2022-05-11 20:55:10

by Gabriel Krisman Bertazi

Subject: [PATCH v4 03/10] f2fs: Simplify the handling of cached insensitive names

Keeping it as qstr avoids the unnecessary conversion in f2fs_match

Signed-off-by: Gabriel Krisman Bertazi <[email protected]>
---
fs/f2fs/dir.c | 52 ++++++++++++++++++++++++++++------------------
fs/f2fs/f2fs.h | 3 ++-
fs/f2fs/recovery.c | 5 +----
3 files changed, 35 insertions(+), 25 deletions(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 166f08623362..c2a02003c5b9 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -81,28 +81,47 @@ int f2fs_init_casefolded_name(const struct inode *dir,
{
#if IS_ENABLED(CONFIG_UNICODE)
struct super_block *sb = dir->i_sb;
+ unsigned char *buf;
+ int len;

if (IS_CASEFOLDED(dir)) {
- fname->cf_name.name = f2fs_kmem_cache_alloc(f2fs_cf_name_slab,
+ buf = f2fs_kmem_cache_alloc(f2fs_cf_name_slab,
GFP_NOFS, false, F2FS_SB(sb));
- if (!fname->cf_name.name)
- return -ENOMEM;
- fname->cf_name.len = utf8_casefold(sb->s_encoding,
- fname->usr_fname,
- fname->cf_name.name,
- F2FS_NAME_LEN);
- if ((int)fname->cf_name.len <= 0) {
- kmem_cache_free(f2fs_cf_name_slab, fname->cf_name.name);
+ if (!buf) {
fname->cf_name.name = NULL;
+ return -ENOMEM;
+ }
+
+ len = utf8_casefold(sb->s_encoding, fname->usr_fname,
+ buf, F2FS_NAME_LEN);
+
+ if (len <= 0) {
+ kmem_cache_free(f2fs_cf_name_slab, buf);
+ buf = NULL;
if (sb_has_strict_encoding(sb))
return -EINVAL;
/* fall back to treating name as opaque byte sequence */
}
+ fname->cf_name.name = buf;
+ fname->cf_name.len = (unsigned int) len;
}
#endif
return 0;
}

+void f2fs_free_casefolded_name(struct f2fs_filename *fname)
+{
+#if IS_ENABLED(CONFIG_UNICODE)
+ unsigned char *buf = (unsigned char *)fname->cf_name.name;
+
+ if (buf) {
+ kmem_cache_free(f2fs_cf_name_slab, buf);
+ fname->cf_name.name = NULL;
+ }
+
+#endif
+}
+
static int __f2fs_setup_filename(const struct inode *dir,
const struct fscrypt_name *crypt_name,
struct f2fs_filename *fname)
@@ -174,12 +193,7 @@ void f2fs_free_filename(struct f2fs_filename *fname)
kfree(fname->crypto_buf.name);
fname->crypto_buf.name = NULL;
#endif
-#if IS_ENABLED(CONFIG_UNICODE)
- if (fname->cf_name.name) {
- kmem_cache_free(f2fs_cf_name_slab, fname->cf_name.name);
- fname->cf_name.name = NULL;
- }
-#endif
+ f2fs_free_casefolded_name(fname);
}

static unsigned long dir_block_index(unsigned int level,
@@ -267,11 +281,9 @@ static inline int f2fs_match_name(const struct inode *dir,
struct fscrypt_name f;

#if IS_ENABLED(CONFIG_UNICODE)
- if (fname->cf_name.name) {
- struct qstr cf = FSTR_TO_QSTR(&fname->cf_name);
-
- return f2fs_match_ci_name(dir, &cf, de_name, de_name_len);
- }
+ if (fname->cf_name.name)
+ return f2fs_match_ci_name(dir, &fname->cf_name,
+ de_name, de_name_len);
#endif
f.usr_fname = fname->usr_fname;
f.disk_name = fname->disk_name;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 68b44015514f..4b6df34fc8b0 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -497,7 +497,7 @@ struct f2fs_filename {
* NULL. In all these cases we fall back to treating the name as an
* opaque byte sequence.
*/
- struct fscrypt_str cf_name;
+ struct qstr cf_name;
#endif
};

@@ -3345,6 +3345,7 @@ struct dentry *f2fs_get_parent(struct dentry *child);
unsigned char f2fs_get_de_type(struct f2fs_dir_entry *de);
int f2fs_init_casefolded_name(const struct inode *dir,
struct f2fs_filename *fname);
+void f2fs_free_casefolded_name(struct f2fs_filename *fname);
int f2fs_setup_filename(struct inode *dir, const struct qstr *iname,
int lookup, struct f2fs_filename *fname);
int f2fs_prepare_lookup(struct inode *dir, struct dentry *dentry,
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index 79773d322c47..3c3a8abf6953 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -149,11 +149,8 @@ static int init_recovered_filename(const struct inode *dir,
if (err)
return err;
f2fs_hash_filename(dir, fname);
-#if IS_ENABLED(CONFIG_UNICODE)
/* Case-sensitive match is fine for recovery */
- kmem_cache_free(f2fs_cf_name_slab, fname->cf_name.name);
- fname->cf_name.name = NULL;
-#endif
+ f2fs_free_casefolded_name(fname);
} else {
f2fs_hash_filename(dir, fname);
}
--
2.36.1

2022-05-12 10:50:08

by Eric Biggers

Subject: Re: [PATCH v4 03/10] f2fs: Simplify the handling of cached insensitive names

On Wed, May 11, 2022 at 03:31:39PM -0400, Gabriel Krisman Bertazi wrote:
> Keeping it as qstr avoids the unnecessary conversion in f2fs_match
>
> Signed-off-by: Gabriel Krisman Bertazi <[email protected]>
> ---
> fs/f2fs/dir.c | 52 ++++++++++++++++++++++++++++------------------
> fs/f2fs/f2fs.h | 3 ++-
> fs/f2fs/recovery.c | 5 +----
> 3 files changed, 35 insertions(+), 25 deletions(-)
>
> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> index 166f08623362..c2a02003c5b9 100644
> --- a/fs/f2fs/dir.c
> +++ b/fs/f2fs/dir.c
> @@ -81,28 +81,47 @@ int f2fs_init_casefolded_name(const struct inode *dir,
> {
> #if IS_ENABLED(CONFIG_UNICODE)
> struct super_block *sb = dir->i_sb;
> + unsigned char *buf;
> + int len;
>
> if (IS_CASEFOLDED(dir)) {
> - fname->cf_name.name = f2fs_kmem_cache_alloc(f2fs_cf_name_slab,
> + buf = f2fs_kmem_cache_alloc(f2fs_cf_name_slab,
> GFP_NOFS, false, F2FS_SB(sb));
> - if (!fname->cf_name.name)
> - return -ENOMEM;
> - fname->cf_name.len = utf8_casefold(sb->s_encoding,
> - fname->usr_fname,
> - fname->cf_name.name,
> - F2FS_NAME_LEN);
> - if ((int)fname->cf_name.len <= 0) {
> - kmem_cache_free(f2fs_cf_name_slab, fname->cf_name.name);
> + if (!buf) {
> fname->cf_name.name = NULL;
> + return -ENOMEM;
> + }
> +
> + len = utf8_casefold(sb->s_encoding, fname->usr_fname,
> + buf, F2FS_NAME_LEN);
> +
> + if (len <= 0) {
> + kmem_cache_free(f2fs_cf_name_slab, buf);
> + buf = NULL;
> if (sb_has_strict_encoding(sb))
> return -EINVAL;
> /* fall back to treating name as opaque byte sequence */
> }
> + fname->cf_name.name = buf;
> + fname->cf_name.len = (unsigned int) len;
> }
> #endif

There's some inconsistent behavior above; now sometimes fname->cf_name.name is
set to NULL on failure and sometime it's not. Also now fname->cf_name.len can
be set to a negative value.

Since struct f2fs_filename is always zero-initialized, how about only setting
the fname->cf_name fields if we actually have a valid value to assign? I.e.

buf = f2fs_kmem_cache_alloc(f2fs_cf_name_slab,
GFP_NOFS, false, F2FS_SB(sb));
if (!buf)
return -ENOMEM;

len = utf8_casefold(sb->s_encoding, fname->usr_fname,
buf, F2FS_NAME_LEN);
if (len <= 0) {
kmem_cache_free(f2fs_cf_name_slab, buf);
if (sb_has_strict_encoding(sb))
return -EINVAL;
/* fall back to treating name as opaque byte sequence */
return 0;
}
fname->cf_name.name = buf;
fname->cf_name.len = len;

> +void f2fs_free_casefolded_name(struct f2fs_filename *fname)
> +{
> +#if IS_ENABLED(CONFIG_UNICODE)
> + unsigned char *buf = (unsigned char *)fname->cf_name.name;
> +
> + if (buf) {
> + kmem_cache_free(f2fs_cf_name_slab, buf);
> + fname->cf_name.name = NULL;
> + }
> +
> +#endif
> +}

Kernel code usually uses static inline stubs for the !CONFIG_$FOO case in cases
like this, as that causes the function calls to be compiled away to nothing when
they're unneeded.

- Eric