f2fs: reduce unncessary locking pages during read
This patch reduces redundant locking and unlocking pages during read operations.
In f2fs_readpage, let's use wait_on_page_locked() instead of lock_page.
And then, when we need to modify any data finally, let's lock the page so that
we can avoid lock contention.
[readpage rule]
- The f2fs_readpage returns unlocked page, or released page too in error cases.
- Its caller should handle read error, -EIO, after locking the page, which
indicates read completion.
- Its caller should check PageUptodate after grab_cache_page.
Signed-off-by: Changman Lee <cm224.lee@samsung.com>
Reviewed-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index 6b82e20..2d86eb2 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -112,11 +112,16 @@
while (1) {
struct fsync_inode_entry *entry;
- if (f2fs_readpage(sbi, page, blkaddr, READ_SYNC))
+ err = f2fs_readpage(sbi, page, blkaddr, READ_SYNC);
+ if (err)
goto out;
- if (cp_ver != cpver_of_node(page))
- goto out;
+ lock_page(page);
+
+ if (cp_ver != cpver_of_node(page)) {
+ err = -EINVAL;
+ goto unlock_out;
+ }
if (!is_fsync_dnode(page))
goto next;
@@ -131,7 +136,7 @@
if (IS_INODE(page) && is_dent_dnode(page)) {
if (recover_inode_page(sbi, page)) {
err = -ENOMEM;
- goto out;
+ goto unlock_out;
}
}
@@ -139,14 +144,14 @@
entry = kmem_cache_alloc(fsync_entry_slab, GFP_NOFS);
if (!entry) {
err = -ENOMEM;
- goto out;
+ goto unlock_out;
}
entry->inode = f2fs_iget(sbi->sb, ino_of_node(page));
if (IS_ERR(entry->inode)) {
err = PTR_ERR(entry->inode);
kmem_cache_free(fsync_entry_slab, entry);
- goto out;
+ goto unlock_out;
}
list_add_tail(&entry->list, head);
@@ -155,15 +160,15 @@
if (IS_INODE(page)) {
err = recover_inode(entry->inode, page);
if (err)
- goto out;
+ goto unlock_out;
}
next:
/* check next segment */
blkaddr = next_blkaddr_of_node(page);
- ClearPageUptodate(page);
}
-out:
+unlock_out:
unlock_page(page);
+out:
__free_pages(page, 0);
return err;
}
@@ -319,8 +324,10 @@
if (f2fs_readpage(sbi, page, blkaddr, READ_SYNC))
goto out;
+ lock_page(page);
+
if (cp_ver != cpver_of_node(page))
- goto out;
+ goto unlock_out;
entry = get_fsync_inode(head, ino_of_node(page));
if (!entry)
@@ -336,10 +343,10 @@
next:
/* check next segment */
blkaddr = next_blkaddr_of_node(page);
- ClearPageUptodate(page);
}
-out:
+unlock_out:
unlock_page(page);
+out:
__free_pages(page, 0);
allocate_new_segments(sbi);
