Commit c6d38301 authored by Joern Engel's avatar Joern Engel
Browse files

[LogFS] Only write journal if dirty 

This prevents unnecessary journal writes.  More importantly it prevents
an oops due to a journal write on failed mount.
parent 9421502b

fs/logfs/gc.c

+3 −3
Original line number Diff line number Diff line
@@ -469,7 +469,7 @@ static void __logfs_gc_pass(struct super_block *sb, int target) 


		/* Sync in-memory state with on-medium state in case they

		 * diverged */

		logfs_write_anchor(super->s_master_inode);

		logfs_write_anchor(sb);

		round += logfs_scan_some(sb);

		if (no_free_segments(sb) >= target)

			goto write_alias;
@@ -613,8 +613,8 @@ void logfs_gc_pass(struct super_block *sb) 
	 */

	if (super->s_dirty_used_bytes + super->s_dirty_free_bytes

			+ LOGFS_MAX_OBJECTSIZE >= super->s_free_bytes)

		logfs_write_anchor(super->s_master_inode);

	__logfs_gc_pass(sb, logfs_super(sb)->s_total_levels);

		logfs_write_anchor(sb);

	__logfs_gc_pass(sb, super->s_total_levels);

	logfs_wl_pass(sb);

	logfs_journal_wl_pass(sb);

}

fs/logfs/journal.c

+7 −4
Original line number Diff line number Diff line
@@ -724,14 +724,17 @@ static int logfs_write_obj_aliases(struct super_block *sb) 
 * bit wasteful, but robustness is more important.  With this we can *always*

 * erase all journal segments except the one containing the most recent commit.

 */

void logfs_write_anchor(struct inode *inode)

void logfs_write_anchor(struct super_block *sb)

{

	struct super_block *sb = inode->i_sb;

	struct logfs_super *super = logfs_super(sb);

	struct logfs_area *area = super->s_journal_area;

	int i, err;



	BUG_ON(logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN);

	if (!(super->s_flags & LOGFS_SB_FLAG_DIRTY))

		return;

	super->s_flags &= ~LOGFS_SB_FLAG_DIRTY;



	BUG_ON(super->s_flags & LOGFS_SB_FLAG_SHUTDOWN);

	mutex_lock(&super->s_journal_mutex);



	/* Do this first or suffer corruption */
@@ -821,7 +824,7 @@ void do_logfs_journal_wl_pass(struct super_block *sb) 
	area->a_is_open = 0;

	area->a_used_bytes = 0;

	/* Write journal */

	logfs_write_anchor(super->s_master_inode);

	logfs_write_anchor(sb);

	/* Write superblocks */

	err = logfs_write_sb(sb);

	BUG_ON(err);

fs/logfs/logfs.h

+2 −2
Original line number Diff line number Diff line
@@ -82,7 +82,7 @@ 


/* Read-only filesystem */

#define LOGFS_SB_FLAG_RO	0x0001

#define LOGFS_SB_FLAG_SEG_ALIAS	0x0002

#define LOGFS_SB_FLAG_DIRTY	0x0002

#define LOGFS_SB_FLAG_OBJ_ALIAS	0x0004

#define LOGFS_SB_FLAG_SHUTDOWN	0x0008
@@ -526,7 +526,7 @@ void logfs_delete_inode(struct inode *inode); 
void logfs_clear_inode(struct inode *inode);



/* journal.c */

void logfs_write_anchor(struct inode *inode);

void logfs_write_anchor(struct super_block *sb);

int logfs_init_journal(struct super_block *sb);

void logfs_cleanup_journal(struct super_block *sb);

int write_alias_journal(struct super_block *sb, u64 ino, u64 bix,

fs/logfs/readwrite.c

+1 −1
Original line number Diff line number Diff line
@@ -421,7 +421,7 @@ static void inode_write_block(struct logfs_block *block) 


	inode = block->inode;

	if (inode->i_ino == LOGFS_INO_MASTER)

		logfs_write_anchor(inode);

		logfs_write_anchor(inode->i_sb);

	else {

		ret = __logfs_write_inode(inode, 0);

		/* see indirect_write_block comment */

fs/logfs/segment.c

+5 −2
Original line number Diff line number Diff line
@@ -352,7 +352,8 @@ int logfs_segment_write(struct inode *inode, struct page *page, 
	int ret;

	void *buf;



	BUG_ON(logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN);

	super->s_flags |= LOGFS_SB_FLAG_DIRTY;

	BUG_ON(super->s_flags & LOGFS_SB_FLAG_SHUTDOWN);

	do_compress = logfs_inode(inode)->li_flags & LOGFS_IF_COMPRESSED;

	if (shadow->gc_level != 0) {

		/* temporarily disable compression for indirect blocks */
@@ -653,11 +654,13 @@ int logfs_segment_read(struct inode *inode, struct page *page, 
int logfs_segment_delete(struct inode *inode, struct logfs_shadow *shadow)

{

	struct super_block *sb = inode->i_sb;

	struct logfs_super *super = logfs_super(sb);

	struct logfs_object_header h;

	u16 len;

	int err;



	BUG_ON(logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN);

	super->s_flags |= LOGFS_SB_FLAG_DIRTY;

	BUG_ON(super->s_flags & LOGFS_SB_FLAG_SHUTDOWN);

	BUG_ON(shadow->old_ofs & LOGFS_FULLY_POPULATED);

	if (!shadow->old_ofs)

		return 0;