summaryrefslogtreecommitdiff
path: root/kernels/linux-libre-rt/3.12-btrfs-relocate-csums.patch
diff options
context:
space:
mode:
Diffstat (limited to 'kernels/linux-libre-rt/3.12-btrfs-relocate-csums.patch')
-rw-r--r--kernels/linux-libre-rt/3.12-btrfs-relocate-csums.patch63
1 files changed, 63 insertions, 0 deletions
diff --git a/kernels/linux-libre-rt/3.12-btrfs-relocate-csums.patch b/kernels/linux-libre-rt/3.12-btrfs-relocate-csums.patch
new file mode 100644
index 000000000..7209276ef
--- /dev/null
+++ b/kernels/linux-libre-rt/3.12-btrfs-relocate-csums.patch
@@ -0,0 +1,63 @@
+From 4577b014d1bc3db386da3246f625888fc48083a9 Mon Sep 17 00:00:00 2001
+From: Josef Bacik <jbacik@fusionio.com>
+Date: Fri, 27 Sep 2013 13:33:09 +0000
+Subject: Btrfs: relocate csums properly with prealloc extents
+
+A user reported a problem where they were getting csum errors when running a
+balance and running systemd's journal. This is because systemd is awesome and
+fallocate()'s its log space and writes into it. Unfortunately we assume that
+when we read in all the csums for an extent that they are sequential starting at
+the bytenr we care about. This obviously isn't the case for prealloc extents,
+where we could have written to the middle of the prealloc extent only, which
+means the csum would be for the bytenr in the middle of our range and not the
+front of our range. Fix this by offsetting the new bytenr we are logging to
+based on the original bytenr the csum was for. With this patch I no longer see
+the csum errors I was seeing. Thanks,
+
+Cc: stable@vger.kernel.org
+Reported-by: Chris Murphy <lists@colorremedies.com>
+Signed-off-by: Josef Bacik <jbacik@fusionio.com>
+Signed-off-by: Chris Mason <chris.mason@fusionio.com>
+---
+diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
+index dec4f5a..0359eec 100644
+--- a/fs/btrfs/relocation.c
++++ b/fs/btrfs/relocation.c
+@@ -4472,6 +4472,7 @@ int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ int ret;
+ u64 disk_bytenr;
++ u64 new_bytenr;
+ LIST_HEAD(list);
+
+ ordered = btrfs_lookup_ordered_extent(inode, file_pos);
+@@ -4483,13 +4484,24 @@ int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
+ if (ret)
+ goto out;
+
+- disk_bytenr = ordered->start;
+ while (!list_empty(&list)) {
+ sums = list_entry(list.next, struct btrfs_ordered_sum, list);
+ list_del_init(&sums->list);
+
+- sums->bytenr = disk_bytenr;
+- disk_bytenr += sums->len;
++ /*
++ * We need to offset the new_bytenr based on where the csum is.
++ * We need to do this because we will read in entire prealloc
++ * extents but we may have written to say the middle of the
++ * prealloc extent, so we need to make sure the csum goes with
++ * the right disk offset.
++ *
++ * We can do this because the data reloc inode refers strictly
++ * to the on disk bytes, so we don't have to worry about
++ * disk_len vs real len like with real inodes since it's all
++ * disk length.
++ */
++ new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
++ sums->bytenr = new_bytenr;
+
+ btrfs_add_ordered_sum(inode, ordered, sums);
+ }
+--
+cgit v0.9.2