[PATCH] btrfs: do not skip re-registration for the mounted device

Anand Jain
2024-02-05T11:45:29Z

We skip device registration for a single device. However, we do not do
that if the device is already mounted, as it might be coming in again
for scanning a different path.

This patch is lightly tested; for verification if it fixes.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
I still have some unknowns about the problem. Pls test if this fixes
the problem.

fs/btrfs/volumes.c | 44 ++++++++++++++++++++++++++++++++++----------
fs/btrfs/volumes.h | 1 -
2 files changed, 34 insertions(+), 11 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 474ab7ed65ea..192c540a650c 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1299,6 +1299,31 @@ int btrfs_forget_devices(dev_t devt)
return ret;
}

+static bool btrfs_skip_registration(struct btrfs_super_block *disk_super,
+ dev_t devt, bool mount_arg_dev)
+{
+ struct btrfs_fs_devices *fs_devices;
+
+ list_for_each_entry(fs_devices, &fs_uuids, fs_list) {
+ struct btrfs_device *device;
+
+ mutex_lock(&fs_devices->device_list_mutex);
+ list_for_each_entry(device, &fs_devices->devices, dev_list) {
+ if (device->devt == devt) {
+ mutex_unlock(&fs_devices->device_list_mutex);
+ return false;
+ }
+ }
+ mutex_unlock(&fs_devices->device_list_mutex);
+ }
+
+ if (!mount_arg_dev && btrfs_super_num_devices(disk_super) == 1 &&
+ !(btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING))
+ return true;
+
+ return false;
+}
+
/*
* Look for a btrfs signature on a device. This may be called out of the mount path
* and we are not allowed to call set_blocksize during the scan. The superblock
@@ -1316,6 +1341,7 @@ struct btrfs_device *btrfs_scan_one_device(const char *path, blk_mode_t flags,
struct btrfs_device *device = NULL;
struct bdev_handle *bdev_handle;
u64 bytenr, bytenr_orig;
+ dev_t devt = 0;
int ret;

lockdep_assert_held(&uuid_mutex);
@@ -1355,18 +1381,16 @@ struct btrfs_device *btrfs_scan_one_device(const char *path, blk_mode_t flags,
goto error_bdev_put;
}

- if (!mount_arg_dev && btrfs_super_num_devices(disk_super) == 1 &&
- !(btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING)) {
- dev_t devt;
+ ret = lookup_bdev(path, &devt);
+ if (ret)
+ btrfs_warn(NULL, "lookup bdev failed for path %s: %d",
+ path, ret);

- ret = lookup_bdev(path, &devt);
- if (ret)
- btrfs_warn(NULL, "lookup bdev failed for path %s: %d",
- path, ret);
- else
+ if (btrfs_skip_registration(disk_super, devt, mount_arg_dev)) {
+ pr_debug("BTRFS: skip registering single non-seed device %s\n",
+ path);
+ if (devt)
btrfs_free_stale_devices(devt, NULL);
-
- pr_debug("BTRFS: skip registering single non-seed device %s\n", path);
device = NULL;
goto free_disk_super;
}
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 53f87f398da7..4ed281f0d1bd 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -792,5 +792,4 @@ bool btrfs_repair_one_zone(struct btrfs_fs_info *fs_info, u64 logical);

bool btrfs_pinned_by_swapfile(struct btrfs_fs_info *fs_info, void *ptr);
u8 *btrfs_sb_fsid_ptr(struct btrfs_super_block *sb);
-
#endif
--
2.39.3