| Message ID | 20211021151528.116818-2-lmb@cloudflare.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [bpf-next,v2,1/3] libfs: support RENAME_EXCHANGE in simple_rename() | expand |
On Thu, Oct 21, 2021 at 8:16 AM Lorenz Bauer <lmb@cloudflare.com> wrote: > > Allow atomic exchange via RENAME_EXCHANGE when using simple_rename. > This affects binderfs, ramfs, hubetlbfs and bpffs. There isn't much > to do except update the various *time fields. > > Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Al, could you please Ack this patch so we can route the whole set through bpf-next tree?
[ Adding Miklos & Greg to Cc for review given e0e0be8a8355 ("libfs: support RENAME_NOREPLACE in
simple_rename()"). If you have a chance, would be great if you could take a look, thanks! ]
On 10/21/21 5:15 PM, Lorenz Bauer wrote:
> Allow atomic exchange via RENAME_EXCHANGE when using simple_rename.
> This affects binderfs, ramfs, hubetlbfs and bpffs. There isn't much
> to do except update the various *time fields.
>
> Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
> ---
> fs/libfs.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/fs/libfs.c b/fs/libfs.c
> index 51b4de3b3447..93c03d593749 100644
> --- a/fs/libfs.c
> +++ b/fs/libfs.c
> @@ -455,9 +455,12 @@ int simple_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
> struct inode *inode = d_inode(old_dentry);
> int they_are_dirs = d_is_dir(old_dentry);
>
> - if (flags & ~RENAME_NOREPLACE)
> + if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
> return -EINVAL;
>
> + if (flags & RENAME_EXCHANGE)
> + goto done;
> +
> if (!simple_empty(new_dentry))
> return -ENOTEMPTY;
>
> @@ -472,6 +475,7 @@ int simple_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
> inc_nlink(new_dir);
> }
>
> +done:
> old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
> new_dir->i_mtime = inode->i_ctime = current_time(old_dir);
>
>
On Thu, Oct 28, 2021 at 1:46 AM Daniel Borkmann <daniel@iogearbox.net> wrote: > > [ Adding Miklos & Greg to Cc for review given e0e0be8a8355 ("libfs: support RENAME_NOREPLACE in > simple_rename()"). If you have a chance, would be great if you could take a look, thanks! ] > > On 10/21/21 5:15 PM, Lorenz Bauer wrote: > > Allow atomic exchange via RENAME_EXCHANGE when using simple_rename. > > This affects binderfs, ramfs, hubetlbfs and bpffs. There isn't much > > to do except update the various *time fields. > > > > Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> > > --- > > fs/libfs.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/fs/libfs.c b/fs/libfs.c > > index 51b4de3b3447..93c03d593749 100644 > > --- a/fs/libfs.c > > +++ b/fs/libfs.c > > @@ -455,9 +455,12 @@ int simple_rename(struct user_namespace *mnt_userns, struct inode *old_dir, > > struct inode *inode = d_inode(old_dentry); > > int they_are_dirs = d_is_dir(old_dentry); > > > > - if (flags & ~RENAME_NOREPLACE) > > + if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) > > return -EINVAL; > > > > + if (flags & RENAME_EXCHANGE) > > + goto done; > > + This is not sufficient. RENAME_EXCHANGE can swap a dir and a non-dir, in which case the parent nlink counters need to be fixed up. See shmem_exchange(). My suggestion is to move that function to libfs.c:simple_rename_exchange(). Thanks, Miklos
On Thu, 28 Oct 2021 at 09:43, Miklos Szeredi <mszeredi@redhat.com> wrote: > > This is not sufficient. RENAME_EXCHANGE can swap a dir and a > non-dir, in which case the parent nlink counters need to be fixed up. > > See shmem_exchange(). My suggestion is to move that function to > libfs.c:simple_rename_exchange(). Thanks for the pointer, I sent a v3. Lorenz
diff --git a/fs/libfs.c b/fs/libfs.c index 51b4de3b3447..93c03d593749 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -455,9 +455,12 @@ int simple_rename(struct user_namespace *mnt_userns, struct inode *old_dir, struct inode *inode = d_inode(old_dentry); int they_are_dirs = d_is_dir(old_dentry); - if (flags & ~RENAME_NOREPLACE) + if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) return -EINVAL; + if (flags & RENAME_EXCHANGE) + goto done; + if (!simple_empty(new_dentry)) return -ENOTEMPTY; @@ -472,6 +475,7 @@ int simple_rename(struct user_namespace *mnt_userns, struct inode *old_dir, inc_nlink(new_dir); } +done: old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = new_dir->i_mtime = inode->i_ctime = current_time(old_dir);
Allow atomic exchange via RENAME_EXCHANGE when using simple_rename. This affects binderfs, ramfs, hubetlbfs and bpffs. There isn't much to do except update the various *time fields. Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> --- fs/libfs.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)