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Subject[PATCH 4/7] ocfs2: slot_map I/O based on max_slots.
Date
The slot map code assumed a slot_map file has one block allocated.
This changes the code to I/O as many blocks as will cover max_slots.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
---
fs/ocfs2/slot_map.c | 128 +++++++++++++++++++++++++++++++++++++++++++--------
1 files changed, 108 insertions(+), 20 deletions(-)

diff --git a/fs/ocfs2/slot_map.c b/fs/ocfs2/slot_map.c
index 762360d..5bddee1 100644
--- a/fs/ocfs2/slot_map.c
+++ b/fs/ocfs2/slot_map.c
@@ -44,7 +44,8 @@

struct ocfs2_slot_info {
struct inode *si_inode;
- struct buffer_head *si_bh;
+ unsigned int si_blocks;
+ struct buffer_head **si_bh;
unsigned int si_num_slots;
unsigned int si_size;
s16 si_global_node_nums[OCFS2_MAX_SLOTS];
@@ -68,7 +69,7 @@ static void ocfs2_update_slot_info(struct ocfs2_slot_info *si)

/* we don't read the slot block here as ocfs2_super_lock
* should've made sure we have the most recent copy. */
- disk_info = (__le16 *) si->si_bh->b_data;
+ disk_info = (__le16 *) si->si_bh[0]->b_data;

for (i = 0; i < si->si_size; i++)
si->si_global_node_nums[i] = le16_to_cpu(disk_info[i]);
@@ -78,13 +79,23 @@ int ocfs2_refresh_slot_info(struct ocfs2_super *osb)
{
int ret;
struct ocfs2_slot_info *si = osb->slot_info;
- struct buffer_head *bh;

if (si == NULL)
return 0;

- bh = si->si_bh;
- ret = ocfs2_read_block(osb, bh->b_blocknr, &bh, 0, si->si_inode);
+ BUG_ON(si->si_blocks == 0);
+ BUG_ON(si->si_bh == NULL);
+
+ mlog(0, "Refreshing slot map, reading %u block(s)\n",
+ si->si_blocks);
+
+ /*
+ * We pass -1 as blocknr because we expect all of si->si_bh to
+ * be !NULL. Thus, ocfs2_read_blocks() will ignore blocknr. If
+ * this is not true, the read of -1 (UINT64_MAX) will fail.
+ */
+ ret = ocfs2_read_blocks(osb, -1, si->si_blocks, si->si_bh, 0,
+ si->si_inode);
if (ret == 0) {
spin_lock(&osb->osb_lock);
ocfs2_update_slot_info(si);
@@ -100,20 +111,42 @@ static int ocfs2_update_disk_slots(struct ocfs2_super *osb,
struct ocfs2_slot_info *si)
{
int status, i;
- __le16 *disk_info = (__le16 *) si->si_bh->b_data;
+ __le16 *disk_info = (__le16 *) si->si_bh[0]->b_data;

spin_lock(&osb->osb_lock);
for (i = 0; i < si->si_size; i++)
disk_info[i] = cpu_to_le16(si->si_global_node_nums[i]);
spin_unlock(&osb->osb_lock);

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

return status;
}

+/*
+ * Calculate how many bytes are needed by the slot map. Returns
+ * an error if the slot map file is too small.
+ */
+static int ocfs2_slot_map_physical_size(struct ocfs2_super *osb,
+ struct inode *inode,
+ unsigned long long *bytes)
+{
+ unsigned long long bytes_needed;
+
+ 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",
+ i_size_read(inode), bytes_needed);
+ return -ENOSPC;
+ }
+
+ *bytes = bytes_needed;
+ return 0;
+}
+
/* try to find global node in the slot info. Returns
* OCFS2_INVALID_SLOT if nothing is found. */
static s16 __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
@@ -188,13 +221,22 @@ int ocfs2_slot_to_node_num_locked(struct ocfs2_super *osb, int slot_num,

static void __ocfs2_free_slot_info(struct ocfs2_slot_info *si)
{
+ unsigned int i;
+
if (si == NULL)
return;

if (si->si_inode)
iput(si->si_inode);
- if (si->si_bh)
- brelse(si->si_bh);
+ if (si->si_bh) {
+ for (i = 0; i < si->si_blocks; i++) {
+ if (si->si_bh[i]) {
+ brelse(si->si_bh[i]);
+ si->si_bh[i] = NULL;
+ }
+ }
+ kfree(si->si_bh);
+ }

kfree(si);
}
@@ -225,12 +267,65 @@ int ocfs2_clear_slot(struct ocfs2_super *osb, s16 slot_num)
return ocfs2_update_disk_slots(osb, osb->slot_info);
}

+static int ocfs2_map_slot_buffers(struct ocfs2_super *osb,
+ struct ocfs2_slot_info *si)
+{
+ int status = 0;
+ u64 blkno;
+ unsigned long long blocks, bytes;
+ unsigned int i;
+ struct buffer_head *bh;
+
+ status = ocfs2_slot_map_physical_size(osb, si->si_inode, &bytes);
+ if (status)
+ goto bail;
+
+ blocks = ocfs2_blocks_for_bytes(si->si_inode->i_sb, bytes);
+ BUG_ON(blocks > UINT_MAX);
+ si->si_blocks = blocks;
+ if (!si->si_blocks)
+ goto bail;
+
+ mlog(0, "Slot map needs %u buffers for %llu bytes\n",
+ si->si_blocks, bytes);
+
+ si->si_bh = kzalloc(sizeof(struct buffer_head *) * si->si_blocks,
+ GFP_KERNEL);
+ if (!si->si_bh) {
+ status = -ENOMEM;
+ mlog_errno(status);
+ goto bail;
+ }
+
+ for (i = 0; i < si->si_blocks; i++) {
+ status = ocfs2_extent_map_get_blocks(si->si_inode, i,
+ &blkno, NULL, NULL);
+ if (status < 0) {
+ mlog_errno(status);
+ goto bail;
+ }
+
+ mlog(0, "Reading slot map block %u at %llu\n", i,
+ (unsigned long long)blkno);
+
+ bh = NULL; /* Acquire a fresh bh */
+ status = ocfs2_read_block(osb, blkno, &bh, 0, si->si_inode);
+ if (status < 0) {
+ mlog_errno(status);
+ goto bail;
+ }
+
+ si->si_bh[i] = bh;
+ }
+
+bail:
+ return status;
+}
+
int ocfs2_init_slot_info(struct ocfs2_super *osb)
{
int status, i;
- u64 blkno;
struct inode *inode = NULL;
- struct buffer_head *bh = NULL;
struct ocfs2_slot_info *si;

si = kzalloc(sizeof(struct ocfs2_slot_info), GFP_KERNEL);
@@ -254,20 +349,13 @@ int ocfs2_init_slot_info(struct ocfs2_super *osb)
goto bail;
}

- status = ocfs2_extent_map_get_blocks(inode, 0ULL, &blkno, NULL, NULL);
- if (status < 0) {
- mlog_errno(status);
- goto bail;
- }
-
- status = ocfs2_read_block(osb, blkno, &bh, 0, inode);
+ si->si_inode = inode;
+ status = ocfs2_map_slot_buffers(osb, si);
if (status < 0) {
mlog_errno(status);
goto bail;
}

- si->si_inode = inode;
- si->si_bh = bh;
osb->slot_info = (struct ocfs2_slot_info *)si;
bail:
if (status < 0 && si)
--
1.5.3.8


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