This tries to fix priority inversion in the below condition resulting in
long checkpoint delay.

f2fs_get_node_info()
 - nat_tree_lock
  -> sleep in journal_rwsem
                                     checkpoint
                                     - waiting for nat_tree_lock

Signed-off-by: Jaegeuk Kim <[email protected]>
---
 fs/f2fs/node.c    | 16 ++++++++--------
 fs/f2fs/segment.c | 22 +++++++++++-----------
 fs/f2fs/segment.h |  2 +-
 3 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 0be9e2d7120e..821a40e02fb4 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -567,13 +567,13 @@ int f2fs_get_node_info(struct f2fs_sb_info *sbi, nid_t 
nid,
        memset(&ne, 0, sizeof(struct f2fs_nat_entry));
 
        /* Check current segment summary */
-       down_read(&curseg->journal_rwsem);
+       read_lock(&curseg->journal_rwlock);
        i = f2fs_lookup_journal_in_cursum(journal, NAT_JOURNAL, nid, 0);
        if (i >= 0) {
                ne = nat_in_journal(journal, i);
                node_info_from_raw_nat(ni, &ne);
        }
-       up_read(&curseg->journal_rwsem);
+       read_unlock(&curseg->journal_rwlock);
        if (i >= 0) {
                up_read(&nm_i->nat_tree_lock);
                goto cache;
@@ -2338,7 +2338,7 @@ static void scan_curseg_cache(struct f2fs_sb_info *sbi)
        struct f2fs_journal *journal = curseg->journal;
        int i;
 
-       down_read(&curseg->journal_rwsem);
+       read_lock(&curseg->journal_rwlock);
        for (i = 0; i < nats_in_cursum(journal); i++) {
                block_t addr;
                nid_t nid;
@@ -2350,7 +2350,7 @@ static void scan_curseg_cache(struct f2fs_sb_info *sbi)
                else
                        remove_free_nid(sbi, nid);
        }
-       up_read(&curseg->journal_rwsem);
+       read_unlock(&curseg->journal_rwlock);
 }
 
 static void scan_free_nid_bits(struct f2fs_sb_info *sbi)
@@ -2799,7 +2799,7 @@ static void remove_nats_in_journal(struct f2fs_sb_info 
*sbi)
        struct f2fs_journal *journal = curseg->journal;
        int i;
 
-       down_write(&curseg->journal_rwsem);
+       write_lock(&curseg->journal_rwlock);
        for (i = 0; i < nats_in_cursum(journal); i++) {
                struct nat_entry *ne;
                struct f2fs_nat_entry raw_ne;
@@ -2831,7 +2831,7 @@ static void remove_nats_in_journal(struct f2fs_sb_info 
*sbi)
                __set_nat_cache_dirty(nm_i, ne);
        }
        update_nats_in_cursum(journal, -i);
-       up_write(&curseg->journal_rwsem);
+       write_unlock(&curseg->journal_rwlock);
 }
 
 static void __adjust_nat_entry_set(struct nat_entry_set *nes,
@@ -2906,7 +2906,7 @@ static int __flush_nat_entry_set(struct f2fs_sb_info *sbi,
                to_journal = false;
 
        if (to_journal) {
-               down_write(&curseg->journal_rwsem);
+               write_lock(&curseg->journal_rwlock);
        } else {
                page = get_next_nat_page(sbi, start_nid);
                if (IS_ERR(page))
@@ -2946,7 +2946,7 @@ static int __flush_nat_entry_set(struct f2fs_sb_info *sbi,
        }
 
        if (to_journal) {
-               up_write(&curseg->journal_rwsem);
+               write_unlock(&curseg->journal_rwlock);
        } else {
                __update_nat_bits(sbi, start_nid, page);
                f2fs_put_page(page, 1);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index f9b7fb785e1d..c397c1c271ec 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2442,9 +2442,9 @@ static void write_current_sum_page(struct f2fs_sb_info 
*sbi,
 
        mutex_lock(&curseg->curseg_mutex);
 
-       down_read(&curseg->journal_rwsem);
+       read_lock(&curseg->journal_rwlock);
        memcpy(&dst->journal, curseg->journal, SUM_JOURNAL_SIZE);
-       up_read(&curseg->journal_rwsem);
+       read_unlock(&curseg->journal_rwlock);
 
        memcpy(dst->entries, src->entries, SUM_ENTRY_SIZE);
        memcpy(&dst->footer, &src->footer, SUM_FOOTER_SIZE);
@@ -3876,9 +3876,9 @@ static int read_normal_summaries(struct f2fs_sb_info 
*sbi, int type)
        mutex_lock(&curseg->curseg_mutex);
 
        /* update journal info */
-       down_write(&curseg->journal_rwsem);
+       write_lock(&curseg->journal_rwlock);
        memcpy(curseg->journal, &sum->journal, SUM_JOURNAL_SIZE);
-       up_write(&curseg->journal_rwsem);
+       write_unlock(&curseg->journal_rwlock);
 
        memcpy(curseg->sum_blk->entries, sum->entries, SUM_ENTRY_SIZE);
        memcpy(&curseg->sum_blk->footer, &sum->footer, SUM_FOOTER_SIZE);
@@ -4136,7 +4136,7 @@ static void remove_sits_in_journal(struct f2fs_sb_info 
*sbi)
        struct f2fs_journal *journal = curseg->journal;
        int i;
 
-       down_write(&curseg->journal_rwsem);
+       write_lock(&curseg->journal_rwlock);
        for (i = 0; i < sits_in_cursum(journal); i++) {
                unsigned int segno;
                bool dirtied;
@@ -4148,7 +4148,7 @@ static void remove_sits_in_journal(struct f2fs_sb_info 
*sbi)
                        add_sit_entry(segno, &SM_I(sbi)->sit_entry_set);
        }
        update_sits_in_cursum(journal, -i);
-       up_write(&curseg->journal_rwsem);
+       write_unlock(&curseg->journal_rwlock);
 }
 
 /*
@@ -4204,7 +4204,7 @@ void f2fs_flush_sit_entries(struct f2fs_sb_info *sbi, 
struct cp_control *cpc)
                        to_journal = false;
 
                if (to_journal) {
-                       down_write(&curseg->journal_rwsem);
+                       write_lock(&curseg->journal_rwlock);
                } else {
                        page = get_next_sit_page(sbi, start_segno);
                        raw_sit = page_address(page);
@@ -4251,7 +4251,7 @@ void f2fs_flush_sit_entries(struct f2fs_sb_info *sbi, 
struct cp_control *cpc)
                }
 
                if (to_journal)
-                       up_write(&curseg->journal_rwsem);
+                       write_unlock(&curseg->journal_rwlock);
                else
                        f2fs_put_page(page, 1);
 
@@ -4432,7 +4432,7 @@ static int build_curseg(struct f2fs_sb_info *sbi)
                array[i].sum_blk = f2fs_kzalloc(sbi, PAGE_SIZE, GFP_KERNEL);
                if (!array[i].sum_blk)
                        return -ENOMEM;
-               init_rwsem(&array[i].journal_rwsem);
+               rwlock_init(&array[i].journal_rwlock);
                array[i].journal = f2fs_kzalloc(sbi,
                                sizeof(struct f2fs_journal), GFP_KERNEL);
                if (!array[i].journal)
@@ -4509,7 +4509,7 @@ static int build_sit_entries(struct f2fs_sb_info *sbi)
                start_blk += readed;
        } while (start_blk < sit_blk_cnt);
 
-       down_read(&curseg->journal_rwsem);
+       read_lock(&curseg->journal_rwlock);
        for (i = 0; i < sits_in_cursum(journal); i++) {
                unsigned int old_valid_blocks;
 
@@ -4551,7 +4551,7 @@ static int build_sit_entries(struct f2fs_sb_info *sbi)
                                                        old_valid_blocks;
                }
        }
-       up_read(&curseg->journal_rwsem);
+       read_unlock(&curseg->journal_rwlock);
 
        if (!err && total_node_blocks != valid_node_count(sbi)) {
                f2fs_err(sbi, "SIT is corrupted node# %u vs %u",
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 050230c70a53..afb9041dc2e6 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -306,7 +306,7 @@ struct victim_selection {
 struct curseg_info {
        struct mutex curseg_mutex;              /* lock for consistency */
        struct f2fs_summary_block *sum_blk;     /* cached summary block */
-       struct rw_semaphore journal_rwsem;      /* protect journal area */
+       rwlock_t journal_rwlock;                /* protect journal area */
        struct f2fs_journal *journal;           /* cached journal info */
        unsigned char alloc_type;               /* current allocation type */
        unsigned short seg_type;                /* segment type like 
CURSEG_XXX_TYPE */
-- 
2.32.0.402.g57bb445576-goog



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