ext3: Don't warn from writepage when readonly inode is spotted after error

WARN_ON_ONCE(IS_RDONLY(inode)) tends to trip when filesystem hits error and is
remounted read-only. This unnecessarily scares users (well, they should be
scared because of filesystem error, but the stack trace distracts them from the
right source of their fear ;-). We could as well just remove the WARN_ON but
it's not hard to fix it to not trip on filesystem with errors and not use more
cycles in the common case so that's what we do.

CC: stable@kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index a8d3217..fbf6599 100644 (file)
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -1623,7 +1623,13 @@ static int ext3_ordered_writepage(struct page *page,
        int err;
 
        J_ASSERT(PageLocked(page));
-       WARN_ON_ONCE(IS_RDONLY(inode));
+       /*
+        * We don't want to warn for emergency remount. The condition is
+        * ordered to avoid dereferencing inode->i_sb in non-error case to
+        * avoid slow-downs.
+        */
+       WARN_ON_ONCE(IS_RDONLY(inode) &&
+                    !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));
 
        /*
         * We give up here if we're reentered, because it might be for a
@@ -1698,7 +1704,13 @@ static int ext3_writeback_writepage(struct page *page,
        int err;
 
        J_ASSERT(PageLocked(page));
-       WARN_ON_ONCE(IS_RDONLY(inode));
+       /*
+        * We don't want to warn for emergency remount. The condition is
+        * ordered to avoid dereferencing inode->i_sb in non-error case to
+        * avoid slow-downs.
+        */
+       WARN_ON_ONCE(IS_RDONLY(inode) &&
+                    !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));
 
        if (ext3_journal_current_handle())
                goto out_fail;
@@ -1741,7 +1753,13 @@ static int ext3_journalled_writepage(struct page *page,
        int err;
 
        J_ASSERT(PageLocked(page));
-       WARN_ON_ONCE(IS_RDONLY(inode));
+       /*
+        * We don't want to warn for emergency remount. The condition is
+        * ordered to avoid dereferencing inode->i_sb in non-error case to
+        * avoid slow-downs.
+        */
+       WARN_ON_ONCE(IS_RDONLY(inode) &&
+                    !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));
 
        if (ext3_journal_current_handle())
                goto no_write;