Support providing info on atomic write unit min and max for an inode.
For simplicity, currently we limit the min at the FS block size, but a
lower limit could be supported in future.
Signed-off-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx>
---
fs/ext4/inode.c | 38 ++++++++++++++++++++++++++++++++++++--
1 file changed, 36 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d185ec54ffa3..c8f974d0f113 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5621,6 +5621,7 @@ int ext4_getattr(struct mnt_idmap *idmap, const struct path *path,
struct ext4_inode *raw_inode;
struct ext4_inode_info *ei = EXT4_I(inode);
unsigned int flags;
+ struct block_device *bdev = inode->i_sb->s_bdev;
if ((request_mask & STATX_BTIME) &&
EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime)) {
@@ -5639,8 +5640,6 @@ int ext4_getattr(struct mnt_idmap *idmap, const struct path *path,
stat->result_mask |= STATX_DIOALIGN;
if (dio_align == 1) {
- struct block_device *bdev = inode->i_sb->s_bdev;
-
/* iomap defaults */
stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;
stat->dio_offset_align = bdev_logical_block_size(bdev);
@@ -5650,6 +5649,41 @@ int ext4_getattr(struct mnt_idmap *idmap, const struct path *path,
}
}
+ if ((request_mask & STATX_WRITE_ATOMIC)) {
+ unsigned int awumin, awumax;
+ unsigned int blocksize = 1 << inode->i_blkbits;
+
+ awumin = queue_atomic_write_unit_min_bytes(bdev->bd_queue);
+ awumax = queue_atomic_write_unit_max_bytes(bdev->bd_queue);
+
+ if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) ||
+ EXT4_SB(inode->i_sb)->s_cluster_ratio > 1) {
+ /*
+ * Currently not supported for non extent files or
+ * with bigalloc
+ */
+ stat->atomic_write_unit_min = 0;
+ stat->atomic_write_unit_max = 0;
+ } else if (awumin && awumax) {
+ /*
+ * For now we support atomic writes which are
+ * at least block size bytes. If that exceeds the
+ * max atomic unit, then don't advertise support
+ */
+ stat->atomic_write_unit_min = max(awumin, blocksize);
+
+ if (awumax < stat->atomic_write_unit_min) {
+ stat->atomic_write_unit_min = 0;
+ stat->atomic_write_unit_max = 0;
+ } else {
+ stat->atomic_write_unit_max = awumax;
+ stat->attributes |= STATX_ATTR_WRITE_ATOMIC;
+ }
+ }
+ stat->attributes_mask |= STATX_ATTR_WRITE_ATOMIC;
+ stat->result_mask |= STATX_WRITE_ATOMIC;
+ }
+
flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
if (flags & EXT4_APPEND_FL)
stat->attributes |= STATX_ATTR_APPEND;
--
2.39.3
