From: Dave Jiang Subject: Re: [PATCH 2 2/2] xfs: fix rt_dev usage for DAX Date: Thu, 1 Feb 2018 17:08:36 -0700 Message-ID: <847ca427-af95-c4dc-9b99-c3ce8a115118@intel.com> References: <151751717968.69886.6978962571680635420.stgit@djiang5-desk3.ch.intel.com> <151751718516.69886.135497175511444689.stgit@djiang5-desk3.ch.intel.com> <20180201232839.GX4849@magnolia> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: "linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org" , Dave Chinner , linux-xfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Darrick J. Wong" Return-path: In-Reply-To: <20180201232839.GX4849@magnolia> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" List-Id: linux-ext4.vger.kernel.org On 02/01/2018 04:28 PM, Darrick J. Wong wrote: >> [PATCH 2 2/2] xfs: fix rt_dev usage for DAX > > "[PATCH v2 2/2]" to distinguish the version number from the patch number > more explicitly. > > On Thu, Feb 01, 2018 at 01:33:05PM -0700, Dave Jiang wrote: >> When using realtime device (rtdev) with xfs where the data device is not >> DAX capable, two issues arise. One is when data device is not DAX but the >> realtime device is DAX capable, we currently disable DAX. >> After passing this check, we are also not marking the inode as DAX capable. >> This change will allow DAX enabled if the data device or the realtime >> device is DAX capable. S_DAX will be marked for the inode if the file is >> residing on a DAX capable device. This will prevent the case of rtdev is not >> DAX and data device is DAX to create realtime files. >> >> Signed-off-by: Dave Jiang >> Reported-by: Darrick Wong >> --- >> fs/xfs/xfs_iops.c | 3 ++- >> fs/xfs/xfs_super.c | 9 ++++++++- >> 2 files changed, 10 insertions(+), 2 deletions(-) >> >> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c >> index 56475fcd76f2..ab352c325301 100644 >> --- a/fs/xfs/xfs_iops.c >> +++ b/fs/xfs/xfs_iops.c >> @@ -1204,7 +1204,8 @@ xfs_diflags_to_iflags( >> 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)) >> + ip->i_d.di_flags2 & XFS_DIFLAG2_DAX) && >> + blk_queue_dax(bdev_get_queue(inode->i_sb->s_bdev))) > > inode->i_sb->s_bdev is the data device bdev, so if the inode is a > realtime file, we're checking the wrong device for daxiness, I think. > > Maybe this whole ugly switch statement should get turned into a helper > function? > > xfs_ioctl_setattr_dax_invalidate needs to pick the right bdev to check. > >> inode->i_flags |= S_DAX; >> } >> >> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c >> index e8a687232614..5ac478924dce 100644 >> --- a/fs/xfs/xfs_super.c >> +++ b/fs/xfs/xfs_super.c >> @@ -1649,11 +1649,18 @@ xfs_fs_fill_super( >> sb->s_flags |= SB_I_VERSION; >> >> if (mp->m_flags & XFS_MOUNT_DAX) { >> + bool rtdev_is_dax = false; >> + >> xfs_warn(mp, >> "DAX enabled. Warning: EXPERIMENTAL, use at your own risk"); >> >> + if (mp->m_rtdev_targp->bt_daxdev) >> + if (bdev_dax_supported(mp->m_rtdev_targp->bt_bdev, >> + sb->s_blocksize) == 0) >> + rtdev_is_dax = true; >> + >> error = bdev_dax_supported(sb->s_bdev, sb->s_blocksize); >> - if (error) { >> + if (error && !rtdev_is_dax) { >> xfs_alert(mp, >> "DAX unsupported by block device. Turning off DAX."); >> mp->m_flags &= ~XFS_MOUNT_DAX; >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in >> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > Does the following patch fix everything for you? > > (Note that we can't switch S_DAX on a running fs so you have to remount > the whole fs after setting the dax flag...) Yes this passes my tests. However it looks like Dave Chinner has additional concerns with regards to changing the S_DAX flag dynamically? > > --D > > -------------------- > > fs: allow per-device dax status checking for filesystems > > Refactor __bdev_dax_supported into a sb_dax_supported helper for > single-bdev filesystems and a regular 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. > > Signed-off-by: Darrick J. Wong > --- > drivers/dax/super.c | 9 +++++---- > 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 | 11 +++++++++-- > include/linux/dax.h | 16 ++++++++++++---- > 7 files changed, 55 insertions(+), 18 deletions(-) > > diff --git a/drivers/dax/super.c b/drivers/dax/super.c > index 3ec8046..c4db84f 100644 > --- a/drivers/dax/super.c > +++ b/drivers/dax/super.c > @@ -72,8 +72,9 @@ EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); > #endif > > /** > - * __bdev_dax_supported() - Check if the device supports dax for filesystem > + * bdev_dax_supported() - Check if the device supports dax for filesystem > * @sb: The superblock of the device > + * @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 > @@ -81,9 +82,9 @@ 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 super_block *sb, struct block_device *bdev, > + int blocksize) > { > - struct block_device *bdev = sb->s_bdev; > struct dax_device *dax_dev; > pgoff_t pgoff; > int err, id; > @@ -125,7 +126,7 @@ int __bdev_dax_supported(struct super_block *sb, int blocksize) > > 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 7646818..6556993 100644 > --- a/fs/ext2/super.c > +++ b/fs/ext2/super.c > @@ -958,7 +958,7 @@ 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 = sb_dax_supported(sb, blocksize); > if (err) > goto failed_mount; > } > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index 7c46693..804a2d6 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -3712,7 +3712,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) > " that may contain inline data"); > goto failed_mount; > } > - err = bdev_dax_supported(sb, blocksize); > + err = sb_dax_supported(sb, blocksize); > if (err) > goto failed_mount; > } > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c > index 89fb1eb..277355f 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(sb, 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 56475fc..66cd61c 100644 > --- a/fs/xfs/xfs_iops.c > +++ b/fs/xfs/xfs_iops.c > @@ -1182,6 +1182,30 @@ 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, > @@ -1200,11 +1224,7 @@ 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 6f1b917..c115bc7 100644 > --- a/fs/xfs/xfs_super.c > +++ b/fs/xfs/xfs_super.c > @@ -1692,11 +1692,18 @@ 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(sb, mp->m_ddev_targp->bt_bdev, > + sb->s_blocksize); > + if (mp->m_rtdev_targp) > + error2 = bdev_dax_supported(sb, > + 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 5258346..1107a98 100644 > --- a/include/linux/dax.h > +++ b/include/linux/dax.h > @@ -40,10 +40,11 @@ static inline void put_dax(struct dax_device *dax_dev) > > 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) > +int bdev_dax_supported(struct super_block *sb, struct block_device *bdev, > + int blocksize); > +static inline int sb_dax_supported(struct super_block *sb, int blocksize) > { > - return __bdev_dax_supported(sb, blocksize); > + return bdev_dax_supported(sb, sb->s_bdev, blocksize); > } > > static inline struct dax_device *fs_dax_get_by_host(const char *host) > @@ -58,7 +59,14 @@ static inline void fs_put_dax(struct dax_device *dax_dev) > > struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev); > #else > -static inline int bdev_dax_supported(struct super_block *sb, int blocksize) > +static inline int bdev_dax_supported(struct super_block *sb, > + struct block_device *bdev, > + int blocksize) > +{ > + return -EOPNOTSUPP; > +} > + > +static inline int sb_dax_supported(struct super_block *sb, int blocksize) > { > return -EOPNOTSUPP; > } >