ext4: fix sleep inside spinlock issue with quota and dealloc (#14739)

Unlock i_block_reservation_lock before vfs_dq_reserve_block().
This patch fixes http://bugzilla.kernel.org/show_bug.cgi?id=14739

CC: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 5 insertions, 6 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ddd0a9c87d9e..ab807963a614 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1816,19 +1816,17 @@ repeat:
 
         md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks;
         total = md_needed + nrblocks;
+        spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 
         /*
          * Make quota reservation here to prevent quota overflow
          * later. Real quota accounting is done at pages writeout
          * time.
          */
-        if (vfs_dq_reserve_block(inode, total)) {
-                spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+        if (vfs_dq_reserve_block(inode, total))
                 return -EDQUOT;
-        }
 
         if (ext4_claim_free_blocks(sbi, total)) {
-                spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
                 vfs_dq_release_reservation_block(inode, total);
                 if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
                         yield();
@@ -1836,10 +1834,11 @@ repeat:
                 }
                 return -ENOSPC;
         }
+        spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
         EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
-        EXT4_I(inode)->i_reserved_meta_blocks = mdblocks;
-
+        EXT4_I(inode)->i_reserved_meta_blocks += md_needed;
         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+
         return 0;       /* success */
 }