From: David Sterba <dsterba@xxxxxxx>
This patch has been added to the 4.1 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit 8089fe62c6603860f6796ca80519b92391292f21 ]
Inodes for delayed iput allocate a trivial helper structure, let's place
the list hook directly into the inode and save a kmalloc (killing a
__GFP_NOFAIL as a bonus) at the cost of increasing size of btrfs_inode.
The inode can be put into the delayed_iputs list more than once and we
have to keep the count. This means we can't use the list_splice to
process a bunch of inodes because we'd lost track of the count if the
inode is put into the delayed iputs again while it's processed.
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
fs/btrfs/btrfs_inode.h | 4 ++++
fs/btrfs/inode.c | 56 ++++++++++++++++++++++----------------------------
2 files changed, 29 insertions(+), 31 deletions(-)
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 0ef5cc1..61205e3 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -192,6 +192,10 @@ struct btrfs_inode {
/* File creation time. */
struct timespec i_otime;
+ /* Hook into fs_info->delayed_iputs */
+ struct list_head delayed_iput;
+ long delayed_iput_count;
+
struct inode vfs_inode;
};
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5136c73..7b898f5 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3080,55 +3080,47 @@ static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
start, (size_t)(end - start + 1));
}
-struct delayed_iput {
- struct list_head list;
- struct inode *inode;
-};
-
-/* JDM: If this is fs-wide, why can't we add a pointer to
- * btrfs_inode instead and avoid the allocation? */
void btrfs_add_delayed_iput(struct inode *inode)
{
struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
- struct delayed_iput *delayed;
+ struct btrfs_inode *binode = BTRFS_I(inode);
if (atomic_add_unless(&inode->i_count, -1, 1))
return;
- delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
- delayed->inode = inode;
-
spin_lock(&fs_info->delayed_iput_lock);
- list_add_tail(&delayed->list, &fs_info->delayed_iputs);
+ if (binode->delayed_iput_count == 0) {
+ ASSERT(list_empty(&binode->delayed_iput));
+ list_add_tail(&binode->delayed_iput, &fs_info->delayed_iputs);
+ } else {
+ binode->delayed_iput_count++;
+ }
spin_unlock(&fs_info->delayed_iput_lock);
}
void btrfs_run_delayed_iputs(struct btrfs_root *root)
{
- LIST_HEAD(list);
struct btrfs_fs_info *fs_info = root->fs_info;
- struct delayed_iput *delayed;
- int empty;
-
- spin_lock(&fs_info->delayed_iput_lock);
- empty = list_empty(&fs_info->delayed_iputs);
- spin_unlock(&fs_info->delayed_iput_lock);
- if (empty)
- return;
down_read(&fs_info->delayed_iput_sem);
-
spin_lock(&fs_info->delayed_iput_lock);
- list_splice_init(&fs_info->delayed_iputs, &list);
- spin_unlock(&fs_info->delayed_iput_lock);
-
- while (!list_empty(&list)) {
- delayed = list_entry(list.next, struct delayed_iput, list);
- list_del(&delayed->list);
- iput(delayed->inode);
- kfree(delayed);
+ while (!list_empty(&fs_info->delayed_iputs)) {
+ struct btrfs_inode *inode;
+
+ inode = list_first_entry(&fs_info->delayed_iputs,
+ struct btrfs_inode, delayed_iput);
+ if (inode->delayed_iput_count) {
+ inode->delayed_iput_count--;
+ list_move_tail(&inode->delayed_iput,
+ &fs_info->delayed_iputs);
+ } else {
+ list_del_init(&inode->delayed_iput);
+ }
+ spin_unlock(&fs_info->delayed_iput_lock);
+ iput(&inode->vfs_inode);
+ spin_lock(&fs_info->delayed_iput_lock);
}
-
+ spin_unlock(&fs_info->delayed_iput_lock);
up_read(&root->fs_info->delayed_iput_sem);
}
@@ -8890,6 +8882,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
ei->dir_index = 0;
ei->last_unlink_trans = 0;
ei->last_log_commit = 0;
+ ei->delayed_iput_count = 0;
spin_lock_init(&ei->lock);
ei->outstanding_extents = 0;
@@ -8914,6 +8907,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
mutex_init(&ei->delalloc_mutex);
btrfs_ordered_inode_tree_init(&ei->ordered_tree);
INIT_LIST_HEAD(&ei->delalloc_inodes);
+ INIT_LIST_HEAD(&ei->delayed_iput);
RB_CLEAR_NODE(&ei->rb_node);
return inode;
--
2.5.0
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