The iomap zeroing interface is smart enough to skip zeroing holes or
unwritten extents. Don't subvert this logic for reflink files.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/xfs/xfs_iomap.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 66e1edbfb2b2..4e771e0f1170 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -955,6 +955,13 @@ static inline bool imap_needs_alloc(struct inode *inode,
(IS_DAX(inode) && imap->br_state == XFS_EXT_UNWRITTEN);
}
+static inline bool needs_cow_for_zeroing(struct xfs_bmbt_irec *imap, int nimaps)
+{
+ return nimaps &&
+ imap->br_startblock != HOLESTARTBLOCK &&
+ imap->br_state != XFS_EXT_UNWRITTEN;
+}
+
static inline bool need_excl_ilock(struct xfs_inode *ip, unsigned flags)
{
/*
@@ -1024,7 +1031,9 @@ xfs_file_iomap_begin(
goto out_unlock;
}
- if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {
+ if (xfs_is_reflink_inode(ip) &&
+ ((flags & IOMAP_WRITE) ||
+ ((flags & IOMAP_ZERO) && needs_cow_for_zeroing(&imap, nimaps)))) {
if (flags & IOMAP_DIRECT) {
/*
* A reflinked inode will result in CoW alloc.
--
2.14.2
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