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  1. Jan 22, 2009
    • Chris Mason's avatar
      Btrfs: stop providing a bmap operation to avoid swapfile corruptions · 35054394
      Chris Mason authored 
      

Swapfiles use bmap to build a list of extents belonging to the file,
and they assume these extents won't change over the life of the file.
They also use resulting list to do IO directly to the block device.

This causes problems for btrfs in a few ways:

btrfs returns logical block numbers through bmap, and these are not suitable
for IO.  They might translate to different devices, raid etc.

COW means that file block mappings are going to change frequently.

Using swapfiles on btrfs will lead to corruption, so we're avoiding the
problem for now by dropping bmap support entirely.  A later commit
will add fiemap support for people that really want to know how
a file is laid out.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
      35054394
    • Yan Zheng's avatar
      Btrfs: fix tree logs parallel sync · 7237f183
      Yan Zheng authored 
      

To improve performance, btrfs_sync_log merges tree log sync
requests. But it wrongly merges sync requests for different
tree logs. If multiple tree logs are synced at the same time,
only one of them actually gets synced.

This patch has following changes to fix the bug:

Move most tree log related fields in btrfs_fs_info to
btrfs_root. This allows merging sync requests separately
for each tree log.

Don't insert root item into the log root tree immediately
after log tree is allocated. Root item for log tree is
inserted when log tree get synced for the first time. This
allows syncing the log root tree without first syncing all
log trees.

At tree-log sync, btrfs_sync_log first sync the log tree;
then updates corresponding root item in the log root tree;
sync the log root tree; then update the super block.

Signed-off-by: default avatarYan Zheng <zheng.yan@oracle.com>
      7237f183
  3. Jan 21, 2009
  5. Jan 17, 2009
    • Chris Mason's avatar
      Btrfs: fix ioctl arg size (userland incompatible change!) · c071fcfd
      Chris Mason authored 
      

The structure used to send device in btrfs ioctl calls was not
properly aligned, and so 32 bit ioctls would not work properly on
64 bit kernels.

We could fix this with compat ioctls, but we're just one byte away
and it doesn't make sense at this stage to carry about the compat ioctls
forever at this stage in the project.

This patch brings the ioctl arg up to an evenly aligned 4k.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
      c071fcfd
    • Chris Mason's avatar
      Btrfs: Clear the device->running_pending flag before bailing on congestion · 1d9e2ae9
      Chris Mason authored 
      

Btrfs maintains a queue of async bio submissions so the checksumming
threads don't have to wait on get_request_wait.  In order to avoid
extra wakeups, this code has a running_pending flag that is used
to tell new submissions they don't need to wake the thread.

When the threads notice congestion on a single device, they
may decide to requeue the job and move on to other devices.  This
makes sure the running_pending flag is cleared before the
job is requeued.

It should help avoid IO stalls by making sure the task is woken up
when new submissions come in.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
      1d9e2ae9
  7. Jan 10, 2009
    • Chris Mason's avatar
      Btrfs: explicitly mark the tree log root for writeback · e293e97e
      Chris Mason authored 
      

Each subvolume has an extent_state_tree used to mark metadata
that needs to be sent to disk while syncing the tree.  This is
used in addition to the dirty bits on the pages themselves so that
a single subvolume can be sent to disk efficiently in disk order.

Normally this marking happens in btrfs_alloc_free_block, which also does
special recording of dirty tree blocks for the tree log roots.

Yan Zheng noticed that when the root of the log tree is allocated, it is added
to the wrong writeback list.  The fix used here is to explicitly set
it dirty as part of tree log creation.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
      e293e97e
  9. Jan 08, 2009
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