tree 9db19a32b309dbf618cd7d3846296fce0b5a2044
parent feebd734134ef18357b0281fb6e7c0a516fe13bc
author Darrick J. Wong <djwong@kernel.org> 1623435593 -0700
committer Darrick J. Wong <djwong@kernel.org> 1627506729 -0700

xfs_io: don't count fsmaps before querying fsmaps

There's a bunch of code in fsmap.c that tries to count the GETFSMAP
records so that it can size the fsmap array appropriately for the
GETFSMAP call.  It's pointless to iterate the entire result set /twice/
(unlike the bmap command where the extent count is actually stored in
the fs metadata), so get rid of the duplicate walk.

In other words: Iterate over the records using the default chunk size
instead of doing one call to find the size and doing a giant allocation
and GETFSMAP call.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>