bcachefs: Don't check for -ENOSPC in page writeback

If at all possible we'd prefer to not fail page writeback unless the
filesystem has been shutdown; allowing errors in page writeback means
things we'd like to assert about i_size consistency between the VFS and
the btree go out the window.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

diff --git a/fs/bcachefs/fs-io.c b/fs/bcachefs/fs-io.c
index 12b785c5005f5a528a0e1bdbfde8163a5c6912eb..ac013bb99a4367dd0e2fabcb055f8914e8016de8 100644 (file)
--- a/fs/bcachefs/fs-io.c
+++ b/fs/bcachefs/fs-io.c
@@ -1144,16 +1144,16 @@ static int __bch2_writepage(struct folio *folio,
 do_io:
        s = bch2_page_state_create(page, __GFP_NOFAIL);
 
-       ret = bch2_get_page_disk_reservation(c, inode, page, true);
-       if (ret) {
-               SetPageError(page);
-               mapping_set_error(page->mapping, ret);
-               unlock_page(page);
-               return 0;
-       }
+       /*
+        * Things get really hairy with errors during writeback:
+        */
+       ret = bch2_get_page_disk_reservation(c, inode, page, false);
+       BUG_ON(ret);
 
        /* Before unlocking the page, get copy of reservations: */
+       spin_lock(&s->lock);
        orig = *s;
+       spin_unlock(&s->lock);
 
        for (i = 0; i < PAGE_SECTORS; i++) {
                if (s->s[i].state < SECTOR_DIRTY)
@@ -1186,7 +1186,7 @@ do_io:
 
        offset = 0;
        while (1) {
-               unsigned sectors = 1, dirty_sectors = 0, reserved_sectors = 0;
+               unsigned sectors = 0, dirty_sectors = 0, reserved_sectors = 0;
                u64 sector;
 
                while (offset < PAGE_SECTORS &&
@@ -1196,16 +1196,15 @@ do_io:
                if (offset == PAGE_SECTORS)
                        break;
 
-               sector = ((u64) page->index << PAGE_SECTOR_SHIFT) + offset;
-
                while (offset + sectors < PAGE_SECTORS &&
-                      orig.s[offset + sectors].state >= SECTOR_DIRTY)
+                      orig.s[offset + sectors].state >= SECTOR_DIRTY) {
+                       reserved_sectors += orig.s[offset + sectors].replicas_reserved;
+                       dirty_sectors += orig.s[offset + sectors].state == SECTOR_DIRTY;
                        sectors++;
-
-               for (i = offset; i < offset + sectors; i++) {
-                       reserved_sectors += orig.s[i].replicas_reserved;
-                       dirty_sectors += orig.s[i].state == SECTOR_DIRTY;
                }
+               BUG_ON(!sectors);
+
+               sector = ((u64) page->index << PAGE_SECTOR_SHIFT) + offset;
 
                if (w->io &&
                    (w->io->op.res.nr_replicas != nr_replicas_this_write ||