2015-12-17 02:41:07

by Daeho Jeong

[permalink] [raw]
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 <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
---
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