| Message ID | 20210826173012.273932-1-bodonnel@redhat.com (mailing list archive) |
|---|---|
| State | Deferred, archived |
| Headers | show |
| Series | xfs: dax: facilitate EXPERIMENTAL warning for dax=inode case | expand |
On Thu, Aug 26, 2021 at 12:30:12PM -0500, Bill O'Donnell wrote: > When dax-mode was tri-stated by adding dax=inode case, the EXPERIMENTAL > warning on mount was missed for the case. Add logic to handle the > warning similar to that of the 'dax=always' case. > > Signed-off-by: Bill O'Donnell <bodonnel@redhat.com> > --- > fs/xfs/xfs_mount.h | 2 ++ > fs/xfs/xfs_super.c | 8 +++++--- > 2 files changed, 7 insertions(+), 3 deletions(-) > > diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h > index e091f3b3fa15..c9243a1b8d05 100644 > --- a/fs/xfs/xfs_mount.h > +++ b/fs/xfs/xfs_mount.h > @@ -277,6 +277,7 @@ typedef struct xfs_mount { > #define XFS_FEAT_NEEDSREPAIR (1ULL << 25) /* needs xfs_repair */ > > /* Mount features */ > +#define XFS_FEAT_DAX_INODE (1ULL << 47) /* DAX enabled */ > #define XFS_FEAT_NOATTR2 (1ULL << 48) /* disable attr2 creation */ > #define XFS_FEAT_NOALIGN (1ULL << 49) /* ignore alignment */ > #define XFS_FEAT_ALLOCSIZE (1ULL << 50) /* user specified allocation size */ > @@ -359,6 +360,7 @@ __XFS_HAS_FEAT(swalloc, SWALLOC) > __XFS_HAS_FEAT(filestreams, FILESTREAMS) > __XFS_HAS_FEAT(dax_always, DAX_ALWAYS) > __XFS_HAS_FEAT(dax_never, DAX_NEVER) > +__XFS_HAS_FEAT(dax_inode, DAX_INODE) > __XFS_HAS_FEAT(norecovery, NORECOVERY) > __XFS_HAS_FEAT(nouuid, NOUUID) > > diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c > index 5e73ac78bf2f..f73f3687f0a8 100644 > --- a/fs/xfs/xfs_super.c > +++ b/fs/xfs/xfs_super.c > @@ -84,15 +84,16 @@ xfs_mount_set_dax_mode( > { > switch (mode) { > case XFS_DAX_INODE: > + mp->m_features |= XFS_FEAT_DAX_INODE; > mp->m_features &= ~(XFS_FEAT_DAX_ALWAYS | XFS_FEAT_DAX_NEVER); > break; > case XFS_DAX_ALWAYS: > mp->m_features |= XFS_FEAT_DAX_ALWAYS; > - mp->m_features &= ~XFS_FEAT_DAX_NEVER; > + mp->m_features &= ~(XFS_FEAT_DAX_NEVER | XFS_FEAT_DAX_INODE); > break; > case XFS_DAX_NEVER: > mp->m_features |= XFS_FEAT_DAX_NEVER; > - mp->m_features &= ~XFS_FEAT_DAX_ALWAYS; > + mp->m_features &= ~(XFS_FEAT_DAX_ALWAYS | XFS_FEAT_DAX_INODE); > break; > } > } > @@ -189,6 +190,7 @@ xfs_fs_show_options( > { XFS_FEAT_LARGE_IOSIZE, ",largeio" }, > { XFS_FEAT_DAX_ALWAYS, ",dax=always" }, > { XFS_FEAT_DAX_NEVER, ",dax=never" }, > + { XFS_FEAT_DAX_INODE, ",dax=inode" }, > { 0, NULL } > }; > struct xfs_mount *mp = XFS_M(root->d_sb); > @@ -1584,7 +1586,7 @@ xfs_fs_fill_super( > if (xfs_has_crc(mp)) > sb->s_flags |= SB_I_VERSION; > > - if (xfs_has_dax_always(mp)) { > + if (xfs_has_dax_always(mp) || xfs_has_dax_inode(mp)) { Er... can't this be done without burning another feature bit by: if (xfs_has_dax_always(mp) || (!xfs_has_dax_always(mp) && !xfs_has_dax_never(mp))) { ... xfs_warn(mp, "DAX IS EXPERIMENTAL"); } --D > bool rtdev_is_dax = false, datadev_is_dax; > > xfs_warn(mp, > -- > 2.31.1 >
On Thu, Aug 26, 2021 at 11:09:47AM -0700, Darrick J. Wong wrote: > On Thu, Aug 26, 2021 at 12:30:12PM -0500, Bill O'Donnell wrote: > > When dax-mode was tri-stated by adding dax=inode case, the EXPERIMENTAL > > warning on mount was missed for the case. Add logic to handle the > > warning similar to that of the 'dax=always' case. > > > > Signed-off-by: Bill O'Donnell <bodonnel@redhat.com> > > --- > > fs/xfs/xfs_mount.h | 2 ++ > > fs/xfs/xfs_super.c | 8 +++++--- > > 2 files changed, 7 insertions(+), 3 deletions(-) > > > > diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h > > index e091f3b3fa15..c9243a1b8d05 100644 > > --- a/fs/xfs/xfs_mount.h > > +++ b/fs/xfs/xfs_mount.h > > @@ -277,6 +277,7 @@ typedef struct xfs_mount { > > #define XFS_FEAT_NEEDSREPAIR (1ULL << 25) /* needs xfs_repair */ > > > > /* Mount features */ > > +#define XFS_FEAT_DAX_INODE (1ULL << 47) /* DAX enabled */ > > #define XFS_FEAT_NOATTR2 (1ULL << 48) /* disable attr2 creation */ > > #define XFS_FEAT_NOALIGN (1ULL << 49) /* ignore alignment */ > > #define XFS_FEAT_ALLOCSIZE (1ULL << 50) /* user specified allocation size */ > > @@ -359,6 +360,7 @@ __XFS_HAS_FEAT(swalloc, SWALLOC) > > __XFS_HAS_FEAT(filestreams, FILESTREAMS) > > __XFS_HAS_FEAT(dax_always, DAX_ALWAYS) > > __XFS_HAS_FEAT(dax_never, DAX_NEVER) > > +__XFS_HAS_FEAT(dax_inode, DAX_INODE) > > __XFS_HAS_FEAT(norecovery, NORECOVERY) > > __XFS_HAS_FEAT(nouuid, NOUUID) > > > > diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c > > index 5e73ac78bf2f..f73f3687f0a8 100644 > > --- a/fs/xfs/xfs_super.c > > +++ b/fs/xfs/xfs_super.c > > @@ -84,15 +84,16 @@ xfs_mount_set_dax_mode( > > { > > switch (mode) { > > case XFS_DAX_INODE: > > + mp->m_features |= XFS_FEAT_DAX_INODE; > > mp->m_features &= ~(XFS_FEAT_DAX_ALWAYS | XFS_FEAT_DAX_NEVER); > > break; > > case XFS_DAX_ALWAYS: > > mp->m_features |= XFS_FEAT_DAX_ALWAYS; > > - mp->m_features &= ~XFS_FEAT_DAX_NEVER; > > + mp->m_features &= ~(XFS_FEAT_DAX_NEVER | XFS_FEAT_DAX_INODE); > > break; > > case XFS_DAX_NEVER: > > mp->m_features |= XFS_FEAT_DAX_NEVER; > > - mp->m_features &= ~XFS_FEAT_DAX_ALWAYS; > > + mp->m_features &= ~(XFS_FEAT_DAX_ALWAYS | XFS_FEAT_DAX_INODE); > > break; > > } > > } > > @@ -189,6 +190,7 @@ xfs_fs_show_options( > > { XFS_FEAT_LARGE_IOSIZE, ",largeio" }, > > { XFS_FEAT_DAX_ALWAYS, ",dax=always" }, > > { XFS_FEAT_DAX_NEVER, ",dax=never" }, > > + { XFS_FEAT_DAX_INODE, ",dax=inode" }, > > { 0, NULL } > > }; > > struct xfs_mount *mp = XFS_M(root->d_sb); > > @@ -1584,7 +1586,7 @@ xfs_fs_fill_super( > > if (xfs_has_crc(mp)) > > sb->s_flags |= SB_I_VERSION; > > > > - if (xfs_has_dax_always(mp)) { > > + if (xfs_has_dax_always(mp) || xfs_has_dax_inode(mp)) { > > Er... can't this be done without burning another feature bit by: > > if (xfs_has_dax_always(mp) || (!xfs_has_dax_always(mp) && > !xfs_has_dax_never(mp))) { > ... > xfs_warn(mp, "DAX IS EXPERIMENTAL"); > } > Good idea. I'll send a v2. Thanks- Bill > --D > > > bool rtdev_is_dax = false, datadev_is_dax; > > > > xfs_warn(mp, > > -- > > 2.31.1 > > >
On 8/26/21 1:09 PM, Darrick J. Wong wrote: > On Thu, Aug 26, 2021 at 12:30:12PM -0500, Bill O'Donnell wrote: >> @@ -1584,7 +1586,7 @@ xfs_fs_fill_super( >> if (xfs_has_crc(mp)) >> sb->s_flags |= SB_I_VERSION; >> >> - if (xfs_has_dax_always(mp)) { >> + if (xfs_has_dax_always(mp) || xfs_has_dax_inode(mp)) { > > Er... can't this be done without burning another feature bit by: > > if (xfs_has_dax_always(mp) || (!xfs_has_dax_always(mp) && > !xfs_has_dax_never(mp))) { > ... > xfs_warn(mp, "DAX IS EXPERIMENTAL"); > } changing this conditional in this way will also fail dax=inode mounts on reflink-capable (i.e. default) filesystems, no? - if (xfs_has_dax_always(mp)) { + if (xfs_has_dax_always(mp) || $NEW_DAX_INODE_TEST) { ... if (xfs_has_reflink(mp)) { xfs_alert(mp, "DAX and reflink cannot be used together!"); error = -EINVAL; goto out_filestream_unmount; } } -Eric
On Thu, Aug 26, 2021 at 01:16:22PM -0500, Eric Sandeen wrote: > > On 8/26/21 1:09 PM, Darrick J. Wong wrote: > > On Thu, Aug 26, 2021 at 12:30:12PM -0500, Bill O'Donnell wrote: > > > > @@ -1584,7 +1586,7 @@ xfs_fs_fill_super( > > > if (xfs_has_crc(mp)) > > > sb->s_flags |= SB_I_VERSION; > > > - if (xfs_has_dax_always(mp)) { > > > + if (xfs_has_dax_always(mp) || xfs_has_dax_inode(mp)) { > > > > Er... can't this be done without burning another feature bit by: > > > > if (xfs_has_dax_always(mp) || (!xfs_has_dax_always(mp) && > > !xfs_has_dax_never(mp))) { > > ... > > xfs_warn(mp, "DAX IS EXPERIMENTAL"); > > } > > changing this conditional in this way will also fail dax=inode mounts on > reflink-capable (i.e. default) filesystems, no? Correct. My original patch tests fine, and still handles the reflink and dax incompatibility. The new suggested logic is problematic. -Bill > > - if (xfs_has_dax_always(mp)) { > + if (xfs_has_dax_always(mp) || $NEW_DAX_INODE_TEST) { > > ... > if (xfs_has_reflink(mp)) { > xfs_alert(mp, > "DAX and reflink cannot be used together!"); > error = -EINVAL; > goto out_filestream_unmount; > } > } > > -Eric >
On 8/26/21 5:08 PM, Bill O'Donnell wrote: > On Thu, Aug 26, 2021 at 01:16:22PM -0500, Eric Sandeen wrote: >> >> On 8/26/21 1:09 PM, Darrick J. Wong wrote: >>> On Thu, Aug 26, 2021 at 12:30:12PM -0500, Bill O'Donnell wrote: >> >>>> @@ -1584,7 +1586,7 @@ xfs_fs_fill_super( >>>> if (xfs_has_crc(mp)) >>>> sb->s_flags |= SB_I_VERSION; >>>> - if (xfs_has_dax_always(mp)) { >>>> + if (xfs_has_dax_always(mp) || xfs_has_dax_inode(mp)) { >>> >>> Er... can't this be done without burning another feature bit by: >>> >>> if (xfs_has_dax_always(mp) || (!xfs_has_dax_always(mp) && >>> !xfs_has_dax_never(mp))) { >>> ... >>> xfs_warn(mp, "DAX IS EXPERIMENTAL"); >>> } >> >> changing this conditional in this way will also fail dax=inode mounts on >> reflink-capable (i.e. default) filesystems, no? > > Correct. My original patch tests fine, and still handles the reflink and dax > incompatibility. The new suggested logic is problematic. > -Bill I think that both your proposed patch and Darrick's suggestion have this problem. "mount -o dax=inode" makes your new xfs_has_dax_inode(mp) true, and in that conditional, if the filesystem has reflink enabled, mount fails: # mkfs.xfs -f /dev/pmem0p1 meta-data=/dev/pmem0p1 isize=512 agcount=4, agsize=4194304 blks = sectsz=4096 attr=2, projid32bit=1 = crc=1 finobt=1, sparse=1, rmapbt=0 = reflink=1 bigtime=0 inobtcount=0 data = bsize=4096 blocks=16777216, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0, ftype=1 log =internal log bsize=4096 blocks=8192, version=2 = sectsz=4096 sunit=1 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 # mount -o dax=inode /dev/pmem0p1 /mnt/test mount: wrong fs type, bad option, bad superblock on /dev/pmem0p1, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so. # dmesg | tail -n 2 [ 192.691733] XFS (pmem0p1): DAX enabled. Warning: EXPERIMENTAL, use at your own risk [ 192.700300] XFS (pmem0p1): DAX and reflink cannot be used together!
On Thu, Aug 26, 2021 at 06:43:44PM -0500, Eric Sandeen wrote: > On 8/26/21 5:08 PM, Bill O'Donnell wrote: > > On Thu, Aug 26, 2021 at 01:16:22PM -0500, Eric Sandeen wrote: > > > > > > On 8/26/21 1:09 PM, Darrick J. Wong wrote: > > > > On Thu, Aug 26, 2021 at 12:30:12PM -0500, Bill O'Donnell wrote: > > > > > > > > @@ -1584,7 +1586,7 @@ xfs_fs_fill_super( > > > > > if (xfs_has_crc(mp)) > > > > > sb->s_flags |= SB_I_VERSION; > > > > > - if (xfs_has_dax_always(mp)) { > > > > > + if (xfs_has_dax_always(mp) || xfs_has_dax_inode(mp)) { > > > > > > > > Er... can't this be done without burning another feature bit by: > > > > > > > > if (xfs_has_dax_always(mp) || (!xfs_has_dax_always(mp) && > > > > !xfs_has_dax_never(mp))) { > > > > ... > > > > xfs_warn(mp, "DAX IS EXPERIMENTAL"); > > > > } > > > > > > changing this conditional in this way will also fail dax=inode mounts on > > > reflink-capable (i.e. default) filesystems, no? > > > > Correct. My original patch tests fine, and still handles the reflink and dax > > incompatibility. The new suggested logic is problematic. > > -Bill > > I think that both your proposed patch and Darrick's suggestion have this problem. > > "mount -o dax=inode" makes your new xfs_has_dax_inode(mp) true, and in that > conditional, if the filesystem has reflink enabled, mount fails: > > # mkfs.xfs -f /dev/pmem0p1 > meta-data=/dev/pmem0p1 isize=512 agcount=4, agsize=4194304 blks > = sectsz=4096 attr=2, projid32bit=1 > = crc=1 finobt=1, sparse=1, rmapbt=0 > = reflink=1 bigtime=0 inobtcount=0 > data = bsize=4096 blocks=16777216, imaxpct=25 > = sunit=0 swidth=0 blks > naming =version 2 bsize=4096 ascii-ci=0, ftype=1 > log =internal log bsize=4096 blocks=8192, version=2 > = sectsz=4096 sunit=1 blks, lazy-count=1 > realtime =none extsz=4096 blocks=0, rtextents=0 > > # mount -o dax=inode /dev/pmem0p1 /mnt/test > mount: wrong fs type, bad option, bad superblock on /dev/pmem0p1, > missing codepage or helper program, or other error > > In some cases useful info is found in syslog - try > dmesg | tail or so. > > # dmesg | tail -n 2 > [ 192.691733] XFS (pmem0p1): DAX enabled. Warning: EXPERIMENTAL, use at your own risk > [ 192.700300] XFS (pmem0p1): DAX and reflink cannot be used together! > So, the "DAX enabled" is a misnomer in this case. However the incompatibility of DAX and reflink is reflected in the next message, and indeed the mount fails. Is it now a matter of fixing the message output so as not to indicate "DAX enabled..."? Thanks- Bill
On 8/27/21 9:03 AM, Bill O'Donnell wrote: > On Thu, Aug 26, 2021 at 06:43:44PM -0500, Eric Sandeen wrote: >> On 8/26/21 5:08 PM, Bill O'Donnell wrote: >>> On Thu, Aug 26, 2021 at 01:16:22PM -0500, Eric Sandeen wrote: >>>> >>>> On 8/26/21 1:09 PM, Darrick J. Wong wrote: >>>>> On Thu, Aug 26, 2021 at 12:30:12PM -0500, Bill O'Donnell wrote: >>>> >>>>>> @@ -1584,7 +1586,7 @@ xfs_fs_fill_super( >>>>>> if (xfs_has_crc(mp)) >>>>>> sb->s_flags |= SB_I_VERSION; >>>>>> - if (xfs_has_dax_always(mp)) { >>>>>> + if (xfs_has_dax_always(mp) || xfs_has_dax_inode(mp)) { >>>>> >>>>> Er... can't this be done without burning another feature bit by: >>>>> >>>>> if (xfs_has_dax_always(mp) || (!xfs_has_dax_always(mp) && >>>>> !xfs_has_dax_never(mp))) { >>>>> ... >>>>> xfs_warn(mp, "DAX IS EXPERIMENTAL"); >>>>> } >>>> >>>> changing this conditional in this way will also fail dax=inode mounts on >>>> reflink-capable (i.e. default) filesystems, no? >>> >>> Correct. My original patch tests fine, and still handles the reflink and dax >>> incompatibility. The new suggested logic is problematic. >>> -Bill >> >> I think that both your proposed patch and Darrick's suggestion have this problem. >> >> "mount -o dax=inode" makes your new xfs_has_dax_inode(mp) true, and in that >> conditional, if the filesystem has reflink enabled, mount fails: >> >> # mkfs.xfs -f /dev/pmem0p1 >> meta-data=/dev/pmem0p1 isize=512 agcount=4, agsize=4194304 blks >> = sectsz=4096 attr=2, projid32bit=1 >> = crc=1 finobt=1, sparse=1, rmapbt=0 >> = reflink=1 bigtime=0 inobtcount=0 >> data = bsize=4096 blocks=16777216, imaxpct=25 >> = sunit=0 swidth=0 blks >> naming =version 2 bsize=4096 ascii-ci=0, ftype=1 >> log =internal log bsize=4096 blocks=8192, version=2 >> = sectsz=4096 sunit=1 blks, lazy-count=1 >> realtime =none extsz=4096 blocks=0, rtextents=0 >> >> # mount -o dax=inode /dev/pmem0p1 /mnt/test >> mount: wrong fs type, bad option, bad superblock on /dev/pmem0p1, >> missing codepage or helper program, or other error >> >> In some cases useful info is found in syslog - try >> dmesg | tail or so. >> >> # dmesg | tail -n 2 >> [ 192.691733] XFS (pmem0p1): DAX enabled. Warning: EXPERIMENTAL, use at your own risk >> [ 192.700300] XFS (pmem0p1): DAX and reflink cannot be used together! >> > > So, the "DAX enabled" is a misnomer in this case. However the incompatibility of DAX and reflink is > reflected in the next message, and indeed the mount fails. Is it now a matter of fixing > the message output so as not to indicate "DAX enabled..."? The mount should not fail, and it does not fail prior to your change. In the past, we did not allow any mixing of a reflink-capable filesystem with dax in any way. Now, with per-inode dax, dax-enabled inodes and reflink-enabled inodes can exist on the same filesystem, you just cannot have an inode which is both dax-enabled and reflinked at the same time. -Eric
On Fri, Aug 27, 2021 at 09:18:32AM -0500, Eric Sandeen wrote: > On 8/27/21 9:03 AM, Bill O'Donnell wrote: > > On Thu, Aug 26, 2021 at 06:43:44PM -0500, Eric Sandeen wrote: > > > On 8/26/21 5:08 PM, Bill O'Donnell wrote: > > > > On Thu, Aug 26, 2021 at 01:16:22PM -0500, Eric Sandeen wrote: > > > > > > > > > > On 8/26/21 1:09 PM, Darrick J. Wong wrote: > > > > > > On Thu, Aug 26, 2021 at 12:30:12PM -0500, Bill O'Donnell wrote: > > > > > > > > > > > > @@ -1584,7 +1586,7 @@ xfs_fs_fill_super( > > > > > > > if (xfs_has_crc(mp)) > > > > > > > sb->s_flags |= SB_I_VERSION; > > > > > > > - if (xfs_has_dax_always(mp)) { > > > > > > > + if (xfs_has_dax_always(mp) || xfs_has_dax_inode(mp)) { > > > > > > > > > > > > Er... can't this be done without burning another feature bit by: > > > > > > > > > > > > if (xfs_has_dax_always(mp) || (!xfs_has_dax_always(mp) && > > > > > > !xfs_has_dax_never(mp))) { > > > > > > ... > > > > > > xfs_warn(mp, "DAX IS EXPERIMENTAL"); > > > > > > } > > > > > > > > > > changing this conditional in this way will also fail dax=inode mounts on > > > > > reflink-capable (i.e. default) filesystems, no? > > > > > > > > Correct. My original patch tests fine, and still handles the reflink and dax > > > > incompatibility. The new suggested logic is problematic. > > > > -Bill > > > > > > I think that both your proposed patch and Darrick's suggestion have this problem. > > > > > > "mount -o dax=inode" makes your new xfs_has_dax_inode(mp) true, and in that > > > conditional, if the filesystem has reflink enabled, mount fails: > > > > > > # mkfs.xfs -f /dev/pmem0p1 > > > meta-data=/dev/pmem0p1 isize=512 agcount=4, agsize=4194304 blks > > > = sectsz=4096 attr=2, projid32bit=1 > > > = crc=1 finobt=1, sparse=1, rmapbt=0 > > > = reflink=1 bigtime=0 inobtcount=0 > > > data = bsize=4096 blocks=16777216, imaxpct=25 > > > = sunit=0 swidth=0 blks > > > naming =version 2 bsize=4096 ascii-ci=0, ftype=1 > > > log =internal log bsize=4096 blocks=8192, version=2 > > > = sectsz=4096 sunit=1 blks, lazy-count=1 > > > realtime =none extsz=4096 blocks=0, rtextents=0 > > > > > > # mount -o dax=inode /dev/pmem0p1 /mnt/test > > > mount: wrong fs type, bad option, bad superblock on /dev/pmem0p1, > > > missing codepage or helper program, or other error > > > > > > In some cases useful info is found in syslog - try > > > dmesg | tail or so. > > > > > > # dmesg | tail -n 2 > > > [ 192.691733] XFS (pmem0p1): DAX enabled. Warning: EXPERIMENTAL, use at your own risk > > > [ 192.700300] XFS (pmem0p1): DAX and reflink cannot be used together! > > > > > > > So, the "DAX enabled" is a misnomer in this case. However the incompatibility of DAX and reflink is > > reflected in the next message, and indeed the mount fails. Is it now a matter of fixing > > the message output so as not to indicate "DAX enabled..."? > > The mount should not fail, and it does not fail prior to your change. > > In the past, we did not allow any mixing of a reflink-capable > filesystem with dax in any way. Now, with per-inode dax, dax-enabled inodes and > reflink-enabled inodes can exist on the same filesystem, you just cannot have an > inode which is both dax-enabled and reflinked at the same time. Ah. I missed that nuance. I had thought the incompatibility was absolute. :/ The manpage for mkfs.xfs may need updating for the inode mode (unless mine is old): ----------------snip------------------ "Note: the filesystem DAX mount option ( -o dax ) is incom‐ patible with reflink-enabled XFS filesystems. To use filesystem DAX with XFS, specify the -m reflink=0 option to mkfs.xfs to disable the reflink feature." ------------------------------------- Thanks- Bill
On 8/27/21 9:25 AM, Bill O'Donnell wrote: > On Fri, Aug 27, 2021 at 09:18:32AM -0500, Eric Sandeen wrote: >> On 8/27/21 9:03 AM, Bill O'Donnell wrote: >>> On Thu, Aug 26, 2021 at 06:43:44PM -0500, Eric Sandeen wrote: >>>> On 8/26/21 5:08 PM, Bill O'Donnell wrote: >>>>> On Thu, Aug 26, 2021 at 01:16:22PM -0500, Eric Sandeen wrote: >>>>>> >>>>>> On 8/26/21 1:09 PM, Darrick J. Wong wrote: >>>>>>> On Thu, Aug 26, 2021 at 12:30:12PM -0500, Bill O'Donnell wrote: >>>>>> >>>>>>>> @@ -1584,7 +1586,7 @@ xfs_fs_fill_super( >>>>>>>> if (xfs_has_crc(mp)) >>>>>>>> sb->s_flags |= SB_I_VERSION; >>>>>>>> - if (xfs_has_dax_always(mp)) { >>>>>>>> + if (xfs_has_dax_always(mp) || xfs_has_dax_inode(mp)) { >>>>>>> >>>>>>> Er... can't this be done without burning another feature bit by: >>>>>>> >>>>>>> if (xfs_has_dax_always(mp) || (!xfs_has_dax_always(mp) && >>>>>>> !xfs_has_dax_never(mp))) { >>>>>>> ... >>>>>>> xfs_warn(mp, "DAX IS EXPERIMENTAL"); >>>>>>> } >>>>>> >>>>>> changing this conditional in this way will also fail dax=inode mounts on >>>>>> reflink-capable (i.e. default) filesystems, no? >>>>> >>>>> Correct. My original patch tests fine, and still handles the reflink and dax >>>>> incompatibility. The new suggested logic is problematic. >>>>> -Bill >>>> >>>> I think that both your proposed patch and Darrick's suggestion have this problem. >>>> >>>> "mount -o dax=inode" makes your new xfs_has_dax_inode(mp) true, and in that >>>> conditional, if the filesystem has reflink enabled, mount fails: >>>> >>>> # mkfs.xfs -f /dev/pmem0p1 >>>> meta-data=/dev/pmem0p1 isize=512 agcount=4, agsize=4194304 blks >>>> = sectsz=4096 attr=2, projid32bit=1 >>>> = crc=1 finobt=1, sparse=1, rmapbt=0 >>>> = reflink=1 bigtime=0 inobtcount=0 >>>> data = bsize=4096 blocks=16777216, imaxpct=25 >>>> = sunit=0 swidth=0 blks >>>> naming =version 2 bsize=4096 ascii-ci=0, ftype=1 >>>> log =internal log bsize=4096 blocks=8192, version=2 >>>> = sectsz=4096 sunit=1 blks, lazy-count=1 >>>> realtime =none extsz=4096 blocks=0, rtextents=0 >>>> >>>> # mount -o dax=inode /dev/pmem0p1 /mnt/test >>>> mount: wrong fs type, bad option, bad superblock on /dev/pmem0p1, >>>> missing codepage or helper program, or other error >>>> >>>> In some cases useful info is found in syslog - try >>>> dmesg | tail or so. >>>> >>>> # dmesg | tail -n 2 >>>> [ 192.691733] XFS (pmem0p1): DAX enabled. Warning: EXPERIMENTAL, use at your own risk >>>> [ 192.700300] XFS (pmem0p1): DAX and reflink cannot be used together! >>>> >>> >>> So, the "DAX enabled" is a misnomer in this case. However the incompatibility of DAX and reflink is >>> reflected in the next message, and indeed the mount fails. Is it now a matter of fixing >>> the message output so as not to indicate "DAX enabled..."? >> >> The mount should not fail, and it does not fail prior to your change. >> >> In the past, we did not allow any mixing of a reflink-capable >> filesystem with dax in any way. Now, with per-inode dax, dax-enabled inodes and >> reflink-enabled inodes can exist on the same filesystem, you just cannot have an >> inode which is both dax-enabled and reflinked at the same time. > > Ah. I missed that nuance. I had thought the incompatibility was > absolute. :/ > > The manpage for mkfs.xfs may need updating for the inode mode > (unless mine is old): > ----------------snip------------------ > "Note: the filesystem DAX mount option ( -o dax ) is incom‐ > patible with reflink-enabled XFS filesystems. To use > filesystem DAX with XFS, specify the -m reflink=0 option to > mkfs.xfs to disable the reflink feature." > ------------------------------------- Hm, looks like the xfs(5) manpage got updated, but it seems mkfs.xfs(8) did not. dax=value Set CPU direct access (DAX) behavior for the current filesystem. This mount option accepts the following values: "dax=inode" DAX will be enabled only on regular files with FS_XFLAG_DAX applied. "dax=never" DAX will not be enabled for any files. FS_XFLAG_DAX will be ignored. "dax=always" DAX will be enabled for all regular files, regardless of the FS_XFLAG_DAX state. If no option is used when mounting a filesystem stored on a DAX capable device, dax=inode will be used as default. For details regarding DAX behavior in kernel, please refer to ker‐ nel's documentation I'll send a patch to fix up the mkfs manpage, thanks. Thanks, -Eric
On Fri, Aug 27, 2021 at 10:35:56AM -0500, Eric Sandeen wrote: > On 8/27/21 9:25 AM, Bill O'Donnell wrote: > > On Fri, Aug 27, 2021 at 09:18:32AM -0500, Eric Sandeen wrote: > > > On 8/27/21 9:03 AM, Bill O'Donnell wrote: > > > > On Thu, Aug 26, 2021 at 06:43:44PM -0500, Eric Sandeen wrote: > > > > > On 8/26/21 5:08 PM, Bill O'Donnell wrote: > > > > > > On Thu, Aug 26, 2021 at 01:16:22PM -0500, Eric Sandeen wrote: > > > > > > > > > > > > > > On 8/26/21 1:09 PM, Darrick J. Wong wrote: > > > > > > > > On Thu, Aug 26, 2021 at 12:30:12PM -0500, Bill O'Donnell wrote: > > > > > > > > > > > > > > > > @@ -1584,7 +1586,7 @@ xfs_fs_fill_super( > > > > > > > > > if (xfs_has_crc(mp)) > > > > > > > > > sb->s_flags |= SB_I_VERSION; > > > > > > > > > - if (xfs_has_dax_always(mp)) { > > > > > > > > > + if (xfs_has_dax_always(mp) || xfs_has_dax_inode(mp)) { > > > > > > > > > > > > > > > > Er... can't this be done without burning another feature bit by: > > > > > > > > > > > > > > > > if (xfs_has_dax_always(mp) || (!xfs_has_dax_always(mp) && > > > > > > > > !xfs_has_dax_never(mp))) { > > > > > > > > ... > > > > > > > > xfs_warn(mp, "DAX IS EXPERIMENTAL"); > > > > > > > > } > > > > > > > > > > > > > > changing this conditional in this way will also fail dax=inode mounts on > > > > > > > reflink-capable (i.e. default) filesystems, no? > > > > > > > > > > > > Correct. My original patch tests fine, and still handles the reflink and dax > > > > > > incompatibility. The new suggested logic is problematic. > > > > > > -Bill > > > > > > > > > > I think that both your proposed patch and Darrick's suggestion have this problem. > > > > > > > > > > "mount -o dax=inode" makes your new xfs_has_dax_inode(mp) true, and in that > > > > > conditional, if the filesystem has reflink enabled, mount fails: > > > > > > > > > > # mkfs.xfs -f /dev/pmem0p1 > > > > > meta-data=/dev/pmem0p1 isize=512 agcount=4, agsize=4194304 blks > > > > > = sectsz=4096 attr=2, projid32bit=1 > > > > > = crc=1 finobt=1, sparse=1, rmapbt=0 > > > > > = reflink=1 bigtime=0 inobtcount=0 > > > > > data = bsize=4096 blocks=16777216, imaxpct=25 > > > > > = sunit=0 swidth=0 blks > > > > > naming =version 2 bsize=4096 ascii-ci=0, ftype=1 > > > > > log =internal log bsize=4096 blocks=8192, version=2 > > > > > = sectsz=4096 sunit=1 blks, lazy-count=1 > > > > > realtime =none extsz=4096 blocks=0, rtextents=0 > > > > > > > > > > # mount -o dax=inode /dev/pmem0p1 /mnt/test > > > > > mount: wrong fs type, bad option, bad superblock on /dev/pmem0p1, > > > > > missing codepage or helper program, or other error > > > > > > > > > > In some cases useful info is found in syslog - try > > > > > dmesg | tail or so. > > > > > > > > > > # dmesg | tail -n 2 > > > > > [ 192.691733] XFS (pmem0p1): DAX enabled. Warning: EXPERIMENTAL, use at your own risk > > > > > [ 192.700300] XFS (pmem0p1): DAX and reflink cannot be used together! > > > > > > > > > > > > > So, the "DAX enabled" is a misnomer in this case. However the incompatibility of DAX and reflink is > > > > reflected in the next message, and indeed the mount fails. Is it now a matter of fixing > > > > the message output so as not to indicate "DAX enabled..."? > > > > > > The mount should not fail, and it does not fail prior to your change. > > > > > > In the past, we did not allow any mixing of a reflink-capable > > > filesystem with dax in any way. Now, with per-inode dax, dax-enabled inodes and > > > reflink-enabled inodes can exist on the same filesystem, you just cannot have an > > > inode which is both dax-enabled and reflinked at the same time. > > > > Ah. I missed that nuance. I had thought the incompatibility was > > absolute. :/ > > > > The manpage for mkfs.xfs may need updating for the inode mode > > (unless mine is old): > > ----------------snip------------------ > > "Note: the filesystem DAX mount option ( -o dax ) is incom‐ > > patible with reflink-enabled XFS filesystems. To use > > filesystem DAX with XFS, specify the -m reflink=0 option to > > mkfs.xfs to disable the reflink feature." > > ------------------------------------- > > Hm, looks like the xfs(5) manpage got updated, but it seems mkfs.xfs(8) did not. > > dax=value > Set CPU direct access (DAX) behavior for the current filesystem. > This mount option accepts the following values: > > "dax=inode" DAX will be enabled only on regular files with > FS_XFLAG_DAX applied. > > "dax=never" DAX will not be enabled for any files. FS_XFLAG_DAX > will be ignored. > > "dax=always" DAX will be enabled for all regular files, regardless > of the FS_XFLAG_DAX state. > > If no option is used when mounting a filesystem stored on a DAX > capable device, dax=inode will be used as default. The documentation here, https://www.kernel.org/doc/Documentation/filesystems/dax.txt adds to the confusion. "-o dax" is a legacy option which is an alias for "dax=always". This may be removed in the future so "-o dax=always" is the preferred method for specifying this behavior. > > For details regarding DAX behavior in kernel, please refer to ker‐ > nel's documentation > > I'll send a patch to fix up the mkfs manpage, thanks. > > Thanks, > -Eric >
On Thu, Aug 26, 2021 at 11:09:47AM -0700, Darrick J. Wong wrote: > On Thu, Aug 26, 2021 at 12:30:12PM -0500, Bill O'Donnell wrote: > > When dax-mode was tri-stated by adding dax=inode case, the EXPERIMENTAL > > warning on mount was missed for the case. Add logic to handle the > > warning similar to that of the 'dax=always' case. > > > > Signed-off-by: Bill O'Donnell <bodonnel@redhat.com> > > --- > > fs/xfs/xfs_mount.h | 2 ++ > > fs/xfs/xfs_super.c | 8 +++++--- > > 2 files changed, 7 insertions(+), 3 deletions(-) ... > > - if (xfs_has_dax_always(mp)) { > > + if (xfs_has_dax_always(mp) || xfs_has_dax_inode(mp)) { > > Er... can't this be done without burning another feature bit by: > > if (xfs_has_dax_always(mp) || (!xfs_has_dax_always(mp) && > !xfs_has_dax_never(mp))) { > ... > xfs_warn(mp, "DAX IS EXPERIMENTAL"); > } Not quite. This will be true at initialization. -Bill
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h index e091f3b3fa15..c9243a1b8d05 100644 --- a/fs/xfs/xfs_mount.h +++ b/fs/xfs/xfs_mount.h @@ -277,6 +277,7 @@ typedef struct xfs_mount { #define XFS_FEAT_NEEDSREPAIR (1ULL << 25) /* needs xfs_repair */ /* Mount features */ +#define XFS_FEAT_DAX_INODE (1ULL << 47) /* DAX enabled */ #define XFS_FEAT_NOATTR2 (1ULL << 48) /* disable attr2 creation */ #define XFS_FEAT_NOALIGN (1ULL << 49) /* ignore alignment */ #define XFS_FEAT_ALLOCSIZE (1ULL << 50) /* user specified allocation size */ @@ -359,6 +360,7 @@ __XFS_HAS_FEAT(swalloc, SWALLOC) __XFS_HAS_FEAT(filestreams, FILESTREAMS) __XFS_HAS_FEAT(dax_always, DAX_ALWAYS) __XFS_HAS_FEAT(dax_never, DAX_NEVER) +__XFS_HAS_FEAT(dax_inode, DAX_INODE) __XFS_HAS_FEAT(norecovery, NORECOVERY) __XFS_HAS_FEAT(nouuid, NOUUID) diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c index 5e73ac78bf2f..f73f3687f0a8 100644 --- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -84,15 +84,16 @@ xfs_mount_set_dax_mode( { switch (mode) { case XFS_DAX_INODE: + mp->m_features |= XFS_FEAT_DAX_INODE; mp->m_features &= ~(XFS_FEAT_DAX_ALWAYS | XFS_FEAT_DAX_NEVER); break; case XFS_DAX_ALWAYS: mp->m_features |= XFS_FEAT_DAX_ALWAYS; - mp->m_features &= ~XFS_FEAT_DAX_NEVER; + mp->m_features &= ~(XFS_FEAT_DAX_NEVER | XFS_FEAT_DAX_INODE); break; case XFS_DAX_NEVER: mp->m_features |= XFS_FEAT_DAX_NEVER; - mp->m_features &= ~XFS_FEAT_DAX_ALWAYS; + mp->m_features &= ~(XFS_FEAT_DAX_ALWAYS | XFS_FEAT_DAX_INODE); break; } } @@ -189,6 +190,7 @@ xfs_fs_show_options( { XFS_FEAT_LARGE_IOSIZE, ",largeio" }, { XFS_FEAT_DAX_ALWAYS, ",dax=always" }, { XFS_FEAT_DAX_NEVER, ",dax=never" }, + { XFS_FEAT_DAX_INODE, ",dax=inode" }, { 0, NULL } }; struct xfs_mount *mp = XFS_M(root->d_sb); @@ -1584,7 +1586,7 @@ xfs_fs_fill_super( if (xfs_has_crc(mp)) sb->s_flags |= SB_I_VERSION; - if (xfs_has_dax_always(mp)) { + if (xfs_has_dax_always(mp) || xfs_has_dax_inode(mp)) { bool rtdev_is_dax = false, datadev_is_dax; xfs_warn(mp,
When dax-mode was tri-stated by adding dax=inode case, the EXPERIMENTAL warning on mount was missed for the case. Add logic to handle the warning similar to that of the 'dax=always' case. Signed-off-by: Bill O'Donnell <bodonnel@redhat.com> --- fs/xfs/xfs_mount.h | 2 ++ fs/xfs/xfs_super.c | 8 +++++--- 2 files changed, 7 insertions(+), 3 deletions(-)