ext4: Provide function to handle transaction restarts

Provide ext4_journal_ensure_credits_fn() function to ensure transaction
has given amount of credits and call helper function to prepare for
restarting a transaction. This allows to remove some boilerplate code
from various places, add proper error handling for the case where
transaction extension or restart fails, and reduces following changes
needed for proper revoke record reservation tracking.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20191105164437.32602-10-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 33 insertions, 57 deletions

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 491f9ee4040e..b79d8ffd3e9b 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -967,55 +967,6 @@ int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
 	return credits;
 }
 
-static int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
-				     int credits, struct buffer_head *bh,
-				     bool dirty, bool block_csum)
-{
-	int error;
-
-	if (!ext4_handle_valid(handle))
-		return 0;
-
-	if (handle->h_buffer_credits >= credits)
-		return 0;
-
-	error = ext4_journal_extend(handle, credits - handle->h_buffer_credits);
-	if (!error)
-		return 0;
-	if (error < 0) {
-		ext4_warning(inode->i_sb, "Extend journal (error %d)", error);
-		return error;
-	}
-
-	if (bh && dirty) {
-		if (block_csum)
-			ext4_xattr_block_csum_set(inode, bh);
-		error = ext4_handle_dirty_metadata(handle, NULL, bh);
-		if (error) {
-			ext4_warning(inode->i_sb, "Handle metadata (error %d)",
-				     error);
-			return error;
-		}
-	}
-
-	error = ext4_journal_restart(handle, credits);
-	if (error) {
-		ext4_warning(inode->i_sb, "Restart journal (error %d)", error);
-		return error;
-	}
-
-	if (bh) {
-		error = ext4_journal_get_write_access(handle, bh);
-		if (error) {
-			ext4_warning(inode->i_sb,
-				     "Get write access failed (error %d)",
-				     error);
-			return error;
-		}
-	}
-	return 0;
-}
-
 static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
 				       int ref_change)
 {
@@ -1149,6 +1100,24 @@ cleanup:
 	return saved_err;
 }
 
+static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
+			struct buffer_head *bh, bool block_csum, bool dirty)
+{
+	int error;
+
+	if (bh && dirty) {
+		if (block_csum)
+			ext4_xattr_block_csum_set(inode, bh);
+		error = ext4_handle_dirty_metadata(handle, NULL, bh);
+		if (error) {
+			ext4_warning(inode->i_sb, "Handle metadata (error %d)",
+				     error);
+			return error;
+		}
+	}
+	return 0;
+}
+
 static void
 ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
 			     struct buffer_head *bh,
@@ -1185,13 +1154,23 @@ ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
 			continue;
 		}
 
-		err = ext4_xattr_ensure_credits(handle, parent, credits, bh,
-						dirty, block_csum);
-		if (err) {
+		err = ext4_journal_ensure_credits_fn(handle, credits, credits,
+			ext4_xattr_restart_fn(handle, parent, bh, block_csum,
+					      dirty));
+		if (err < 0) {
 			ext4_warning_inode(ea_inode, "Ensure credits err=%d",
 					   err);
 			continue;
 		}
+		if (err > 0) {
+			err = ext4_journal_get_write_access(handle, bh);
+			if (err) {
+				ext4_warning_inode(ea_inode,
+						"Re-get write access err=%d",
+						err);
+				continue;
+			}
+		}
 
 		err = ext4_xattr_inode_dec_ref(handle, ea_inode);
 		if (err) {
@@ -2862,11 +2841,8 @@ int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 	struct inode *ea_inode;
 	int error;
 
-	error = ext4_xattr_ensure_credits(handle, inode, extra_credits,
-					  NULL /* bh */,
-					  false /* dirty */,
-					  false /* block_csum */);
-	if (error) {
+	error = ext4_journal_ensure_credits(handle, extra_credits);
+	if (error < 0) {
 		EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
 		goto cleanup;
 	}