linux-kernel - [PATCH 31/42] ext4: fix initialization of UNINIT bitmap blocks

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Date:	Thu,  9 Oct 2008 00:05:49 -0400
From:	Theodore Ts'o <tytso@....edu>
To:	linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:	Frederic Bohe <frederic.bohe@...l.net>,
	"Theodore Ts'o" <tytso@....edu>
Subject: [PATCH 31/42] ext4: fix initialization of UNINIT bitmap blocks

From: Frederic Bohe <frederic.bohe@...l.net>

We must always initialize uninitialized bitmap blocks even if the
buffer head is marked uptodate, since it could have been read in by a
userspace program.  So always initialized the bitmap block if it is
marked uninitialzied and not dirty; it will marked initialized as soon
as we allocate a block or inode out of that bitmap.

Signed-off-by: Frederic Bohe <frederic.bohe@...l.net>
Signed-off-by: "Theodore Ts'o" <tytso@....edu>
---
 fs/ext4/balloc.c  |    4 +++-
 fs/ext4/ialloc.c  |    4 +++-
 fs/ext4/mballoc.c |    4 +++-
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 59566c0..bd2ece2 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -319,9 +319,11 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
 			    block_group, bitmap_blk);
 		return NULL;
 	}
-	if (bh_uptodate_or_lock(bh))
+	if (buffer_uptodate(bh) &&
+	    !(desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))
 		return bh;
 
+	lock_buffer(bh);
 	spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
 	if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 		ext4_init_block_bitmap(sb, bh, block_group, desc);
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 1343bf1..fe34d74 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -115,9 +115,11 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 			    block_group, bitmap_blk);
 		return NULL;
 	}
-	if (bh_uptodate_or_lock(bh))
+	if (buffer_uptodate(bh) &&
+	    !(desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
 		return bh;
 
+	lock_buffer(bh);
 	spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
 	if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
 		ext4_init_inode_bitmap(sb, bh, block_group, desc);
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index c84b68f..28bf8ef 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -782,9 +782,11 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
 		if (bh[i] == NULL)
 			goto out;
 
-		if (bh_uptodate_or_lock(bh[i]))
+		if (buffer_uptodate(bh[i]) &&
+		    !(desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))
 			continue;
 
+		lock_buffer(bh[i]);
 		spin_lock(sb_bgl_lock(EXT4_SB(sb), first_group + i));
 		if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 			ext4_init_block_bitmap(sb, bh[i],
-- 
1.5.6.1.205.ge2c7.dirty

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