xfsprogs: defragment free space [58/62]
These patches contain experimental code to enable userspace to defragment
the free space in a filesystem. Two purposes are imagined for this
functionality: clearing space at the end of a filesystem before
shrinking it, and clearing free space in anticipation of making a large
allocation.
The first patch adds a new fallocate mode that allows userspace to
allocate free space from the filesystem into a file. The goal here is
to allow the filesystem shrink process to prevent allocation from a
certain part of the filesystem while a free space defragmenter evacuates
all the files from the doomed part of the filesystem.
The second patch amends the online repair system to allow the sysadmin
to forcibly rebuild metadata structures, even if they're not corrupt.
Without adding an ioctl to move metadata btree blocks, this is the only
way to dislodge metadata.
This patchset also includes a separate inode migration tool as
prototyped by Dave Chinner in 2020.
This has been running on the djcloud for months with no problems. Enjoy!
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
spaceman: move inodes with hardlinks
When a inode to be moved to a different AG has multiple hard links,
we need to "move" all the hard links, too. To do this, we need to
create temporary hardlinks to the new file, and then use rename
exchange to swap all the hardlinks that point to the old inode
with new hardlinks that point to the new inode.
We already know that an inode has hard links via the path discovery,
and we can check it against the link count that is reported for the
inode before we start building the link farm.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
4 files changed
