[04/79] ext4: split inode_operations for encrypted symlinks off the rest
diff mbox

Message ID 1430803373-4948-4-git-send-email-viro@ZenIV.linux.org.uk
State New
Headers show

Commit Message

Al Viro May 5, 2015, 5:21 a.m. UTC
From: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/ext4/ext4.h    |  1 +
 fs/ext4/inode.c   | 10 ++++++++--
 fs/ext4/namei.c   |  9 +++++----
 fs/ext4/symlink.c | 30 ++++++++++--------------------
 4 files changed, 24 insertions(+), 26 deletions(-)

Comments

Jan Kara May 5, 2015, 9:10 a.m. UTC | #1
On Tue 05-05-15 06:21:38, Al Viro wrote:
> From: Al Viro <viro@zeniv.linux.org.uk>
> 
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
  Looks good. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/ext4/ext4.h    |  1 +
>  fs/ext4/inode.c   | 10 ++++++++--
>  fs/ext4/namei.c   |  9 +++++----
>  fs/ext4/symlink.c | 30 ++++++++++--------------------
>  4 files changed, 24 insertions(+), 26 deletions(-)
> 
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index ef267ad..2640913 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -2849,6 +2849,7 @@ extern int ext4_mpage_readpages(struct address_space *mapping,
>  				unsigned nr_pages);
>  
>  /* symlink.c */
> +extern const struct inode_operations ext4_encrypted_symlink_inode_operations;
>  extern const struct inode_operations ext4_symlink_inode_operations;
>  extern const struct inode_operations ext4_fast_symlink_inode_operations;
>  
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index cbd0654..a320558 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -4211,8 +4211,14 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
>  		inode->i_op = &ext4_dir_inode_operations;
>  		inode->i_fop = &ext4_dir_operations;
>  	} else if (S_ISLNK(inode->i_mode)) {
> -		if (ext4_inode_is_fast_symlink(inode) &&
> -		    !ext4_encrypted_inode(inode)) {
> +		if (ext4_encrypted_inode(inode)) {
> +#ifdef CONFIG_EXT4_FS_ENCRYPTION
> +			inode->i_op = &ext4_encrypted_symlink_inode_operations;
> +			ext4_set_aops(inode);
> +#else
> +			BUILD_BUG();
> +#endif
> +		} else if (ext4_inode_is_fast_symlink(inode)) {
>  			inode->i_op = &ext4_fast_symlink_inode_operations;
>  			nd_terminate_link(ei->i_data, inode->i_size,
>  				sizeof(ei->i_data) - 1);
> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
> index 7223b0b..84b1920 100644
> --- a/fs/ext4/namei.c
> +++ b/fs/ext4/namei.c
> @@ -3266,10 +3266,12 @@ static int ext4_symlink(struct inode *dir,
>  			goto err_drop_inode;
>  		sd->len = cpu_to_le16(ostr.len);
>  		disk_link.name = (char *) sd;
> +		inode->i_op = &ext4_encrypted_symlink_inode_operations;
>  	}
>  
>  	if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
> -		inode->i_op = &ext4_symlink_inode_operations;
> +		if (!encryption_required)
> +			inode->i_op = &ext4_symlink_inode_operations;
>  		ext4_set_aops(inode);
>  		/*
>  		 * We cannot call page_symlink() with transaction started
> @@ -3309,9 +3311,8 @@ static int ext4_symlink(struct inode *dir,
>  	} else {
>  		/* clear the extent format for fast symlink */
>  		ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
> -		inode->i_op = encryption_required ?
> -			&ext4_symlink_inode_operations :
> -			&ext4_fast_symlink_inode_operations;
> +		if (!encryption_required)
> +			inode->i_op = &ext4_fast_symlink_inode_operations;
>  		memcpy((char *)&EXT4_I(inode)->i_data, disk_link.name,
>  		       disk_link.len);
>  		inode->i_size = disk_link.len - 1;
> diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
> index 19f78f2..4ea5a01 100644
> --- a/fs/ext4/symlink.c
> +++ b/fs/ext4/symlink.c
> @@ -35,9 +35,6 @@ static void *ext4_follow_link(struct dentry *dentry, struct nameidata *nd)
>  	int res;
>  	u32 plen, max_size = inode->i_sb->s_blocksize;
>  
> -	if (!ext4_encrypted_inode(inode))
> -		return page_follow_link_light(dentry, nd);
> -
>  	ctx = ext4_get_fname_crypto_ctx(inode, inode->i_sb->s_blocksize);
>  	if (IS_ERR(ctx))
>  		return ctx;
> @@ -97,18 +94,16 @@ errout:
>  	return ERR_PTR(res);
>  }
>  
> -static void ext4_put_link(struct dentry *dentry, struct nameidata *nd,
> -			  void *cookie)
> -{
> -	struct page *page = cookie;
> -
> -	if (!page) {
> -		kfree(nd_get_link(nd));
> -	} else {
> -		kunmap(page);
> -		page_cache_release(page);
> -	}
> -}
> +const struct inode_operations ext4_encrypted_symlink_inode_operations = {
> +	.readlink	= generic_readlink,
> +	.follow_link    = ext4_follow_link,
> +	.put_link       = kfree_put_link,
> +	.setattr	= ext4_setattr,
> +	.setxattr	= generic_setxattr,
> +	.getxattr	= generic_getxattr,
> +	.listxattr	= ext4_listxattr,
> +	.removexattr	= generic_removexattr,
> +};
>  #endif
>  
>  static void *ext4_follow_fast_link(struct dentry *dentry, struct nameidata *nd)
> @@ -120,13 +115,8 @@ static void *ext4_follow_fast_link(struct dentry *dentry, struct nameidata *nd)
>  
>  const struct inode_operations ext4_symlink_inode_operations = {
>  	.readlink	= generic_readlink,
> -#ifdef CONFIG_EXT4_FS_ENCRYPTION
> -	.follow_link    = ext4_follow_link,
> -	.put_link       = ext4_put_link,
> -#else
>  	.follow_link	= page_follow_link_light,
>  	.put_link	= page_put_link,
> -#endif
>  	.setattr	= ext4_setattr,
>  	.setxattr	= generic_setxattr,
>  	.getxattr	= generic_getxattr,
> -- 
> 2.1.4
> 
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Linus Torvalds May 5, 2015, 3:01 p.m. UTC | #2
On Mon, May 4, 2015 at 10:21 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
>         } else if (S_ISLNK(inode->i_mode)) {
> -               if (ext4_inode_is_fast_symlink(inode) &&
> -                   !ext4_encrypted_inode(inode)) {
> +               if (ext4_encrypted_inode(inode)) {
> +#ifdef CONFIG_EXT4_FS_ENCRYPTION
> +                       inode->i_op = &ext4_encrypted_symlink_inode_operations;
> +                       ext4_set_aops(inode);
> +#else
> +                       BUILD_BUG();
> +#endif
> +               } else if (ext4_inode_is_fast_symlink(inode)) {
>                         inode->i_op = &ext4_fast_symlink_inode_operations;
>                         nd_terminate_link(ei->i_data, inode->i_size,
>                                 sizeof(ei->i_data) - 1);

Ugh. Could we aim to *not* add code like this.

Instead, just declare (but don't define) the
ext4_encrypted_symlink_inode_operations thing, so that *if* somebody
uses it they get a link error, and make sure that
"ext4_encrypted_inode()" ends up always returning zero when encryption
isn't enabled, so that the compiler will actually optimize the whole
thing out (which apparently is already the case, judging by the
build-bug-on.

I really prefer to not see #ifdef's inside the middle of anything but
trivial helper functions. I know we have them, and I wish we didn't,
but at least we can aim to not add more of them.

                         Linus
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Al Viro May 5, 2015, 3:10 p.m. UTC | #3
On Tue, May 05, 2015 at 08:01:52AM -0700, Linus Torvalds wrote:
> Ugh. Could we aim to *not* add code like this.
> 
> Instead, just declare (but don't define) the
> ext4_encrypted_symlink_inode_operations thing, so that *if* somebody
> uses it they get a link error, and make sure that
> "ext4_encrypted_inode()" ends up always returning zero when encryption
> isn't enabled, so that the compiler will actually optimize the whole
> thing out (which apparently is already the case, judging by the
> build-bug-on.

Sure, no problem.  BUILD_BUG_ON was used only because it triggered an
error earlier, I simply forgot to rip it out afterwards.
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Patch
diff mbox

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index ef267ad..2640913 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2849,6 +2849,7 @@  extern int ext4_mpage_readpages(struct address_space *mapping,
 				unsigned nr_pages);
 
 /* symlink.c */
+extern const struct inode_operations ext4_encrypted_symlink_inode_operations;
 extern const struct inode_operations ext4_symlink_inode_operations;
 extern const struct inode_operations ext4_fast_symlink_inode_operations;
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index cbd0654..a320558 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4211,8 +4211,14 @@  struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 		inode->i_op = &ext4_dir_inode_operations;
 		inode->i_fop = &ext4_dir_operations;
 	} else if (S_ISLNK(inode->i_mode)) {
-		if (ext4_inode_is_fast_symlink(inode) &&
-		    !ext4_encrypted_inode(inode)) {
+		if (ext4_encrypted_inode(inode)) {
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+			inode->i_op = &ext4_encrypted_symlink_inode_operations;
+			ext4_set_aops(inode);
+#else
+			BUILD_BUG();
+#endif
+		} else if (ext4_inode_is_fast_symlink(inode)) {
 			inode->i_op = &ext4_fast_symlink_inode_operations;
 			nd_terminate_link(ei->i_data, inode->i_size,
 				sizeof(ei->i_data) - 1);
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 7223b0b..84b1920 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3266,10 +3266,12 @@  static int ext4_symlink(struct inode *dir,
 			goto err_drop_inode;
 		sd->len = cpu_to_le16(ostr.len);
 		disk_link.name = (char *) sd;
+		inode->i_op = &ext4_encrypted_symlink_inode_operations;
 	}
 
 	if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
-		inode->i_op = &ext4_symlink_inode_operations;
+		if (!encryption_required)
+			inode->i_op = &ext4_symlink_inode_operations;
 		ext4_set_aops(inode);
 		/*
 		 * We cannot call page_symlink() with transaction started
@@ -3309,9 +3311,8 @@  static int ext4_symlink(struct inode *dir,
 	} else {
 		/* clear the extent format for fast symlink */
 		ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
-		inode->i_op = encryption_required ?
-			&ext4_symlink_inode_operations :
-			&ext4_fast_symlink_inode_operations;
+		if (!encryption_required)
+			inode->i_op = &ext4_fast_symlink_inode_operations;
 		memcpy((char *)&EXT4_I(inode)->i_data, disk_link.name,
 		       disk_link.len);
 		inode->i_size = disk_link.len - 1;
diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
index 19f78f2..4ea5a01 100644
--- a/fs/ext4/symlink.c
+++ b/fs/ext4/symlink.c
@@ -35,9 +35,6 @@  static void *ext4_follow_link(struct dentry *dentry, struct nameidata *nd)
 	int res;
 	u32 plen, max_size = inode->i_sb->s_blocksize;
 
-	if (!ext4_encrypted_inode(inode))
-		return page_follow_link_light(dentry, nd);
-
 	ctx = ext4_get_fname_crypto_ctx(inode, inode->i_sb->s_blocksize);
 	if (IS_ERR(ctx))
 		return ctx;
@@ -97,18 +94,16 @@  errout:
 	return ERR_PTR(res);
 }
 
-static void ext4_put_link(struct dentry *dentry, struct nameidata *nd,
-			  void *cookie)
-{
-	struct page *page = cookie;
-
-	if (!page) {
-		kfree(nd_get_link(nd));
-	} else {
-		kunmap(page);
-		page_cache_release(page);
-	}
-}
+const struct inode_operations ext4_encrypted_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link    = ext4_follow_link,
+	.put_link       = kfree_put_link,
+	.setattr	= ext4_setattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext4_listxattr,
+	.removexattr	= generic_removexattr,
+};
 #endif
 
 static void *ext4_follow_fast_link(struct dentry *dentry, struct nameidata *nd)
@@ -120,13 +115,8 @@  static void *ext4_follow_fast_link(struct dentry *dentry, struct nameidata *nd)
 
 const struct inode_operations ext4_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-	.follow_link    = ext4_follow_link,
-	.put_link       = ext4_put_link,
-#else
 	.follow_link	= page_follow_link_light,
 	.put_link	= page_put_link,
-#endif
 	.setattr	= ext4_setattr,
 	.setxattr	= generic_setxattr,
 	.getxattr	= generic_getxattr,