set-ext4_dax_aops-for-dax-files

   1 ext4, dax: set ext4_dax_aops for dax files
   2
   3 From: Toshi Kani <toshi.kani@hpe.com>
   4
   5 Sync syscall to DAX file needs to flush processor cache, but it
   6 currently does not flush to existing DAX files.  This is because
   7 'ext4_da_aops' is set to address_space_operations of existing DAX
   8 files, instead of 'ext4_dax_aops', since S_DAX flag is set after
   9 ext4_set_aops() in the open path.
  10
  11   New file
  12   --------
  13   lookup_open
  14     ext4_create
  15       __ext4_new_inode
  16         ext4_set_inode_flags   // Set S_DAX flag
  17       ext4_set_aops            // Set aops to ext4_dax_aops
  18
  19   Existing file
  20   -------------
  21   lookup_open
  22     ext4_lookup
  23       ext4_iget
  24         ext4_set_aops          // Set aops to ext4_da_aops
  25         ext4_set_inode_flags   // Set S_DAX flag
  26
  27 Change ext4_iget() to initialize i_flags before ext4_set_aops().
  28
  29 Fixes: 5f0663bb4a64 ("ext4, dax: introduce ext4_dax_aops")
  30 Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
  31 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  32 Suggested-by: Jan Kara <jack@suse.cz>
  33 Cc: stable@vger.kernel.org
  34 ---
  35  fs/ext4/inode.c |    2 +-
  36  1 file changed, 1 insertion(+), 1 deletion(-)
  37
  38 diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
  39 index e4acaa980467..b19387b75f2b 100644
  40 --- a/fs/ext4/inode.c
  41 +++ b/fs/ext4/inode.c
  42 @@ -4896,6 +4896,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
  43                  * not initialized on a new filesystem. */
  44         }
  45         ei->i_flags = le32_to_cpu(raw_inode->i_flags);
  46 +       ext4_set_inode_flags(inode);
  47         inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
  48         ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
  49         if (ext4_has_feature_64bit(sb))
  50 @@ -5042,7 +5043,6 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
  51                 goto bad_inode;
  52         }
  53         brelse(iloc.bh);
  54 -       ext4_set_inode_flags(inode);
  55
  56         unlock_new_inode(inode);
  57         return inode;
  58