg_checksum = 0;
+		csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group,
+				     sizeof(le_group));
+		csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp,
+				     sbi->s_desc_size);
+		gdp->bg_checksum = old_csum;
+
+		crc = csum32 & 0xFFFF;
+		goto out;
 	}
 
+	/* old crc16 code */
+	offset = offsetof(struct ext4_group_desc, bg_checksum);
+
+	crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
+	crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
+	crc = crc16(crc, (__u8 *)gdp, offset);
+	offset += sizeof(gdp->bg_checksum); /* skip checksum */
+	/* for checksum of struct ext4_group_desc do the rest...*/
+	if ((sbi->s_es->s_feature_incompat &
+	     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
+	    offset < le16_to_cpu(sbi->s_es->s_desc_size))
+		crc = crc16(crc, (__u8 *)gdp + offset,
+			    le16_to_cpu(sbi->s_es->s_desc_size) -
+				offset);
+
+out:
 	return cpu_to_le16(crc);
 }
 
-int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 block_group,
+int ext4_group_desc_csum_verify(struct super_block *sb, __u32 block_group,
 				struct ext4_group_desc *gdp)
 {
-	if ((sbi->s_es->s_feature_ro_compat &
-	     cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) &&
-	    (gdp->bg_checksum != ext4_group_desc_csum(sbi, block_group, gdp)))
+	if (ext4_has_group_desc_csum(sb) &&
+	    (gdp->bg_checksum != ext4_group_desc_csum(EXT4_SB(sb),
+						      block_group, gdp)))
 		return 0;
 
 	return 1;
 }
 
+void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group,
+			      struct ext4_group_desc *gdp)
+{
+	if (!ext4_has_group_desc_csum(sb))
+		return;
+	gdp->bg_checksum = ext4_group_desc_csum(EXT4_SB(sb), block_group, gdp);
+}
+
 /* Called at mount-time, super-block is locked */
 static int ext4_check_descriptors(struct super_block *sb,
 				  ext4_group_t *first_not_zeroed)
@@ -2043,7 +2069,7 @@ static int ext4_check_descriptors(struct super_block *sb,
 			return 0;
 		}
 		ext4_lock_group(sb, i);
-		if (!ext4_group_desc_csum_verify(sbi, i, gdp)) {
+		if (!ext4_group_desc_csum_verify(sb, i, gdp)) {
 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
 				 "Checksum for group %u failed (%u!=%u)",
 				 i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
@@ -3069,6 +3095,13 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto cantfind_ext4;
 	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
 
+	/* Warn if metadata_csum and gdt_csum are both set. */
+	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
+	    EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+		ext4_warning(sb, KERN_INFO "metadata_csum and uninit_bg are "
+			     "redundant flags; please run fsck.");
+
 	/* Check for a known checksum algorithm */
 	if (!ext4_verify_csum_type(sb, es)) {
 		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
@@ -4400,7 +4433,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 				struct ext4_group_desc *gdp =
 					ext4_get_group_desc(sb, g, NULL);
 
-				if (!ext4_group_desc_csum_verify(sbi, g, gdp)) {
+				if (!ext4_group_desc_csum_verify(sb, g, gdp)) {
 					ext4_msg(sb, KERN_ERR,
 	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
 		g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),
-- 
cgit v1.2.3-70-g09d2


From bb3d132a24cd8bf5e7773b2d9f9baa58b07a7dae Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Mon, 28 May 2012 14:16:57 -0400
Subject: ext4: fix potential NULL dereference in ext4_free_inodes_counts()

The ext4_get_group_desc() function returns NULL on error, and
ext4_free_inodes_count() function dereferences it without checking.
There is a check on the next line, but it's too late.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
---
 fs/ext4/ialloc.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

(limited to 'fs/ext4/ialloc.c')

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index a044a9b77491..ea32d7e1d6e3 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -508,10 +508,12 @@ fallback_retry:
 	for (i = 0; i < ngroups; i++) {
 		grp = (parent_group + i) % ngroups;
 		desc = ext4_get_group_desc(sb, grp, NULL);
-		grp_free = ext4_free_inodes_count(sb, desc);
-		if (desc && grp_free && grp_free >= avefreei) {
-			*group = grp;
-			return 0;
+		if (desc) {
+			grp_free = ext4_free_inodes_count(sb, desc);
+			if (grp_free && grp_free >= avefreei) {
+				*group = grp;
+				return 0;
+			}
 		}
 	}
 
-- 
cgit v1.2.3-70-g09d2


From 6f2e9f0e7d795214b9cf5a47724a273b705fd113 Mon Sep 17 00:00:00 2001
From: Tao Ma <boyu.mt@taobao.com>
Date: Mon, 28 May 2012 18:20:59 -0400
Subject: ext4: protect group inode free counting with group lock

Now when we set the group inode free count, we don't have a proper
group lock so that multiple threads may decrease the inode free
count at the same time. And e2fsck will complain something like:

Free inodes count wrong for group #1 (1, counted=0).
Fix? no

Free inodes count wrong for group #2 (3, counted=0).
Fix? no

Directories count wrong for group #2 (780, counted=779).
Fix? no

Free inodes count wrong for group #3 (2272, counted=2273).
Fix? no

So this patch try to protect it with the ext4_lock_group.

btw, it is found by xfstests test case 269 and the volume is
mkfsed with the parameter
"-O ^resize_inode,^uninit_bg,extent,meta_bg,flex_bg,ext_attr"
and I have run it 100 times and the error in e2fsck doesn't
show up again.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/ext4/ialloc.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'fs/ext4/ialloc.c')

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index ea32d7e1d6e3..03583ab52e0e 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -797,7 +797,10 @@ got:
 			ext4_itable_unused_set(sb, gdp,
 					(EXT4_INODES_PER_GROUP(sb) - ino));
 		up_read(&grp->alloc_sem);
+	} else {
+		ext4_lock_group(sb, group);
 	}
+
 	ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
 	if (S_ISDIR(mode)) {
 		ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
@@ -811,8 +814,8 @@ got:
 		ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
 					   EXT4_INODES_PER_GROUP(sb) / 8);
 		ext4_group_desc_csum_set(sb, group, gdp);
-		ext4_unlock_group(sb, group);
 	}
+	ext4_unlock_group(sb, group);
 
 	BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
 	err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
-- 
cgit v1.2.3-70-g09d2