ext4: prevent ext4_quota_write() from failing due to ENOSPC

In order to prevent quota block tracking to be inaccurate when
ext4_quota_write() fails with ENOSPC, we make two changes.  The quota
file can now use the reserved block (since the quota file is arguably
file system metadata), and ext4_quota_write() now uses
ext4_should_retry_alloc() to retry the block allocation after a commit
has completed and released some blocks for allocation.

This fixes failures of xfstests generic/270:

Quota error (device vdc): write_blk: dquota write failed
Quota error (device vdc): qtree_write_dquot: Error -28 occurred while creating quota

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 5 insertions, 5 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 263a46c488c7..e8a67b8ba90c 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -731,18 +731,18 @@ int ext4_get_block(struct inode *inode, sector_t iblock,
  * `handle' can be NULL if create is zero
  */
 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
-                                ext4_lblk_t block, int create)
+                                ext4_lblk_t block, int map_flags)
 {
         struct ext4_map_blocks map;
         struct buffer_head *bh;
+        int create = map_flags & EXT4_GET_BLOCKS_CREATE;
         int err;
 
         J_ASSERT(handle != NULL || create == 0);
 
         map.m_lblk = block;
         map.m_len = 1;
-        err = ext4_map_blocks(handle, inode, &map,
-                              create ? EXT4_GET_BLOCKS_CREATE : 0);
+        err = ext4_map_blocks(handle, inode, &map, map_flags);
 
         if (err == 0)
                 return create ? ERR_PTR(-ENOSPC) : NULL;
@@ -788,11 +788,11 @@ errout:
 }
 
 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
-                               ext4_lblk_t block, int create)
+                               ext4_lblk_t block, int map_flags)
 {
         struct buffer_head *bh;
 
-        bh = ext4_getblk(handle, inode, block, create);
+        bh = ext4_getblk(handle, inode, block, map_flags);
         if (IS_ERR(bh))
                 return bh;
         if (!bh || buffer_uptodate(bh))