end_of_last_block = start_pos + num_bytes - 1;
+ /*
+ * The pages may have already been dirty, clear out old accounting so
+ * we can set things up properly
+ */
+ clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos, end_of_last_block,
+ EXTENT_DIRTY | EXTENT_DELALLOC |
+ EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 0, 0, cached);
+
if (!btrfs_is_free_space_inode(BTRFS_I(inode))) {
if (start_pos >= isize &&
!(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC)) {
}
if (ordered)
btrfs_put_ordered_extent(ordered);
- clear_extent_bit(&inode->io_tree, start_pos, last_pos,
- EXTENT_DIRTY | EXTENT_DELALLOC |
- EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
- 0, 0, cached_state);
+
*lockstart = start_pos;
*lockend = last_pos;
ret = 1;
}
+ /*
+ * It's possible the pages are dirty right now, but we don't want
+ * to clean them yet because copy_from_user may catch a page fault
+ * and we might have to fall back to one page at a time. If that
+ * happens, we'll unlock these pages and we'd have a window where
+ * reclaim could sneak in and drop the once-dirty page on the floor
+ * without writing it.
+ *
+ * We have the pages locked and the extent range locked, so there's
+ * no way someone can start IO on any dirty pages in this range.
+ *
+ * We'll call btrfs_dirty_pages() later on, and that will flip around
+ * delalloc bits and dirty the pages as required.
+ */
for (i = 0; i < num_pages; i++) {
- if (clear_page_dirty_for_io(pages[i]))
- account_page_redirty(pages[i]);
set_page_extent_mapped(pages[i]);
WARN_ON(!PageLocked(pages[i]));
}
goto out;
inode_lock(inode);
+
+ /*
+ * We take the dio_sem here because the tree log stuff can race with
+ * lockless dio writes and get an extent map logged for an extent we
+ * never waited on. We need it this high up for lockdep reasons.
+ */
+ down_write(&BTRFS_I(inode)->dio_sem);
+
atomic_inc(&root->log_batch);
+ /*
+ * Before we acquired the inode's lock, someone may have dirtied more
+ * pages in the target range. We need to make sure that writeback for
+ * any such pages does not start while we are logging the inode, because
+ * if it does, any of the following might happen when we are not doing a
+ * full inode sync:
+ *
+ * 1) We log an extent after its writeback finishes but before its
+ * checksums are added to the csum tree, leading to -EIO errors
+ * when attempting to read the extent after a log replay.
+ *
+ * 2) We can end up logging an extent before its writeback finishes.
+ * Therefore after the log replay we will have a file extent item
+ * pointing to an unwritten extent (and no data checksums as well).
+ *
+ * So trigger writeback for any eventual new dirty pages and then we
+ * wait for all ordered extents to complete below.
+ */
+ ret = start_ordered_ops(inode, start, end);
+ if (ret) {
+ inode_unlock(inode);
+ goto out;
+ }
+
/*
* We have to do this here to avoid the priority inversion of waiting on
* IO of a lower priority task while holding a transaciton open.
*/
ret = btrfs_wait_ordered_range(inode, start, len);
if (ret) {
+ up_write(&BTRFS_I(inode)->dio_sem);
inode_unlock(inode);
goto out;
}
* checked called fsync.
*/
ret = filemap_check_wb_err(inode->i_mapping, file->f_wb_err);
+ up_write(&BTRFS_I(inode)->dio_sem);
inode_unlock(inode);
goto out;
}
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
+ up_write(&BTRFS_I(inode)->dio_sem);
inode_unlock(inode);
goto out;
}
* file again, but that will end up using the synchronization
* inside btrfs_sync_log to keep things safe.
*/
+ up_write(&BTRFS_I(inode)->dio_sem);
inode_unlock(inode);
/*
}
ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
- min_size, 0);
+ min_size, false);
BUG_ON(ret);
trans->block_rsv = rsv;
}
ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
- rsv, min_size, 0);
+ rsv, min_size, false);
BUG_ON(ret); /* shouldn't happen */
trans->block_rsv = rsv;
git.samba.org / sfrench / cifs-2.6.git / blobdiff