Since we do a delalloc reserve in btrfs_truncate_block we can deadlock
with freeze. If somebody else is trying to allocate metadata for this
inode and it gets stuck in start_delalloc_inodes because of freeze we
will deadlock. Be safe and move this outside of a trans handle. This
also has a side-effect of making sure that we're not leaving stale data
behind in the other_encoding or encryption case. Not an issue now since
nobody uses it, but it would be a problem in the future.
Signed-off-by: Josef Bacik <jba...@fb.com>
---
fs/btrfs/inode.c | 119 ++++++++++++++++++++-----------------------------------
1 file changed, 44 insertions(+), 75 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 3cbddfc181dc..46b5632a7c6d 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4364,47 +4364,11 @@ static int truncate_space_check(struct
btrfs_trans_handle *trans,
}
-static int truncate_inline_extent(struct inode *inode,
- struct btrfs_path *path,
- struct btrfs_key *found_key,
- const u64 item_end,
- const u64 new_size)
-{
- struct extent_buffer *leaf = path->nodes[0];
- int slot = path->slots[0];
- struct btrfs_file_extent_item *fi;
- u32 size = (u32)(new_size - found_key->offset);
- struct btrfs_root *root = BTRFS_I(inode)->root;
-
- fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
-
- if (btrfs_file_extent_compression(leaf, fi) != BTRFS_COMPRESS_NONE) {
- loff_t offset = new_size;
- loff_t page_end = ALIGN(offset, PAGE_SIZE);
-
- /*
- * Zero out the remaining of the last page of our inline extent,
- * instead of directly truncating our inline extent here - that
- * would be much more complex (decompressing all the data, then
- * compressing the truncated data, which might be bigger than
- * the size of the inline extent, resize the extent, etc).
- * We release the path because to get the page we might need to
- * read the extent item from disk (data not in the page cache).
- */
- btrfs_release_path(path);
- return btrfs_truncate_block(inode, offset, page_end - offset,
- 0);
- }
-
- btrfs_set_file_extent_ram_bytes(leaf, fi, size);
- size = btrfs_file_extent_calc_inline_size(size);
- btrfs_truncate_item(root->fs_info, path, size, 1);
-
- if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
- inode_sub_bytes(inode, item_end + 1 - new_size);
-
- return 0;
-}
+/*
+ * Return this if we need to call truncate_block for the last bit of the
+ * truncate.
+ */
+#define NEED_TRUNCATE_BLOCK 1
/*
* this can truncate away extent items, csum items and directory items.
@@ -4565,11 +4529,6 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle
*trans,
if (found_type != BTRFS_EXTENT_DATA_KEY)
goto delete;
- if (del_item)
- last_size = found_key.offset;
- else
- last_size = new_size;
-
if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
u64 num_dec;
extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
@@ -4611,40 +4570,29 @@ int btrfs_truncate_inode_items(struct
btrfs_trans_handle *trans,
*/
if (!del_item &&
btrfs_file_extent_encryption(leaf, fi) == 0 &&
- btrfs_file_extent_other_encoding(leaf, fi) == 0) {
-
+ btrfs_file_extent_other_encoding(leaf, fi) == 0 &&
+ btrfs_file_extent_compression(leaf, fi) == 0) {
+ u32 size = (u32)(new_size - found_key.offset);
+ btrfs_set_file_extent_ram_bytes(leaf, fi, size);
+ size = btrfs_file_extent_calc_inline_size(size);
+ btrfs_truncate_item(root->fs_info, path, size,
1);
+ } else if (!del_item) {
/*
- * Need to release path in order to truncate a
- * compressed extent. So delete any accumulated
- * extent items so far.
+ * We have to bail so the last_size is set to
+ * just before this extent.
*/
- if (btrfs_file_extent_compression(leaf, fi) !=
- BTRFS_COMPRESS_NONE && pending_del_nr) {
- err = btrfs_del_items(trans, root, path,
- pending_del_slot,
- pending_del_nr);
- if (err) {
- btrfs_abort_transaction(trans,
- err);
- goto error;
- }
- pending_del_nr = 0;
- }
+ err = NEED_TRUNCATE_BLOCK;
+ break;
+ }
- err = truncate_inline_extent(inode, path,
- &found_key,
- item_end,
- new_size);
- if (err) {
- btrfs_abort_transaction(trans, err);
- goto error;
- }
- } else if (test_bit(BTRFS_ROOT_REF_COWS,
- &root->state)) {
+ if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
inode_sub_bytes(inode, item_end + 1 - new_size);
- }
}
delete:
+ if (del_item)
+ last_size = found_key.offset;
+ else
+ last_size = new_size;
if (del_item) {
if (!pending_del_nr) {
/* no pending yet, add ourselves */
@@ -9342,12 +9290,12 @@ static int btrfs_truncate(struct inode *inode)
ret = btrfs_truncate_inode_items(trans, root, inode,
inode->i_size,
BTRFS_EXTENT_DATA_KEY);
+ trans->block_rsv = &fs_info->trans_block_rsv;
if (ret != -ENOSPC && ret != -EAGAIN) {
err = ret;
break;
}
- trans->block_rsv = &fs_info->trans_block_rsv;
ret = btrfs_update_inode(trans, root, inode);
if (ret) {
err = ret;
@@ -9371,6 +9319,27 @@ static int btrfs_truncate(struct inode *inode)
trans->block_rsv = rsv;
}
+ /*
+ * We can't call btrfs_truncate_block inside a trans handle as we could
+ * deadlock with freeze, if we got NEED_TRUNCATE_BLOCK then we know
+ * we've truncated everything except the last little bit, and can do
+ * btrfs_truncate_block and then update the disk_i_size.
+ */
+ if (ret == NEED_TRUNCATE_BLOCK) {
+ btrfs_end_transaction(trans);
+ btrfs_btree_balance_dirty(fs_info);
+
+ ret = btrfs_truncate_block(inode, inode->i_size, 0, 0);
+ if (ret)
+ goto out;
+ trans = btrfs_start_transaction(root, 1);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ goto out;
+ }
+ btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
+ }
+
if (ret == 0 && inode->i_nlink > 0) {
trans->block_rsv = root->orphan_block_rsv;
ret = btrfs_orphan_del(trans, BTRFS_I(inode));
--
2.7.4
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