Re: [PATCH v10 00/21] Support ext4 on NV-DIMMs

Boaz Harrosh
2014-08-28T08:09:29Z

On 08/27/2014 06:45 AM, Matthew Wilcox wrote:
> One of the primary uses for NV-DIMMs is to expose them as a block device
> and use a filesystem to store files on the NV-DIMM. While that works,
> it currently wastes memory and CPU time buffering the files in the page
> cache. We have support in ext2 for bypassing the page cache, but it
> has some races which are unfixable in the current design. This series
> of patches rewrite the underlying support, and add support for direct
> access to ext4.
>
> Note that patch 6/21 has been included in
> https://git.kernel.org/cgit/linux/kernel/git/viro/vfs.git/log/?h=for-next-candidate
>

Matthew hi

Could you please push this to the regular or a new public tree?

(Old versions are at: https://github.com/01org/prd)

Thanks
Boaz

> This iteration of the patchset rebases to 3.17-rc2, changes the page fault
> locking, fixes a couple of bugs and makes a few other minor changes.
>
> - Move the calculation of the maximum size available at the requested
> location from the ->direct_access implementations to bdev_direct_access()
> - Fix a comment typo (Ross Zwisler)
> - Check that the requested length is positive in bdev_direct_access(). If
> it is not, assume that it's an errno, and just return it.
> - Fix some whitespace issues flagged by checkpatch
> - Added the Acked-by responses from Kirill that I forget in the last round
> - Added myself to MAINTAINERS for DAX
> - Fixed compilation with !CONFIG_DAX (Vishal Verma)
> - Revert the locking in the page fault handler back to an earlier version.
> If we hit the race that we were trying to protect against, we will leave
> blocks allocated past the end of the file. They will be removed on file
> removal, the next truncate, or fsck.
>
>
> Matthew Wilcox (20):
> axonram: Fix bug in direct_access
> Change direct_access calling convention
> Fix XIP fault vs truncate race
> Allow page fault handlers to perform the COW
> Introduce IS_DAX(inode)
> Add copy_to_iter(), copy_from_iter() and iov_iter_zero()
> Replace XIP read and write with DAX I/O
> Replace ext2_clear_xip_target with dax_clear_blocks
> Replace the XIP page fault handler with the DAX page fault handler
> Replace xip_truncate_page with dax_truncate_page
> Replace XIP documentation with DAX documentation
> Remove get_xip_mem
> ext2: Remove ext2_xip_verify_sb()
> ext2: Remove ext2_use_xip
> ext2: Remove xip.c and xip.h
> Remove CONFIG_EXT2_FS_XIP and rename CONFIG_FS_XIP to CONFIG_FS_DAX
> ext2: Remove ext2_aops_xip
> Get rid of most mentions of XIP in ext2
> xip: Add xip_zero_page_range
> brd: Rename XIP to DAX
>
> Ross Zwisler (1):
> ext4: Add DAX functionality
>
> Documentation/filesystems/Locking | 3 -
> Documentation/filesystems/dax.txt | 91 +++++++
> Documentation/filesystems/ext4.txt | 2 +
> Documentation/filesystems/xip.txt | 68 -----
> MAINTAINERS | 6 +
> arch/powerpc/sysdev/axonram.c | 19 +-
> drivers/block/Kconfig | 13 +-
> drivers/block/brd.c | 26 +-
> drivers/s390/block/dcssblk.c | 21 +-
> fs/Kconfig | 21 +-
> fs/Makefile | 1 +
> fs/block_dev.c | 40 +++
> fs/dax.c | 497 +++++++++++++++++++++++++++++++++++++
> fs/exofs/inode.c | 1 -
> fs/ext2/Kconfig | 11 -
> fs/ext2/Makefile | 1 -
> fs/ext2/ext2.h | 10 +-
> fs/ext2/file.c | 45 +++-
> fs/ext2/inode.c | 38 +--
> fs/ext2/namei.c | 13 +-
> fs/ext2/super.c | 53 ++--
> fs/ext2/xip.c | 91 -------
> fs/ext2/xip.h | 26 --
> fs/ext4/ext4.h | 6 +
> fs/ext4/file.c | 49 +++-
> fs/ext4/indirect.c | 18 +-
> fs/ext4/inode.c | 51 ++--
> fs/ext4/namei.c | 10 +-
> fs/ext4/super.c | 39 ++-
> fs/open.c | 5 +-
> include/linux/blkdev.h | 6 +-
> include/linux/fs.h | 49 +++-
> include/linux/mm.h | 1 +
> include/linux/uio.h | 3 +
> mm/Makefile | 1 -
> mm/fadvise.c | 6 +-
> mm/filemap.c | 6 +-
> mm/filemap_xip.c | 483 -----------------------------------
> mm/iov_iter.c | 237 ++++++++++++++++--
> mm/madvise.c | 2 +-
> mm/memory.c | 33 ++-
> 41 files changed, 1229 insertions(+), 873 deletions(-)
> create mode 100644 Documentation/filesystems/dax.txt
> delete mode 100644 Documentation/filesystems/xip.txt
> create mode 100644 fs/dax.c
> delete mode 100644 fs/ext2/xip.c
> delete mode 100644 fs/ext2/xip.h
> delete mode 100644 mm/filemap_xip.c
>