On Mon 24-09-12 15:44:18, Dmitry Monakhov wrote:
> If we have enough aggressive DIO readers, truncate and other dio
> waiters will wait forever inside inode_dio_wait(). It is reasonable
> to disable nonlock DIO read optimization during truncate.
Umm, actually this is a problem with any inode_dio_wait() call in ext4,
isn't it? So I'd just create ext4_inode_dio_wait() doing
ext4_inode_block_unlocked_dio(inode);
inode_dio_wait(inode);
ext4_inode_resume_unlocked_dio(inode);
and use it instead of inode_dio_wait().
Honza
> Signed-off-by: Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
> ---
> fs/ext4/inode.c | 8 ++++++--
> 1 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 32e9701..d3f86e7 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -4330,9 +4330,13 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
> if (attr->ia_valid & ATTR_SIZE) {
> if (attr->ia_size != inode->i_size) {
> truncate_setsize(inode, attr->ia_size);
> - /* Inode size will be reduced, wait for dio in flight */
> - if (orphan)
> + /* Inode size will be reduced, wait for dio in flight.
> + * Temproraly disable unlocked DIO to prevent livelock */
^^ Temporarily
> + if (orphan) {
> + ext4_inode_block_unlocked_dio(inode);
> inode_dio_wait(inode);
> + ext4_inode_resume_unlocked_dio(inode);
> + }
> }
> ext4_truncate(inode);
> }
> --
> 1.7.7.6
>
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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