Btrfs: Fix disk_i_size update corner case
There are some cases file extents are inserted without involving
ordered struct. In these cases, we update disk_i_size directly,
without checking pending ordered extent and DELALLOC bit. This
patch extends btrfs_ordered_update_i_size() to handle these cases.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 5799bc4..9b16073 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -291,16 +291,16 @@
/*
* remove an ordered extent from the tree. No references are dropped
- * but, anyone waiting on this extent is woken up.
+ * and you must wake_up entry->wait. You must hold the tree mutex
+ * while you call this function.
*/
-int btrfs_remove_ordered_extent(struct inode *inode,
+static int __btrfs_remove_ordered_extent(struct inode *inode,
struct btrfs_ordered_extent *entry)
{
struct btrfs_ordered_inode_tree *tree;
struct rb_node *node;
tree = &BTRFS_I(inode)->ordered_tree;
- mutex_lock(&tree->mutex);
node = &entry->rb_node;
rb_erase(node, &tree->tree);
tree->last = NULL;
@@ -326,9 +326,26 @@
}
spin_unlock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
+ return 0;
+}
+
+/*
+ * remove an ordered extent from the tree. No references are dropped
+ * but any waiters are woken.
+ */
+int btrfs_remove_ordered_extent(struct inode *inode,
+ struct btrfs_ordered_extent *entry)
+{
+ struct btrfs_ordered_inode_tree *tree;
+ int ret;
+
+ tree = &BTRFS_I(inode)->ordered_tree;
+ mutex_lock(&tree->mutex);
+ ret = __btrfs_remove_ordered_extent(inode, entry);
mutex_unlock(&tree->mutex);
wake_up(&entry->wait);
- return 0;
+
+ return ret;
}
/*
@@ -589,7 +606,7 @@
* After an extent is done, call this to conditionally update the on disk
* i_size. i_size is updated to cover any fully written part of the file.
*/
-int btrfs_ordered_update_i_size(struct inode *inode,
+int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
struct btrfs_ordered_extent *ordered)
{
struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
@@ -597,18 +614,30 @@
u64 disk_i_size;
u64 new_i_size;
u64 i_size_test;
+ u64 i_size = i_size_read(inode);
struct rb_node *node;
+ struct rb_node *prev = NULL;
struct btrfs_ordered_extent *test;
+ int ret = 1;
+
+ if (ordered)
+ offset = entry_end(ordered);
mutex_lock(&tree->mutex);
disk_i_size = BTRFS_I(inode)->disk_i_size;
+ /* truncate file */
+ if (disk_i_size > i_size) {
+ BTRFS_I(inode)->disk_i_size = i_size;
+ ret = 0;
+ goto out;
+ }
+
/*
* if the disk i_size is already at the inode->i_size, or
* this ordered extent is inside the disk i_size, we're done
*/
- if (disk_i_size >= inode->i_size ||
- ordered->file_offset + ordered->len <= disk_i_size) {
+ if (disk_i_size == i_size || offset <= disk_i_size) {
goto out;
}
@@ -616,8 +645,7 @@
* we can't update the disk_isize if there are delalloc bytes
* between disk_i_size and this ordered extent
*/
- if (test_range_bit(io_tree, disk_i_size,
- ordered->file_offset + ordered->len - 1,
+ if (test_range_bit(io_tree, disk_i_size, offset - 1,
EXTENT_DELALLOC, 0, NULL)) {
goto out;
}
@@ -626,20 +654,32 @@
* if we find an ordered extent then we can't update disk i_size
* yet
*/
- node = &ordered->rb_node;
- while (1) {
- node = rb_prev(node);
- if (!node)
- break;
+ if (ordered) {
+ node = rb_prev(&ordered->rb_node);
+ } else {
+ prev = tree_search(tree, offset);
+ /*
+ * we insert file extents without involving ordered struct,
+ * so there should be no ordered struct cover this offset
+ */
+ if (prev) {
+ test = rb_entry(prev, struct btrfs_ordered_extent,
+ rb_node);
+ BUG_ON(offset_in_entry(test, offset));
+ }
+ node = prev;
+ }
+ while (node) {
test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
if (test->file_offset + test->len <= disk_i_size)
break;
- if (test->file_offset >= inode->i_size)
+ if (test->file_offset >= i_size)
break;
if (test->file_offset >= disk_i_size)
goto out;
+ node = rb_prev(node);
}
- new_i_size = min_t(u64, entry_end(ordered), i_size_read(inode));
+ new_i_size = min_t(u64, offset, i_size);
/*
* at this point, we know we can safely update i_size to at least
@@ -647,7 +687,14 @@
* walk forward and see if ios from higher up in the file have
* finished.
*/
- node = rb_next(&ordered->rb_node);
+ if (ordered) {
+ node = rb_next(&ordered->rb_node);
+ } else {
+ if (prev)
+ node = rb_next(prev);
+ else
+ node = rb_first(&tree->tree);
+ }
i_size_test = 0;
if (node) {
/*
@@ -655,10 +702,10 @@
* between our ordered extent and the next one.
*/
test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
- if (test->file_offset > entry_end(ordered))
+ if (test->file_offset > offset)
i_size_test = test->file_offset;
} else {
- i_size_test = i_size_read(inode);
+ i_size_test = i_size;
}
/*
@@ -667,15 +714,25 @@
* are no delalloc bytes in this area, it is safe to update
* disk_i_size to the end of the region.
*/
- if (i_size_test > entry_end(ordered) &&
- !test_range_bit(io_tree, entry_end(ordered), i_size_test - 1,
- EXTENT_DELALLOC, 0, NULL)) {
- new_i_size = min_t(u64, i_size_test, i_size_read(inode));
+ if (i_size_test > offset &&
+ !test_range_bit(io_tree, offset, i_size_test - 1,
+ EXTENT_DELALLOC, 0, NULL)) {
+ new_i_size = min_t(u64, i_size_test, i_size);
}
BTRFS_I(inode)->disk_i_size = new_i_size;
+ ret = 0;
out:
+ /*
+ * we need to remove the ordered extent with the tree lock held
+ * so that other people calling this function don't find our fully
+ * processed ordered entry and skip updating the i_size
+ */
+ if (ordered)
+ __btrfs_remove_ordered_extent(inode, ordered);
mutex_unlock(&tree->mutex);
- return 0;
+ if (ordered)
+ wake_up(&ordered->wait);
+ return ret;
}
/*