[PATCH] ext3: online resizing

The patch below adds online resize capability to ext3 based on Andreas
patch for 2.4 and fixed up by Stephen.

The patch also removes s_debts:

s_debts is currently not used by ext3 (it is created, destroyed and checked
but never set).  Remove it for now.

Resurrecting this will require adding it back in changed form.  In existing
form it's already unsafe wrt.  byte-tearing as it performs unlocked byte
increment/decrement on words which may be being accessed simultaneously on
other CPUs.  It is also the only in-memory dynamic table which needs to be
extended by online-resize, so locking it will require care.


Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 43 insertions, 3 deletions

diff --git a/include/linux/ext3_fs.h b/include/linux/ext3_fs.h
index d8063d133646..d44abc7bd33a 100644
--- a/include/linux/ext3_fs.h
+++ b/include/linux/ext3_fs.h
@@ -196,6 +196,31 @@ struct ext3_group_desc
 #define EXT3_STATE_JDATA		0x00000001 /* journaled data exists */
 #define EXT3_STATE_NEW			0x00000002 /* inode is newly created */
 
+
+/* Used to pass group descriptor data when online resize is done */
+struct ext3_new_group_input {
+	__u32 group;            /* Group number for this data */
+	__u32 block_bitmap;     /* Absolute block number of block bitmap */
+	__u32 inode_bitmap;     /* Absolute block number of inode bitmap */
+	__u32 inode_table;      /* Absolute block number of inode table start */
+	__u32 blocks_count;     /* Total number of blocks in this group */
+	__u16 reserved_blocks;  /* Number of reserved blocks in this group */
+	__u16 unused;
+};
+
+/* The struct ext3_new_group_input in kernel space, with free_blocks_count */
+struct ext3_new_group_data {
+	__u32 group;
+	__u32 block_bitmap;
+	__u32 inode_bitmap;
+	__u32 inode_table;
+	__u32 blocks_count;
+	__u16 reserved_blocks;
+	__u16 unused;
+	__u32 free_blocks_count;
+};
+
+
 /*
  * ioctl commands
  */
@@ -203,6 +228,8 @@ struct ext3_group_desc
 #define	EXT3_IOC_SETFLAGS		_IOW('f', 2, long)
 #define	EXT3_IOC_GETVERSION		_IOR('f', 3, long)
 #define	EXT3_IOC_SETVERSION		_IOW('f', 4, long)
+#define EXT3_IOC_GROUP_EXTEND		_IOW('f', 7, unsigned long)
+#define EXT3_IOC_GROUP_ADD		_IOW('f', 8,struct ext3_new_group_input)
 #define	EXT3_IOC_GETVERSION_OLD		_IOR('v', 1, long)
 #define	EXT3_IOC_SETVERSION_OLD		_IOW('v', 2, long)
 #ifdef CONFIG_JBD_DEBUG
@@ -421,7 +448,7 @@ struct ext3_super_block {
 	 */
 	__u8	s_prealloc_blocks;	/* Nr of blocks to try to preallocate*/
 	__u8	s_prealloc_dir_blocks;	/* Nr to preallocate for dirs */
-	__u16	s_padding1;
+	__u16	s_reserved_gdt_blocks;	/* Per group desc for online growth */
 	/*
 	 * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
 	 */
@@ -687,6 +714,8 @@ extern unsigned long ext3_bg_num_gdb(struct super_block *sb, int group);
 extern int ext3_new_block (handle_t *, struct inode *, unsigned long, int *);
 extern void ext3_free_blocks (handle_t *, struct inode *, unsigned long,
 			      unsigned long);
+extern void ext3_free_blocks_sb (handle_t *, struct super_block *,
+				 unsigned long, unsigned long, int *);
 extern unsigned long ext3_count_free_blocks (struct super_block *);
 extern void ext3_check_blocks_bitmap (struct super_block *);
 extern struct ext3_group_desc * ext3_get_group_desc(struct super_block * sb,
@@ -749,6 +778,13 @@ extern int ext3_orphan_del(handle_t *, struct inode *);
 extern int ext3_htree_fill_tree(struct file *dir_file, __u32 start_hash,
 				__u32 start_minor_hash, __u32 *next_hash);
 
+/* resize.c */
+extern int ext3_group_add(struct super_block *sb,
+				struct ext3_new_group_data *input);
+extern int ext3_group_extend(struct super_block *sb,
+				struct ext3_super_block *es,
+				unsigned long n_blocks_count);
+
 /* super.c */
 extern void ext3_error (struct super_block *, const char *, const char *, ...)
 	__attribute__ ((format (printf, 3, 4)));
diff --git a/include/linux/ext3_fs_sb.h b/include/linux/ext3_fs_sb.h
index 8dde72f32851..ac5fb22c5b7c 100644
--- a/include/linux/ext3_fs_sb.h
+++ b/include/linux/ext3_fs_sb.h
@@ -54,7 +54,6 @@ struct ext3_sb_info {
 	u32 s_next_generation;
 	u32 s_hash_seed[4];
 	int s_def_hash_version;
-        u8 *s_debts;
 	struct percpu_counter s_freeblocks_counter;
 	struct percpu_counter s_freeinodes_counter;
 	struct percpu_counter s_dirs_counter;
diff --git a/include/linux/ext3_jbd.h b/include/linux/ext3_jbd.h
index 7f8ebe737856..6fb856859b69 100644
--- a/include/linux/ext3_jbd.h
+++ b/include/linux/ext3_jbd.h
@@ -188,9 +188,14 @@ __ext3_journal_dirty_metadata(const char *where,
 #define ext3_journal_dirty_metadata(handle, bh) \
 	__ext3_journal_dirty_metadata(__FUNCTION__, (handle), (bh))
 
-handle_t *ext3_journal_start(struct inode *inode, int nblocks);
+handle_t *ext3_journal_start_sb(struct super_block *sb, int nblocks);
 int __ext3_journal_stop(const char *where, handle_t *handle);
 
+static inline handle_t *ext3_journal_start(struct inode *inode, int nblocks)
+{
+	return ext3_journal_start_sb(inode->i_sb, nblocks);
+}
+
 #define ext3_journal_stop(handle) \
 	__ext3_journal_stop(__FUNCTION__, (handle))