f2fs: avoid race for summary information

In order to do GC more reliably, I'd like to lock the vicitm summary page
until its GC is completed, and also prevent any checkpoint process.

Reviewed-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 136c0f7a670bd3def779f2ae945d30b0aa0d6870..e97f30157aa6cd87b82ead2536aa6556599759ab 100644 (file)
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -642,12 +642,6 @@ static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
        if (IS_ERR(sum_page))
                return;
 
-       /*
-        * CP needs to lock sum_page. In this time, we don't need
-        * to lock this page, because this summary page is not gone anywhere.
-        * Also, this page is not gonna be updated before GC is done.
-        */
-       unlock_page(sum_page);
        sum = page_address(sum_page);
 
        switch (GET_SUM_TYPE((&sum->footer))) {
@@ -661,7 +655,7 @@ static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
        stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
        stat_inc_call_count(sbi->stat_info);
 
-       f2fs_put_page(sum_page, 0);
+       f2fs_put_page(sum_page, 1);
 }
 
 int f2fs_gc(struct f2fs_sb_info *sbi)

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 8510c5ed402e42c7e80f28d5f5ccf58df2125c2e..95298ef68262e00b086ab6333db7c2799b9fb054 100644 (file)
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1149,7 +1149,7 @@ static int f2fs_write_node_pages(struct address_space *mapping,
 
        /* First check balancing cached NAT entries */
        if (try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK)) {
-               write_checkpoint(sbi, false);
+               f2fs_sync_fs(sbi->sb, true);
                return 0;
        }
 

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 728c20a8e4568bd71e01fbbd42497e4b58a1b4ef..ca54133466535046ed0195d7be37723c8a18672c 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -137,10 +137,13 @@ int f2fs_sync_fs(struct super_block *sb, int sync)
        if (!sbi->s_dirty && !get_pages(sbi, F2FS_DIRTY_NODES))
                return 0;
 
-       if (sync)
+       if (sync) {
+               mutex_lock(&sbi->gc_mutex);
                write_checkpoint(sbi, false);
-       else
+               mutex_unlock(&sbi->gc_mutex);
+       } else {
                f2fs_balance_fs(sbi);
+       }
 
        return 0;
 }