From 5463e7c18e51152104aba9614e6abfc039a8b710 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Tue, 21 Apr 2015 10:40:54 -0700 Subject: [PATCH 1/2] Revert "f2fs: enhance multi-threads performance" This reports performance regression by Yuanhan Liu. The basic idea was to reduce one-point mutex, but it turns out this causes another contention like context swithes. https://lkml.org/lkml/2015/4/21/11 Until finishing the analysis on this issue, I'd like to revert this for a while. This reverts commit 78373b7319abdf15050af5b1632c4c8b8b398f33. --- fs/f2fs/data.c | 7 +++++++ fs/f2fs/f2fs.h | 1 + fs/f2fs/super.c | 1 + 3 files changed, 9 insertions(+) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index b91b0e10678e..1e1aae669fa8 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -1513,6 +1513,7 @@ static int f2fs_write_data_pages(struct address_space *mapping, { struct inode *inode = mapping->host; struct f2fs_sb_info *sbi = F2FS_I_SB(inode); + bool locked = false; int ret; long diff; @@ -1533,7 +1534,13 @@ static int f2fs_write_data_pages(struct address_space *mapping, diff = nr_pages_to_write(sbi, DATA, wbc); + if (!S_ISDIR(inode->i_mode)) { + mutex_lock(&sbi->writepages); + locked = true; + } ret = write_cache_pages(mapping, wbc, __f2fs_writepage, mapping); + if (locked) + mutex_unlock(&sbi->writepages); f2fs_submit_merged_bio(sbi, DATA, WRITE); diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index d8921cf2ba9a..8de34ab6d5b1 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -625,6 +625,7 @@ struct f2fs_sb_info { struct mutex cp_mutex; /* checkpoint procedure lock */ struct rw_semaphore cp_rwsem; /* blocking FS operations */ struct rw_semaphore node_write; /* locking node writes */ + struct mutex writepages; /* mutex for writepages() */ wait_queue_head_t cp_wait; struct inode_management im[MAX_INO_ENTRY]; /* manage inode cache */ diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 160b88346b24..b2dd1b01f076 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -1035,6 +1035,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent) sbi->raw_super = raw_super; sbi->raw_super_buf = raw_super_buf; mutex_init(&sbi->gc_mutex); + mutex_init(&sbi->writepages); mutex_init(&sbi->cp_mutex); init_rwsem(&sbi->node_write); clear_sbi_flag(sbi, SBI_POR_DOING); From 7263b1bd0490fca68ee7eedb0b6973cb86d4701c Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Wed, 22 Apr 2015 11:03:48 -0700 Subject: [PATCH 2/2] f2fs: fix wrong error hanlder in f2fs_follow_link The page_follow_link_light returns NULL and its error pointer was remained in nd->path. Reported-by: Dan Carpenter Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/namei.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c index 7e3794edae42..658e8079aaf9 100644 --- a/fs/f2fs/namei.c +++ b/fs/f2fs/namei.c @@ -298,16 +298,14 @@ static int f2fs_unlink(struct inode *dir, struct dentry *dentry) static void *f2fs_follow_link(struct dentry *dentry, struct nameidata *nd) { - struct page *page; + struct page *page = page_follow_link_light(dentry, nd); - page = page_follow_link_light(dentry, nd); - if (IS_ERR(page)) + if (IS_ERR_OR_NULL(page)) return page; /* this is broken symlink case */ if (*nd_get_link(nd) == 0) { - kunmap(page); - page_cache_release(page); + page_put_link(dentry, nd, page); return ERR_PTR(-ENOENT); } return page;