[PATCH V10 11/11] fs/xfs: Update xfs_ioctl_setattr_dax_invalidate()

ira.weiny
2020-04-22T21:21:56Z

From: Ira Weiny <ira.weiny@intel.com>

Because of the separation of FS_XFLAG_DAX from S_DAX and the delayed
setting of S_DAX, data invalidation no longer needs to happen when
FS_XFLAG_DAX is changed.

Change xfs_ioctl_setattr_dax_invalidate() to be
xfs_ioctl_dax_check_set_cache() and alter the code to reflect the new
functionality.

Furthermore, we no longer need the locking so we remove the join_flags
logic.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>

---
Changes from V9:
Change name of function to xfs_ioctl_setattr_prepare_dax()

Changes from V8:
Change name of function to xfs_ioctl_dax_check_set_cache()
Update commit message
Fix bit manipulations

Changes from V7:
Use new flag_inode_dontcache()
Skip don't cache if mount over ride is active.

Changes from v6:
Fix completely broken implementation and update commit message.
Use the new VFS layer I_DONTCACHE to facilitate inode eviction
and S_DAX changing on drop_caches

Changes from v5:
New patch
---
fs/xfs/xfs_ioctl.c | 108 +++++++++------------------------------------
1 file changed, 20 insertions(+), 88 deletions(-)

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 104495ac187c..aa1a8bd7d68d 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1245,64 +1245,26 @@ xfs_ioctl_setattr_xflags(
return 0;
}

-/*
- * If we are changing DAX flags, we have to ensure the file is clean and any
- * cached objects in the address space are invalidated and removed. This
- * requires us to lock out other IO and page faults similar to a truncate
- * operation. The locks need to be held until the transaction has been committed
- * so that the cache invalidation is atomic with respect to the DAX flag
- * manipulation.
- */
-static int
-xfs_ioctl_setattr_dax_invalidate(
+static void
+xfs_ioctl_setattr_prepare_dax(
struct xfs_inode *ip,
- struct fsxattr *fa,
- int *join_flags)
+ struct fsxattr *fa)
{
- struct inode *inode = VFS_I(ip);
- struct super_block *sb = inode->i_sb;
- int error;
-
- *join_flags = 0;
-
- /*
- * It is only valid to set the DAX flag on regular files and
- * directories on filesystems where the block size is equal to the page
- * size. On directories it serves as an inherited hint so we don't
- * have to check the device for dax support or flush pagecache.
- */
- if (fa->fsx_xflags & FS_XFLAG_DAX) {
- struct xfs_buftarg *target = xfs_inode_buftarg(ip);
-
- if (!bdev_dax_supported(target->bt_bdev, sb->s_blocksize))
- return -EINVAL;
- }
-
- /* If the DAX state is not changing, we have nothing to do here. */
- if ((fa->fsx_xflags & FS_XFLAG_DAX) && IS_DAX(inode))
- return 0;
- if (!(fa->fsx_xflags & FS_XFLAG_DAX) && !IS_DAX(inode))
- return 0;
+ struct xfs_mount *mp = ip->i_mount;
+ struct inode *inode = VFS_I(ip);

if (S_ISDIR(inode->i_mode))
- return 0;
-
- /* lock, flush and invalidate mapping in preparation for flag change */
- xfs_ilock(ip, XFS_MMAPLOCK_EXCL | XFS_IOLOCK_EXCL);
- error = filemap_write_and_wait(inode->i_mapping);
- if (error)
- goto out_unlock;
- error = invalidate_inode_pages2(inode->i_mapping);
- if (error)
- goto out_unlock;
-
- *join_flags = XFS_MMAPLOCK_EXCL | XFS_IOLOCK_EXCL;
- return 0;
+ return;

-out_unlock:
- xfs_iunlock(ip, XFS_MMAPLOCK_EXCL | XFS_IOLOCK_EXCL);
- return error;
+ if ((mp->m_flags & XFS_MOUNT_DAX_ALWAYS) ||
+ (mp->m_flags & XFS_MOUNT_DAX_NEVER))
+ return;

+ if (((fa->fsx_xflags & FS_XFLAG_DAX) &&
+ !(ip->i_d.di_flags2 & XFS_DIFLAG2_DAX)) ||
+ (!(fa->fsx_xflags & FS_XFLAG_DAX) &&
+ (ip->i_d.di_flags2 & XFS_DIFLAG2_DAX)))
+ mark_inode_dontcache(inode);
}

/*
@@ -1310,17 +1272,10 @@ xfs_ioctl_setattr_dax_invalidate(
* have permission to do so. On success, return a clean transaction and the
* inode locked exclusively ready for further operation specific checks. On
* failure, return an error without modifying or locking the inode.
- *
- * The inode might already be IO locked on call. If this is the case, it is
- * indicated in @join_flags and we take full responsibility for ensuring they
- * are unlocked from now on. Hence if we have an error here, we still have to
- * unlock them. Otherwise, once they are joined to the transaction, they will
- * be unlocked on commit/cancel.
*/
static struct xfs_trans *
xfs_ioctl_setattr_get_trans(
- struct xfs_inode *ip,
- int join_flags)
+ struct xfs_inode *ip)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
@@ -1337,8 +1292,7 @@ xfs_ioctl_setattr_get_trans(
goto out_unlock;

xfs_ilock(ip, XFS_ILOCK_EXCL);
- xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL | join_flags);
- join_flags = 0;
+ xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);

/*
* CAP_FOWNER overrides the following restrictions:
@@ -1359,8 +1313,6 @@ xfs_ioctl_setattr_get_trans(
out_cancel:
xfs_trans_cancel(tp);
out_unlock:
- if (join_flags)
- xfs_iunlock(ip, join_flags);
return ERR_PTR(error);
}

@@ -1486,7 +1438,6 @@ xfs_ioctl_setattr(
struct xfs_dquot *pdqp = NULL;
struct xfs_dquot *olddquot = NULL;
int code;
- int join_flags = 0;

trace_xfs_ioctl_setattr(ip);

@@ -1510,18 +1461,9 @@ xfs_ioctl_setattr(
return code;
}

- /*
- * Changing DAX config may require inode locking for mapping
- * invalidation. These need to be held all the way to transaction commit
- * or cancel time, so need to be passed through to
- * xfs_ioctl_setattr_get_trans() so it can apply them to the join call
- * appropriately.
- */
- code = xfs_ioctl_setattr_dax_invalidate(ip, fa, &join_flags);
- if (code)
- goto error_free_dquots;
+ xfs_ioctl_setattr_prepare_dax(ip, fa);

- tp = xfs_ioctl_setattr_get_trans(ip, join_flags);
+ tp = xfs_ioctl_setattr_get_trans(ip);
if (IS_ERR(tp)) {
code = PTR_ERR(tp);
goto error_free_dquots;
@@ -1651,7 +1593,6 @@ xfs_ioc_setxflags(
struct fsxattr fa;
struct fsxattr old_fa;
unsigned int flags;
- int join_flags = 0;
int error;

if (copy_from_user(&flags, arg, sizeof(flags)))
@@ -1668,18 +1609,9 @@ xfs_ioc_setxflags(
if (error)
return error;

- /*
- * Changing DAX config may require inode locking for mapping
- * invalidation. These need to be held all the way to transaction commit
- * or cancel time, so need to be passed through to
- * xfs_ioctl_setattr_get_trans() so it can apply them to the join call
- * appropriately.
- */
- error = xfs_ioctl_setattr_dax_invalidate(ip, &fa, &join_flags);
- if (error)
- goto out_drop_write;
+ xfs_ioctl_setattr_prepare_dax(ip, &fa);

- tp = xfs_ioctl_setattr_get_trans(ip, join_flags);
+ tp = xfs_ioctl_setattr_get_trans(ip);
if (IS_ERR(tp)) {
error = PTR_ERR(tp);
goto out_drop_write;
--
2.25.1