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Commit 386a2ef8 authored by Joel Becker's avatar Joel Becker Committed by Mark Fasheh
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ocfs2: New slot map format 



The old slot map had a few limitations:

- It was limited to one block, so the maximum slot count was 255.
- Each slot was signed 16bits, limiting node numbers to INT16_MAX.
- An empty slot was marked by the magic 0xFFFF (-1).

The new slot map format provides 32bit node numbers (UINT32_MAX), a
separate space to mark a slot in use, and extra room to grow.  The slot
map is now bounded by i_size, not a block.

Signed-off-by: default avatarJoel Becker <joel.becker@oracle.com>
Signed-off-by: default avatarMark Fasheh <mfasheh@suse.com>
parent fb86b1f0

fs/ocfs2/ocfs2.h

+7 −0
Original line number Diff line number Diff line
@@ -374,6 +374,13 @@ static inline int ocfs2_mount_local(struct ocfs2_super *osb) 
	return (osb->s_feature_incompat & OCFS2_FEATURE_INCOMPAT_LOCAL_MOUNT);

}



static inline int ocfs2_uses_extended_slot_map(struct ocfs2_super *osb)

{

	return (osb->s_feature_incompat &

		OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP);

}





#define OCFS2_IS_VALID_DINODE(ptr)					\

	(!strcmp((ptr)->i_signature, OCFS2_INODE_SIGNATURE))

fs/ocfs2/ocfs2_fs.h

+29 −2
Original line number Diff line number Diff line
@@ -88,7 +88,8 @@ 
#define OCFS2_FEATURE_COMPAT_SUPP	OCFS2_FEATURE_COMPAT_BACKUP_SB

#define OCFS2_FEATURE_INCOMPAT_SUPP	(OCFS2_FEATURE_INCOMPAT_LOCAL_MOUNT \

					 | OCFS2_FEATURE_INCOMPAT_SPARSE_ALLOC \

					 | OCFS2_FEATURE_INCOMPAT_INLINE_DATA)

					 | OCFS2_FEATURE_INCOMPAT_INLINE_DATA \

					 | OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP)

#define OCFS2_FEATURE_RO_COMPAT_SUPP	OCFS2_FEATURE_RO_COMPAT_UNWRITTEN



/*
@@ -125,6 +126,10 @@ 
/* Support for data packed into inode blocks */

#define OCFS2_FEATURE_INCOMPAT_INLINE_DATA	0x0040



/* Support for the extended slot map */

#define OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP 0x100





/*

 * backup superblock flag is used to indicate that this volume

 * has backup superblocks.
@@ -476,7 +481,8 @@ struct ocfs2_extent_block 


/*

 * On disk slot map for OCFS2.  This defines the contents of the "slot_map"

 * system file.

 * system file.  A slot is valid if it contains a node number >= 0.  The

 * value -1 (0xFFFF) is OCFS2_INVALID_SLOT.  This marks a slot empty.

 */

struct ocfs2_slot_map {

/*00*/	__le16 sm_slots[0];
@@ -486,6 +492,27 @@ struct ocfs2_slot_map { 
 */

};



struct ocfs2_extended_slot {

/*00*/	__u8	es_valid;

	__u8	es_reserved1[3];

	__le32	es_node_num;

/*10*/

};



/*

 * The extended slot map, used when OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP

 * is set.  It separates out the valid marker from the node number, and

 * has room to grow.  Unlike the old slot map, this format is defined by

 * i_size.

 */

struct ocfs2_slot_map_extended {

/*00*/	struct ocfs2_extended_slot se_slots[0];

/*

 * Actual size is i_size of the slot_map system file.  It should

 * match s_max_slots * sizeof(struct ocfs2_extended_slot)

 */

};



/*

 * On disk superblock for OCFS2

 * Note that it is contained inside an ocfs2_dinode, so all offsets

fs/ocfs2/slot_map.c

+97 −13
Original line number Diff line number Diff line
@@ -49,6 +49,8 @@ struct ocfs2_slot { 
};



struct ocfs2_slot_info {

	int si_extended;

	int si_slots_per_block;

	struct inode *si_inode;

	unsigned int si_blocks;

	struct buffer_head **si_bh;
@@ -78,17 +80,37 @@ static void ocfs2_set_slot(struct ocfs2_slot_info *si, 
	si->si_slots[slot_num].sl_node_num = node_num;

}



/* This version is for the extended slot map */

static void ocfs2_update_slot_info_extended(struct ocfs2_slot_info *si)

{

	int b, i, slotno;

	struct ocfs2_slot_map_extended *se;



	slotno = 0;

	for (b = 0; b < si->si_blocks; b++) {

		se = (struct ocfs2_slot_map_extended *)si->si_bh[b]->b_data;

		for (i = 0;

		     (i < si->si_slots_per_block) &&

		     (slotno < si->si_num_slots);

		     i++, slotno++) {

			if (se->se_slots[i].es_valid)

				ocfs2_set_slot(si, slotno,

					       le32_to_cpu(se->se_slots[i].es_node_num));

			else

				ocfs2_invalidate_slot(si, slotno);

		}

	}

}



/*

 * Post the slot information on disk into our slot_info struct.

 * Must be protected by osb_lock.

 */

static void ocfs2_update_slot_info(struct ocfs2_slot_info *si)

static void ocfs2_update_slot_info_old(struct ocfs2_slot_info *si)

{

	int i;

	struct ocfs2_slot_map *sm;



	/* we don't read the slot block here as ocfs2_super_lock

	 * should've made sure we have the most recent copy. */

	sm = (struct ocfs2_slot_map *)si->si_bh[0]->b_data;



	for (i = 0; i < si->si_num_slots; i++) {
@@ -99,6 +121,18 @@ static void ocfs2_update_slot_info(struct ocfs2_slot_info *si) 
	}

}



static void ocfs2_update_slot_info(struct ocfs2_slot_info *si)

{

	/*

	 * The slot data will have been refreshed when ocfs2_super_lock

	 * was taken.

	 */

	if (si->si_extended)

		ocfs2_update_slot_info_extended(si);

	else

		ocfs2_update_slot_info_old(si);

}



int ocfs2_refresh_slot_info(struct ocfs2_super *osb)

{

	int ret;
@@ -131,13 +165,31 @@ int ocfs2_refresh_slot_info(struct ocfs2_super *osb) 


/* post the our slot info stuff into it's destination bh and write it

 * out. */

static int ocfs2_update_disk_slots(struct ocfs2_super *osb,

				   struct ocfs2_slot_info *si)

static void ocfs2_update_disk_slot_extended(struct ocfs2_slot_info *si,

					    int slot_num,

					    struct buffer_head **bh)

{

	int blkind = slot_num / si->si_slots_per_block;

	int slotno = slot_num % si->si_slots_per_block;

	struct ocfs2_slot_map_extended *se;



	BUG_ON(blkind >= si->si_blocks);



	se = (struct ocfs2_slot_map_extended *)si->si_bh[blkind]->b_data;

	se->se_slots[slotno].es_valid = si->si_slots[slot_num].sl_valid;

	if (si->si_slots[slot_num].sl_valid)

		se->se_slots[slotno].es_node_num =

			cpu_to_le32(si->si_slots[slot_num].sl_node_num);

	*bh = si->si_bh[blkind];

}



static void ocfs2_update_disk_slot_old(struct ocfs2_slot_info *si,

				       int slot_num,

				       struct buffer_head **bh)

{

	int status, i;

	int i;

	struct ocfs2_slot_map *sm;



	spin_lock(&osb->osb_lock);

	sm = (struct ocfs2_slot_map *)si->si_bh[0]->b_data;

	for (i = 0; i < si->si_num_slots; i++) {

		if (si->si_slots[i].sl_valid)
@@ -146,9 +198,24 @@ static int ocfs2_update_disk_slots(struct ocfs2_super *osb, 
		else

			sm->sm_slots[i] = cpu_to_le16(OCFS2_INVALID_SLOT);

	}

	*bh = si->si_bh[0];

}



static int ocfs2_update_disk_slot(struct ocfs2_super *osb,

				  struct ocfs2_slot_info *si,

				  int slot_num)

{

	int status;

	struct buffer_head *bh;



	spin_lock(&osb->osb_lock);

	if (si->si_extended)

		ocfs2_update_disk_slot_extended(si, slot_num, &bh);

	else

		ocfs2_update_disk_slot_old(si, slot_num, &bh);

	spin_unlock(&osb->osb_lock);



	status = ocfs2_write_block(osb, si->si_bh[0], si->si_inode);

	status = ocfs2_write_block(osb, bh, si->si_inode);

	if (status < 0)

		mlog_errno(status);
@@ -165,7 +232,12 @@ static int ocfs2_slot_map_physical_size(struct ocfs2_super *osb, 
{

	unsigned long long bytes_needed;



	if (ocfs2_uses_extended_slot_map(osb)) {

		bytes_needed = osb->max_slots *

			sizeof(struct ocfs2_extended_slot);

	} else {

		bytes_needed = osb->max_slots * sizeof(__le16);

	}

	if (bytes_needed > i_size_read(inode)) {

		mlog(ML_ERROR,

		     "Slot map file is too small!  (size %llu, needed %llu)\n",
@@ -279,7 +351,7 @@ int ocfs2_clear_slot(struct ocfs2_super *osb, int slot_num) 
	ocfs2_invalidate_slot(si, slot_num);

	spin_unlock(&osb->osb_lock);



	return ocfs2_update_disk_slots(osb, osb->slot_info);

	return ocfs2_update_disk_slot(osb, osb->slot_info, slot_num);

}



static int ocfs2_map_slot_buffers(struct ocfs2_super *osb,
@@ -301,6 +373,16 @@ static int ocfs2_map_slot_buffers(struct ocfs2_super *osb, 
	if (!si->si_blocks)

		goto bail;



	if (si->si_extended)

		si->si_slots_per_block =

			(osb->sb->s_blocksize /

			 sizeof(struct ocfs2_extended_slot));

	else

		si->si_slots_per_block = osb->sb->s_blocksize / sizeof(__le16);



	/* The size checks above should ensure this */

	BUG_ON((osb->max_slots / si->si_slots_per_block) > blocks);



	mlog(0, "Slot map needs %u buffers for %llu bytes\n",

	     si->si_blocks, bytes);
@@ -352,6 +434,7 @@ int ocfs2_init_slot_info(struct ocfs2_super *osb) 
		goto bail;

	}



	si->si_extended = ocfs2_uses_extended_slot_map(osb);

	si->si_num_slots = osb->max_slots;

	si->si_slots = (struct ocfs2_slot *)((char *)si +

					     sizeof(struct ocfs2_slot_info));
@@ -425,7 +508,7 @@ int ocfs2_find_slot(struct ocfs2_super *osb) 


	mlog(0, "taking node slot %d\n", osb->slot_num);



	status = ocfs2_update_disk_slots(osb, si);

	status = ocfs2_update_disk_slot(osb, si, osb->slot_num);

	if (status < 0)

		mlog_errno(status);
@@ -436,7 +519,7 @@ bail: 


void ocfs2_put_slot(struct ocfs2_super *osb)

{

	int status;

	int status, slot_num;

	struct ocfs2_slot_info *si = osb->slot_info;



	if (!si)
@@ -445,11 +528,12 @@ void ocfs2_put_slot(struct ocfs2_super *osb) 
	spin_lock(&osb->osb_lock);

	ocfs2_update_slot_info(si);



	slot_num = osb->slot_num;

	ocfs2_invalidate_slot(si, osb->slot_num);

	osb->slot_num = OCFS2_INVALID_SLOT;

	spin_unlock(&osb->osb_lock);



	status = ocfs2_update_disk_slots(osb, si);

	status = ocfs2_update_disk_slot(osb, si, slot_num);

	if (status < 0) {

		mlog_errno(status);

		goto bail;