From: Josef Bacik <josef@toxicpanda.com>
Date: Fri, 17 Jan 2020 09:02:22 -0500
Subject: btrfs: use the file extent tree infrastructure
Git-commit: 9ddc959e802bf7555a0be543205ddcba2bae98bf
Patch-mainline: v5.7-rc1
References: bsc#1181998
We want to use this everywhere we modify the file extent items
permanently. These include:
1) Inserting new file extents for writes and prealloc extents.
2) Truncating inode items.
3) btrfs_cont_expand().
4) Insert inline extents.
5) Insert new extents from log replay.
6) Insert a new extent for clone, as it could be past i_size.
7) Hole punching
For hole punching in particular it might seem it's not necessary because
anybody extending would use btrfs_cont_expand, however there is a corner
that still can give us trouble. Start with an empty file and
fallocate KEEP_SIZE 1M-2M
We now have a 0 length file, and a hole file extent from 0-1M, and a
prealloc extent from 1M-2M. Now
punch 1M-1.5M
Because this is past i_size we have
[HOLE EXTENT][ NOTHING ][PREALLOC]
[0 1M][1M 1.5M][1.5M 2M]
with an i_size of 0. Now if we pwrite 0-1.5M we'll increas our i_size
to 1.5M, but our disk_i_size is still 0 until the ordered extent
completes.
However if we now immediately truncate 2M on the file we'll just call
btrfs_cont_expand(inode, 1.5M, 2M), since our old i_size is 1.5M. If we
commit the transaction here and crash we'll expose the gap.
To fix this we need to clear the file extent mapping for the range that
we punched but didn't insert a corresponding file extent for. This will
mean the truncate will only get an disk_i_size set to 1M if we crash
before the finish ordered io happens.
I've written an xfstest to reproduce the problem and validate this fix.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
fs/btrfs/delayed-inode.c | 3 ++
fs/btrfs/file.c | 32 +++++++++++++++++++++++++++
fs/btrfs/inode.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++-
fs/btrfs/tree-log.c | 5 ++++
4 files changed, 94 insertions(+), 1 deletion(-)
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1743,6 +1743,7 @@ static void fill_stack_inode_item(struct
int btrfs_fill_inode(struct inode *inode, u32 *rdev)
{
+ struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
struct btrfs_delayed_node *delayed_node;
struct btrfs_inode_item *inode_item;
@@ -1762,6 +1763,8 @@ int btrfs_fill_inode(struct inode *inode
i_uid_write(inode, btrfs_stack_inode_uid(inode_item));
i_gid_write(inode, btrfs_stack_inode_gid(inode_item));
btrfs_i_size_write(BTRFS_I(inode), btrfs_stack_inode_size(inode_item));
+ btrfs_inode_set_file_extent_range(BTRFS_I(inode), 0,
+ round_up(i_size_read(inode), fs_info->sectorsize));
inode->i_mode = btrfs_stack_inode_mode(inode_item);
set_nlink(inode, btrfs_stack_inode_nlink(inode_item));
inode_set_bytes(inode, btrfs_stack_inode_nbytes(inode_item));
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2473,6 +2473,11 @@ static int btrfs_insert_clone_extent(str
btrfs_mark_buffer_dirty(leaf);
btrfs_release_path(path);
+ ret = btrfs_inode_set_file_extent_range(BTRFS_I(inode),
+ clone_info->file_offset, clone_len);
+ if (ret)
+ return ret;
+
/* If it's a hole, nothing more needs to be done. */
if (clone_info->disk_offset == 0)
return 0;
@@ -2583,6 +2588,24 @@ int btrfs_punch_hole_range(struct inode
btrfs_abort_transaction(trans, ret);
break;
}
+ } else if (!clone_info && cur_offset < drop_end) {
+ /*
+ * We are past the i_size here, but since we didn't
+ * insert holes we need to clear the mapped area so we
+ * know to not set disk_i_size in this area until a new
+ * file extent is inserted here.
+ */
+ ret = btrfs_inode_clear_file_extent_range(BTRFS_I(inode),
+ cur_offset, drop_end - cur_offset);
+ if (ret) {
+ /*
+ * We couldn't clear our area, so we could
+ * presumably adjust up and corrupt the fs, so
+ * we need to abort.
+ */
+ btrfs_abort_transaction(trans, ret);
+ break;
+ }
}
if (clone_info && drop_end > clone_info->file_offset) {
@@ -2673,6 +2696,15 @@ int btrfs_punch_hole_range(struct inode
btrfs_abort_transaction(trans, ret);
goto out_trans;
}
+ } else if (!clone_info && cur_offset < drop_end) {
+ /* See the comment in the loop above for the reasoning here. */
+ ret = btrfs_inode_clear_file_extent_range(BTRFS_I(inode),
+ cur_offset, drop_end - cur_offset);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ goto out_trans;
+ }
+
}
if (clone_info) {
ret = btrfs_insert_clone_extent(trans, inode, path, clone_info,
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -271,6 +271,15 @@ static int insert_inline_extent(struct b
btrfs_release_path(path);
/*
+ * We align size to sectorsize for inline extents just for simplicity
+ * sake.
+ */
+ size = ALIGN(size, root->fs_info->sectorsize);
+ ret = btrfs_inode_set_file_extent_range(BTRFS_I(inode), start, size);
+ if (ret)
+ goto fail;
+
+ /*
* we're an inline extent, so nobody can
* extend the file past i_size without locking
* a page we already have locked.
@@ -2246,6 +2255,11 @@ static int insert_reserved_file_extent(s
ins.offset = disk_num_bytes;
ins.type = BTRFS_EXTENT_ITEM_KEY;
+ ret = btrfs_inode_set_file_extent_range(BTRFS_I(inode), file_pos,
+ ram_bytes);
+ if (ret)
+ goto out;
+
/*
* Release the reserved range from inode dirty range map, as it is
* already moved into delayed_ref_head
@@ -4390,6 +4404,8 @@ search_again:
}
while (1) {
+ u64 clear_start = 0, clear_len = 0;
+
fi = NULL;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
@@ -4440,6 +4456,8 @@ search_again:
if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
u64 num_dec;
+
+ clear_start = found_key.offset;
extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
if (!del_item) {
u64 orig_num_bytes =
@@ -4447,6 +4465,7 @@ search_again:
extent_num_bytes = ALIGN(new_size -
found_key.offset,
fs_info->sectorsize);
+ clear_start = ALIGN(new_size, fs_info->sectorsize);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_num_bytes);
num_dec = (orig_num_bytes -
@@ -4472,6 +4491,7 @@ search_again:
inode_sub_bytes(inode, num_dec);
}
}
+ clear_len = num_dec;
} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
/*
* we can't truncate inline items that have had
@@ -4493,12 +4513,33 @@ search_again:
*/
ret = NEED_TRUNCATE_BLOCK;
break;
+ } else {
+ /*
+ * Inline extents are special, we just treat
+ * them as a full sector worth in the file
+ * extent tree just for simplicity sake.
+ */
+ clear_len = fs_info->sectorsize;
}
if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
inode_sub_bytes(inode, item_end + 1 - new_size);
}
delete:
+ /*
+ * We use btrfs_truncate_inode_items() to clean up log trees for
+ * multiple fsyncs, and in this case we don't want to clear the
+ * file extent range because it's just the log.
+ */
+ if (root == BTRFS_I(inode)->root) {
+ ret = btrfs_inode_clear_file_extent_range(BTRFS_I(inode),
+ clear_start, clear_len);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ break;
+ }
+ }
+
if (del_item)
last_size = found_key.offset;
else
@@ -4820,14 +4861,21 @@ int btrfs_cont_expand(struct inode *inod
}
last_byte = min(extent_map_end(em), block_end);
last_byte = ALIGN(last_byte, fs_info->sectorsize);
+ hole_size = last_byte - cur_offset;
+
if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
struct extent_map *hole_em;
- hole_size = last_byte - cur_offset;
err = maybe_insert_hole(root, inode, cur_offset,
hole_size);
if (err)
break;
+
+ err = btrfs_inode_set_file_extent_range(BTRFS_I(inode),
+ cur_offset, hole_size);
+ if (err)
+ break;
+
btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
cur_offset + hole_size - 1, 0);
hole_em = alloc_extent_map();
@@ -4860,6 +4908,11 @@ int btrfs_cont_expand(struct inode *inod
hole_size - 1, 0);
}
free_extent_map(hole_em);
+ } else {
+ err = btrfs_inode_set_file_extent_range(BTRFS_I(inode),
+ cur_offset, hole_size);
+ if (err)
+ break;
}
next:
free_extent_map(em);
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -844,6 +844,11 @@ static noinline int replay_one_extent(st
goto out;
}
+ ret = btrfs_inode_set_file_extent_range(BTRFS_I(inode), start,
+ extent_end - start);
+ if (ret)
+ goto out;
+
inode_add_bytes(inode, nbytes);
update_inode:
ret = btrfs_update_inode(trans, root, inode);