2016-03-07 12:05 GMT+09:00 Satoru Takeuchi <takeuchi_satoru@xxxxxxxxxxxxxx>:
> - It's better to show a warning message for the exceptional case
> that one of objectid (in most case, inode number) reaches its
> highest value. Show this message only once to avoid filling
> dmesg with it.
> - EOVERFLOW is more proper return value for this case.
> ENOSPC is for "No space left on device" case and objectid isn't
> related to any device.
I have concern about EOVERFLOW. The value returned here will
go through to the user space via btrfs_find_free_ino() and btrfs_create().
It means that "creat" and "mkdir" can now return EOVERFLOW when it
failed to assign new inode number. Such behavior would disagree with
other file systems, which result in user space programs to be
confused.
Also, I don't think EOVERFLOW described in "creat(2)" (or open(2))
suits for this case. As far as I read the following man page from
creat(2),
giving ENOSPC is better option here.
> ENOSPC: pathname was to be created but the device containing pathname has no room for the new file.
> EOVERFLOW:
> pathname refers to a regular file that is too large to be opened.
> (snip)
> Signed-off-by: Satoru Takeuchi <takeuchi_satoru@xxxxxxxxxxxxxx>
> ---
> This patch can be applied to 4.5-rc7
> ---
> fs/btrfs/inode-map.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
> index e50316c..f5e3228 100644
> --- a/fs/btrfs/inode-map.c
> +++ b/fs/btrfs/inode-map.c
> @@ -556,7 +556,15 @@ int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid)
> mutex_lock(&root->objectid_mutex);
>
> if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
> - ret = -ENOSPC;
> + static bool __warned = false;
> +
> + if (unlikely(!__warned)) {
> + btrfs_warn(root->fs_info,
> + "The objectid of root %llu reaches its highest value.\n",
> + root->root_key.objectid);
> + __warned = true;
> + }
> + ret = -EOVERFLOW;
> goto out;
> }
>
> --
> 2.5.0
> --
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