int committed;
int error;
int lockmode;
+ int bmapi_flags = XFS_BMAPI_PREALLOC;
rt = XFS_IS_REALTIME_INODE(ip);
extsz = xfs_get_extsz_hint(ip);
* Allocate and setup the transaction
*/
tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT);
+
+ /*
+ * For DAX, we do not allocate unwritten extents, but instead we zero
+ * the block before we commit the transaction. Ideally we'd like to do
+ * this outside the transaction context, but if we commit and then crash
+ * we may not have zeroed the blocks and this will be exposed on
+ * recovery of the allocation. Hence we must zero before commit.
+ * Further, if we are mapping unwritten extents here, we need to zero
+ * and convert them to written so that we don't need an unwritten extent
+ * callback for DAX. This also means that we need to be able to dip into
+ * the reserve block pool if there is no space left but we need to do
+ * unwritten extent conversion.
+ */
+ if (IS_DAX(VFS_I(ip))) {
+ bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO;
+ tp->t_flags |= XFS_TRANS_RESERVE;
+ }
error = xfs_trans_reserve(tp, &M_RES(mp)->tr_write,
resblks, resrtextents);
/*
xfs_bmap_init(&free_list, &firstfsb);
nimaps = 1;
error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
- XFS_BMAPI_PREALLOC, &firstfsb, resblks, imap,
+ bmapi_flags, &firstfsb, resblks, imap,
&nimaps, &free_list);
if (error)
goto out_bmap_cancel;
error = xfs_bmap_finish(&tp, &free_list, &committed);
if (error)
goto out_bmap_cancel;
+
error = xfs_trans_commit(tp);
if (error)
goto out_unlock;