From: Prasad Singamsetty <prasad.singamsetty@xxxxxxxxxx>
Extend statx system call to return additional info for atomic write support
support if the specified file is a block device.
Add initial support for a block device.
Signed-off-by: Prasad Singamsetty <prasad.singamsetty@xxxxxxxxxx>
Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx>
---
block/bdev.c | 21 +++++++++++++++++++++
fs/stat.c | 10 ++++++++++
include/linux/blkdev.h | 4 ++++
include/linux/stat.h | 2 ++
include/uapi/linux/stat.h | 7 ++++++-
5 files changed, 43 insertions(+), 1 deletion(-)
diff --git a/block/bdev.c b/block/bdev.c
index 1795c7d4b99e..6a5fd5abaadc 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -1014,3 +1014,24 @@ void bdev_statx_dioalign(struct inode *inode, struct kstat *stat)
blkdev_put_no_open(bdev);
}
+
+/*
+ * Handle statx for block devices to get properties of WRITE ATOMIC
+ * feature support.
+ */
+void bdev_statx_atomic(struct inode *inode, struct kstat *stat)
+{
+ struct block_device *bdev;
+
+ bdev = blkdev_get_no_open(inode->i_rdev);
+ if (!bdev)
+ return;
+
+ stat->atomic_write_unit_min = queue_atomic_write_unit_min(bdev->bd_queue);
+ stat->atomic_write_unit_max = queue_atomic_write_unit_max(bdev->bd_queue);
+ stat->attributes |= STATX_ATTR_WRITE_ATOMIC;
+ stat->attributes_mask |= STATX_ATTR_WRITE_ATOMIC;
+ stat->result_mask |= STATX_WRITE_ATOMIC;
+
+ blkdev_put_no_open(bdev);
+}
diff --git a/fs/stat.c b/fs/stat.c
index 7c238da22ef0..d20334a0e9ae 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -256,6 +256,14 @@ static int vfs_statx(int dfd, struct filename *filename, int flags,
bdev_statx_dioalign(inode, stat);
}
+ /* Handle STATX_WRITE_ATOMIC for block devices */
+ if (request_mask & STATX_WRITE_ATOMIC) {
+ struct inode *inode = d_backing_inode(path.dentry);
+
+ if (S_ISBLK(inode->i_mode))
+ bdev_statx_atomic(inode, stat);
+ }
+
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
@@ -636,6 +644,8 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer)
tmp.stx_mnt_id = stat->mnt_id;
tmp.stx_dio_mem_align = stat->dio_mem_align;
tmp.stx_dio_offset_align = stat->dio_offset_align;
+ tmp.stx_atomic_write_unit_min = stat->atomic_write_unit_min;
+ tmp.stx_atomic_write_unit_max = stat->atomic_write_unit_max;
return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
}
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6b6f2992338c..19d33b2897b2 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1527,6 +1527,7 @@ 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_atomic(struct inode *inode, struct kstat *stat);
void printk_all_partitions(void);
#else
static inline void invalidate_bdev(struct block_device *bdev)
@@ -1546,6 +1547,9 @@ static inline void sync_bdevs(bool wait)
static inline void bdev_statx_dioalign(struct inode *inode, struct kstat *stat)
{
}
+static inline void bdev_statx_atomic(struct inode *inode, struct kstat *stat)
+{
+}
static inline void printk_all_partitions(void)
{
}
diff --git a/include/linux/stat.h b/include/linux/stat.h
index 52150570d37a..dfa69ecfaacf 100644
--- a/include/linux/stat.h
+++ b/include/linux/stat.h
@@ -53,6 +53,8 @@ struct kstat {
u32 dio_mem_align;
u32 dio_offset_align;
u64 change_cookie;
+ u32 atomic_write_unit_max;
+ u32 atomic_write_unit_min;
};
/* These definitions are internal to the kernel for now. Mainly used by nfsd. */
diff --git a/include/uapi/linux/stat.h b/include/uapi/linux/stat.h
index 7cab2c65d3d7..c99d7cac2aa6 100644
--- a/include/uapi/linux/stat.h
+++ b/include/uapi/linux/stat.h
@@ -127,7 +127,10 @@ struct statx {
__u32 stx_dio_mem_align; /* Memory buffer alignment for direct I/O */
__u32 stx_dio_offset_align; /* File offset alignment for direct I/O */
/* 0xa0 */
- __u64 __spare3[12]; /* Spare space for future expansion */
+ __u32 stx_atomic_write_unit_max;
+ __u32 stx_atomic_write_unit_min;
+ /* 0xb0 */
+ __u64 __spare3[11]; /* Spare space for future expansion */
/* 0x100 */
};
@@ -154,6 +157,7 @@ struct statx {
#define STATX_BTIME 0x00000800U /* Want/got stx_btime */
#define STATX_MNT_ID 0x00001000U /* Got stx_mnt_id */
#define STATX_DIOALIGN 0x00002000U /* Want/got direct I/O alignment info */
+#define STATX_WRITE_ATOMIC 0x00004000U /* Want/got atomic_write_* fields */
#define STATX__RESERVED 0x80000000U /* Reserved for future struct statx expansion */
@@ -189,6 +193,7 @@ struct statx {
#define STATX_ATTR_MOUNT_ROOT 0x00002000 /* Root of a mount */
#define STATX_ATTR_VERITY 0x00100000 /* [I] Verity protected file */
#define STATX_ATTR_DAX 0x00200000 /* File is currently in DAX state */
+#define STATX_ATTR_WRITE_ATOMIC 0x00400000 /* File supports atomic write operations */
#endif /* _UAPI_LINUX_STAT_H */
--
2.31.1
