Messages in this thread | | | From | OGAWA Hirofumi <> | Subject | Re: [RFC PATCH 2/3] fat: add renameat2 RENAME_EXCHANGE flag support | Date | Mon, 23 May 2022 02:42:44 +0900 |
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Javier Martinez Canillas <javierm@redhat.com> writes:
> The renameat2 RENAME_EXCHANGE flag allows to atomically exchange two paths > but is currently not supported by the Linux vfat filesystem driver. > > Add a vfat_rename_exchange() helper function that implements this support. > > The super block lock is acquired during the operation to ensure atomicity, > and in the error path actions made are reversed also with the mutex held, > making the whole operation transactional.
I'm not fully reviewed yet though (write order and race), basically looks like good.
> + /* if directories are not the same, get ".." info to update */ > + if (old_dir != new_dir) { > + if (S_ISDIR(old_inode->i_mode)) > + if (fat_get_dotdot_entry(old_inode, &old_dotdot_bh, &old_dotdot_de)) { > + err = -EIO; > + goto out; > + } > + if (S_ISDIR(new_inode->i_mode)) > + if (fat_get_dotdot_entry(new_inode, &new_dotdot_bh, &new_dotdot_de)) { > + err = -EIO; > + goto out; > + } > + }
It may not be linux coding style though, please add {}
if () { ... }
for non one liner body.
> + /* update ".." directory entry info */ > + if (old_dotdot_de) { > + fat_set_start(old_dotdot_de, MSDOS_I(new_dir)->i_logstart); > + mark_buffer_dirty_inode(old_dotdot_bh, old_inode); > + if (IS_DIRSYNC(new_dir)) { > + err = sync_dirty_buffer(old_dotdot_bh); > + if (err) > + goto error_old_dotdot; > + } > + drop_nlink(old_dir); > + inc_nlink(new_dir); > + } > + > + if (new_dotdot_de) { > + fat_set_start(new_dotdot_de, MSDOS_I(old_dir)->i_logstart); > + mark_buffer_dirty_inode(new_dotdot_bh, new_inode); > + if (IS_DIRSYNC(old_dir)) { > + err = sync_dirty_buffer(new_dotdot_bh); > + if (err) > + goto error_new_dotdot; > + } > + drop_nlink(new_dir); > + inc_nlink(old_dir); > + }
There are some copy&paste codes, for example above, it may be better to use function and consolidate? If you had some intent, it is ok though.
Thanks. -- OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
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