ext4: Fix remaining racy updates of EXT4_I(inode)->i_flags
Dmitry Monakhov [Sat, 5 Jun 2010 15:51:27 +0000 (11:51 -0400)]
A few functions were still modifying i_flags in a racy manner.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/inode.c

index 19df61c..42272d6 100644 (file)
@@ -4942,20 +4942,26 @@ void ext4_set_inode_flags(struct inode *inode)
 /* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
 void ext4_get_inode_flags(struct ext4_inode_info *ei)
 {
-       unsigned int flags = ei->vfs_inode.i_flags;
-
-       ei->i_flags &= ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
-                       EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|EXT4_DIRSYNC_FL);
-       if (flags & S_SYNC)
-               ei->i_flags |= EXT4_SYNC_FL;
-       if (flags & S_APPEND)
-               ei->i_flags |= EXT4_APPEND_FL;
-       if (flags & S_IMMUTABLE)
-               ei->i_flags |= EXT4_IMMUTABLE_FL;
-       if (flags & S_NOATIME)
-               ei->i_flags |= EXT4_NOATIME_FL;
-       if (flags & S_DIRSYNC)
-               ei->i_flags |= EXT4_DIRSYNC_FL;
+       unsigned int vfs_fl;
+       unsigned long old_fl, new_fl;
+
+       do {
+               vfs_fl = ei->vfs_inode.i_flags;
+               old_fl = ei->i_flags;
+               new_fl = old_fl & ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
+                               EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|
+                               EXT4_DIRSYNC_FL);
+               if (vfs_fl & S_SYNC)
+                       new_fl |= EXT4_SYNC_FL;
+               if (vfs_fl & S_APPEND)
+                       new_fl |= EXT4_APPEND_FL;
+               if (vfs_fl & S_IMMUTABLE)
+                       new_fl |= EXT4_IMMUTABLE_FL;
+               if (vfs_fl & S_NOATIME)
+                       new_fl |= EXT4_NOATIME_FL;
+               if (vfs_fl & S_DIRSYNC)
+                       new_fl |= EXT4_DIRSYNC_FL;
+       } while (cmpxchg(&ei->i_flags, old_fl, new_fl) != old_fl);
 }
 
 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
@@ -5191,7 +5197,7 @@ static int ext4_inode_blocks_set(handle_t *handle,
                 */
                raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
                raw_inode->i_blocks_high = 0;
-               ei->i_flags &= ~EXT4_HUGE_FILE_FL;
+               ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
                return 0;
        }
        if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
@@ -5204,9 +5210,9 @@ static int ext4_inode_blocks_set(handle_t *handle,
                 */
                raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
                raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
-               ei->i_flags &= ~EXT4_HUGE_FILE_FL;
+               ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
        } else {
-               ei->i_flags |= EXT4_HUGE_FILE_FL;
+               ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
                /* i_block is stored in file system block size */
                i_blocks = i_blocks >> (inode->i_blkbits - 9);
                raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);