ext4: rationalize ext4_extents.h inclusion

Previously, ext4_extents.h was being included at the end of ext4.h,
which was bad for a number of reasons: (a) it was not being included
in the expected place, and (b) it caused the header to be included
multiple times.  There were #ifdef's to prevent this from causing any
problems, but it still was unnecessary.

By moving the function declarations that were in ext4_extents.h to
ext4.h, which is standard practice for where the function declarations
for the rest of ext4.h can be found, we can remove ext4_extents.h from
being included in ext4.h at all, and then we can only include
ext4_extents.h where it is needed in ext4's source files.

It should be possible to move a few more things into ext4.h, and
further reduce the number of source files that need to #include
ext4_extents.h, but that's a cleanup for another day.
Reported-by: Sachin Kamat <sachin.kamat@linaro.org>
Reported-by: Wei Yongjun <weiyj.lk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/ext4.h

@@ -57,6 +57,16 @@
 #define ext4_debug(fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
 #endif
 
+/*
+ * Turn on EXT_DEBUG to get lots of info about extents operations.
+ */
+#define EXT_DEBUG__
+#ifdef EXT_DEBUG
+#define ext_debug(fmt, ...)	printk(fmt, ##__VA_ARGS__)
+#else
+#define ext_debug(fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
+#endif
+
 #define EXT4_ERROR_INODE(inode, fmt, a...) \
 	ext4_error_inode((inode), __func__, __LINE__, 0, (fmt), ## a)
 
@@ -2399,6 +2409,9 @@ extern int ext4_check_blockref(const char *, unsigned int,
 			       struct inode *, __le32 *, unsigned int);
 
 /* extents.c */
+struct ext4_ext_path;
+struct ext4_extent;
+
 extern int ext4_ext_tree_init(handle_t *handle, struct inode *);
 extern int ext4_ext_writepage_trans_blocks(struct inode *, int);
 extern int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks,
@@ -2416,8 +2429,27 @@ extern int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset,
 			  ssize_t len);
 extern int ext4_map_blocks(handle_t *handle, struct inode *inode,
 			   struct ext4_map_blocks *map, int flags);
+extern int ext4_ext_calc_metadata_amount(struct inode *inode,
+					 ext4_lblk_t lblocks);
+extern int ext4_extent_tree_init(handle_t *, struct inode *);
+extern int ext4_ext_calc_credits_for_single_extent(struct inode *inode,
+						   int num,
+						   struct ext4_ext_path *path);
+extern int ext4_can_extents_be_merged(struct inode *inode,
+				      struct ext4_extent *ex1,
+				      struct ext4_extent *ex2);
+extern int ext4_ext_insert_extent(handle_t *, struct inode *,
+				  struct ext4_ext_path *,
+				  struct ext4_extent *, int);
+extern struct ext4_ext_path *ext4_ext_find_extent(struct inode *, ext4_lblk_t,
+						  struct ext4_ext_path *);
+extern void ext4_ext_drop_refs(struct ext4_ext_path *);
+extern int ext4_ext_check_inode(struct inode *inode);
+extern int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk);
 extern int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 			__u64 start, __u64 len);
+
+
 /* move_extent.c */
 extern int ext4_move_extents(struct file *o_filp, struct file *d_filp,
 			     __u64 start_orig, __u64 start_donor,
@@ -2505,6 +2537,4 @@ extern void ext4_resize_end(struct super_block *sb);
 
 #endif	/* __KERNEL__ */
 
-#include "ext4_extents.h"
-
 #endif	/* _EXT4_H */

fs/ext4/ext4_extents.h

@@ -42,16 +42,6 @@
  */
 #define CHECK_BINSEARCH__
 
-/*
- * Turn on EXT_DEBUG to get lots of info about extents operations.
- */
-#define EXT_DEBUG__
-#ifdef EXT_DEBUG
-#define ext_debug(fmt, ...)	printk(fmt, ##__VA_ARGS__)
-#else
-#define ext_debug(fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
-#endif
-
 /*
  * If EXT_STATS is defined then stats numbers are collected.
  * These number will be displayed at umount time.
@@ -286,20 +276,5 @@ static inline void ext4_idx_store_pblock(struct ext4_extent_idx *ix,
 				     0xffff);
 }
 
-extern int ext4_ext_calc_metadata_amount(struct inode *inode,
-					 ext4_lblk_t lblocks);
-extern int ext4_extent_tree_init(handle_t *, struct inode *);
-extern int ext4_ext_calc_credits_for_single_extent(struct inode *inode,
-						   int num,
-						   struct ext4_ext_path *path);
-extern int ext4_can_extents_be_merged(struct inode *inode,
-				      struct ext4_extent *ex1,
-				      struct ext4_extent *ex2);
-extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *, int);
-extern struct ext4_ext_path *ext4_ext_find_extent(struct inode *, ext4_lblk_t,
-							struct ext4_ext_path *);
-extern void ext4_ext_drop_refs(struct ext4_ext_path *);
-extern int ext4_ext_check_inode(struct inode *inode);
-extern int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk);
 #endif /* _EXT4_EXTENTS */
 

fs/ext4/extents.c

@@ -41,6 +41,7 @@
 #include <asm/uaccess.h>
 #include <linux/fiemap.h>
 #include "ext4_jbd2.h"
+#include "ext4_extents.h"
 
 #include <trace/events/ext4.h>
 

fs/ext4/indirect.c

@@ -22,6 +22,7 @@
 
 #include "ext4_jbd2.h"
 #include "truncate.h"
+#include "ext4_extents.h"	/* Needed for EXT_MAX_BLOCKS */
 
 #include <trace/events/ext4.h>
 

fs/ext4/migrate.c

@@ -14,6 +14,7 @@
 
 #include <linux/slab.h>
 #include "ext4_jbd2.h"
+#include "ext4_extents.h"
 
 /*
  * The contiguous blocks details which can be

fs/ext4/move_extent.c

@@ -18,6 +18,7 @@
 #include <linux/slab.h>
 #include "ext4_jbd2.h"
 #include "ext4.h"
+#include "ext4_extents.h"
 
 /**
  * get_ext_path - Find an extent path for designated logical block number.

fs/ext4/page-io.c

@@ -27,7 +27,6 @@
 #include "ext4_jbd2.h"
 #include "xattr.h"
 #include "acl.h"
-#include "ext4_extents.h"
 
 static struct kmem_cache *io_page_cachep, *io_end_cachep;
 

fs/ext4/super.c

@@ -45,12 +45,11 @@
 #include <linux/freezer.h>
 
 #include "ext4.h"
-#include "ext4_extents.h"
+#include "ext4_extents.h"	/* Needed for trace points definition */
 #include "ext4_jbd2.h"
 #include "xattr.h"
 #include "acl.h"
 #include "mballoc.h"
-#include "ext4_extents.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/ext4.h>