On Mon, Mar 21, 2022 at 11:00:02PM -0400, Gabriel Krisman Bertazi wrote:
> By using fscrypt_name 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.
>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
> ---
> fs/ext4/namei.c | 26 ++++++++++++--------------
> include/linux/fscrypt.h | 4 ++++
> 2 files changed, 16 insertions(+), 14 deletions(-)
>
> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
> index 8976e5a28c73..71b4b05fae89 100644
> --- a/fs/ext4/namei.c
> +++ b/fs/ext4/namei.c
> @@ -1321,10 +1321,9 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
> /**
> * ext4_ci_compare() - Match (case-insensitive) a name with a dirent.
> * @parent: Inode of the parent of the dentry.
> - * @name: name under lookup.
> + * @fname: 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
> @@ -1333,8 +1332,9 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
> * Return: > 0 if the directory entry matches, 0 if it doesn't match, or
> * < 0 on error.
> */
> -static int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
> - u8 *de_name, size_t de_name_len, bool quick)
> +static int ext4_ci_compare(const struct inode *parent,
> + const struct fscrypt_name *fname,
> + 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 +1357,10 @@ static int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
> entry.len = decrypted_name.len;
> }
>
> - if (quick)
> - ret = utf8_strncasecmp_folded(um, name, &entry);
> + if (fname->cf_name.name)
> + ret = utf8_strncasecmp_folded(um, &fname->cf_name, &entry);
> else
> - ret = utf8_strncasecmp(um, name, &entry);
> + ret = utf8_strncasecmp(um, fname->usr_fname, &entry);
>
> if (!ret)
> match = true;
> @@ -1370,8 +1370,8 @@ static int ext4_ci_compare(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 = ((fname->usr_fname->len == entry.len) &&
> + !memcmp(fname->usr_fname->name, entry.name, entry.len));
> }
>
> out:
> @@ -1440,6 +1440,8 @@ static bool ext4_match(struct inode *parent,
> #endif
>
> #if IS_ENABLED(CONFIG_UNICODE)
> + f.cf_name = fname->cf_name;
> +
> if (parent->i_sb->s_encoding && IS_CASEFOLDED(parent) &&
> (!IS_ENCRYPTED(parent) || fscrypt_has_encryption_key(parent))) {
> if (fname->cf_name.name) {
> @@ -1451,13 +1453,9 @@ static bool ext4_match(struct inode *parent,
> return false;
> }
> }
> - ret = ext4_ci_compare(parent, &fname->cf_name, de->name,
> - de->name_len, true);
> - } else {
> - ret = ext4_ci_compare(parent, fname->usr_fname,
> - de->name, de->name_len, false);
> }
>
> + ret = ext4_ci_compare(parent, &f, de->name, de->name_len);
> if (ret < 0) {
> /*
> * Treat comparison errors as not a match. The
> diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
> index 91ea9477e9bd..5dc4b3c805e4 100644
> --- a/include/linux/fscrypt.h
> +++ b/include/linux/fscrypt.h
> @@ -36,6 +36,10 @@ struct fscrypt_name {
> u32 minor_hash;
> struct fscrypt_str crypto_buf;
> bool is_nokey_name;
> +
> +#ifdef CONFIG_UNICODE
> + struct qstr cf_name;
> +#endif
> };
>
This seems like the wrong approach. struct fscrypt_name shouldn't have fields
that aren't used by the fs/crypto/ layer.
Did you check what f2fs does? It has a struct f2fs_filename to represent
everything f2fs needs to know about a filename, and it only uses
struct fscrypt_name when communicating with the fs/crypto/ layer.
struct ext4_filename already exists. Couldn't you use that here?
- Eric
