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-rw-r--r--fs/ext4/crypto.c10
-rw-r--r--fs/ext4/ext4.h35
-rw-r--r--fs/ext4/namei.c122
-rw-r--r--fs/ext4/super.c4
-rw-r--r--fs/f2fs/dir.c105
-rw-r--r--fs/f2fs/f2fs.h16
-rw-r--r--fs/f2fs/namei.c10
-rw-r--r--fs/f2fs/recovery.c9
-rw-r--r--fs/f2fs/super.c8
-rw-r--r--fs/libfs.c74
-rw-r--r--include/linux/fs.h4
11 files changed, 195 insertions, 202 deletions
diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index 7ae0b61258a7..0a056d97e640 100644
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -31,11 +31,10 @@ int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname,
ext4_fname_from_fscrypt_name(fname, &name);
-#if IS_ENABLED(CONFIG_UNICODE)
err = ext4_fname_setup_ci_filename(dir, iname, fname);
if (err)
ext4_fname_free_filename(fname);
-#endif
+
return err;
}
@@ -51,11 +50,9 @@ int ext4_fname_prepare_lookup(struct inode *dir, struct dentry *dentry,
ext4_fname_from_fscrypt_name(fname, &name);
-#if IS_ENABLED(CONFIG_UNICODE)
err = ext4_fname_setup_ci_filename(dir, &dentry->d_name, fname);
if (err)
ext4_fname_free_filename(fname);
-#endif
return err;
}
@@ -70,10 +67,7 @@ void ext4_fname_free_filename(struct ext4_filename *fname)
fname->usr_fname = NULL;
fname->disk_name.name = NULL;
-#if IS_ENABLED(CONFIG_UNICODE)
- kfree(fname->cf_name.name);
- fname->cf_name.name = NULL;
-#endif
+ ext4_fname_free_ci_filename(fname);
}
static bool uuid_is_zero(__u8 u[16])
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 983dad8c07ec..8007abd4972d 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2511,7 +2511,7 @@ struct ext4_filename {
struct fscrypt_str crypto_buf;
#endif
#if IS_ENABLED(CONFIG_UNICODE)
- struct fscrypt_str cf_name;
+ struct qstr cf_name;
#endif
};
@@ -2745,8 +2745,25 @@ ext4_fsblk_t ext4_inode_to_goal_block(struct inode *);
#if IS_ENABLED(CONFIG_UNICODE)
extern int ext4_fname_setup_ci_filename(struct inode *dir,
- const struct qstr *iname,
- struct ext4_filename *fname);
+ const struct qstr *iname,
+ struct ext4_filename *fname);
+
+static inline void ext4_fname_free_ci_filename(struct ext4_filename *fname)
+{
+ kfree(fname->cf_name.name);
+ fname->cf_name.name = NULL;
+}
+#else
+static inline int ext4_fname_setup_ci_filename(struct inode *dir,
+ const struct qstr *iname,
+ struct ext4_filename *fname)
+{
+ return 0;
+}
+
+static inline void ext4_fname_free_ci_filename(struct ext4_filename *fname)
+{
+}
#endif
/* ext4 encryption related stuff goes here crypto.c */
@@ -2769,16 +2786,11 @@ static inline int ext4_fname_setup_filename(struct inode *dir,
int lookup,
struct ext4_filename *fname)
{
- int err = 0;
fname->usr_fname = iname;
fname->disk_name.name = (unsigned char *) iname->name;
fname->disk_name.len = iname->len;
-#if IS_ENABLED(CONFIG_UNICODE)
- err = ext4_fname_setup_ci_filename(dir, iname, fname);
-#endif
-
- return err;
+ return ext4_fname_setup_ci_filename(dir, iname, fname);
}
static inline int ext4_fname_prepare_lookup(struct inode *dir,
@@ -2790,10 +2802,7 @@ static inline int ext4_fname_prepare_lookup(struct inode *dir,
static inline void ext4_fname_free_filename(struct ext4_filename *fname)
{
-#if IS_ENABLED(CONFIG_UNICODE)
- kfree(fname->cf_name.name);
- fname->cf_name.name = NULL;
-#endif
+ ext4_fname_free_ci_filename(fname);
}
static inline int ext4_ioctl_get_encryption_pwsalt(struct file *filp,
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index a630b27a4cc6..e6769b97a970 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1390,62 +1390,11 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
}
#if IS_ENABLED(CONFIG_UNICODE)
-/*
- * Test whether a case-insensitive directory entry matches the filename
- * being searched for. If quick is set, assume the name being looked up
- * is already in the casefolded form.
- *
- * Returns: 0 if the directory entry matches, more than 0 if it
- * doesn't match or less than zero 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)
-{
- const struct super_block *sb = parent->i_sb;
- const struct unicode_map *um = sb->s_encoding;
- struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len);
- struct qstr entry = QSTR_INIT(de_name, de_name_len);
- int ret;
-
- if (IS_ENCRYPTED(parent)) {
- const struct fscrypt_str encrypted_name =
- FSTR_INIT(de_name, de_name_len);
-
- decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL);
- if (!decrypted_name.name)
- return -ENOMEM;
- ret = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name,
- &decrypted_name);
- if (ret < 0)
- goto out;
- entry.name = decrypted_name.name;
- entry.len = decrypted_name.len;
- }
-
- if (quick)
- ret = utf8_strncasecmp_folded(um, name, &entry);
- else
- ret = utf8_strncasecmp(um, name, &entry);
- if (ret < 0) {
- /* Handle invalid character sequence as either an error
- * or as an opaque byte sequence.
- */
- if (sb_has_strict_encoding(sb))
- ret = -EINVAL;
- else if (name->len != entry.len)
- ret = 1;
- else
- ret = !!memcmp(name->name, entry.name, entry.len);
- }
-out:
- kfree(decrypted_name.name);
- return ret;
-}
-
int ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
struct ext4_filename *name)
{
- struct fscrypt_str *cf_name = &name->cf_name;
+ struct qstr *cf_name = &name->cf_name;
+ unsigned char *buf;
struct dx_hash_info *hinfo = &name->hinfo;
int len;
@@ -1455,18 +1404,18 @@ int ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
return 0;
}
- cf_name->name = kmalloc(EXT4_NAME_LEN, GFP_NOFS);
- if (!cf_name->name)
+ buf = kmalloc(EXT4_NAME_LEN, GFP_NOFS);
+ if (!buf)
return -ENOMEM;
- len = utf8_casefold(dir->i_sb->s_encoding,
- iname, cf_name->name,
- EXT4_NAME_LEN);
+ len = utf8_casefold(dir->i_sb->s_encoding, iname, buf, EXT4_NAME_LEN);
if (len <= 0) {
- kfree(cf_name->name);
- cf_name->name = NULL;
+ kfree(buf);
+ buf = NULL;
}
+ cf_name->name = buf;
cf_name->len = (unsigned) len;
+
if (!IS_ENCRYPTED(dir))
return 0;
@@ -1502,22 +1451,29 @@ static bool ext4_match(struct inode *parent,
#if IS_ENABLED(CONFIG_UNICODE)
if (IS_CASEFOLDED(parent) &&
(!IS_ENCRYPTED(parent) || fscrypt_has_encryption_key(parent))) {
- if (fname->cf_name.name) {
- struct qstr cf = {.name = fname->cf_name.name,
- .len = fname->cf_name.len};
- if (IS_ENCRYPTED(parent)) {
- if (fname->hinfo.hash != EXT4_DIRENT_HASH(de) ||
- fname->hinfo.minor_hash !=
- EXT4_DIRENT_MINOR_HASH(de)) {
-
- return false;
- }
- }
- return !ext4_ci_compare(parent, &cf, de->name,
- de->name_len, true);
- }
- return !ext4_ci_compare(parent, fname->usr_fname, de->name,
- de->name_len, false);
+ /*
+ * Just checking IS_ENCRYPTED(parent) below is not
+ * sufficient to decide whether one can use the hash for
+ * skipping the string comparison, because the key might
+ * have been added right after
+ * ext4_fname_setup_ci_filename(). In this case, a hash
+ * mismatch will be a false negative. Therefore, make
+ * sure cf_name was properly initialized before
+ * considering the calculated hash.
+ */
+ if (IS_ENCRYPTED(parent) && fname->cf_name.name &&
+ (fname->hinfo.hash != EXT4_DIRENT_HASH(de) ||
+ fname->hinfo.minor_hash != EXT4_DIRENT_MINOR_HASH(de)))
+ return false;
+ /*
+ * Treat comparison errors as not a match. The
+ * only case where it happens is on a disk
+ * corruption or ENOMEM.
+ */
+
+ return generic_ci_match(parent, fname->usr_fname,
+ &fname->cf_name, de->name,
+ de->name_len) > 0;
}
#endif
@@ -1869,8 +1825,7 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi
}
}
-#if IS_ENABLED(CONFIG_UNICODE)
- if (!inode && IS_CASEFOLDED(dir)) {
+ if (IS_ENABLED(CONFIG_UNICODE) && !inode && IS_CASEFOLDED(dir)) {
/* Eventually we want to call d_add_ci(dentry, NULL)
* for negative dentries in the encoding case as
* well. For now, prevent the negative dentry
@@ -1878,7 +1833,7 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi
*/
return NULL;
}
-#endif
+
return d_splice_alias(inode, dentry);
}
@@ -3208,16 +3163,14 @@ static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
ext4_fc_track_unlink(handle, dentry);
retval = ext4_mark_inode_dirty(handle, dir);
-#if IS_ENABLED(CONFIG_UNICODE)
/* VFS negative dentries are incompatible with Encoding and
* Case-insensitiveness. Eventually we'll want avoid
* invalidating the dentries here, alongside with returning the
* negative dentries at ext4_lookup(), when it is better
* supported by the VFS for the CI case.
*/
- if (IS_CASEFOLDED(dir))
+ if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))
d_invalidate(dentry);
-#endif
end_rmdir:
brelse(bh);
@@ -3319,16 +3272,15 @@ static int ext4_unlink(struct inode *dir, struct dentry *dentry)
goto out_trace;
retval = __ext4_unlink(dir, &dentry->d_name, d_inode(dentry), dentry);
-#if IS_ENABLED(CONFIG_UNICODE)
+
/* VFS negative dentries are incompatible with Encoding and
* Case-insensitiveness. Eventually we'll want avoid
* invalidating the dentries here, alongside with returning the
* negative dentries at ext4_lookup(), when it is better
* supported by the VFS for the CI case.
*/
- if (IS_CASEFOLDED(dir))
+ if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))
d_invalidate(dentry);
-#endif
out_trace:
trace_ext4_unlink_exit(dentry, retval);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index c682fb927b64..d2d2254a9ded 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3586,14 +3586,12 @@ int ext4_feature_set_ok(struct super_block *sb, int readonly)
return 0;
}
-#if !IS_ENABLED(CONFIG_UNICODE)
- if (ext4_has_feature_casefold(sb)) {
+ if (!IS_ENABLED(CONFIG_UNICODE) && ext4_has_feature_casefold(sb)) {
ext4_msg(sb, KERN_ERR,
"Filesystem with casefold feature cannot be "
"mounted without CONFIG_UNICODE");
return 0;
}
-#endif
if (readonly)
return 1;
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 02c9355176d3..cbd7a5e96a37 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -42,35 +42,49 @@ static unsigned int bucket_blocks(unsigned int level)
return 4;
}
+#if IS_ENABLED(CONFIG_UNICODE)
/* If @dir is casefolded, initialize @fname->cf_name from @fname->usr_fname. */
int f2fs_init_casefolded_name(const struct inode *dir,
struct f2fs_filename *fname)
{
-#if IS_ENABLED(CONFIG_UNICODE)
struct super_block *sb = dir->i_sb;
+ unsigned char *buf;
+ int len;
if (IS_CASEFOLDED(dir) &&
!is_dot_dotdot(fname->usr_fname->name, fname->usr_fname->len)) {
- fname->cf_name.name = f2fs_kmem_cache_alloc(f2fs_cf_name_slab,
- GFP_NOFS, false, F2FS_SB(sb));
- if (!fname->cf_name.name)
+ buf = f2fs_kmem_cache_alloc(f2fs_cf_name_slab,
+ GFP_NOFS, false, F2FS_SB(sb));
+ if (!buf)
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);
- fname->cf_name.name = NULL;
+
+ 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;
}
-#endif
+
return 0;
}
+void f2fs_free_casefolded_name(struct f2fs_filename *fname)
+{
+ 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 /* CONFIG_UNICODE */
+
static int __f2fs_setup_filename(const struct inode *dir,
const struct fscrypt_name *crypt_name,
struct f2fs_filename *fname)
@@ -142,12 +156,7 @@ 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,
@@ -176,58 +185,6 @@ static struct f2fs_dir_entry *find_in_block(struct inode *dir,
return f2fs_find_target_dentry(&d, fname, max_slots);
}
-#if IS_ENABLED(CONFIG_UNICODE)
-/*
- * Test whether a case-insensitive directory entry matches the filename
- * being searched for.
- *
- * Returns 1 for a match, 0 for no match, and -errno on an error.
- */
-static int f2fs_match_ci_name(const struct inode *dir, const struct qstr *name,
- const u8 *de_name, u32 de_name_len)
-{
- const struct super_block *sb = dir->i_sb;
- const struct unicode_map *um = sb->s_encoding;
- struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len);
- struct qstr entry = QSTR_INIT(de_name, de_name_len);
- int res;
-
- if (IS_ENCRYPTED(dir)) {
- const struct fscrypt_str encrypted_name =
- FSTR_INIT((u8 *)de_name, de_name_len);
-
- if (WARN_ON_ONCE(!fscrypt_has_encryption_key(dir)))
- return -EINVAL;
-
- decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL);
- if (!decrypted_name.name)
- return -ENOMEM;
- res = fscrypt_fname_disk_to_usr(dir, 0, 0, &encrypted_name,
- &decrypted_name);
- if (res < 0)
- goto out;
- entry.name = decrypted_name.name;
- entry.len = decrypted_name.len;
- }
-
- res = utf8_strncasecmp_folded(um, name, &entry);
- /*
- * In strict mode, ignore invalid names. In non-strict mode,
- * fall back to treating them as opaque byte sequences.
- */
- if (res < 0 && !sb_has_strict_encoding(sb)) {
- res = name->len == entry.len &&
- memcmp(name->name, entry.name, name->len) == 0;
- } else {
- /* utf8_strncasecmp_folded returns 0 on match */
- res = (res == 0);
- }
-out:
- kfree(decrypted_name.name);
- return res;
-}
-#endif /* CONFIG_UNICODE */
-
static inline int f2fs_match_name(const struct inode *dir,
const struct f2fs_filename *fname,
const u8 *de_name, u32 de_name_len)
@@ -235,11 +192,11 @@ 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);
+ if (fname->cf_name.name)
+ return generic_ci_match(dir, fname->usr_fname,
+ &fname->cf_name,
+ de_name, de_name_len);
- return f2fs_match_ci_name(dir, &cf, 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 1974b6aff397..8a9d910aa552 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -531,7 +531,7 @@ struct f2fs_filename {
* internal operation where usr_fname is also 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
};
@@ -3533,8 +3533,22 @@ int f2fs_get_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
/*
* dir.c
*/
+#if IS_ENABLED(CONFIG_UNICODE)
int f2fs_init_casefolded_name(const struct inode *dir,
struct f2fs_filename *fname);
+void f2fs_free_casefolded_name(struct f2fs_filename *fname);
+#else
+static inline int f2fs_init_casefolded_name(const struct inode *dir,
+ struct f2fs_filename *fname)
+{
+ return 0;
+}
+
+static inline void f2fs_free_casefolded_name(struct f2fs_filename *fname)
+{
+}
+#endif /* CONFIG_UNICODE */
+
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/namei.c b/fs/f2fs/namei.c
index e54f8c08bda8..1ecde2b45e99 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -576,8 +576,7 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
goto out_iput;
}
out_splice:
-#if IS_ENABLED(CONFIG_UNICODE)
- if (!inode && IS_CASEFOLDED(dir)) {
+ if (IS_ENABLED(CONFIG_UNICODE) && !inode && IS_CASEFOLDED(dir)) {
/* Eventually we want to call d_add_ci(dentry, NULL)
* for negative dentries in the encoding case as
* well. For now, prevent the negative dentry
@@ -586,7 +585,7 @@ out_splice:
trace_f2fs_lookup_end(dir, dentry, ino, err);
return NULL;
}
-#endif
+
new = d_splice_alias(inode, dentry);
trace_f2fs_lookup_end(dir, !IS_ERR_OR_NULL(new) ? new : dentry,
ino, IS_ERR(new) ? PTR_ERR(new) : err);
@@ -639,16 +638,15 @@ static int f2fs_unlink(struct inode *dir, struct dentry *dentry)
f2fs_delete_entry(de, page, dir, inode);
f2fs_unlock_op(sbi);
-#if IS_ENABLED(CONFIG_UNICODE)
/* VFS negative dentries are incompatible with Encoding and
* Case-insensitiveness. Eventually we'll want avoid
* invalidating the dentries here, alongside with returning the
* negative dentries at f2fs_lookup(), when it is better
* supported by the VFS for the CI case.
*/
- if (IS_CASEFOLDED(dir))
+ if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))
d_invalidate(dentry);
-#endif
+
if (IS_DIRSYNC(dir))
f2fs_sync_fs(sbi->sb, 1);
fail:
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index 496aee53c38a..8712e264071f 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -46,10 +46,6 @@
static struct kmem_cache *fsync_entry_slab;
-#if IS_ENABLED(CONFIG_UNICODE)
-extern struct kmem_cache *f2fs_cf_name_slab;
-#endif
-
bool f2fs_space_for_roll_forward(struct f2fs_sb_info *sbi)
{
s64 nalloc = percpu_counter_sum_positive(&sbi->alloc_valid_block_count);
@@ -153,11 +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);
}
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 1f1b3647a998..df4cf31f93df 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -321,7 +321,7 @@ struct kmem_cache *f2fs_cf_name_slab;
static int __init f2fs_create_casefold_cache(void)
{
f2fs_cf_name_slab = f2fs_kmem_cache_create("f2fs_casefolded_name",
- F2FS_NAME_LEN);
+ F2FS_NAME_LEN);
return f2fs_cf_name_slab ? 0 : -ENOMEM;
}
@@ -1326,13 +1326,13 @@ default_check:
return -EINVAL;
}
#endif
-#if !IS_ENABLED(CONFIG_UNICODE)
- if (f2fs_sb_has_casefold(sbi)) {
+
+ if (!IS_ENABLED(CONFIG_UNICODE) && f2fs_sb_has_casefold(sbi)) {
f2fs_err(sbi,
"Filesystem with casefold feature cannot be mounted without CONFIG_UNICODE");
return -EINVAL;
}
-#endif
+
/*
* The BLKZONED feature indicates that the drive was formatted with
* zone alignment optimization. This is optional for host-aware
diff --git a/fs/libfs.c b/fs/libfs.c
index b635ee5adbcc..8aa34870449f 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -1854,6 +1854,80 @@ static const struct dentry_operations generic_ci_dentry_ops = {
.d_revalidate = fscrypt_d_revalidate,
#endif
};
+
+/**
+ * generic_ci_match() - Match a name (case-insensitively) with a dirent.
+ * This is a filesystem helper for comparison with directory entries.
+ * generic_ci_d_compare should be used in VFS' ->d_compare instead.
+ *
+ * @parent: Inode of the parent of the dirent under comparison
+ * @name: name under lookup.
+ * @folded_name: Optional pre-folded name under lookup
+ * @de_name: Dirent name.
+ * @de_name_len: dirent name length.
+ *
+ * Test whether a case-insensitive directory entry matches the filename
+ * being searched. If @folded_name is provided, it is used instead of
+ * recalculating the casefold of @name.
+ *
+ * Return: > 0 if the directory entry matches, 0 if it doesn't match, or
+ * < 0 on error.
+ */
+int generic_ci_match(const struct inode *parent,
+ const struct qstr *name,
+ const struct qstr *folded_name,
+ const u8 *de_name, u32 de_name_len)
+{
+ const struct super_block *sb = parent->i_sb;
+ const struct unicode_map *um = sb->s_encoding;
+ struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len);
+ struct qstr dirent = QSTR_INIT(de_name, de_name_len);
+ int res = 0;
+
+ if (IS_ENCRYPTED(parent)) {
+ const struct fscrypt_str encrypted_name =
+ FSTR_INIT((u8 *) de_name, de_name_len);
+
+ if (WARN_ON_ONCE(!fscrypt_has_encryption_key(parent)))
+ return -EINVAL;
+
+ decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL);
+ if (!decrypted_name.name)
+ return -ENOMEM;
+ res = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name,
+ &decrypted_name);
+ if (res < 0) {
+ kfree(decrypted_name.name);
+ return res;
+ }
+ dirent.name = decrypted_name.name;
+ dirent.len = decrypted_name.len;
+ }
+
+ /*
+ * Attempt a case-sensitive match first. It is cheaper and
+ * should cover most lookups, including all the sane
+ * applications that expect a case-sensitive filesystem.
+ */
+
+ if (dirent.len == name->len &&
+ !memcmp(name->name, dirent.name, dirent.len))
+ goto out;
+
+ if (folded_name->name)
+ res = utf8_strncasecmp_folded(um, folded_name, &dirent);
+ else
+ res = utf8_strncasecmp(um, name, &dirent);
+
+out:
+ kfree(decrypted_name.name);
+ if (res < 0 && sb_has_strict_encoding(sb)) {
+ pr_err_ratelimited("Directory contains filename that is invalid UTF-8");
+ return 0;
+ }
+ return !res;
+}
+EXPORT_SYMBOL(generic_ci_match);
#endif
#ifdef CONFIG_FS_ENCRYPTION
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 2fa06a4d197a..0e76af38a6ad 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3369,6 +3369,10 @@ extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
extern int generic_check_addressable(unsigned, u64);
extern void generic_set_sb_d_ops(struct super_block *sb);
+extern int generic_ci_match(const struct inode *parent,
+ const struct qstr *name,
+ const struct qstr *folded_name,
+ const u8 *de_name, u32 de_name_len);
static inline bool sb_has_encoding(const struct super_block *sb)
{