ext4: Use bitops to read/modify EXT4_I(inode)->i_state

At several places we modify EXT4_I(inode)->i_state without holding
i_mutex (ext4_release_file, ext4_bmap, ext4_journalled_writepage,
ext4_do_update_inode, ...). These modifications are racy and we can
lose updates to i_state. So convert handling of i_state to use bitops
which are atomic.

Cc: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

7 files changed, 71 insertions, 51 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 307ecd13a762..ffe1334c891e 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -313,17 +313,6 @@ static inline __u32 ext4_mask_flags(umode_t mode, __u32 flags)
 		return flags & EXT4_OTHER_FLMASK;
 }
 
-/*
- * Inode dynamic state flags
- */
-#define EXT4_STATE_JDATA		0x00000001 /* journaled data exists */
-#define EXT4_STATE_NEW			0x00000002 /* inode is newly created */
-#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 */
-#define EXT4_STATE_DIO_UNWRITTEN	0x00000040 /* need convert on dio done*/
-
 /* Used to pass group descriptor data when online resize is done */
 struct ext4_new_group_input {
 	__u32 group;		/* Group number for this data */
@@ -631,7 +620,7 @@ struct ext4_inode_info {
 	 * near to their parent directory's inode.
 	 */
 	ext4_group_t	i_block_group;
-	__u32	i_state;		/* Dynamic state flags for ext4 */
+	unsigned long	i_state_flags;		/* Dynamic state flags */
 
 	ext4_lblk_t		i_dir_start_lookup;
 #ifdef CONFIG_EXT4_FS_XATTR
@@ -1051,6 +1040,34 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
 		(ino >= EXT4_FIRST_INO(sb) &&
 		 ino <= le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count));
 }
+
+/*
+ * Inode dynamic state flags
+ */
+enum {
+	EXT4_STATE_JDATA,		/* journaled data exists */
+	EXT4_STATE_NEW,			/* inode is newly created */
+	EXT4_STATE_XATTR,		/* has in-inode xattrs */
+	EXT4_STATE_NO_EXPAND,		/* No space for expansion */
+	EXT4_STATE_DA_ALLOC_CLOSE,	/* Alloc DA blks on close */
+	EXT4_STATE_EXT_MIGRATE,		/* Inode is migrating */
+	EXT4_STATE_DIO_UNWRITTEN,	/* need convert on dio done*/
+};
+
+static inline int ext4_test_inode_state(struct inode *inode, int bit)
+{
+	return test_bit(bit, &EXT4_I(inode)->i_state_flags);
+}
+
+static inline void ext4_set_inode_state(struct inode *inode, int bit)
+{
+	set_bit(bit, &EXT4_I(inode)->i_state_flags);
+}
+
+static inline void ext4_clear_inode_state(struct inode *inode, int bit)
+{
+	clear_bit(bit, &EXT4_I(inode)->i_state_flags);
+}
 #else
 /* Assume that user mode programs are passing in an ext4fs superblock, not
  * a kernel struct super_block.  This will allow us to call the feature-test
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index c56877972b0e..54616157c0f3 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3076,7 +3076,7 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
 		if (io)
 			io->flag = DIO_AIO_UNWRITTEN;
 		else
-			EXT4_I(inode)->i_state |= EXT4_STATE_DIO_UNWRITTEN;
+			ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
 		goto out;
 	}
 	/* async DIO end_io complete, convert the filled extent to written */
@@ -3362,8 +3362,8 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
 			if (io)
 				io->flag = DIO_AIO_UNWRITTEN;
 			else
-				EXT4_I(inode)->i_state |=
-					EXT4_STATE_DIO_UNWRITTEN;;
+				ext4_set_inode_state(inode,
+						     EXT4_STATE_DIO_UNWRITTEN);
 		}
 	}
 	err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
@@ -3739,7 +3739,7 @@ static int ext4_xattr_fiemap(struct inode *inode,
 	int error = 0;
 
 	/* in-inode? */
-	if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
+	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 		struct ext4_iloc iloc;
 		int offset;	/* offset of xattr in inode */
 
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 9630583cef28..f6071ce0b155 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -35,9 +35,9 @@
  */
 static int ext4_release_file(struct inode *inode, struct file *filp)
 {
-	if (EXT4_I(inode)->i_state & EXT4_STATE_DA_ALLOC_CLOSE) {
+	if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
 		ext4_alloc_da_blocks(inode);
-		EXT4_I(inode)->i_state &= ~EXT4_STATE_DA_ALLOC_CLOSE;
+		ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
 	}
 	/* if we are the last writer on the inode, drop the block reservation */
 	if ((filp->f_mode & FMODE_WRITE) &&
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index f3624ead4f6c..2fab5adae1e2 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -1029,7 +1029,8 @@ got:
 	inode->i_generation = sbi->s_next_generation++;
 	spin_unlock(&sbi->s_next_gen_lock);
 
-	ei->i_state = EXT4_STATE_NEW;
+	ei->i_state_flags = 0;
+	ext4_set_inode_state(inode, EXT4_STATE_NEW);
 
 	ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 1a3d7b232cd7..3e530119d7f0 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1307,7 +1307,7 @@ 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_state &= ~EXT4_STATE_EXT_MIGRATE;
+			ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
 		}
 
 		/*
@@ -1794,7 +1794,7 @@ static int ext4_journalled_write_end(struct file *file,
 	new_i_size = pos + copied;
 	if (new_i_size > inode->i_size)
 		i_size_write(inode, pos+copied);
-	EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
+	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
 	if (new_i_size > EXT4_I(inode)->i_disksize) {
 		ext4_update_i_disksize(inode, new_i_size);
 		ret2 = ext4_mark_inode_dirty(handle, inode);
@@ -2632,7 +2632,7 @@ static int __ext4_journalled_writepage(struct page *page,
 		ret = err;
 
 	walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one);
-	EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
+	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
 out:
 	return ret;
 }
@@ -3303,7 +3303,8 @@ static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
 		filemap_write_and_wait(mapping);
 	}
 
-	if (EXT4_JOURNAL(inode) && EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
+	if (EXT4_JOURNAL(inode) &&
+	    ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
 		/*
 		 * This is a REALLY heavyweight approach, but the use of
 		 * bmap on dirty files is expected to be extremely rare:
@@ -3322,7 +3323,7 @@ static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
 		 * everything they get.
 		 */
 
-		EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA;
+		ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
 		journal = EXT4_JOURNAL(inode);
 		jbd2_journal_lock_updates(journal);
 		err = jbd2_journal_flush(journal);
@@ -3790,8 +3791,8 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 		if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) {
 			ext4_free_io_end(iocb->private);
 			iocb->private = NULL;
-		} else if (ret > 0 && (EXT4_I(inode)->i_state &
-				       EXT4_STATE_DIO_UNWRITTEN)) {
+		} else if (ret > 0 && ext4_test_inode_state(inode,
+						EXT4_STATE_DIO_UNWRITTEN)) {
 			int err;
 			/*
 			 * for non AIO case, since the IO is already
@@ -3801,7 +3802,7 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 							     offset, ret);
 			if (err < 0)
 				ret = err;
-			EXT4_I(inode)->i_state &= ~EXT4_STATE_DIO_UNWRITTEN;
+			ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
 		}
 		return ret;
 	}
@@ -4457,7 +4458,7 @@ void ext4_truncate(struct inode *inode)
 		return;
 
 	if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
-		ei->i_state |= EXT4_STATE_DA_ALLOC_CLOSE;
+		ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
 
 	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
 		ext4_ext_truncate(inode);
@@ -4743,7 +4744,7 @@ int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
 {
 	/* We have all inode data except xattrs in memory here. */
 	return __ext4_get_inode_loc(inode, iloc,
-		!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR));
+		!ext4_test_inode_state(inode, EXT4_STATE_XATTR));
 }
 
 void ext4_set_inode_flags(struct inode *inode)
@@ -4837,7 +4838,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 	}
 	inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
 
-	ei->i_state = 0;
+	ei->i_state_flags = 0;
 	ei->i_dir_start_lookup = 0;
 	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
 	/* We now have enough fields to check if the inode was active or not.
@@ -4920,7 +4921,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 					EXT4_GOOD_OLD_INODE_SIZE +
 					ei->i_extra_isize;
 			if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
-				ei->i_state |= EXT4_STATE_XATTR;
+				ext4_set_inode_state(inode, EXT4_STATE_XATTR);
 		}
 	} else
 		ei->i_extra_isize = 0;
@@ -5060,7 +5061,7 @@ static int ext4_do_update_inode(handle_t *handle,
 
 	/* For fields not not tracking in the in-memory inode,
 	 * initialise them to zero for new inodes. */
-	if (ei->i_state & EXT4_STATE_NEW)
+	if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
 		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
 
 	ext4_get_inode_flags(ei);
@@ -5156,7 +5157,7 @@ static int ext4_do_update_inode(handle_t *handle,
 	rc = ext4_handle_dirty_metadata(handle, inode, bh);
 	if (!err)
 		err = rc;
-	ei->i_state &= ~EXT4_STATE_NEW;
+	ext4_clear_inode_state(inode, EXT4_STATE_NEW);
 
 	ext4_update_inode_fsync_trans(handle, inode, 0);
 out_brelse:
@@ -5580,8 +5581,8 @@ static int ext4_expand_extra_isize(struct inode *inode,
 	entry = IFIRST(header);
 
 	/* No extended attributes present */
-	if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR) ||
-		header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
+	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
+	    header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
 		memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
 			new_extra_isize);
 		EXT4_I(inode)->i_extra_isize = new_extra_isize;
@@ -5625,7 +5626,7 @@ int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
 	err = ext4_reserve_inode_write(handle, inode, &iloc);
 	if (ext4_handle_valid(handle) &&
 	    EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
-	    !(EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND)) {
+	    !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
 		/*
 		 * We need extra buffer credits since we may write into EA block
 		 * with this same handle. If journal_extend fails, then it will
@@ -5639,7 +5640,8 @@ int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
 						      sbi->s_want_extra_isize,
 						      iloc, handle);
 			if (ret) {
-				EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
+				ext4_set_inode_state(inode,
+						     EXT4_STATE_NO_EXPAND);
 				if (mnt_count !=
 					le16_to_cpu(sbi->s_es->s_mnt_count)) {
 					ext4_warning(inode->i_sb, __func__,
diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
index 81415814b00b..46a4101e0aec 100644
--- a/fs/ext4/migrate.c
+++ b/fs/ext4/migrate.c
@@ -365,12 +365,12 @@ static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
 	 * happened after we started the migrate. We need to
 	 * fail the migrate
 	 */
-	if (!(EXT4_I(inode)->i_state & EXT4_STATE_EXT_MIGRATE)) {
+	if (!ext4_test_inode_state(inode, EXT4_STATE_EXT_MIGRATE)) {
 		retval = -EAGAIN;
 		up_write(&EXT4_I(inode)->i_data_sem);
 		goto err_out;
 	} else
-		EXT4_I(inode)->i_state &= ~EXT4_STATE_EXT_MIGRATE;
+		ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
 	/*
 	 * We have the extent map build with the tmp inode.
 	 * Now copy the i_data across
@@ -533,7 +533,7 @@ int ext4_ext_migrate(struct inode *inode)
 	 * allocation.
 	 */
 	down_read((&EXT4_I(inode)->i_data_sem));
-	EXT4_I(inode)->i_state |= EXT4_STATE_EXT_MIGRATE;
+	ext4_set_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
 	up_read((&EXT4_I(inode)->i_data_sem));
 
 	handle = ext4_journal_start(inode, 1);
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index f3a2f7ed45aa..c619a7ea670d 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -267,7 +267,7 @@ ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 	void *end;
 	int error;
 
-	if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
+	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 		return -ENODATA;
 	error = ext4_get_inode_loc(inode, &iloc);
 	if (error)
@@ -396,7 +396,7 @@ ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 	void *end;
 	int error;
 
-	if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
+	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 		return 0;
 	error = ext4_get_inode_loc(inode, &iloc);
 	if (error)
@@ -908,7 +908,7 @@ ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 	is->s.base = is->s.first = IFIRST(header);
 	is->s.here = is->s.first;
 	is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
-	if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
+	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 		error = ext4_xattr_check_names(IFIRST(header), is->s.end);
 		if (error)
 			return error;
@@ -940,10 +940,10 @@ ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
 	header = IHDR(inode, ext4_raw_inode(&is->iloc));
 	if (!IS_LAST_ENTRY(s->first)) {
 		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
-		EXT4_I(inode)->i_state |= EXT4_STATE_XATTR;
+		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
 	} else {
 		header->h_magic = cpu_to_le32(0);
-		EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR;
+		ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
 	}
 	return 0;
 }
@@ -986,8 +986,8 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 	if (strlen(name) > 255)
 		return -ERANGE;
 	down_write(&EXT4_I(inode)->xattr_sem);
-	no_expand = EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND;
-	EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
+	no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
+	ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
 
 	error = ext4_get_inode_loc(inode, &is.iloc);
 	if (error)
@@ -997,10 +997,10 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 	if (error)
 		goto cleanup;
 
-	if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) {
+	if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
 		struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
 		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
-		EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW;
+		ext4_clear_inode_state(inode, EXT4_STATE_NEW);
 	}
 
 	error = ext4_xattr_ibody_find(inode, &i, &is);
@@ -1052,7 +1052,7 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 		ext4_xattr_update_super_block(handle, inode->i_sb);
 		inode->i_ctime = ext4_current_time(inode);
 		if (!value)
-			EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
+			ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
 		error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
 		/*
 		 * The bh is consumed by ext4_mark_iloc_dirty, even with
@@ -1067,7 +1067,7 @@ cleanup:
 	brelse(is.iloc.bh);
 	brelse(bs.bh);
 	if (no_expand == 0)
-		EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
+		ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
 	up_write(&EXT4_I(inode)->xattr_sem);
 	return error;
 }