[PATCH 4/6] xfs: add a free space extent change reservation
From: Dave Chinner <david@fromorbit.com>
Date: 2021-05-27 04:52:12
Subsystem:
filesystems (vfs and infrastructure), the rest, xfs filesystem · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds, Carlos Maiolino
From: Dave Chinner <redacted> Lots of the transaction reservation code reserves space for an extent allocation. It is inconsistently implemented, and many of them get it wrong. Introduce a new function to calculate the log space reservation for adding or removing an extent from the free space btrees. This function reserves space for logging the AGF, the AGFL and the free space btrees, avoiding the need to account for them seperately in every reservation that manipulates free space. Signed-off-by: Dave Chinner <redacted> --- fs/xfs/libxfs/xfs_trans_resv.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c
index d1a0848cb52e..6363cacb790f 100644
--- a/fs/xfs/libxfs/xfs_trans_resv.c
+++ b/fs/xfs/libxfs/xfs_trans_resv.c@@ -79,6 +79,23 @@ xfs_allocfree_log_count( return blocks; } +/* + * Log reservation required to add or remove a single extent to the free space + * btrees. This requires modifying: + * + * the agf header: 1 sector + * the agfl header: 1 sector + * the allocation btrees: 2 trees * (max depth - 1) * block size + */ +uint +xfs_allocfree_extent_res( + struct xfs_mount *mp) +{ + return xfs_calc_buf_res(2, mp->m_sb.sb_sectsize) + + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 1), + XFS_FSB_TO_B(mp, 1)); +} + /* * Logging inodes is really tricksy. They are logged in memory format, * which means that what we write into the log doesn't directly translate into
--
2.31.1