ext4: avoid running out of journal credits when appending to an inline file

commit 8bc1379b82b8e809eef77a9fedbb75c6c297be19 upstream.

Use a separate journal transaction if it turns out that we need to
convert an inline file to use an data block.  Otherwise we could end
up failing due to not having journal credits.

This addresses CVE-2018-10883.

https://bugzilla.kernel.org/show_bug.cgi?id=200071

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
[fengc@google.com: 4.4 and 4.9 backport: adjust context]
Signed-off-by: Chenbo Feng <fengc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 3 insertions, 56 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 43e27d8ec770..567a6c7af677 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3038,9 +3038,6 @@ extern struct buffer_head *ext4_get_first_inline_block(struct inode *inode,
 extern int ext4_inline_data_fiemap(struct inode *inode,
 				   struct fiemap_extent_info *fieinfo,
 				   int *has_inline, __u64 start, __u64 len);
-extern int ext4_try_to_evict_inline_data(handle_t *handle,
-					 struct inode *inode,
-					 int needed);
 extern void ext4_inline_data_truncate(struct inode *inode, int *has_inline);
 
 extern int ext4_convert_inline_data(struct inode *inode);
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 211539a7adfc..6779a9f1de3b 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -889,11 +889,11 @@ retry_journal:
 	flags |= AOP_FLAG_NOFS;
 
 	if (ret == -ENOSPC) {
+		ext4_journal_stop(handle);
 		ret = ext4_da_convert_inline_data_to_extent(mapping,
 							    inode,
 							    flags,
 							    fsdata);
-		ext4_journal_stop(handle);
 		if (ret == -ENOSPC &&
 		    ext4_should_retry_alloc(inode->i_sb, &retries))
 			goto retry_journal;
@@ -1865,42 +1865,6 @@ out:
 	return (error < 0 ? error : 0);
 }
 
-/*
- * Called during xattr set, and if we can sparse space 'needed',
- * just create the extent tree evict the data to the outer block.
- *
- * We use jbd2 instead of page cache to move data to the 1st block
- * so that the whole transaction can be committed as a whole and
- * the data isn't lost because of the delayed page cache write.
- */
-int ext4_try_to_evict_inline_data(handle_t *handle,
-				  struct inode *inode,
-				  int needed)
-{
-	int error;
-	struct ext4_xattr_entry *entry;
-	struct ext4_inode *raw_inode;
-	struct ext4_iloc iloc;
-
-	error = ext4_get_inode_loc(inode, &iloc);
-	if (error)
-		return error;
-
-	raw_inode = ext4_raw_inode(&iloc);
-	entry = (struct ext4_xattr_entry *)((void *)raw_inode +
-					    EXT4_I(inode)->i_inline_off);
-	if (EXT4_XATTR_LEN(entry->e_name_len) +
-	    EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size)) < needed) {
-		error = -ENOSPC;
-		goto out;
-	}
-
-	error = ext4_convert_inline_data_nolock(handle, inode, &iloc);
-out:
-	brelse(iloc.bh);
-	return error;
-}
-
 void ext4_inline_data_truncate(struct inode *inode, int *has_inline)
 {
 	handle_t *handle;
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 7d6da09e637b..38385bcb9148 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1086,22 +1086,8 @@ int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
 	if (EXT4_I(inode)->i_extra_isize == 0)
 		return -ENOSPC;
 	error = ext4_xattr_set_entry(i, s, inode);
-	if (error) {
-		if (error == -ENOSPC &&
-		    ext4_has_inline_data(inode)) {
-			error = ext4_try_to_evict_inline_data(handle, inode,
-					EXT4_XATTR_LEN(strlen(i->name) +
-					EXT4_XATTR_SIZE(i->value_len)));
-			if (error)
-				return error;
-			error = ext4_xattr_ibody_find(inode, i, is);
-			if (error)
-				return error;
-			error = ext4_xattr_set_entry(i, s, inode);
-		}
-		if (error)
-			return error;
-	}
+	if (error)
+		return error;
 	header = IHDR(inode, ext4_raw_inode(&is->iloc));
 	if (!IS_LAST_ENTRY(s->first)) {
 		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);