On Fri, Jul 19, 2024 at 6:12 PM Hongbo Li wrote:
>
> Add function nilfs2_tmpfile to support O_TMPFILE file creation.
>
> tmpfile testcases(generic/(004,389,509,530,531) except
> generic/389,530 (need acl and shutdown supported) now run/pass.
>
> Signed-off-by: Hongbo Li <lihongbo22@xxxxxxxxxx>
> ---
> fs/nilfs2/namei.c | 31 +++++++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
>
> diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c
> index c950139db6ef..a36667d7a5e8 100644
> --- a/fs/nilfs2/namei.c
> +++ b/fs/nilfs2/namei.c
> @@ -125,6 +125,36 @@ nilfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
> return err;
> }
>
> +static int nilfs_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
> + struct file *file, umode_t mode)
> +{
> + struct inode *inode;
> + struct nilfs_transaction_info ti;
> + int err;
> +
> + err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
> + if (err)
> + return err;
> +
> + inode = nilfs_new_inode(dir, mode);
> + err = PTR_ERR(inode);
> + if (!IS_ERR(inode)) {
> + inode->i_op = &nilfs_file_inode_operations;
> + inode->i_fop = &nilfs_file_operations;
> + inode->i_mapping->a_ops = &nilfs_aops;
> + nilfs_mark_inode_dirty(inode);
> + d_tmpfile(file, inode);
> + unlock_new_inode(inode);
> + err = 0;
> + }
> + if (!err)
> + err = nilfs_transaction_commit(dir->i_sb);
> + else
> + nilfs_transaction_abort(dir->i_sb);
> +
> + return finish_open_simple(file, err);
> +}
> +
> static int nilfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
> struct dentry *dentry, const char *symname)
> {
> @@ -544,6 +574,7 @@ const struct inode_operations nilfs_dir_inode_operations = {
> .mkdir = nilfs_mkdir,
> .rmdir = nilfs_rmdir,
> .mknod = nilfs_mknod,
> + .tmpfile = nilfs_tmpfile,
> .rename = nilfs_rename,
> .setattr = nilfs_setattr,
> .permission = nilfs_permission,
> --
> 2.34.1
>
Hi Hongbo,
Thank you for the patch suggestion.
As for the O_TMPFILE support, with this implementation, when the file
system crashes in an unclean way, the inodes generated in the ifile
metadata file by nilfs_new_inode() are not released and remain
orphaned.
I think that this problem needs to be solved first.
If you could propose a mechanism to repair orphaned inodes at mount
time, I would like to apply it.
Is that possible?
For example,
A method of constructing an on-disk chain list of inodes that starts
from the latest checkpoint of cpfile, or a reserved inode (inode
number 0, etc.) of ifile, registering them there, and releasing them
during recovery at mount time.
Alternatively, a less efficient method would be to perform a full scan
of ifile metadata when recovery occurs at mount time,
and release those whose link count does not match the inode bitmap.
If we actually implement it, I think we need to discuss the method to
be determined.
This issue takes priority, but I would like to make another comment
about the implementation of your proposal:
The call to nilfs_mark_inode_dirty() involves copying the on-memory
inode data to the ifile, so it must be done after the on-memory inode
update is complete. Therefore, move it after the call to d_tmpfile().
(we need to check if this swap actually works without side effects).
Also, the function name in the changelog is a type for "nilfs_tmpfile".
That's all for now.
Thanks,
Ryusuke Konishi
