Btrfs: wait on ordered extents at the last possible moment
Since we don't actually copy the extent information from the source tree in
the fast case we don't need to wait for ordered io to be completed in order
to fsync, we just need to wait for the io to be completed. So when we're
logging our file just attach all of the ordered extents to the log, and then
when the log syncs just wait for IO_DONE on the ordered extents and then
write the super. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 9027bb1..7de720d 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2281,6 +2281,7 @@
unsigned long log_transid = 0;
mutex_lock(&root->log_mutex);
+ log_transid = root->log_transid;
index1 = root->log_transid % 2;
if (atomic_read(&root->log_commit[index1])) {
wait_log_commit(trans, root, root->log_transid);
@@ -2308,11 +2309,11 @@
/* bail out if we need to do a full commit */
if (root->fs_info->last_trans_log_full_commit == trans->transid) {
ret = -EAGAIN;
+ btrfs_free_logged_extents(log, log_transid);
mutex_unlock(&root->log_mutex);
goto out;
}
- log_transid = root->log_transid;
if (log_transid % 2 == 0)
mark = EXTENT_DIRTY;
else
@@ -2324,6 +2325,7 @@
ret = btrfs_write_marked_extents(log, &log->dirty_log_pages, mark);
if (ret) {
btrfs_abort_transaction(trans, root, ret);
+ btrfs_free_logged_extents(log, log_transid);
mutex_unlock(&root->log_mutex);
goto out;
}
@@ -2363,6 +2365,7 @@
}
root->fs_info->last_trans_log_full_commit = trans->transid;
btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
+ btrfs_free_logged_extents(log, log_transid);
mutex_unlock(&log_root_tree->log_mutex);
ret = -EAGAIN;
goto out;
@@ -2373,6 +2376,7 @@
btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
wait_log_commit(trans, log_root_tree,
log_root_tree->log_transid);
+ btrfs_free_logged_extents(log, log_transid);
mutex_unlock(&log_root_tree->log_mutex);
ret = 0;
goto out;
@@ -2392,6 +2396,7 @@
*/
if (root->fs_info->last_trans_log_full_commit == trans->transid) {
btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
+ btrfs_free_logged_extents(log, log_transid);
mutex_unlock(&log_root_tree->log_mutex);
ret = -EAGAIN;
goto out_wake_log_root;
@@ -2402,10 +2407,12 @@
EXTENT_DIRTY | EXTENT_NEW);
if (ret) {
btrfs_abort_transaction(trans, root, ret);
+ btrfs_free_logged_extents(log, log_transid);
mutex_unlock(&log_root_tree->log_mutex);
goto out_wake_log_root;
}
btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
+ btrfs_wait_logged_extents(log, log_transid);
btrfs_set_super_log_root(root->fs_info->super_for_commit,
log_root_tree->node->start);
@@ -2475,6 +2482,14 @@
EXTENT_DIRTY | EXTENT_NEW, GFP_NOFS);
}
+ /*
+ * We may have short-circuited the log tree with the full commit logic
+ * and left ordered extents on our list, so clear these out to keep us
+ * from leaking inodes and memory.
+ */
+ btrfs_free_logged_extents(log, 0);
+ btrfs_free_logged_extents(log, 1);
+
free_extent_buffer(log->node);
kfree(log);
}
@@ -3271,14 +3286,18 @@
struct btrfs_root *log = root->log_root;
struct btrfs_file_extent_item *fi;
struct extent_buffer *leaf;
+ struct btrfs_ordered_extent *ordered;
struct list_head ordered_sums;
struct btrfs_map_token token;
struct btrfs_key key;
- u64 csum_offset = em->mod_start - em->start;
- u64 csum_len = em->mod_len;
+ u64 mod_start = em->mod_start;
+ u64 mod_len = em->mod_len;
+ u64 csum_offset;
+ u64 csum_len;
u64 extent_offset = em->start - em->orig_start;
u64 block_len;
int ret;
+ int index = log->log_transid % 2;
bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
INIT_LIST_HEAD(&ordered_sums);
@@ -3362,6 +3381,92 @@
csum_len = block_len;
}
+ /*
+ * First check and see if our csums are on our outstanding ordered
+ * extents.
+ */
+again:
+ spin_lock_irq(&log->log_extents_lock[index]);
+ list_for_each_entry(ordered, &log->logged_list[index], log_list) {
+ struct btrfs_ordered_sum *sum;
+
+ if (!mod_len)
+ break;
+
+ if (ordered->inode != inode)
+ continue;
+
+ if (ordered->file_offset + ordered->len <= mod_start ||
+ mod_start + mod_len <= ordered->file_offset)
+ continue;
+
+ /*
+ * We are going to copy all the csums on this ordered extent, so
+ * go ahead and adjust mod_start and mod_len in case this
+ * ordered extent has already been logged.
+ */
+ if (ordered->file_offset > mod_start) {
+ if (ordered->file_offset + ordered->len >=
+ mod_start + mod_len)
+ mod_len = ordered->file_offset - mod_start;
+ /*
+ * If we have this case
+ *
+ * |--------- logged extent ---------|
+ * |----- ordered extent ----|
+ *
+ * Just don't mess with mod_start and mod_len, we'll
+ * just end up logging more csums than we need and it
+ * will be ok.
+ */
+ } else {
+ if (ordered->file_offset + ordered->len <
+ mod_start + mod_len) {
+ mod_len = (mod_start + mod_len) -
+ (ordered->file_offset + ordered->len);
+ mod_start = ordered->file_offset +
+ ordered->len;
+ } else {
+ mod_len = 0;
+ }
+ }
+
+ /*
+ * To keep us from looping for the above case of an ordered
+ * extent that falls inside of the logged extent.
+ */
+ if (test_and_set_bit(BTRFS_ORDERED_LOGGED_CSUM,
+ &ordered->flags))
+ continue;
+ atomic_inc(&ordered->refs);
+ spin_unlock_irq(&log->log_extents_lock[index]);
+ /*
+ * we've dropped the lock, we must either break or
+ * start over after this.
+ */
+
+ wait_event(ordered->wait, ordered->csum_bytes_left == 0);
+
+ list_for_each_entry(sum, &ordered->list, list) {
+ ret = btrfs_csum_file_blocks(trans, log, sum);
+ if (ret) {
+ btrfs_put_ordered_extent(ordered);
+ goto unlocked;
+ }
+ }
+ btrfs_put_ordered_extent(ordered);
+ goto again;
+
+ }
+ spin_unlock_irq(&log->log_extents_lock[index]);
+unlocked:
+
+ if (!mod_len || ret)
+ return ret;
+
+ csum_offset = mod_start - em->start;
+ csum_len = mod_len;
+
/* block start is already adjusted for the file extent offset. */
ret = btrfs_lookup_csums_range(log->fs_info->csum_root,
em->block_start + csum_offset,
@@ -3393,6 +3498,7 @@
struct extent_map_tree *tree = &BTRFS_I(inode)->extent_tree;
u64 test_gen;
int ret = 0;
+ int num = 0;
INIT_LIST_HEAD(&extents);
@@ -3401,16 +3507,31 @@
list_for_each_entry_safe(em, n, &tree->modified_extents, list) {
list_del_init(&em->list);
+
+ /*
+ * Just an arbitrary number, this can be really CPU intensive
+ * once we start getting a lot of extents, and really once we
+ * have a bunch of extents we just want to commit since it will
+ * be faster.
+ */
+ if (++num > 32768) {
+ list_del_init(&tree->modified_extents);
+ ret = -EFBIG;
+ goto process;
+ }
+
if (em->generation <= test_gen)
continue;
/* Need a ref to keep it from getting evicted from cache */
atomic_inc(&em->refs);
set_bit(EXTENT_FLAG_LOGGING, &em->flags);
list_add_tail(&em->list, &extents);
+ num++;
}
list_sort(NULL, &extents, extent_cmp);
+process:
while (!list_empty(&extents)) {
em = list_entry(extents.next, struct extent_map, list);
@@ -3513,6 +3634,8 @@
mutex_lock(&BTRFS_I(inode)->log_mutex);
+ btrfs_get_logged_extents(log, inode);
+
/*
* a brute force approach to making sure we get the most uptodate
* copies of everything.
@@ -3656,6 +3779,8 @@
BTRFS_I(inode)->logged_trans = trans->transid;
BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->last_sub_trans;
out_unlock:
+ if (err)
+ btrfs_free_logged_extents(log, log->log_transid);
mutex_unlock(&BTRFS_I(inode)->log_mutex);
btrfs_free_path(path);
@@ -3822,7 +3947,6 @@
end_trans:
dput(old_parent);
if (ret < 0) {
- WARN_ON(ret != -ENOSPC);
root->fs_info->last_trans_log_full_commit = trans->transid;
ret = 1;
}