[PATCH v4 0/8] speculative preallocation inode tracking

Brian Foster
2012-09-27T17:42:54Z

Hi all,

This is v3 of the speculative preallocation inode tracking patchset. This
functionality tracks inodes with post-EOF speculative preallocation for the
purpose of background and on-demand trimming.

Background scanning occurs on a longish interval (5 minutes by default) and in
a best-effort mode (i.e., inodes are skipped due to lock contention or dirty
cache). The intent is to clear up post-EOF blocks on inodes that might have
allocations hanging around due to open-write-close sequences (NFS).

On demand scanning is provided via a new ioctl and supports various parameters
such as scan mode, filtering by quota id and minimum file size. A pending use
case for on demand scanning is for accurate quota accounting via the gluster
scale out filesystem (i.e., to free up preallocated space when near a usage
limit).

Brian

v4:
- Fix the broken need_iolock parameter to the xfs_free_eofblocks() call in
patch 5 (thanks to Ben M. for testing). This is a one line change. All
other patches equivalent to v3. This version survives an xfstests run (with
XFS_DEBUG enabled this time :P).

v3:
- Pushed dirty cache check up into patch 5 (minor clean up).
- Reworked xfs_can_free_eofblocks() in patch 3 as per Dave C.'s review.
- Rebased from linus' tree to the XFS tree.

v2:
- Remove unnecessary inode flag clear helper.
- Condense eofblocks set/clear tag functions.
- Move clear tag call into xfs_free_eofblocks().
- Modify AG walk infrastructure to support tag-based walk and utilize this
functionality for the eofblocks scan (as opposed to the previous code
duplicated from reclaim scanning).
- Improve ioctl functionality: new data structure fields/flags, validate quota
is enabled.
- Increase default background scanning interval to 5 minutes, add tunable.

Brian Foster (8):
xfs: add EOFBLOCKS inode tagging/untagging
xfs: support a tag-based inode_ag_iterator
xfs: create helper to check whether to free eofblocks on inode
xfs: export xfs_free_eofblocks() and return EAGAIN on trylock failure
xfs: create function to scan and clear EOFBLOCKS inodes
xfs: add XFS_IOC_FREE_EOFBLOCKS ioctl
xfs: add enhanced filtering to EOFBLOCKS scan
xfs: add background scanning to clear EOFBLOCKS inodes

fs/xfs/xfs_ag.h | 1 +
fs/xfs/xfs_fs.h | 23 +++++
fs/xfs/xfs_globals.c | 1 +
fs/xfs/xfs_ioctl.c | 20 ++++
fs/xfs/xfs_iomap.c | 7 ++
fs/xfs/xfs_iops.c | 3 +
fs/xfs/xfs_linux.h | 1 +
fs/xfs/xfs_mount.h | 2 +
fs/xfs/xfs_qm_syscalls.c | 5 +-
fs/xfs/xfs_sync.c | 215 ++++++++++++++++++++++++++++++++++++++++++++--
fs/xfs/xfs_sync.h | 11 ++-
fs/xfs/xfs_sysctl.c | 9 ++
fs/xfs/xfs_sysctl.h | 1 +
fs/xfs/xfs_trace.h | 6 ++
fs/xfs/xfs_vnodeops.c | 27 +++---
fs/xfs/xfs_vnodeops.h | 41 +++++++++-
16 files changed, 344 insertions(+), 29 deletions(-)

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1.7.7.6