Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
 "A few bug fixes and add support for file-system level encryption in
  ext4"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (31 commits)
  ext4 crypto: enable encryption feature flag
  ext4 crypto: add symlink encryption
  ext4 crypto: enable filename encryption
  ext4 crypto: filename encryption modifications
  ext4 crypto: partial update to namei.c for fname crypto
  ext4 crypto: insert encrypted filenames into a leaf directory block
  ext4 crypto: teach ext4_htree_store_dirent() to store decrypted filenames
  ext4 crypto: filename encryption facilities
  ext4 crypto: implement the ext4 decryption read path
  ext4 crypto: implement the ext4 encryption write path
  ext4 crypto: inherit encryption policies on inode and directory create
  ext4 crypto: enforce context consistency
  ext4 crypto: add encryption key management facilities
  ext4 crypto: add ext4 encryption facilities
  ext4 crypto: add encryption policy and password salt support
  ext4 crypto: add encryption xattr support
  ext4 crypto: export ext4_empty_dir()
  ext4 crypto: add ext4 encryption Kconfig
  ext4 crypto: reserve codepoints used by the ext4 encryption feature
  ext4 crypto: add ext4_mpage_readpages()
  ...

1 files changed, 123 insertions, 7 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index b49cf6e59953..366476e71e10 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -20,7 +20,6 @@
 
 #include <linux/fs.h>
 #include <linux/time.h>
-#include <linux/jbd2.h>
 #include <linux/highuid.h>
 #include <linux/pagemap.h>
 #include <linux/quotaops.h>
@@ -36,7 +35,6 @@
 #include <linux/kernel.h>
 #include <linux/printk.h>
 #include <linux/slab.h>
-#include <linux/ratelimit.h>
 #include <linux/bitops.h>
 
 #include "ext4_jbd2.h"
@@ -140,7 +138,7 @@ static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
 /*
  * Test whether an inode is a fast symlink.
  */
-static int ext4_inode_is_fast_symlink(struct inode *inode)
+int ext4_inode_is_fast_symlink(struct inode *inode)
 {
         int ea_blocks = EXT4_I(inode)->i_file_acl ?
 		EXT4_CLUSTER_SIZE(inode->i_sb) >> 9 : 0;
@@ -887,6 +885,95 @@ int do_journal_get_write_access(handle_t *handle,
 
 static int ext4_get_block_write_nolock(struct inode *inode, sector_t iblock,
 		   struct buffer_head *bh_result, int create);
+
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
+				  get_block_t *get_block)
+{
+	unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+	unsigned to = from + len;
+	struct inode *inode = page->mapping->host;
+	unsigned block_start, block_end;
+	sector_t block;
+	int err = 0;
+	unsigned blocksize = inode->i_sb->s_blocksize;
+	unsigned bbits;
+	struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
+	bool decrypt = false;
+
+	BUG_ON(!PageLocked(page));
+	BUG_ON(from > PAGE_CACHE_SIZE);
+	BUG_ON(to > PAGE_CACHE_SIZE);
+	BUG_ON(from > to);
+
+	if (!page_has_buffers(page))
+		create_empty_buffers(page, blocksize, 0);
+	head = page_buffers(page);
+	bbits = ilog2(blocksize);
+	block = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits);
+
+	for (bh = head, block_start = 0; bh != head || !block_start;
+	    block++, block_start = block_end, bh = bh->b_this_page) {
+		block_end = block_start + blocksize;
+		if (block_end <= from || block_start >= to) {
+			if (PageUptodate(page)) {
+				if (!buffer_uptodate(bh))
+					set_buffer_uptodate(bh);
+			}
+			continue;
+		}
+		if (buffer_new(bh))
+			clear_buffer_new(bh);
+		if (!buffer_mapped(bh)) {
+			WARN_ON(bh->b_size != blocksize);
+			err = get_block(inode, block, bh, 1);
+			if (err)
+				break;
+			if (buffer_new(bh)) {
+				unmap_underlying_metadata(bh->b_bdev,
+							  bh->b_blocknr);
+				if (PageUptodate(page)) {
+					clear_buffer_new(bh);
+					set_buffer_uptodate(bh);
+					mark_buffer_dirty(bh);
+					continue;
+				}
+				if (block_end > to || block_start < from)
+					zero_user_segments(page, to, block_end,
+							   block_start, from);
+				continue;
+			}
+		}
+		if (PageUptodate(page)) {
+			if (!buffer_uptodate(bh))
+				set_buffer_uptodate(bh);
+			continue;
+		}
+		if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
+		    !buffer_unwritten(bh) &&
+		    (block_start < from || block_end > to)) {
+			ll_rw_block(READ, 1, &bh);
+			*wait_bh++ = bh;
+			decrypt = ext4_encrypted_inode(inode) &&
+				S_ISREG(inode->i_mode);
+		}
+	}
+	/*
+	 * If we issued read requests, let them complete.
+	 */
+	while (wait_bh > wait) {
+		wait_on_buffer(*--wait_bh);
+		if (!buffer_uptodate(*wait_bh))
+			err = -EIO;
+	}
+	if (unlikely(err))
+		page_zero_new_buffers(page, from, to);
+	else if (decrypt)
+		err = ext4_decrypt_one(inode, page);
+	return err;
+}
+#endif
+
 static int ext4_write_begin(struct file *file, struct address_space *mapping,
 			    loff_t pos, unsigned len, unsigned flags,
 			    struct page **pagep, void **fsdata)
@@ -949,11 +1036,19 @@ retry_journal:
 	/* In case writeback began while the page was unlocked */
 	wait_for_stable_page(page);
 
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+	if (ext4_should_dioread_nolock(inode))
+		ret = ext4_block_write_begin(page, pos, len,
+					     ext4_get_block_write);
+	else
+		ret = ext4_block_write_begin(page, pos, len,
+					     ext4_get_block);
+#else
 	if (ext4_should_dioread_nolock(inode))
 		ret = __block_write_begin(page, pos, len, ext4_get_block_write);
 	else
 		ret = __block_write_begin(page, pos, len, ext4_get_block);
-
+#endif
 	if (!ret && ext4_should_journal_data(inode)) {
 		ret = ext4_walk_page_buffers(handle, page_buffers(page),
 					     from, to, NULL,
@@ -2575,7 +2670,12 @@ retry_journal:
 	/* In case writeback began while the page was unlocked */
 	wait_for_stable_page(page);
 
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+	ret = ext4_block_write_begin(page, pos, len,
+				     ext4_da_get_block_prep);
+#else
 	ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
+#endif
 	if (ret < 0) {
 		unlock_page(page);
 		ext4_journal_stop(handle);
@@ -2821,7 +2921,7 @@ static int ext4_readpage(struct file *file, struct page *page)
 		ret = ext4_readpage_inline(inode, page);
 
 	if (ret == -EAGAIN)
-		return mpage_readpage(page, ext4_get_block);
+		return ext4_mpage_readpages(page->mapping, NULL, page, 1);
 
 	return ret;
 }
@@ -2836,7 +2936,7 @@ ext4_readpages(struct file *file, struct address_space *mapping,
 	if (ext4_has_inline_data(inode))
 		return 0;
 
-	return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
+	return ext4_mpage_readpages(mapping, pages, NULL, nr_pages);
 }
 
 static void ext4_invalidatepage(struct page *page, unsigned int offset,
@@ -3033,6 +3133,9 @@ static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 		get_block_func = ext4_get_block_write;
 		dio_flags = DIO_LOCKING;
 	}
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+	BUG_ON(ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode));
+#endif
 	if (IS_DAX(inode))
 		ret = dax_do_io(iocb, inode, iter, offset, get_block_func,
 				ext4_end_io_dio, dio_flags);
@@ -3097,6 +3200,11 @@ static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+	if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode))
+		return 0;
+#endif
+
 	/*
 	 * If we are doing data journalling we don't support O_DIRECT
 	 */
@@ -3261,6 +3369,13 @@ static int __ext4_block_zero_page_range(handle_t *handle,
 		/* Uhhuh. Read error. Complain and punt. */
 		if (!buffer_uptodate(bh))
 			goto unlock;
+		if (S_ISREG(inode->i_mode) &&
+		    ext4_encrypted_inode(inode)) {
+			/* We expect the key to be set. */
+			BUG_ON(!ext4_has_encryption_key(inode));
+			BUG_ON(blocksize != PAGE_CACHE_SIZE);
+			WARN_ON_ONCE(ext4_decrypt_one(inode, page));
+		}
 	}
 	if (ext4_should_journal_data(inode)) {
 		BUFFER_TRACE(bh, "get write access");
@@ -4096,7 +4211,8 @@ 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)) {
+		if (ext4_inode_is_fast_symlink(inode) &&
+		    !ext4_encrypted_inode(inode)) {
 			inode->i_op = &ext4_fast_symlink_inode_operations;
 			nd_terminate_link(ei->i_data, inode->i_size,
 				sizeof(ei->i_data) - 1);