From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sandeen.net ([63.231.237.45]:36852 "EHLO sandeen.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030408AbeEYWc1 (ORCPT ); Fri, 25 May 2018 18:32:27 -0400 Subject: Re: [PATCH resend 1/7] fs: allow per-device dax status checking for filesystems To: Ross Zwisler , Toshi Kani , Mike Snitzer , dm-devel@redhat.com Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-xfs@vger.kernel.org, "Darrick J. Wong" References: <20180525220055.18920-1-ross.zwisler@linux.intel.com> <20180525220055.18920-2-ross.zwisler@linux.intel.com> From: Eric Sandeen Message-ID: <924994ed-64c8-ca11-75c1-cb1a1f0f6d94@sandeen.net> Date: Fri, 25 May 2018 17:32:25 -0500 MIME-Version: 1.0 In-Reply-To: <20180525220055.18920-2-ross.zwisler@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 5/25/18 5:00 PM, Ross Zwisler wrote: > From: "Darrick J. Wong" > > Remove __bdev_dax_supported and change to bdev_dax_supported that takes a > bdev parameter. This enables multi-device filesystems like xfs to check > that a dax device can work for the particular filesystem. Once that's > in place, actually fix all the parts of XFS where we need to be able to > distinguish between datadev and rtdev. > > This patch fixes the problem where we screw up the dax support checking > in xfs if the datadev and rtdev have different dax capabilities. I wonder where we might be able to document this wrinkle, i.e. mount -o dax means at least /one/ of the devices must support it, and then at runtime whichever file you try to use dax on still needs to be on a device that supports it ... but ok, anyway this seems fine functionally. you've assured me that xfstests are coming ;) Reviewed-by: Eric Sandeen > Signed-off-by: Darrick J. Wong > Signed-off-by: Ross Zwisler > --- > drivers/dax/super.c | 30 +++++++++++++++--------------- > fs/ext2/super.c | 2 +- > fs/ext4/super.c | 2 +- > fs/xfs/xfs_ioctl.c | 3 ++- > fs/xfs/xfs_iops.c | 30 +++++++++++++++++++++++++----- > fs/xfs/xfs_super.c | 10 ++++++++-- > include/linux/dax.h | 10 +++------- > 7 files changed, 55 insertions(+), 32 deletions(-) > > diff --git a/drivers/dax/super.c b/drivers/dax/super.c > index 2b2332b605e4..9206539c8330 100644 > --- a/drivers/dax/super.c > +++ b/drivers/dax/super.c > @@ -73,8 +73,8 @@ EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); > #endif > > /** > - * __bdev_dax_supported() - Check if the device supports dax for filesystem > - * @sb: The superblock of the device > + * bdev_dax_supported() - Check if the device supports dax for filesystem > + * @bdev: block device to check > * @blocksize: The block size of the device > * > * This is a library function for filesystems to check if the block device > @@ -82,33 +82,33 @@ EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); > * > * Return: negative errno if unsupported, 0 if supported. > */ > -int __bdev_dax_supported(struct super_block *sb, int blocksize) > +int bdev_dax_supported(struct block_device *bdev, int blocksize) > { > - struct block_device *bdev = sb->s_bdev; > struct dax_device *dax_dev; > pgoff_t pgoff; > int err, id; > void *kaddr; > pfn_t pfn; > long len; > + char buf[BDEVNAME_SIZE]; > > if (blocksize != PAGE_SIZE) { > - pr_debug("VFS (%s): error: unsupported blocksize for dax\n", > - sb->s_id); > + pr_debug("%s: error: unsupported blocksize for dax\n", > + bdevname(bdev, buf)); > return -EINVAL; > } > > err = bdev_dax_pgoff(bdev, 0, PAGE_SIZE, &pgoff); > if (err) { > - pr_debug("VFS (%s): error: unaligned partition for dax\n", > - sb->s_id); > + pr_debug("%s: error: unaligned partition for dax\n", > + bdevname(bdev, buf)); > return err; > } > > dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); > if (!dax_dev) { > - pr_debug("VFS (%s): error: device does not support dax\n", > - sb->s_id); > + pr_debug("%s: error: device does not support dax\n", > + bdevname(bdev, buf)); > return -EOPNOTSUPP; > } > > @@ -119,8 +119,8 @@ int __bdev_dax_supported(struct super_block *sb, int blocksize) > put_dax(dax_dev); > > if (len < 1) { > - pr_debug("VFS (%s): error: dax access failed (%ld)\n", > - sb->s_id, len); > + pr_debug("%s: error: dax access failed (%ld)\n", > + bdevname(bdev, buf), len); > return len < 0 ? len : -EIO; > } > > @@ -137,14 +137,14 @@ int __bdev_dax_supported(struct super_block *sb, int blocksize) > } else if (pfn_t_devmap(pfn)) { > /* pass */; > } else { > - pr_debug("VFS (%s): error: dax support not enabled\n", > - sb->s_id); > + pr_debug("%s: error: dax support not enabled\n", > + bdevname(bdev, buf)); > return -EOPNOTSUPP; > } > > return 0; > } > -EXPORT_SYMBOL_GPL(__bdev_dax_supported); > +EXPORT_SYMBOL_GPL(bdev_dax_supported); > #endif > > enum dax_device_flags { > diff --git a/fs/ext2/super.c b/fs/ext2/super.c > index de1694512f1f..9627c3054b5c 100644 > --- a/fs/ext2/super.c > +++ b/fs/ext2/super.c > @@ -961,7 +961,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent) > blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size); > > if (sbi->s_mount_opt & EXT2_MOUNT_DAX) { > - err = bdev_dax_supported(sb, blocksize); > + err = bdev_dax_supported(sb->s_bdev, blocksize); > if (err) { > ext2_msg(sb, KERN_ERR, > "DAX unsupported by block device. Turning off DAX."); > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index eb104e8476f0..089170e99895 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -3732,7 +3732,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) > " that may contain inline data"); > sbi->s_mount_opt &= ~EXT4_MOUNT_DAX; > } > - err = bdev_dax_supported(sb, blocksize); > + err = bdev_dax_supported(sb->s_bdev, blocksize); > if (err) { > ext4_msg(sb, KERN_ERR, > "DAX unsupported by block device. Turning off DAX."); > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c > index 89fb1eb80aae..0effd46b965f 100644 > --- a/fs/xfs/xfs_ioctl.c > +++ b/fs/xfs/xfs_ioctl.c > @@ -1103,7 +1103,8 @@ xfs_ioctl_setattr_dax_invalidate( > if (fa->fsx_xflags & FS_XFLAG_DAX) { > if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))) > return -EINVAL; > - if (bdev_dax_supported(sb, sb->s_blocksize) < 0) > + if (bdev_dax_supported(xfs_find_bdev_for_inode(VFS_I(ip)), > + sb->s_blocksize) < 0) > return -EINVAL; > } > > diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c > index a3ed3c811dfa..6e83acf74a95 100644 > --- a/fs/xfs/xfs_iops.c > +++ b/fs/xfs/xfs_iops.c > @@ -1195,6 +1195,30 @@ static const struct inode_operations xfs_inline_symlink_inode_operations = { > .update_time = xfs_vn_update_time, > }; > > +/* Figure out if this file actually supports DAX. */ > +static bool > +xfs_inode_supports_dax( > + struct xfs_inode *ip) > +{ > + struct xfs_mount *mp = ip->i_mount; > + > + /* Only supported on non-reflinked files. */ > + if (!S_ISREG(VFS_I(ip)->i_mode) || xfs_is_reflink_inode(ip)) > + return false; > + > + /* DAX mount option or DAX iflag must be set. */ > + if (!(mp->m_flags & XFS_MOUNT_DAX) && > + !(ip->i_d.di_flags2 & XFS_DIFLAG2_DAX)) > + return false; > + > + /* Block size must match page size */ > + if (mp->m_sb.sb_blocksize != PAGE_SIZE) > + return false; > + > + /* Device has to support DAX too. */ > + return xfs_find_daxdev_for_inode(VFS_I(ip)) != NULL; > +} > + > STATIC void > xfs_diflags_to_iflags( > struct inode *inode, > @@ -1213,11 +1237,7 @@ xfs_diflags_to_iflags( > inode->i_flags |= S_SYNC; > if (flags & XFS_DIFLAG_NOATIME) > inode->i_flags |= S_NOATIME; > - if (S_ISREG(inode->i_mode) && > - ip->i_mount->m_sb.sb_blocksize == PAGE_SIZE && > - !xfs_is_reflink_inode(ip) && > - (ip->i_mount->m_flags & XFS_MOUNT_DAX || > - ip->i_d.di_flags2 & XFS_DIFLAG2_DAX)) > + if (xfs_inode_supports_dax(ip)) > inode->i_flags |= S_DAX; > } > > diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c > index d71424052917..62188c2a4c36 100644 > --- a/fs/xfs/xfs_super.c > +++ b/fs/xfs/xfs_super.c > @@ -1690,11 +1690,17 @@ xfs_fs_fill_super( > sb->s_flags |= SB_I_VERSION; > > if (mp->m_flags & XFS_MOUNT_DAX) { > + int error2 = 0; > + > xfs_warn(mp, > "DAX enabled. Warning: EXPERIMENTAL, use at your own risk"); > > - error = bdev_dax_supported(sb, sb->s_blocksize); > - if (error) { > + error = bdev_dax_supported(mp->m_ddev_targp->bt_bdev, > + sb->s_blocksize); > + if (mp->m_rtdev_targp) > + error2 = bdev_dax_supported(mp->m_rtdev_targp->bt_bdev, > + sb->s_blocksize); > + if (error && error2) { > xfs_alert(mp, > "DAX unsupported by block device. Turning off DAX."); > mp->m_flags &= ~XFS_MOUNT_DAX; > diff --git a/include/linux/dax.h b/include/linux/dax.h > index f9eb22ad341e..509a85ac8470 100644 > --- a/include/linux/dax.h > +++ b/include/linux/dax.h > @@ -64,12 +64,7 @@ static inline bool dax_write_cache_enabled(struct dax_device *dax_dev) > struct writeback_control; > int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff); > #if IS_ENABLED(CONFIG_FS_DAX) > -int __bdev_dax_supported(struct super_block *sb, int blocksize); > -static inline int bdev_dax_supported(struct super_block *sb, int blocksize) > -{ > - return __bdev_dax_supported(sb, blocksize); > -} > - > +int bdev_dax_supported(struct block_device *bdev, int blocksize); > static inline struct dax_device *fs_dax_get_by_host(const char *host) > { > return dax_get_by_host(host); > @@ -84,7 +79,8 @@ struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev); > int dax_writeback_mapping_range(struct address_space *mapping, > struct block_device *bdev, struct writeback_control *wbc); > #else > -static inline int bdev_dax_supported(struct super_block *sb, int blocksize) > +static inline int bdev_dax_supported(struct block_device *bdev, > + int blocksize) > { > return -EOPNOTSUPP; > } >