[LU-16856] LU-14729 broke a grants for the fallocate files.

• Status: Open
• Project: Lustre
• Type: Bug
• Priority: Critical
• Reporter: Alexey Lyashkov
• Assignee: WC Triage
• Resolution: Unresolved
• Severity: 3

Description

commit 9810341a839c27b7a53cdc047e0395f8f906c4bf (refs/changes/94/43994/4)
introduce a change

+               /*
+                * Convert unwritten extent might need split extents, could
+                * not skip it.
+                */
+               if (osd_is_mapped(dt, lnb[i].lnb_file_offset, &mapped) &&
+                   !(mapped.flags & FIEMAP_EXTENT_UNWRITTEN)) {
                        lnb[i].lnb_flags |= OBD_BRW_MAPPED;
                        continue;
                }

It caused an fallocated extents counted as new write extents for grants, but space is already allocated and grants should don't used for this case. It caused a write lost in case OST is full and grants can't be provided as first check will return false.

        for (i = 0; i < npages; i++) {
                if (lnb[i].lnb_rc == -ENOSPC &&
                    (lnb[i].lnb_flags & OBD_BRW_MAPPED)) {
                        /* Allow the write to proceed if overwriting an
                         * existing block
                         */
                        lnb[i].lnb_rc = 0;
                }

                if (lnb[i].lnb_rc) { /* ENOSPC, network RPC error, etc. */
                        CDEBUG(D_INODE, "Skipping [%d] == %d\n", i,
                               lnb[i].lnb_rc);
                        LASSERT(lnb[i].lnb_page);
                        generic_error_remove_page(inode->i_mapping,
                                                  lnb[i].lnb_page);
                        continue;
                }