ext4: store EXT4_EXT_MIGRATE in i_state instead of i_flags

EXT4_EXT_MIGRATE is only intended to be used for an in-memory flag,
and the hex value assigned to it collides with FS_DIRECTIO_FL (which
is also stored in i_flags).  There's no reason for the
EXT4_EXT_MIGRATE bit to be stored in i_flags, so we switch it to use
i_state instead.

Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

3 files changed, 13 insertions, 15 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 2a0f75d55fad..84e7f1d00a83 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -268,7 +268,6 @@ struct flex_groups {
 #define EXT4_TOPDIR_FL                  0x00020000 /* Top of directory hierarchies*/
 #define EXT4_HUGE_FILE_FL               0x00040000 /* Set to each huge file */
 #define EXT4_EXTENTS_FL                 0x00080000 /* Inode uses extents */
-#define EXT4_EXT_MIGRATE                0x00100000 /* Inode is migrating */
 #define EXT4_RESERVED_FL                0x80000000 /* reserved for ext4 lib */
 
 #define EXT4_FL_USER_VISIBLE            0x000BDFFF /* User visible flags */
@@ -306,6 +305,7 @@ static inline __u32 ext4_mask_flags(umode_t mode, __u32 flags)
 #define EXT4_STATE_XATTR                0x00000004 /* has in-inode xattrs */
 #define EXT4_STATE_NO_EXPAND            0x00000008 /* No space for expansion */
 #define EXT4_STATE_DA_ALLOC_CLOSE       0x00000010 /* Alloc DA blks on close */
+#define EXT4_STATE_EXT_MIGRATE          0x00000020 /* Inode is migrating */
 
 /* Used to pass group descriptor data when online resize is done */
 struct ext4_new_group_input {
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5a8979259c9a..a5b4ce40cc66 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1255,8 +1255,7 @@ int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
                          * i_data's format changing.  Force the migrate
                          * to fail by clearing migrate flags
                          */
-                        EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags &
-                                                        ~EXT4_EXT_MIGRATE;
+                        EXT4_I(inode)->i_state &= ~EXT4_STATE_EXT_MIGRATE;
                 }
         }
 
@@ -4596,8 +4595,7 @@ static int ext4_do_update_inode(handle_t *handle,
         if (ext4_inode_blocks_set(handle, raw_inode, ei))
                 goto out_brelse;
         raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
-        /* clear the migrate flag in the raw_inode */
-        raw_inode->i_flags = cpu_to_le32(ei->i_flags & ~EXT4_EXT_MIGRATE);
+        raw_inode->i_flags = cpu_to_le32(ei->i_flags);
         if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
             cpu_to_le32(EXT4_OS_HURD))
                 raw_inode->i_file_acl_high =
diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
index 05361ad5b80a..bf519f239ae6 100644
--- a/fs/ext4/migrate.c
+++ b/fs/ext4/migrate.c
@@ -353,17 +353,16 @@ static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
 
         down_write(&EXT4_I(inode)->i_data_sem);
         /*
-         * if EXT4_EXT_MIGRATE is cleared a block allocation
+         * if EXT4_STATE_EXT_MIGRATE is cleared a block allocation
          * happened after we started the migrate. We need to
          * fail the migrate
          */
-        if (!(EXT4_I(inode)->i_flags & EXT4_EXT_MIGRATE)) {
+        if (!(EXT4_I(inode)->i_state & EXT4_STATE_EXT_MIGRATE)) {
                 retval = -EAGAIN;
                 up_write(&EXT4_I(inode)->i_data_sem);
                 goto err_out;
         } else
-                EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags &
-                                                        ~EXT4_EXT_MIGRATE;
+                EXT4_I(inode)->i_state &= ~EXT4_STATE_EXT_MIGRATE;
         /*
          * We have the extent map build with the tmp inode.
          * Now copy the i_data across
@@ -517,14 +516,15 @@ int ext4_ext_migrate(struct inode *inode)
          * when we add extents we extent the journal
          */
         /*
-         * Even though we take i_mutex we can still cause block allocation
-         * via mmap write to holes. If we have allocated new blocks we fail
-         * migrate.  New block allocation will clear EXT4_EXT_MIGRATE flag.
-         * The flag is updated with i_data_sem held to prevent racing with
-         * block allocation.
+         * Even though we take i_mutex we can still cause block
+         * allocation via mmap write to holes. If we have allocated
+         * new blocks we fail migrate.  New block allocation will
+         * clear EXT4_STATE_EXT_MIGRATE flag.  The flag is updated
+         * with i_data_sem held to prevent racing with block
+         * allocation.
          */
         down_read((&EXT4_I(inode)->i_data_sem));
-        EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags | EXT4_EXT_MIGRATE;
+        EXT4_I(inode)->i_state |= EXT4_STATE_EXT_MIGRATE;
         up_read((&EXT4_I(inode)->i_data_sem));
 
         handle = ext4_journal_start(inode, 1);