On Thu, Dec 01, 2016 at 01:46:10PM -0800, Liu Bo wrote:
> btrfs_ordered_update_i_size can be called by truncate and endio, but only endio
> takes ordered_extent which contains the completed IO.
>
> while truncating down a file, if there are some in-flight IOs,
> btrfs_ordered_update_i_size in endio will set disk_i_size to @orig_offset that
> is zero. If truncating-down fails somehow, we try to recover in memory isize
> with this zero'd disk_i_size.
>
> Fix it by only updating disk_i_size with @orig_offset when
> btrfs_ordered_update_i_size is not called from endio while truncating down and
> waiting for in-flight IOs completing their work before recover in-memory size.
>
> Besides fixing the above issue, add an assertion for last_size to double check
> we truncate down to the desired size.
>
> Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
> ---
> fs/btrfs/inode.c | 14 ++++++++++++++
> fs/btrfs/ordered-data.c | 9 +++++++--
> 2 files changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 09157dd..ef3594d 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -4682,6 +4682,13 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
>
> btrfs_free_path(path);
>
> + if (err == 0) {
> + /* only inline file may have last_size != new_size */
> + if (new_size >= root->sectorsize ||
> + new_size > root->fs_info->max_inline)
> + ASSERT(last_size == new_size);
> + }
> +
This ASSERT has been hit by fstests/generic/299, and it didn't show up
the first time I tested, I'm trying to figure out whether we have
problems in code or in this ASSERT.
Thanks,
-liubo
> if (be_nice && bytes_deleted > SZ_32M) {
> unsigned long updates = trans->delayed_ref_updates;
> if (updates) {
> @@ -5064,6 +5071,13 @@ static int btrfs_setsize(struct inode *inode, struct iattr *attr)
> if (ret && inode->i_nlink) {
> int err;
>
> + /* To get a stable disk_i_size */
> + err = btrfs_wait_ordered_range(inode, 0, (u64)-1);
> + if (err) {
> + btrfs_orphan_del(NULL, inode);
> + return err;
> + }
> +
> /*
> * failed to truncate, disk_i_size is only adjusted down
> * as we remove extents, so it should represent the true
> diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
> index b2d1e95..5eaa25a 100644
> --- a/fs/btrfs/ordered-data.c
> +++ b/fs/btrfs/ordered-data.c
> @@ -982,8 +982,13 @@ int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
> }
> disk_i_size = BTRFS_I(inode)->disk_i_size;
>
> - /* truncate file */
> - if (disk_i_size > i_size) {
> + /*
> + * truncate file.
> + * If ordered is not NULL, then this is called from endio and
> + * disk_i_size will be updated by either truncate itself or any
> + * in-flight IOs which are inside the disk_i_size.
> + */
> + if (!ordered && disk_i_size > i_size) {
> BTRFS_I(inode)->disk_i_size = orig_offset;
> ret = 0;
> goto out;
> --
> 2.5.5
>
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