statx: stx_subvol

Add a new statx field for (sub)volume identifiers, as implemented by
btrfs and bcachefs.

This includes bcachefs support; we'll definitely want btrfs support as
well.

Link: https://lore.kernel.org/linux-fsdevel/2uvhm6gweyl7iyyp2xpfryvcu2g3padagaeqcbiavjyiis6prl@yjm725bizncq/
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Link: https://lore.kernel.org/r/20240308022914.196982-1-kent.overstreet@linux.dev
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index 0ccee05..99a0abe 100644 (file)
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -841,6 +841,9 @@ static int bch2_getattr(struct mnt_idmap *idmap,
        stat->blksize   = block_bytes(c);
        stat->blocks    = inode->v.i_blocks;
 
+       stat->subvol    = inode->ei_subvol;
+       stat->result_mask |= STATX_SUBVOL;
+
        if (request_mask & STATX_BTIME) {
                stat->result_mask |= STATX_BTIME;
                stat->btime = bch2_time_to_timespec(c, inode->ei_inode.bi_otime);

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 3770153..8cf692c 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8779,6 +8779,9 @@ static int btrfs_getattr(struct mnt_idmap *idmap,
        generic_fillattr(idmap, request_mask, inode, stat);
        stat->dev = BTRFS_I(inode)->root->anon_dev;
 
+       stat->subvol = BTRFS_I(inode)->root->root_key.objectid;
+       stat->result_mask |= STATX_SUBVOL;
+
        spin_lock(&BTRFS_I(inode)->lock);
        delalloc_bytes = BTRFS_I(inode)->new_delalloc_bytes;
        inode_bytes = inode_get_bytes(inode);

diff --git a/fs/stat.c b/fs/stat.c
index 77cdc69..70bd3e8 100644 (file)
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -658,6 +658,7 @@ 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_subvol = stat->subvol;
 
        return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 }

diff --git a/include/linux/stat.h b/include/linux/stat.h
index 5215057..bf92441 100644 (file)
--- a/include/linux/stat.h
+++ b/include/linux/stat.h
@@ -53,6 +53,7 @@ struct kstat {
        u32             dio_mem_align;
        u32             dio_offset_align;
        u64             change_cookie;
+       u64             subvol;
 };
 
 /* 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 2f2ee82..67626d5 100644 (file)
--- a/include/uapi/linux/stat.h
+++ b/include/uapi/linux/stat.h
@@ -126,8 +126,9 @@ struct statx {
        __u64   stx_mnt_id;
        __u32   stx_dio_mem_align;      /* Memory buffer alignment for direct I/O */
        __u32   stx_dio_offset_align;   /* File offset alignment for direct I/O */
+       __u64   stx_subvol;     /* Subvolume identifier */
        /* 0xa0 */
-       __u64   __spare3[12];   /* Spare space for future expansion */
+       __u64   __spare3[11];   /* Spare space for future expansion */
        /* 0x100 */
 };
 
@@ -155,6 +156,7 @@ struct statx {
 #define STATX_MNT_ID           0x00001000U     /* Got stx_mnt_id */
 #define STATX_DIOALIGN         0x00002000U     /* Want/got direct I/O alignment info */
 #define STATX_MNT_ID_UNIQUE    0x00004000U     /* Want/got extended stx_mount_id */
+#define STATX_SUBVOL           0x00008000U     /* Want/got stx_subvol */
 
 #define STATX__RESERVED                0x80000000U     /* Reserved for future struct statx expansion */