[PATCH v3 3/4] btrfs: use latest_dev in btrfs_show_devname
STALE1858d
From: Anand Jain <hidden>
Date: 2021-08-20 11:29:17
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
Revision v3 of 4 in this series.
Revisions (4)
- v1 [diff vs current]
- v2 [diff vs current]
- v3 current
- v5 [diff vs current]
latest_dev is updated according to the changes to the device list. That means we could use the latest_dev->name to show the device name in /proc/self/mounts. So this patch makes that change. Signed-off-by: Anand Jain <redacted> --- RFC because, With this patch, /proc/self/mounts might not show the lowest devid device as we did before. We show the device that has the greatest generation and, we used it to build the tree. Are we ok with this change and, it won't affect the ABI? IMO it should be ok. v2 use latest_dev so that device path is also shown v3 add missing rcu_lock in show_devname fs/btrfs/super.c | 24 +++--------------------- 1 file changed, 3 insertions(+), 21 deletions(-)
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 64ecbdb50c1a..61682a143bf3 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c@@ -2464,30 +2464,12 @@ static int btrfs_unfreeze(struct super_block *sb) static int btrfs_show_devname(struct seq_file *m, struct dentry *root) { struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb); - struct btrfs_device *dev, *first_dev = NULL; - /* - * Lightweight locking of the devices. We should not need - * device_list_mutex here as we only read the device data and the list - * is protected by RCU. Even if a device is deleted during the list - * traversals, we'll get valid data, the freeing callback will wait at - * least until the rcu_read_unlock. - */ rcu_read_lock(); - list_for_each_entry_rcu(dev, &fs_info->fs_devices->devices, dev_list) { - if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state)) - continue; - if (!dev->name) - continue; - if (!first_dev || dev->devid < first_dev->devid) - first_dev = dev; - } - - if (first_dev) - seq_escape(m, rcu_str_deref(first_dev->name), " \t\n\\"); - else - WARN_ON(1); + seq_escape(m, rcu_str_deref(fs_info->fs_devices->latest_dev->name), + " \t\n\\"); rcu_read_unlock(); + return 0; }
--
2.31.1