| Message ID | 1720962326-19300-1-git-send-email-zhanglikernel@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | : btrfs: print warning message if bdev_file_open_by_path function fails during mount | expand |
On Sun, Jul 14, 2024 at 2:06 PM Li Zhang <zhanglikernel@gmail.com> wrote: > > [ENHANCEMENT] > When mounting a btrfs filesystem, the filesystem opens the > block device, and if this fails, there is no message about > it. Print a message about it to help debugging. > > [IMPLEMENTATION] > Print warning message if bdev_file_open_by_path fails. > > [TEST] > I have a btrfs filesystem on three block devices, > one of which is write-protected, so regular mounts fail, > but there is no message in dmesg. > > /dev/vdb normal > /dev/vdc write protected > /dev/vdd normal > > Before patch: > $ sudo mount /dev/vdb /mnt/ > mount: mount(2) failed: no such file or directory > $ sudo dmesg # Show only messages about missing block devices > .... > [ 352.947196] BTRFS error (device vdb): devid 2 uuid 4ee2c625-a3b2-4fe0-b411-756b23e08533 missing > .... > > After patch: > $ sudo mount /dev/vdb /mnt/ > mount: mount(2) failed: no such file or directory > $ sudo dmesg # Show bdev_file_open_by_path failed. > .... > [ 352.944328] bdev_file_open_by_path failed device_path:/dev/vdc ret::-13 > [ 352.947196] BTRFS error (device vdb): missing devid 2 uuid 4ee2c625-a3b2-4fe0-b411-756b23e08533 > .... > > Signed-off-by: Li Zhang <zhanglikernel@gmail.com> > --- > fs/btrfs/volumes.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index c39145e..0713b44 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -476,6 +476,7 @@ static noinline struct btrfs_fs_devices *find_fsid( > > if (IS_ERR(*bdev_file)) { > ret = PTR_ERR(*bdev_file); > + printk(KERN_WARNING "bdev_file_open_by_path failed device_path:%s ret::%d\n", device_path, ret); Please use the btrfs helpers to print messages: btrfs_warn(), btrfs_err(), btrfs_crit(), etc. This is what we prefer to do. About the message itself: 1) Don't use a function name like bdev_file_open_by_path in the message, we don't do that anywhere else, and we have 3 different places calling it; 2) Try to comply with the style we follow. After a ":" leave a space for better readability; 3) Don't use "::", we don't do it anywhere else and it's even inconsistent with the rest of the message you added; 4) An error level is more appropriate since we have a failure. Look at the example we have at device_list_add(): btrfs_err(NULL, "failed to lookup block device for path %s: %d", path, error); So I would suggest changing it to: btrfs_err(NULL, "failed to open device for path %s with flags 0x%x: %d", device_path, flags, ret); Thanks. > goto error; > } > bdev = file_bdev(*bdev_file); > -- > 1.8.3.1 > >
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index c39145e..0713b44 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -476,6 +476,7 @@ static noinline struct btrfs_fs_devices *find_fsid( if (IS_ERR(*bdev_file)) { ret = PTR_ERR(*bdev_file); + printk(KERN_WARNING "bdev_file_open_by_path failed device_path:%s ret::%d\n", device_path, ret); goto error; } bdev = file_bdev(*bdev_file);
[ENHANCEMENT] When mounting a btrfs filesystem, the filesystem opens the block device, and if this fails, there is no message about it. Print a message about it to help debugging. [IMPLEMENTATION] Print warning message if bdev_file_open_by_path fails. [TEST] I have a btrfs filesystem on three block devices, one of which is write-protected, so regular mounts fail, but there is no message in dmesg. /dev/vdb normal /dev/vdc write protected /dev/vdd normal Before patch: $ sudo mount /dev/vdb /mnt/ mount: mount(2) failed: no such file or directory $ sudo dmesg # Show only messages about missing block devices .... [ 352.947196] BTRFS error (device vdb): devid 2 uuid 4ee2c625-a3b2-4fe0-b411-756b23e08533 missing .... After patch: $ sudo mount /dev/vdb /mnt/ mount: mount(2) failed: no such file or directory $ sudo dmesg # Show bdev_file_open_by_path failed. .... [ 352.944328] bdev_file_open_by_path failed device_path:/dev/vdc ret::-13 [ 352.947196] BTRFS error (device vdb): missing devid 2 uuid 4ee2c625-a3b2-4fe0-b411-756b23e08533 .... Signed-off-by: Li Zhang <zhanglikernel@gmail.com> --- fs/btrfs/volumes.c | 1 + 1 file changed, 1 insertion(+)