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: Joel Becker <joel.becker@xxxxxxxxxx>
---
fs/ocfs2/ocfs2.h | 7 +++
fs/ocfs2/ocfs2_fs.h | 31 +++++++++++++-
fs/ocfs2/slot_map.c | 110 +++++++++++++++++++++++++++++++++++++++++++++------
3 files changed, 133 insertions(+), 15 deletions(-)
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 95f783d..f78e9ed 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -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))
diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index 3299116..c495023 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -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
diff --git a/fs/ocfs2/slot_map.c b/fs/ocfs2/slot_map.c
index e7e7a74..63fb1b2 100644
--- a/fs/ocfs2/slot_map.c
+++ b/fs/ocfs2/slot_map.c
@@ -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;
- bytes_needed = osb->max_slots * sizeof(__le16);
+ 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;
--
1.5.3.8
--
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