[v4,0/8] btrfs: free space tree mounting fixes

Message

Boris Burkov Oct. 21, 2020, 11:06 p.m. UTC

This patch set cleans up issues surrounding enabling and disabling various
free space cache features and their reporting in /proc/mounts.  Because the
improvements became somewhat complex, the series starts by lifting rw mount
logic into a single place.

The first patch is a setup patch that unifies very similar logic between a
normal rw mount and a ro->rw remount. This is a useful setup step for adding
more functionality to ro->rw remounts.

The second patch fixes the omission of orphan inode cleanup on a few trees
during ro->rw remount.

The third patch adds enabling the free space tree to ro->rw remount.

The fourth patch sets up for more accurate /proc/mounts by ensuring that
cache_generation > 0 iff space_cache is enabled.

The fifth patch is the more accurate /proc/mounts logic.

The sixth patch is a convenience kernel message that complains when we skip
enabling the free space tree on remount.

The seventh patch removes the space cache v1 free space item and free space
inodes when space cache v1 is disabled (nospace_cache or space_cache=v2).

The eighth patch stops re-creating the free space objects when we are not
using space_cache=v1

changes for v4:
Patch 1/8: New
Patch 2/8: New
Patch 3/8: (was Patch 1) Made much simpler by lifting of Patch 1. Simply add
           free space tree creation to lifted rw mount logic.
Patch 4/8: Split out from old Patch 2. Add an fs_info flag to avoid surprises
           when a different transaction updates the cache_generation.
Patch 5/8: Split out from old Patch 2, but no change logically.
Patch 6/8: Split out from old Patch 1. Formatting fixes.
Patch 7/8: (was Patch 3) Rely on delayed_iput running after orphan cleanup
           (setup in patch 2) to pull iputs out of mount path, per review.
Patch 8/8: No change.

changes for v3:
Patch 1/4: Change failure to warning logging.
Patch 2/4: New; fixes mount option printing.
Patch 3/4: Fix orphan inode vs. delayed iput bug, change remove function
           to take inode as a sink.
Patch 4/4: No changes.

changes for v2:
Patch 1/3: made remount _only_ work in ro->rw case, added comment.
Patch 2/3: added btrfs_ prefix to non-static function, removed bad
           whitespace.


Boris Burkov (8):
  btrfs: lift rw mount setup from mount and remount
  btrfs: cleanup all orphan inodes on ro->rw remount
  btrfs: create free space tree on ro->rw remount
  btrfs: keep sb cache_generation consistent with space_cache
  btrfs: use sb state to print space_cache mount option
  btrfs: warn when remount will not create the free space tree
  btrfs: remove free space items when disabling space cache v1
  btrfs: skip space_cache v1 setup when not using it

 fs/btrfs/block-group.c      |  42 ++---------
 fs/btrfs/ctree.h            |   3 +
 fs/btrfs/disk-io.c          | 141 ++++++++++++++++++++----------------
 fs/btrfs/disk-io.h          |   1 +
 fs/btrfs/free-space-cache.c | 121 +++++++++++++++++++++++++++++++
 fs/btrfs/free-space-cache.h |   6 ++
 fs/btrfs/super.c            |  59 ++++++---------
 fs/btrfs/transaction.c      |   2 +
 8 files changed, 241 insertions(+), 134 deletions(-)