From: Josef Bacik Date: Wed, 22 Jul 2020 15:12:46 +0000 (-0400) Subject: btrfs: don't show full path of bind mounts in subvol= X-Git-Tag: v5.15~2817^2~29 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3ef3959b29c4a5bd65526ab310a1a18ae533172a;p=platform%2Fkernel%2Flinux-starfive.git btrfs: don't show full path of bind mounts in subvol= Chris Murphy reported a problem where rpm ostree will bind mount a bunch of things for whatever voodoo it's doing. But when it does this /proc/mounts shows something like /dev/sda /mnt/test btrfs rw,relatime,subvolid=256,subvol=/foo 0 0 /dev/sda /mnt/test/baz btrfs rw,relatime,subvolid=256,subvol=/foo/bar 0 0 Despite subvolid=256 being subvol=/foo. This is because we're just spitting out the dentry of the mount point, which in the case of bind mounts is the source path for the mountpoint. Instead we should spit out the path to the actual subvol. Fix this by looking up the name for the subvolid we have mounted. With this fix the same test looks like this /dev/sda /mnt/test btrfs rw,relatime,subvolid=256,subvol=/foo 0 0 /dev/sda /mnt/test/baz btrfs rw,relatime,subvolid=256,subvol=/foo 0 0 Reported-by: Chris Murphy CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba --- diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index aa73422b..9b4e9c4 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1386,6 +1386,7 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) { struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb); const char *compress_type; + const char *subvol_name; if (btrfs_test_opt(info, DEGRADED)) seq_puts(seq, ",degraded"); @@ -1472,8 +1473,13 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) seq_puts(seq, ",ref_verify"); seq_printf(seq, ",subvolid=%llu", BTRFS_I(d_inode(dentry))->root->root_key.objectid); - seq_puts(seq, ",subvol="); - seq_dentry(seq, dentry, " \t\n\\"); + subvol_name = btrfs_get_subvol_name_from_objectid(info, + BTRFS_I(d_inode(dentry))->root->root_key.objectid); + if (!IS_ERR(subvol_name)) { + seq_puts(seq, ",subvol="); + seq_escape(seq, subvol_name, " \t\n\\"); + kfree(subvol_name); + } return 0; }