On Wed, May 11, 2022 at 03:31:40PM -0400, Gabriel Krisman Bertazi wrote:
> By using a new type here, we can hide most of the caching casefold logic
> from ext4. The condition in ext4_match is now quite redundant, but this
> is addressed in the next patch.
>
> This doesn't use ext4_filename to keep it generic, since the function
> will be moved to libfs to be shared with f2fs.
>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
>
> --
> Changes since v1:
> - Instead of (ab)using fscrypt_name, create a new type (ebiggers).
> ---
> fs/ext4/namei.c | 32 +++++++++++++++-----------------
> include/linux/fs.h | 5 +++++
> 2 files changed, 20 insertions(+), 17 deletions(-)
>
> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
> index 84fdb23f09b8..5296ced2e43e 100644
> --- a/fs/ext4/namei.c
> +++ b/fs/ext4/namei.c
> @@ -1321,20 +1321,19 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
> /**
> * ext4_match_ci() - Match (case-insensitive) a name with a dirent.
> * @parent: Inode of the parent of the dentry.
> - * @name: name under lookup.
> + * @uname: name under lookup.
> * @de_name: Dirent name.
> * @de_name_len: dirent name length.
> - * @quick: whether @name is already casefolded.
> *
> * Test whether a case-insensitive directory entry matches the filename
> - * being searched. If quick is set, the @name being looked up is
> - * already in the casefolded form.
> + * being searched.
> *
> * Return: > 0 if the directory entry matches, 0 if it doesn't match, or
> * < 0 on error.
> */
> -static int ext4_match_ci(const struct inode *parent, const struct qstr *name,
> - u8 *de_name, size_t de_name_len, bool quick)
> +static int ext4_match_ci(const struct inode *parent,
> + const struct unicode_name *uname,
> + u8 *de_name, size_t de_name_len)
> {
> const struct super_block *sb = parent->i_sb;
> const struct unicode_map *um = sb->s_encoding;
> @@ -1357,10 +1356,10 @@ static int ext4_match_ci(const struct inode *parent, const struct qstr *name,
> entry.len = decrypted_name.len;
> }
>
> - if (quick)
> - ret = utf8_strncasecmp_folded(um, name, &entry);
> + if (uname->folded_name->name)
> + ret = utf8_strncasecmp_folded(um, uname->folded_name, &entry);
> else
> - ret = utf8_strncasecmp(um, name, &entry);
> + ret = utf8_strncasecmp(um, uname->usr_name, &entry);
>
> if (!ret)
> match = true;
> @@ -1370,8 +1369,8 @@ static int ext4_match_ci(const struct inode *parent, const struct qstr *name,
> * the names have invalid characters.
> */
> ret = 0;
> - match = ((name->len == entry.len) &&
> - !memcmp(name->name, entry.name, entry.len));
> + match = ((uname->usr_name->len == entry.len) &&
> + !memcmp(uname->usr_name->name, entry.name, entry.len));
> }
>
> out:
> @@ -1441,6 +1440,10 @@ static bool ext4_match(struct inode *parent,
> #if IS_ENABLED(CONFIG_UNICODE)
> if (parent->i_sb->s_encoding && IS_CASEFOLDED(parent) &&
> (!IS_ENCRYPTED(parent) || fscrypt_has_encryption_key(parent))) {
> + struct unicode_name u = {
> + .folded_name = &fname->cf_name,
> + .usr_name = fname->usr_fname
> + };
> int ret;
>
> if (fname->cf_name.name) {
> @@ -1452,14 +1455,9 @@ static bool ext4_match(struct inode *parent,
> return false;
> }
> }
> -
> - ret = ext4_match_ci(parent, &fname->cf_name, de->name,
> - de->name_len, true);
> - } else {
> - ret = ext4_match_ci(parent, fname->usr_fname,
> - de->name, de->name_len, false);
> }
>
> + ret = ext4_match_ci(parent, &u, de->name, de->name_len);
> if (ret < 0) {
> /*
> * Treat comparison errors as not a match. The
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index e2d892b201b0..3f76a18a5f40 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -3358,6 +3358,11 @@ extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
>
> extern int generic_check_addressable(unsigned, u64);
>
> +struct unicode_name {
> + const struct qstr *folded_name;
> + const struct qstr *usr_name;
> +};
> +
> extern void generic_set_encrypted_ci_d_ops(struct dentry *dentry);
>
> #ifdef CONFIG_MIGRATION
I don't really see the point of this. The only times struct unicode_name gets
used are when one is initialized on the stack for a single call to
generic_ci_match(). So the end result is just that the function prototype is:
int generic_ci_match(const struct inode *parent,
const struct unicode_name *uname,
const u8 *de_name, size_t de_name_len);
... instead of:
int generic_ci_match(const struct inode *parent, const struct qstr *usr_fname,
const struct qstr *folded_name,
const u8 *de_name, size_t de_name_len);
So the only effect is to consolidate two parameters into one. I don't think
it's worth it, given that the struct is being created on-demand.
Also note that filenames are not necessarily valid Unicode, so "unicode_name" is
a bit misleading.
- Eric
