ext4: Fix potential quota deadlock

[karo-tx-linux.git] / fs / ext4 / inode.c

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index a31980dd9b86ff7336393559b12011667dea6589..ddd0a9c87d9eef7d3c3dd8e8b9d4cc85b4f43ed7 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1046,7 +1046,7 @@ static int ext4_calc_metadata_amount(struct inode *inode, int blocks)
 static void ext4_da_update_reserve_space(struct inode *inode, int used)
 {
        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
-       int total, mdb, mdb_free;
+       int total, mdb, mdb_free, mdb_claim = 0;
 
        spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
        /* recalculate the number of metablocks still need to be reserved */
@@ -1059,7 +1059,9 @@ static void ext4_da_update_reserve_space(struct inode *inode, int used)
 
        if (mdb_free) {
                /* Account for allocated meta_blocks */
-               mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
+               mdb_claim = EXT4_I(inode)->i_allocated_meta_blocks;
+               BUG_ON(mdb_free < mdb_claim);
+               mdb_free -= mdb_claim;
 
                /* update fs dirty blocks counter */
                percpu_counter_sub(&sbi->s_dirtyblocks_counter, mdb_free);
@@ -1070,8 +1072,11 @@ static void ext4_da_update_reserve_space(struct inode *inode, int used)
        /* update per-inode reservations */
        BUG_ON(used  > EXT4_I(inode)->i_reserved_data_blocks);
        EXT4_I(inode)->i_reserved_data_blocks -= used;
+       percpu_counter_sub(&sbi->s_dirtyblocks_counter, used + mdb_claim);
        spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 
+       vfs_dq_claim_block(inode, used + mdb_claim);
+
        /*
         * free those over-booking quota for metadata blocks
         */