linux-ext4 - [PATCH v2] ext4: make sure to revoke all the freeable blocks in ext4_free

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Message-id: <1450316940-10774-1-git-send-email-daeho.jeong@samsung.com>
Date:	Thu, 17 Dec 2015 10:49:00 +0900
From:	Daeho Jeong <daeho.jeong@...sung.com>
To:	tytso@....edu, jack@...e.cz, linux-ext4@...r.kernel.org,
	daeho.jeong@...sung.com
Subject: [PATCH v2] ext4: make sure to revoke all the freeable blocks in
 ext4_free_blocks

Now, ext4_free_blocks() doesn't revoke data blocks of per-file data
journalled inode and it can cause file data inconsistency problems.
Even though data blocks of per-file data journalled inode are already
forgotten by jbd2_journal_invalidatepage() in advance of invoking
ext4_free_blocks(), we still need to revoke the data blocks here.
Moreover some of the metadata blocks, which are not found by
sb_find_get_block(), are still needed to be revoked, but this is also
missing here.

Signed-off-by: Daeho Jeong <daeho.jeong@...sung.com>
Reviewed-by: Jan Kara <jack@...e.cz>
---
 fs/ext4/mballoc.c |   32 +++++++++++++-------------------
 1 file changed, 13 insertions(+), 19 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 61eaf74..26419d6 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4695,16 +4695,6 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
 	}
 
 	/*
-	 * We need to make sure we don't reuse the freed block until
-	 * after the transaction is committed, which we can do by
-	 * treating the block as metadata, below.  We make an
-	 * exception if the inode is to be written in writeback mode
-	 * since writeback mode has weak data consistency guarantees.
-	 */
-	if (!ext4_should_writeback_data(inode))
-		flags |= EXT4_FREE_BLOCKS_METADATA;
-
-	/*
 	 * If the extent to be freed does not begin on a cluster
 	 * boundary, we need to deal with partial clusters at the
 	 * beginning and end of the extent.  Normally we will free
@@ -4738,14 +4728,13 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
 
 	if (!bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
 		int i;
+		int is_metadata = flags & EXT4_FREE_BLOCKS_METADATA;
 
 		for (i = 0; i < count; i++) {
 			cond_resched();
-			bh = sb_find_get_block(inode->i_sb, block + i);
-			if (!bh)
-				continue;
-			ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
-				    inode, bh, block + i);
+			if (is_metadata)
+				bh = sb_find_get_block(inode->i_sb, block + i);
+			ext4_forget(handle, is_metadata, inode, bh, block + i);
 		}
 	}
 
@@ -4819,12 +4808,17 @@ do_more:
 	if (err)
 		goto error_return;
 
-	if ((flags & EXT4_FREE_BLOCKS_METADATA) && ext4_handle_valid(handle)) {
+	/*
+	 * We need to make sure we don't reuse the freed block until after the
+	 * transaction is committed. We make an exception if the inode is to be
+	 * written in writeback mode since writeback mode has weak data
+	 * consistency guarantees.
+	 */
+	if (ext4_handle_valid(handle) &&
+	    ((flags & EXT4_FREE_BLOCKS_METADATA) ||
+	     !ext4_should_writeback_data(inode))) {
 		struct ext4_free_data *new_entry;
 		/*
-		 * blocks being freed are metadata. these blocks shouldn't
-		 * be used until this transaction is committed
-		 *
 		 * We use __GFP_NOFAIL because ext4_free_blocks() is not allowed
 		 * to fail.
 		 */
-- 
1.7.9.5

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