Re: [PATCH 2/2] statx: move STATX_ATTR_DAX attribute handling to filesystems
From: Darrick J. Wong <hidden>
Date: 2020-12-01 17:40:14
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On Tue, Dec 01, 2020 at 10:59:36AM -0600, Eric Sandeen wrote:
quoted hunk ↗ jump to hunk
It's a bit odd to set STATX_ATTR_DAX into the statx attributes in the VFS; while the VFS can detect the current DAX state, it is the filesystem which actually sets S_DAX on the inode, and the filesystem is the place that knows whether DAX is something that the "filesystem actually supports" [1] so that the statx attributes_mask can be properly set. So, move STATX_ATTR_DAX attribute setting to the individual dax-capable filesystems, and update the attributes_mask there as well. [1] 3209f68b3ca4 statx: Include a mask for stx_attributes in struct statx Signed-off-by: Eric Sandeen <redacted> --- fs/ext2/inode.c | 6 +++++- fs/ext4/inode.c | 5 ++++- fs/stat.c | 3 --- fs/xfs/xfs_iops.c | 5 ++++- 4 files changed, 13 insertions(+), 6 deletions(-)diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index 11c5c6fe75bb..3550783a6ea0 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c@@ -1653,11 +1653,15 @@ int ext2_getattr(const struct path *path, struct kstat *stat, stat->attributes |= STATX_ATTR_IMMUTABLE; if (flags & EXT2_NODUMP_FL) stat->attributes |= STATX_ATTR_NODUMP; + if (IS_DAX(inode)) + stat->attributes |= STATX_ATTR_DAX; + stat->attributes_mask |= (STATX_ATTR_APPEND | STATX_ATTR_COMPRESSED | STATX_ATTR_ENCRYPTED | STATX_ATTR_IMMUTABLE | - STATX_ATTR_NODUMP); + STATX_ATTR_NODUMP | + STATX_ATTR_DAX); generic_fillattr(inode, stat); return 0;diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 0d8385aea898..848a0f2b154e 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c@@ -5550,13 +5550,16 @@ int ext4_getattr(const struct path *path, struct kstat *stat, stat->attributes |= STATX_ATTR_NODUMP; if (flags & EXT4_VERITY_FL) stat->attributes |= STATX_ATTR_VERITY; + if (IS_DAX(inode)) + stat->attributes |= STATX_ATTR_DAX; stat->attributes_mask |= (STATX_ATTR_APPEND | STATX_ATTR_COMPRESSED | STATX_ATTR_ENCRYPTED | STATX_ATTR_IMMUTABLE | STATX_ATTR_NODUMP | - STATX_ATTR_VERITY); + STATX_ATTR_VERITY | + STATX_ATTR_DAX); generic_fillattr(inode, stat); return 0;diff --git a/fs/stat.c b/fs/stat.c index dacecdda2e79..5bd90949c69b 100644 --- a/fs/stat.c +++ b/fs/stat.c@@ -80,9 +80,6 @@ int vfs_getattr_nosec(const struct path *path, struct kstat *stat, if (IS_AUTOMOUNT(inode)) stat->attributes |= STATX_ATTR_AUTOMOUNT; - if (IS_DAX(inode)) - stat->attributes |= STATX_ATTR_DAX; - if (inode->i_op->getattr) return inode->i_op->getattr(path, stat, request_mask, query_flags);diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c index 1414ab79eacf..56deda7042fd 100644 --- a/fs/xfs/xfs_iops.c +++ b/fs/xfs/xfs_iops.c@@ -575,10 +575,13 @@ xfs_vn_getattr( stat->attributes |= STATX_ATTR_APPEND; if (ip->i_d.di_flags & XFS_DIFLAG_NODUMP) stat->attributes |= STATX_ATTR_NODUMP; + if (IS_DAX(inode)) + stat->attributes |= STATX_ATTR_DAX; stat->attributes_mask |= (STATX_ATTR_IMMUTABLE | STATX_ATTR_APPEND | - STATX_ATTR_NODUMP); + STATX_ATTR_NODUMP | + STATX_ATTR_DAX);
TBH I preferred your previous iteration on this, which only set the DAX bit in the attributes_mask if the underlying storage was pmem and the blocksize was correct, etc. since it made it easier to distinguish between a filesystem where you /could/ have DAX (but it wasn't currently enabled) and a filesystem where it just isn't possible. That might be enough to satisfy any critics who want to be able to detect DAX support from an installer program. --D
switch (inode->i_mode & S_IFMT) {
case S_IFBLK:
--
2.17.0