On Fri, Jun 22, 2018 at 10:19:15AM +0200, Jan Kara wrote: > On Wed 20-06-18 16:15:03, Ross Zwisler wrote: > > Follow the lead of xfs_break_dax_layouts() and add synchronization between > > operations in ext4 which remove blocks from an inode (hole punch, truncate > > down, etc.) and pages which are pinned due to DAX DMA operations. > > > > Signed-off-by: Ross Zwisler <[email protected]> > > --- > > fs/ext4/ext4.h | 1 + > > fs/ext4/extents.c | 12 ++++++++++++ > > fs/ext4/inode.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ > > fs/ext4/truncate.h | 1 + > > 4 files changed, 62 insertions(+) > > > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > > index 0b127853c584..34bccd64d83d 100644 > > --- a/fs/ext4/ext4.h > > +++ b/fs/ext4/ext4.h > > @@ -2460,6 +2460,7 @@ extern int ext4_get_inode_loc(struct inode *, struct > > ext4_iloc *); > > extern int ext4_inode_attach_jinode(struct inode *inode); > > extern int ext4_can_truncate(struct inode *inode); > > extern int ext4_truncate(struct inode *); > > +extern int ext4_break_layouts(struct inode *); > > extern int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t > > length); > > extern int ext4_truncate_restart_trans(handle_t *, struct inode *, int > > nblocks); > > extern void ext4_set_inode_flags(struct inode *); > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > > index 0057fe3f248d..a6aef06f455b 100644 > > --- a/fs/ext4/extents.c > > +++ b/fs/ext4/extents.c > > @@ -4820,6 +4820,13 @@ static long ext4_zero_range(struct file *file, > > loff_t offset, > > * released from page cache. > > */ > > down_write(&EXT4_I(inode)->i_mmap_sem); > > + > > + ret = ext4_break_layouts(inode); > > + if (ret) { > > + up_write(&EXT4_I(inode)->i_mmap_sem); > > + goto out_mutex; > > + } > > + > > ret = ext4_update_disksize_before_punch(inode, offset, len); > > if (ret) { > > up_write(&EXT4_I(inode)->i_mmap_sem); > > @@ -5493,6 +5500,11 @@ int ext4_collapse_range(struct inode *inode, loff_t > > offset, loff_t len) > > * page cache. > > */ > > down_write(&EXT4_I(inode)->i_mmap_sem); > > + > > + ret = ext4_break_layouts(inode); > > + if (ret) > > + goto out_mmap; > > + > > /* > > * Need to round down offset to be aligned with page size boundary > > * for page size > block size. > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > > index 2ea07efbe016..c795e5118745 100644 > > --- a/fs/ext4/inode.c > > +++ b/fs/ext4/inode.c > > @@ -4193,6 +4193,41 @@ int ext4_update_disksize_before_punch(struct inode > > *inode, loff_t offset, > > return 0; > > } > > > > +static void ext4_wait_dax_page(struct ext4_inode_info *ei, bool > > *did_unlock) > > +{ > > + *did_unlock = true; > > + up_write(&ei->i_mmap_sem); > > + schedule(); > > + down_write(&ei->i_mmap_sem); > > +} > > + > > +int ext4_break_layouts(struct inode *inode) > > +{ > > + struct ext4_inode_info *ei = EXT4_I(inode); > > + struct page *page; > > + bool retry; > > + int error; > > + > > + if (unlikely(!rwsem_is_locked(&ei->i_mmap_sem))) { > > + WARN_ON_ONCE(1); > > + return -EINVAL; > > + } > > This could be shortened as: > > if (WARN_ON_ONCE(!rwsem_is_locked(&ei->i_mmap_sem))) { > } > > couldn't it?
Yep, that's much better. Thank you for the review. > Besides that the patch looks to me. You can add: > > Reviewed-by: Jan Kara <[email protected]> > > And I'm really wondering which protection are we still missing that you are > still able to hit the warning with these patches applied. I'm also very curious and am going to dig into that this week. _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
