[PATCH 17/21] fs: xfs: iomap atomic write support
From: John Garry <john.g.garry@oracle.com>
Date: 2023-09-29 10:30:07
Also in:
linux-block, linux-fsdevel, linux-nvme, linux-xfs, lkml
Subsystem:
filesystems (vfs and infrastructure), the rest, xfs filesystem · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds, Carlos Maiolino
Ensure that when creating a mapping that we adhere to all the atomic write rules. We check that the mapping covers the complete range of the write to ensure that we'll be just creating a single mapping. Currently minimum granularity is the FS block size, but it should be possibly to support lower in future. Signed-off-by: John Garry <john.g.garry@oracle.com> --- fs/xfs/xfs_iomap.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+)
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 70fe873951f3..3424fcfc04f5 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c@@ -783,6 +783,7 @@ xfs_direct_write_iomap_begin( { struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; + struct xfs_sb *m_sb = &mp->m_sb; struct xfs_bmbt_irec imap, cmap; xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset); xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
@@ -814,6 +815,41 @@ xfs_direct_write_iomap_begin( if (error) goto out_unlock; + if (flags & IOMAP_ATOMIC_WRITE) { + xfs_filblks_t unit_min_fsb, unit_max_fsb; + + xfs_ip_atomic_write_attr(ip, &unit_min_fsb, &unit_max_fsb); + + if (!imap_spans_range(&imap, offset_fsb, end_fsb)) { + error = -EIO; + goto out_unlock; + } + + if (offset % m_sb->sb_blocksize || + length % m_sb->sb_blocksize) { + error = -EIO; + goto out_unlock; + } + + if (imap.br_blockcount == unit_min_fsb || + imap.br_blockcount == unit_max_fsb) { + /* min and max must be a power-of-2 */ + } else if (imap.br_blockcount < unit_min_fsb || + imap.br_blockcount > unit_max_fsb) { + error = -EIO; + goto out_unlock; + } else if (!is_power_of_2(imap.br_blockcount)) { + error = -EIO; + goto out_unlock; + } + + if (imap.br_startoff && + imap.br_startoff % imap.br_blockcount) { + error = -EIO; + goto out_unlock; + } + } + if (imap_needs_cow(ip, flags, &imap, nimaps)) { error = -EAGAIN; if (flags & IOMAP_NOWAIT)
--
2.31.1