[PATCH v2 11/14] fs: xfs: Support FS_XFLAG_ATOMICWRITES for forcealign

John Garry
2024-03-04T13:07:41Z

Add initial support for FS_XFLAG_ATOMICWRITES for forcealign enabled.

Current kernel support for atomic writes is based on HW support (for atomic
writes). As such, it is required to ensure extent alignment with
atomic_write_unit_max so that an atomic write can result in a single
HW-compliant IO operation.

rtvol also guarantees extent alignment, but we are basing support initially
on forcealign, which is not supported for rtvol yet.

Signed-off-by: John Garry <john.g.garry@oracle.com>
---
fs/xfs/libxfs/xfs_format.h | 13 ++++++++++---
fs/xfs/libxfs/xfs_sb.c | 2 ++
fs/xfs/xfs_inode.c | 2 ++
fs/xfs/xfs_inode.h | 5 +++++
fs/xfs/xfs_ioctl.c | 15 +++++++++++++--
fs/xfs/xfs_mount.h | 2 ++
fs/xfs/xfs_super.c | 4 ++++
7 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 2d9f5430efc3..5f54f9b3755e 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -354,12 +354,16 @@ xfs_sb_has_compat_feature(
#define XFS_SB_FEAT_RO_COMPAT_REFLINK (1 << 2) /* reflinked files */
#define XFS_SB_FEAT_RO_COMPAT_INOBTCNT (1 << 3) /* inobt block counts */
#define XFS_SB_FEAT_RO_COMPAT_FORCEALIGN (1 << 30) /* aligned file data extents */
+#define XFS_SB_FEAT_RO_COMPAT_ATOMICWRITES (1 << 31) /* atomicwrites enabled */
+
#define XFS_SB_FEAT_RO_COMPAT_ALL \
(XFS_SB_FEAT_RO_COMPAT_FINOBT | \
XFS_SB_FEAT_RO_COMPAT_RMAPBT | \
XFS_SB_FEAT_RO_COMPAT_REFLINK| \
- XFS_SB_FEAT_RO_COMPAT_INOBTCNT | \
- XFS_SB_FEAT_RO_COMPAT_FORCEALIGN)
+ XFS_SB_FEAT_RO_COMPAT_INOBTCNT| \
+ XFS_SB_FEAT_RO_COMPAT_FORCEALIGN| \
+ XFS_SB_FEAT_RO_COMPAT_ATOMICWRITES)
+
#define XFS_SB_FEAT_RO_COMPAT_UNKNOWN ~XFS_SB_FEAT_RO_COMPAT_ALL
static inline bool
xfs_sb_has_ro_compat_feature(
@@ -1089,6 +1093,7 @@ static inline void xfs_dinode_put_rdev(struct xfs_dinode *dip, xfs_dev_t rdev)
#define XFS_DIFLAG2_NREXT64_BIT 4 /* large extent counters */
/* data extent mappings for regular files must be aligned to extent size hint */
#define XFS_DIFLAG2_FORCEALIGN_BIT 5
+#define XFS_DIFLAG2_ATOMICWRITES_BIT 6

#define XFS_DIFLAG2_DAX (1 << XFS_DIFLAG2_DAX_BIT)
#define XFS_DIFLAG2_REFLINK (1 << XFS_DIFLAG2_REFLINK_BIT)
@@ -1096,10 +1101,12 @@ static inline void xfs_dinode_put_rdev(struct xfs_dinode *dip, xfs_dev_t rdev)
#define XFS_DIFLAG2_BIGTIME (1 << XFS_DIFLAG2_BIGTIME_BIT)
#define XFS_DIFLAG2_NREXT64 (1 << XFS_DIFLAG2_NREXT64_BIT)
#define XFS_DIFLAG2_FORCEALIGN (1 << XFS_DIFLAG2_FORCEALIGN_BIT)
+#define XFS_DIFLAG2_ATOMICWRITES (1 << XFS_DIFLAG2_ATOMICWRITES_BIT)

#define XFS_DIFLAG2_ANY \
(XFS_DIFLAG2_DAX | XFS_DIFLAG2_REFLINK | XFS_DIFLAG2_COWEXTSIZE | \
- XFS_DIFLAG2_BIGTIME | XFS_DIFLAG2_NREXT64 | XFS_DIFLAG2_FORCEALIGN)
+ XFS_DIFLAG2_BIGTIME | XFS_DIFLAG2_NREXT64 | XFS_DIFLAG2_FORCEALIGN | \
+ XFS_DIFLAG2_ATOMICWRITES)

static inline bool xfs_dinode_has_bigtime(const struct xfs_dinode *dip)
{
diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index f2c16a028fae..d7bb3e34dd69 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -165,6 +165,8 @@ xfs_sb_version_to_features(
features |= XFS_FEAT_INOBTCNT;
if (sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_FORCEALIGN)
features |= XFS_FEAT_FORCEALIGN;
+ if (sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_ATOMICWRITES)
+ features |= XFS_FEAT_ATOMICWRITES;
if (sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_FTYPE)
features |= XFS_FEAT_FTYPE;
if (sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_SPINODES)
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index bbb8886f1d32..14020ab1450c 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -645,6 +645,8 @@ xfs_ip2xflags(
flags |= FS_XFLAG_COWEXTSIZE;
if (ip->i_diflags2 & XFS_DIFLAG2_FORCEALIGN)
flags |= FS_XFLAG_FORCEALIGN;
+ if (ip->i_diflags2 & XFS_DIFLAG2_ATOMICWRITES)
+ flags |= FS_XFLAG_ATOMICWRITES;
}

if (xfs_inode_has_attr_fork(ip))
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index b6c42c27943e..f56bdbb74ad7 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -310,6 +310,11 @@ static inline bool xfs_inode_forcealign(struct xfs_inode *ip)
return ip->i_diflags2 & XFS_DIFLAG2_FORCEALIGN;
}

+static inline bool xfs_inode_atomicwrites(struct xfs_inode *ip)
+{
+ return ip->i_diflags2 & XFS_DIFLAG2_ATOMICWRITES;
+}
+
/*
* Return the buftarg used for data allocations on a given inode.
*/
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 867d8d51a3d0..f118a1ae39b5 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1112,6 +1112,8 @@ xfs_flags2diflags2(
di_flags2 |= XFS_DIFLAG2_COWEXTSIZE;
if (xflags & FS_XFLAG_FORCEALIGN)
di_flags2 |= XFS_DIFLAG2_FORCEALIGN;
+ if (xflags & FS_XFLAG_ATOMICWRITES)
+ di_flags2 |= XFS_DIFLAG2_ATOMICWRITES;

return di_flags2;
}
@@ -1124,10 +1126,12 @@ xfs_ioctl_setattr_xflags(
{
struct xfs_mount *mp = ip->i_mount;
bool rtflag = (fa->fsx_xflags & FS_XFLAG_REALTIME);
+ bool atomic_writes = fa->fsx_xflags & FS_XFLAG_ATOMICWRITES;
uint64_t i_flags2;

- if (rtflag != XFS_IS_REALTIME_INODE(ip)) {
- /* Can't change realtime flag if any extents are allocated. */
+ /* Can't change RT or atomic flags if any extents are allocated. */
+ if (rtflag != XFS_IS_REALTIME_INODE(ip) ||
+ atomic_writes != xfs_inode_atomicwrites(ip)) {
if (ip->i_df.if_nextents || ip->i_delayed_blks)
return -EINVAL;
}
@@ -1164,6 +1168,13 @@ xfs_ioctl_setattr_xflags(
return -EINVAL;
}

+ if (atomic_writes) {
+ if (!xfs_has_atomicwrites(mp))
+ return -EINVAL;
+ if (!(fa->fsx_xflags & FS_XFLAG_FORCEALIGN))
+ return -EINVAL;
+ }
+
ip->i_diflags = xfs_flags2diflags(ip, fa->fsx_xflags);
ip->i_diflags2 = i_flags2;

diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index e1ef31675db3..3b60d8a1d396 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -290,6 +290,7 @@ typedef struct xfs_mount {
#define XFS_FEAT_NEEDSREPAIR (1ULL << 25) /* needs xfs_repair */
#define XFS_FEAT_NREXT64 (1ULL << 26) /* large extent counters */
#define XFS_FEAT_FORCEALIGN (1ULL << 27) /* aligned file data extents */
+#define XFS_FEAT_ATOMICWRITES (1ULL << 28) /* atomic writes support */

/* Mount features */
#define XFS_FEAT_NOATTR2 (1ULL << 48) /* disable attr2 creation */
@@ -354,6 +355,7 @@ __XFS_HAS_FEAT(bigtime, BIGTIME)
__XFS_HAS_FEAT(needsrepair, NEEDSREPAIR)
__XFS_HAS_FEAT(large_extent_counts, NREXT64)
__XFS_HAS_FEAT(forcealign, FORCEALIGN)
+__XFS_HAS_FEAT(atomicwrites, ATOMICWRITES)

/*
* Mount features
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 74dcafddf6a9..efe4b4234b2e 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1712,6 +1712,10 @@ xfs_fs_fill_super(
xfs_warn(mp,
"EXPERIMENTAL forced data extent alignment feature in use. Use at your own risk!");

+ if (xfs_has_atomicwrites(mp))
+ xfs_warn(mp,
+"EXPERIMENTAL atomicwrites feature in use. Use at your own risk!");
+
if (xfs_has_reflink(mp)) {
if (mp->m_sb.sb_rblocks) {
xfs_alert(mp,
--
2.31.1