Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: Fix remaining racy updates of EXT4_I(inode)->i_flags
  ext4: Make sure the MOVE_EXT ioctl can't overwrite append-only files

2 files changed, 26 insertions, 17 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 19df61c321fd..42272d67955a 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -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);
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 3a6c92ac131c..52abfa12762a 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -960,6 +960,9 @@ mext_check_arguments(struct inode *orig_inode,
                 return -EINVAL;
         }
 
+        if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode))
+                return -EPERM;
+
         /* Ext4 move extent does not support swapfile */
         if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) {
                 ext4_debug("ext4 move extent: The argument files should "