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>

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ddd0a9c87d9eef7d3c3dd8e8b9d4cc85b4f43ed7..ab807963a61494f2aca5bae2f01ec364fec20a7a 100644 (file)
--- 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 */
 }