ext4: Avoid races caused by on-line resizing and SMP memory reordering

[mirror_ubuntu-bionic-kernel.git] / fs / ext4 / inode.c

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 96f3366f59f6ee7c179f4dfc579577c6a58aabc4..4e7f363e3030a1b3f062b4c9b1068371324e7b6a 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4965,7 +4965,8 @@ static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
  */
 int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
 {
-       int groups, gdpblocks;
+       ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
+       int gdpblocks;
        int idxblocks;
        int ret = 0;
 
@@ -4992,8 +4993,8 @@ int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
                groups += nrblocks;
 
        gdpblocks = groups;
-       if (groups > EXT4_SB(inode->i_sb)->s_groups_count)
-               groups = EXT4_SB(inode->i_sb)->s_groups_count;
+       if (groups > ngroups)
+               groups = ngroups;
        if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
                gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;