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-rw-r--r--fs/crypto/hooks.c15
-rw-r--r--fs/ext4/namei.c1
-rw-r--r--fs/ext4/super.c1
-rw-r--r--fs/f2fs/namei.c1
-rw-r--r--fs/f2fs/super.c1
-rw-r--r--fs/libfs.c102
-rw-r--r--fs/overlayfs/params.c14
-rw-r--r--fs/ubifs/dir.c1
-rw-r--r--fs/ubifs/super.c1
-rw-r--r--include/linux/fs.h11
-rw-r--r--include/linux/fscrypt.h66
11 files changed, 128 insertions, 86 deletions
diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c
index 52504dd478d3..104771c3d3f6 100644
--- a/fs/crypto/hooks.c
+++ b/fs/crypto/hooks.c
@@ -102,11 +102,8 @@ int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
if (err && err != -ENOENT)
return err;
- if (fname->is_nokey_name) {
- spin_lock(&dentry->d_lock);
- dentry->d_flags |= DCACHE_NOKEY_NAME;
- spin_unlock(&dentry->d_lock);
- }
+ fscrypt_prepare_dentry(dentry, fname->is_nokey_name);
+
return err;
}
EXPORT_SYMBOL_GPL(__fscrypt_prepare_lookup);
@@ -131,12 +128,10 @@ EXPORT_SYMBOL_GPL(__fscrypt_prepare_lookup);
int fscrypt_prepare_lookup_partial(struct inode *dir, struct dentry *dentry)
{
int err = fscrypt_get_encryption_info(dir, true);
+ bool is_nokey_name = (!err && !fscrypt_has_encryption_key(dir));
+
+ fscrypt_prepare_dentry(dentry, is_nokey_name);
- if (!err && !fscrypt_has_encryption_key(dir)) {
- spin_lock(&dentry->d_lock);
- dentry->d_flags |= DCACHE_NOKEY_NAME;
- spin_unlock(&dentry->d_lock);
- }
return err;
}
EXPORT_SYMBOL_GPL(fscrypt_prepare_lookup_partial);
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 05b647e6bc19..5e4f65c14dfb 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1762,7 +1762,6 @@ static struct buffer_head *ext4_lookup_entry(struct inode *dir,
struct buffer_head *bh;
err = ext4_fname_prepare_lookup(dir, dentry, &fname);
- generic_set_encrypted_ci_d_ops(dentry);
if (err == -ENOENT)
return NULL;
if (err)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index dcba0f85dfe2..215b4614eb15 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5484,6 +5484,7 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
goto failed_mount4;
}
+ generic_set_sb_d_ops(sb);
sb->s_root = d_make_root(root);
if (!sb->s_root) {
ext4_msg(sb, KERN_ERR, "get root dentry failed");
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index b3bb815fc6aa..f7f63a567d86 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -531,7 +531,6 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
}
err = f2fs_prepare_lookup(dir, dentry, &fname);
- generic_set_encrypted_ci_d_ops(dentry);
if (err == -ENOENT)
goto out_splice;
if (err)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index d45ab0992ae5..8d9bd880ffd8 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -4660,6 +4660,7 @@ try_onemore:
goto free_node_inode;
}
+ generic_set_sb_d_ops(sb);
sb->s_root = d_make_root(root); /* allocate root dentry */
if (!sb->s_root) {
err = -ENOMEM;
diff --git a/fs/libfs.c b/fs/libfs.c
index 6182e2b03094..78c71a9e2e18 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -1738,16 +1738,28 @@ bool is_empty_dir_inode(struct inode *inode)
static int generic_ci_d_compare(const struct dentry *dentry, unsigned int len,
const char *str, const struct qstr *name)
{
- const struct dentry *parent = READ_ONCE(dentry->d_parent);
- const struct inode *dir = READ_ONCE(parent->d_inode);
- const struct super_block *sb = dentry->d_sb;
- const struct unicode_map *um = sb->s_encoding;
- struct qstr qstr = QSTR_INIT(str, len);
+ const struct dentry *parent;
+ const struct inode *dir;
char strbuf[DNAME_INLINE_LEN];
- int ret;
+ struct qstr qstr;
+
+ /*
+ * 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.
+ *
+ * This comparison is safe under RCU because the caller
+ * guarantees the consistency between str and len. See
+ * __d_lookup_rcu_op_compare() for details.
+ */
+ if (len == name->len && !memcmp(str, name->name, len))
+ return 0;
+ parent = READ_ONCE(dentry->d_parent);
+ dir = READ_ONCE(parent->d_inode);
if (!dir || !IS_CASEFOLDED(dir))
- goto fallback;
+ return 1;
+
/*
* If the dentry name is stored in-line, then it may be concurrently
* modified by a rename. If this happens, the VFS will eventually retry
@@ -1758,20 +1770,14 @@ static int generic_ci_d_compare(const struct dentry *dentry, unsigned int len,
if (len <= DNAME_INLINE_LEN - 1) {
memcpy(strbuf, str, len);
strbuf[len] = 0;
- qstr.name = strbuf;
+ str = strbuf;
/* prevent compiler from optimizing out the temporary buffer */
barrier();
}
- ret = utf8_strncasecmp(um, name, &qstr);
- if (ret >= 0)
- return ret;
+ qstr.len = len;
+ qstr.name = str;
- if (sb_has_strict_encoding(sb))
- return -EINVAL;
-fallback:
- if (len != name->len)
- return 1;
- return !!memcmp(str, name->name, len);
+ return utf8_strncasecmp(dentry->d_sb->s_encoding, name, &qstr);
}
/**
@@ -1800,73 +1806,45 @@ static int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str)
static const struct dentry_operations generic_ci_dentry_ops = {
.d_hash = generic_ci_d_hash,
.d_compare = generic_ci_d_compare,
-};
-#endif
-
#ifdef CONFIG_FS_ENCRYPTION
-static const struct dentry_operations generic_encrypted_dentry_ops = {
.d_revalidate = fscrypt_d_revalidate,
+#endif
};
#endif
-#if defined(CONFIG_FS_ENCRYPTION) && IS_ENABLED(CONFIG_UNICODE)
-static const struct dentry_operations generic_encrypted_ci_dentry_ops = {
- .d_hash = generic_ci_d_hash,
- .d_compare = generic_ci_d_compare,
+#ifdef CONFIG_FS_ENCRYPTION
+static const struct dentry_operations generic_encrypted_dentry_ops = {
.d_revalidate = fscrypt_d_revalidate,
};
#endif
/**
- * generic_set_encrypted_ci_d_ops - helper for setting d_ops for given dentry
- * @dentry: dentry to set ops on
- *
- * Casefolded directories need d_hash and d_compare set, so that the dentries
- * contained in them are handled case-insensitively. Note that these operations
- * are needed on the parent directory rather than on the dentries in it, and
- * while the casefolding flag can be toggled on and off on an empty directory,
- * dentry_operations can't be changed later. As a result, if the filesystem has
- * casefolding support enabled at all, we have to give all dentries the
- * casefolding operations even if their inode doesn't have the casefolding flag
- * currently (and thus the casefolding ops would be no-ops for now).
- *
- * Encryption works differently in that the only dentry operation it needs is
- * d_revalidate, which it only needs on dentries that have the no-key name flag.
- * The no-key flag can't be set "later", so we don't have to worry about that.
+ * generic_set_sb_d_ops - helper for choosing the set of
+ * filesystem-wide dentry operations for the enabled features
+ * @sb: superblock to be configured
*
- * Finally, to maximize compatibility with overlayfs (which isn't compatible
- * with certain dentry operations) and to avoid taking an unnecessary
- * performance hit, we use custom dentry_operations for each possible
- * combination rather than always installing all operations.
+ * Filesystems supporting casefolding and/or fscrypt can call this
+ * helper at mount-time to configure sb->s_d_op to best set of dentry
+ * operations required for the enabled features. The helper must be
+ * called after these have been configured, but before the root dentry
+ * is created.
*/
-void generic_set_encrypted_ci_d_ops(struct dentry *dentry)
+void generic_set_sb_d_ops(struct super_block *sb)
{
-#ifdef CONFIG_FS_ENCRYPTION
- bool needs_encrypt_ops = dentry->d_flags & DCACHE_NOKEY_NAME;
-#endif
#if IS_ENABLED(CONFIG_UNICODE)
- bool needs_ci_ops = dentry->d_sb->s_encoding;
-#endif
-#if defined(CONFIG_FS_ENCRYPTION) && IS_ENABLED(CONFIG_UNICODE)
- if (needs_encrypt_ops && needs_ci_ops) {
- d_set_d_op(dentry, &generic_encrypted_ci_dentry_ops);
+ if (sb->s_encoding) {
+ sb->s_d_op = &generic_ci_dentry_ops;
return;
}
#endif
#ifdef CONFIG_FS_ENCRYPTION
- if (needs_encrypt_ops) {
- d_set_d_op(dentry, &generic_encrypted_dentry_ops);
- return;
- }
-#endif
-#if IS_ENABLED(CONFIG_UNICODE)
- if (needs_ci_ops) {
- d_set_d_op(dentry, &generic_ci_dentry_ops);
+ if (sb->s_cop) {
+ sb->s_d_op = &generic_encrypted_dentry_ops;
return;
}
#endif
}
-EXPORT_SYMBOL(generic_set_encrypted_ci_d_ops);
+EXPORT_SYMBOL(generic_set_sb_d_ops);
/**
* inode_maybe_inc_iversion - increments i_version
diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c
index 112b4b12f825..36dcc530ac28 100644
--- a/fs/overlayfs/params.c
+++ b/fs/overlayfs/params.c
@@ -280,12 +280,20 @@ static int ovl_mount_dir_check(struct fs_context *fc, const struct path *path,
{
struct ovl_fs_context *ctx = fc->fs_private;
- if (ovl_dentry_weird(path->dentry))
- return invalfc(fc, "filesystem on %s not supported", name);
-
if (!d_is_dir(path->dentry))
return invalfc(fc, "%s is not a directory", name);
+ /*
+ * Root dentries of case-insensitive capable filesystems might
+ * not have the dentry operations set, but still be incompatible
+ * with overlayfs. Check explicitly to prevent post-mount
+ * failures.
+ */
+ if (sb_has_encoding(path->mnt->mnt_sb))
+ return invalfc(fc, "case-insensitive capable filesystem on %s not supported", name);
+
+ if (ovl_dentry_weird(path->dentry))
+ return invalfc(fc, "filesystem on %s not supported", name);
/*
* Check whether upper path is read-only here to report failures
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index e413a9cf8ee3..551148de66cd 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -205,7 +205,6 @@ static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry,
dbg_gen("'%pd' in dir ino %lu", dentry, dir->i_ino);
err = fscrypt_prepare_lookup(dir, dentry, &nm);
- generic_set_encrypted_ci_d_ops(dentry);
if (err == -ENOENT)
return d_splice_alias(NULL, dentry);
if (err)
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 09e270d6ed02..304646b03e99 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -2239,6 +2239,7 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
goto out_umount;
}
+ generic_set_sb_d_ops(sb);
sb->s_root = d_make_root(root);
if (!sb->s_root) {
err = -ENOMEM;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d15d808e8e31..30323dc70b7a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3310,7 +3310,16 @@ extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
extern int generic_check_addressable(unsigned, u64);
-extern void generic_set_encrypted_ci_d_ops(struct dentry *dentry);
+extern void generic_set_sb_d_ops(struct super_block *sb);
+
+static inline bool sb_has_encoding(const struct super_block *sb)
+{
+#if IS_ENABLED(CONFIG_UNICODE)
+ return !!sb->s_encoding;
+#else
+ return false;
+#endif
+}
int may_setattr(struct mnt_idmap *idmap, struct inode *inode,
unsigned int ia_valid);
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index 12f9e455d569..772f822dc6b8 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -192,6 +192,8 @@ struct fscrypt_operations {
unsigned int *num_devs);
};
+int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags);
+
static inline struct fscrypt_inode_info *
fscrypt_get_inode_info(const struct inode *inode)
{
@@ -221,15 +223,29 @@ static inline bool fscrypt_needs_contents_encryption(const struct inode *inode)
}
/*
- * When d_splice_alias() moves a directory's no-key alias to its plaintext alias
- * as a result of the encryption key being added, DCACHE_NOKEY_NAME must be
- * cleared. Note that we don't have to support arbitrary moves of this flag
- * because fscrypt doesn't allow no-key names to be the source or target of a
- * rename().
+ * When d_splice_alias() moves a directory's no-key alias to its
+ * plaintext alias as a result of the encryption key being added,
+ * DCACHE_NOKEY_NAME must be cleared and there might be an opportunity
+ * to disable d_revalidate. Note that we don't have to support the
+ * inverse operation because fscrypt doesn't allow no-key names to be
+ * the source or target of a rename().
*/
static inline void fscrypt_handle_d_move(struct dentry *dentry)
{
- dentry->d_flags &= ~DCACHE_NOKEY_NAME;
+ /*
+ * VFS calls fscrypt_handle_d_move even for non-fscrypt
+ * filesystems.
+ */
+ if (dentry->d_flags & DCACHE_NOKEY_NAME) {
+ dentry->d_flags &= ~DCACHE_NOKEY_NAME;
+
+ /*
+ * Other filesystem features might be handling dentry
+ * revalidation, in which case it cannot be disabled.
+ */
+ if (dentry->d_op->d_revalidate == fscrypt_d_revalidate)
+ dentry->d_flags &= ~DCACHE_OP_REVALIDATE;
+ }
}
/**
@@ -261,6 +277,35 @@ static inline bool fscrypt_is_nokey_name(const struct dentry *dentry)
return dentry->d_flags & DCACHE_NOKEY_NAME;
}
+static inline void fscrypt_prepare_dentry(struct dentry *dentry,
+ bool is_nokey_name)
+{
+ /*
+ * This code tries to only take ->d_lock when necessary to write
+ * to ->d_flags. We shouldn't be peeking on d_flags for
+ * DCACHE_OP_REVALIDATE unlocked, but in the unlikely case
+ * there is a race, the worst it can happen is that we fail to
+ * unset DCACHE_OP_REVALIDATE and pay the cost of an extra
+ * d_revalidate.
+ */
+ if (is_nokey_name) {
+ spin_lock(&dentry->d_lock);
+ dentry->d_flags |= DCACHE_NOKEY_NAME;
+ spin_unlock(&dentry->d_lock);
+ } else if (dentry->d_flags & DCACHE_OP_REVALIDATE &&
+ dentry->d_op->d_revalidate == fscrypt_d_revalidate) {
+ /*
+ * Unencrypted dentries and encrypted dentries where the
+ * key is available are always valid from fscrypt
+ * perspective. Avoid the cost of calling
+ * fscrypt_d_revalidate unnecessarily.
+ */
+ spin_lock(&dentry->d_lock);
+ dentry->d_flags &= ~DCACHE_OP_REVALIDATE;
+ spin_unlock(&dentry->d_lock);
+ }
+}
+
/* crypto.c */
void fscrypt_enqueue_decrypt_work(struct work_struct *);
@@ -368,7 +413,6 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode,
bool fscrypt_match_name(const struct fscrypt_name *fname,
const u8 *de_name, u32 de_name_len);
u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name);
-int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags);
/* bio.c */
bool fscrypt_decrypt_bio(struct bio *bio);
@@ -425,6 +469,11 @@ static inline bool fscrypt_is_nokey_name(const struct dentry *dentry)
return false;
}
+static inline void fscrypt_prepare_dentry(struct dentry *dentry,
+ bool is_nokey_name)
+{
+}
+
/* crypto.c */
static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work)
{
@@ -982,6 +1031,9 @@ static inline int fscrypt_prepare_lookup(struct inode *dir,
fname->usr_fname = &dentry->d_name;
fname->disk_name.name = (unsigned char *)dentry->d_name.name;
fname->disk_name.len = dentry->d_name.len;
+
+ fscrypt_prepare_dentry(dentry, false);
+
return 0;
}
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-11-24 22:14:17 +0000