wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
}
+static void set_btree_ioerr(struct page *page)
+{
+ struct extent_buffer *eb = (struct extent_buffer *)page->private;
+ struct btrfs_inode *btree_ino = BTRFS_I(eb->fs_info->btree_inode);
+
+ SetPageError(page);
+ if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
+ return;
+
+ /*
+ * If writeback for a btree extent that doesn't belong to a log tree
+ * failed, increment the counter transaction->eb_write_errors.
+ * We do this because while the transaction is running and before it's
+ * committing (when we call filemap_fdata[write|wait]_range against
+ * the btree inode), we might have
+ * btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
+ * returns an error or an error happens during writeback, when we're
+ * committing the transaction we wouldn't know about it, since the pages
+ * can be no longer dirty nor marked anymore for writeback (if a
+ * subsequent modification to the extent buffer didn't happen before the
+ * transaction commit), which makes filemap_fdata[write|wait]_range not
+ * able to find the pages tagged with SetPageError at transaction
+ * commit time. So if this happens we must abort the transaction,
+ * otherwise we commit a super block with btree roots that point to
+ * btree nodes/leafs whose content on disk is invalid - either garbage
+ * or the content of some node/leaf from a past generation that got
+ * cowed or deleted and is no longer valid.
+ *
+ * Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
+ * not be enough - we need to distinguish between log tree extents vs
+ * non-log tree extents, and the next filemap_fdatawait_range() call
+ * will catch and clear such errors in the mapping - and that call might
+ * be from a log sync and not from a transaction commit. Also, checking
+ * for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
+ * not done and would not be reliable - the eb might have been released
+ * from memory and reading it back again means that flag would not be
+ * set (since it's a runtime flag, not persisted on disk).
+ *
+ * Using the flags below in the btree inode also makes us achieve the
+ * goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
+ * writeback for all dirty pages and before filemap_fdatawait_range()
+ * is called, the writeback for all dirty pages had already finished
+ * with errors - because we were not using AS_EIO/AS_ENOSPC,
+ * filemap_fdatawait_range() would return success, as it could not know
+ * that writeback errors happened (the pages were no longer tagged for
+ * writeback).
+ */
+ switch (eb->log_index) {
+ case -1:
+ set_bit(BTRFS_INODE_BTREE_ERR, &btree_ino->runtime_flags);
+ break;
+ case 0:
+ set_bit(BTRFS_INODE_BTREE_LOG1_ERR, &btree_ino->runtime_flags);
+ break;
+ case 1:
+ set_bit(BTRFS_INODE_BTREE_LOG2_ERR, &btree_ino->runtime_flags);
+ break;
+ default:
+ BUG(); /* unexpected, logic error */
+ }
+}
+
static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
{
struct bio_vec *bvec;
BUG_ON(!eb);
done = atomic_dec_and_test(&eb->io_pages);
- if (err || test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) {
- set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
+ if (err || test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
ClearPageUptodate(page);
- SetPageError(page);
+ set_btree_ioerr(page);
}
end_page_writeback(page);
int rw = (epd->sync_io ? WRITE_SYNC : WRITE) | REQ_META;
int ret = 0;
- clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
+ clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
num_pages = num_extent_pages(eb->start, eb->len);
atomic_set(&eb->io_pages, num_pages);
if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID)
0, epd->bio_flags, bio_flags);
epd->bio_flags = bio_flags;
if (ret) {
- set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
- SetPageError(p);
+ set_btree_ioerr(p);
+ end_page_writeback(p);
if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
end_extent_buffer_writeback(eb);
ret = -EIO;
}
if (unlikely(ret)) {
- for (; i < num_pages; i++)
- unlock_page(eb->pages[i]);
+ for (; i < num_pages; i++) {
+ struct page *p = eb->pages[i];
+ clear_page_dirty_for_io(p);
+ unlock_page(p);
+ }
}
return ret;
goto unlock_exit;
}
- clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
+ clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
eb->read_mirror = 0;
atomic_set(&eb->io_pages, num_reads);
for (i = start_i; i < num_pages; i++) {
projects / linux-2.6-block.git / blobdiff