Patchwork [3.5.y.z,extended,stable] Patch "Btrfs: make sure nbytes are right after log replay" has been added to staging queue

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Submitter Luis Henriques
Date April 17, 2013, 2:43 p.m.
Message ID <1366209832-15902-1-git-send-email-luis.henriques@canonical.com>
Download mbox | patch
Permalink /patch/237256/
State New
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Comments

Luis Henriques - April 17, 2013, 2:43 p.m.
This is a note to let you know that I have just added a patch titled

    Btrfs: make sure nbytes are right after log replay

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

From f60cab04277466ac0608fd046c753ec9e95a70ad Mon Sep 17 00:00:00 2001
From: Josef Bacik <jbacik@fusionio.com>
Date: Fri, 5 Apr 2013 20:50:09 +0000
Subject: [PATCH] Btrfs: make sure nbytes are right after log replay

commit 4bc4bee4595662d8bff92180d5c32e3313a704b0 upstream.

While trying to track down a tree log replay bug I noticed that fsck was always
complaining about nbytes not being right for our fsynced file.  That is because
the new fsync stuff doesn't wait for ordered extents to complete, so the inodes
nbytes are not necessarily updated properly when we log it.  So to fix this we
need to set nbytes to whatever it is on the inode that is on disk, so when we
replay the extents we can just add the bytes that are being added as we replay
the extent.  This makes it work for the case that we have the wrong nbytes or
the case that we logged everything and nbytes is actually correct.  With this
I'm no longer getting nbytes errors out of btrfsck.

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
[ luis: adjust context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 fs/btrfs/tree-log.c | 48 ++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 42 insertions(+), 6 deletions(-)

--
1.8.1.2

Patch

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index aad8644..5a1ff11 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -315,6 +315,7 @@  static noinline int overwrite_item(struct btrfs_trans_handle *trans,
 	unsigned long src_ptr;
 	unsigned long dst_ptr;
 	int overwrite_root = 0;
+	bool inode_item = key->type == BTRFS_INODE_ITEM_KEY;

 	if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
 		overwrite_root = 1;
@@ -324,6 +325,9 @@  static noinline int overwrite_item(struct btrfs_trans_handle *trans,

 	/* look for the key in the destination tree */
 	ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
+	if (ret < 0)
+		return ret;
+
 	if (ret == 0) {
 		char *src_copy;
 		char *dst_copy;
@@ -365,6 +369,30 @@  static noinline int overwrite_item(struct btrfs_trans_handle *trans,
 			return 0;
 		}

+		/*
+		 * We need to load the old nbytes into the inode so when we
+		 * replay the extents we've logged we get the right nbytes.
+		 */
+		if (inode_item) {
+			struct btrfs_inode_item *item;
+			u64 nbytes;
+
+			item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+					      struct btrfs_inode_item);
+			nbytes = btrfs_inode_nbytes(path->nodes[0], item);
+			item = btrfs_item_ptr(eb, slot,
+					      struct btrfs_inode_item);
+			btrfs_set_inode_nbytes(eb, item, nbytes);
+		}
+	} else if (inode_item) {
+		struct btrfs_inode_item *item;
+
+		/*
+		 * New inode, set nbytes to 0 so that the nbytes comes out
+		 * properly when we replay the extents.
+		 */
+		item = btrfs_item_ptr(eb, slot, struct btrfs_inode_item);
+		btrfs_set_inode_nbytes(eb, item, 0);
 	}
 insert:
 	btrfs_release_path(path);
@@ -486,7 +514,7 @@  static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
 	u64 extent_end;
 	u64 alloc_hint;
 	u64 start = key->offset;
-	u64 saved_nbytes;
+	u64 nbytes = 0;
 	struct btrfs_file_extent_item *item;
 	struct inode *inode = NULL;
 	unsigned long size;
@@ -496,10 +524,19 @@  static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
 	found_type = btrfs_file_extent_type(eb, item);

 	if (found_type == BTRFS_FILE_EXTENT_REG ||
-	    found_type == BTRFS_FILE_EXTENT_PREALLOC)
-		extent_end = start + btrfs_file_extent_num_bytes(eb, item);
-	else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+	    found_type == BTRFS_FILE_EXTENT_PREALLOC) {
+		nbytes = btrfs_file_extent_num_bytes(eb, item);
+		extent_end = start + nbytes;
+
+		/*
+		 * We don't add to the inodes nbytes if we are prealloc or a
+		 * hole.
+		 */
+		if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
+			nbytes = 0;
+	} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 		size = btrfs_file_extent_inline_len(eb, item);
+		nbytes = btrfs_file_extent_ram_bytes(eb, item);
 		extent_end = (start + size + mask) & ~mask;
 	} else {
 		ret = 0;
@@ -548,7 +585,6 @@  static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
 	}
 	btrfs_release_path(path);

-	saved_nbytes = inode_get_bytes(inode);
 	/* drop any overlapping extents */
 	ret = btrfs_drop_extents(trans, inode, start, extent_end,
 				 &alloc_hint, 1);
@@ -636,7 +672,7 @@  static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
 		BUG_ON(ret);
 	}

-	inode_set_bytes(inode, saved_nbytes);
+	inode_add_bytes(inode, nbytes);
 	btrfs_update_inode(trans, root, inode);
 out:
 	if (inode)