jbd2: don't clear and reset errors after waiting on writeback

Resetting this flag is almost certainly racy, and will be problematic
with some coming changes.

Make filemap_fdatawait_keep_errors return int, but not clear the flag(s).
Have jbd2 call it instead of filemap_fdatawait and don't attempt to
re-set the error flag if it fails.

Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>

1 files changed, 14 insertions, 2 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 6f1be573a5e6..e5711b2728f4 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -309,6 +309,16 @@ int filemap_check_errors(struct address_space *mapping)
 }
 EXPORT_SYMBOL(filemap_check_errors);
 
+static int filemap_check_and_keep_errors(struct address_space *mapping)
+{
+        /* Check for outstanding write errors */
+        if (test_bit(AS_EIO, &mapping->flags))
+                return -EIO;
+        if (test_bit(AS_ENOSPC, &mapping->flags))
+                return -ENOSPC;
+        return 0;
+}
+
 /**
  * __filemap_fdatawrite_range - start writeback on mapping dirty pages in range
  * @mapping:    address space structure to write
@@ -453,15 +463,17 @@ EXPORT_SYMBOL(filemap_fdatawait_range);
  * call sites are system-wide / filesystem-wide data flushers: e.g. sync(2),
  * fsfreeze(8)
  */
-void filemap_fdatawait_keep_errors(struct address_space *mapping)
+int filemap_fdatawait_keep_errors(struct address_space *mapping)
 {
         loff_t i_size = i_size_read(mapping->host);
 
         if (i_size == 0)
-                return;
+                return 0;
 
         __filemap_fdatawait_range(mapping, 0, i_size - 1);
+        return filemap_check_and_keep_errors(mapping);
 }
+EXPORT_SYMBOL(filemap_fdatawait_keep_errors);
 
 /**
  * filemap_fdatawait - wait for all under-writeback pages to complete