[PATCH v4 06/11] block: Add atomic write support for statx

John Garry
2024-02-19T13:04:44Z

From: Prasad Singamsetty <prasad.singamsetty@oracle.com>

Extend statx system call to return additional info for atomic write support
support if the specified file is a block device.

Signed-off-by: Prasad Singamsetty <prasad.singamsetty@oracle.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
block/bdev.c | 37 +++++++++++++++++++++++++++----------
fs/stat.c | 13 ++++++-------
include/linux/blkdev.h | 5 +++--
3 files changed, 36 insertions(+), 19 deletions(-)

diff --git a/block/bdev.c b/block/bdev.c
index e9f1b12bd75c..0dada9902bd4 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -1116,24 +1116,41 @@ void sync_bdevs(bool wait)
iput(old_inode);
}

+#define BDEV_STATX_SUPPORTED_MASK (STATX_DIOALIGN | STATX_WRITE_ATOMIC)
+
/*
- * Handle STATX_DIOALIGN for block devices.
- *
- * Note that the inode passed to this is the inode of a block device node file,
- * not the block device's internal inode. Therefore it is *not* valid to use
- * I_BDEV() here; the block device has to be looked up by i_rdev instead.
+ * Handle STATX_{DIOALIGN, WRITE_ATOMIC} for block devices.
*/
-void bdev_statx_dioalign(struct inode *inode, struct kstat *stat)
+void bdev_statx(struct dentry *dentry, struct kstat *stat, u32 request_mask)
{
struct block_device *bdev;

- bdev = blkdev_get_no_open(inode->i_rdev);
+ if (!(request_mask & BDEV_STATX_SUPPORTED_MASK))
+ return;
+
+ /*
+ * Note that d_backing_inode() returns the inode of a block device node
+ * file, not the block device's internal inode. Therefore it is *not*
+ * valid to use I_BDEV() here; the block device has to be looked up by
+ * i_rdev instead.
+ */
+ bdev = blkdev_get_no_open(d_backing_inode(dentry)->i_rdev);
if (!bdev)
return;

- stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;
- stat->dio_offset_align = bdev_logical_block_size(bdev);
- stat->result_mask |= STATX_DIOALIGN;
+ if (request_mask & STATX_DIOALIGN) {
+ stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;
+ stat->dio_offset_align = bdev_logical_block_size(bdev);
+ stat->result_mask |= STATX_DIOALIGN;
+ }
+
+ if (request_mask & STATX_WRITE_ATOMIC && bdev_can_atomic_write(bdev)) {
+ struct request_queue *bd_queue = bdev->bd_queue;
+
+ generic_fill_statx_atomic_writes(stat,
+ queue_atomic_write_unit_min_bytes(bd_queue),
+ queue_atomic_write_unit_max_bytes(bd_queue));
+ }

blkdev_put_no_open(bdev);
}
diff --git a/fs/stat.c b/fs/stat.c
index 522787a4ab6a..bd0618477702 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -290,13 +290,12 @@ static int vfs_statx(int dfd, struct filename *filename, int flags,
stat->attributes |= STATX_ATTR_MOUNT_ROOT;
stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;

- /* Handle STATX_DIOALIGN for block devices. */
- if (request_mask & STATX_DIOALIGN) {
- struct inode *inode = d_backing_inode(path.dentry);
-
- if (S_ISBLK(inode->i_mode))
- bdev_statx_dioalign(inode, stat);
- }
+ /* If this is a block device inode, override the filesystem
+ * attributes with the block device specific parameters
+ * that need to be obtained from the bdev backing inode
+ */
+ if (S_ISBLK(d_backing_inode(path.dentry)->i_mode))
+ bdev_statx(path.dentry, stat, request_mask);

path_put(&path);
if (retry_estale(error, lookup_flags)) {
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 40ed56ef4937..4f04456f1250 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1541,7 +1541,7 @@ int sync_blockdev(struct block_device *bdev);
int sync_blockdev_range(struct block_device *bdev, loff_t lstart, loff_t lend);
int sync_blockdev_nowait(struct block_device *bdev);
void sync_bdevs(bool wait);
-void bdev_statx_dioalign(struct inode *inode, struct kstat *stat);
+void bdev_statx(struct dentry *dentry, struct kstat *stat, u32 request_mask);
void printk_all_partitions(void);
int __init early_lookup_bdev(const char *pathname, dev_t *dev);
#else
@@ -1559,7 +1559,8 @@ static inline int sync_blockdev_nowait(struct block_device *bdev)
static inline void sync_bdevs(bool wait)
{
}
-static inline void bdev_statx_dioalign(struct inode *inode, struct kstat *stat)
+static inline void bdev_statx(struct dentry *dentry, struct kstat *stat,
+ u32 request_mask)
{
}
static inline void printk_all_partitions(void)
--
2.31.1