On 2024/2/22 10:15, Zhiguo Niu wrote:


On Thu, Feb 22, 2024 at 9:37 AM Chao Yu <c...@kernel.org 
<mailto:c...@kernel.org>> wrote:

    On 2024/2/20 14:11, Zhiguo Niu wrote:
     > There is low probability that an out-of-bounds segment will be got
     > on a small-capacity device. In order to prevent subsequent write requests
     > allocating block address from this invalid segment, which may cause
     > unexpected issue, stop checkpoint should be performed.
     >
     > Also introduce a new stop cp reason: STOP_CP_REASON_NO_SEGMENT.
     >
     > Signed-off-by: Zhiguo Niu <zhiguo....@unisoc.com 
<mailto:zhiguo....@unisoc.com>>
     > ---
     > changes of v4: use more suitable MACRO name according to Chao's 
suggestions
     > changes of v3: correct MACRO spelling and update based on the lastes code
     > ---
     > ---
     >   fs/f2fs/segment.c       | 7 ++++++-
     >   include/linux/f2fs_fs.h | 1 +
     >   2 files changed, 7 insertions(+), 1 deletion(-)
     >
     > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
     > index c25aaec..e42e34c 100644
     > --- a/fs/f2fs/segment.c
     > +++ b/fs/f2fs/segment.c
     > @@ -2665,7 +2665,12 @@ static void get_new_segment(struct f2fs_sb_info 
*sbi,
     >       if (secno >= MAIN_SECS(sbi)) {
     >               secno = find_first_zero_bit(free_i->free_secmap,
     >                                                       MAIN_SECS(sbi));
     > -             f2fs_bug_on(sbi, secno >= MAIN_SECS(sbi));
     > +             if (secno >= MAIN_SECS(sbi)) {
     > +                     f2fs_stop_checkpoint(sbi, false,
     > +                             STOP_CP_REASON_NO_SEGMENT);

    We should relocate stop_checkpoint(sbi, false, STOP_CP_REASON_NO_SEGMENT) 
outside
    segmap_lock spinlock, due to it may sleep in f2fs_flush_merged_writes().

Indeed it is. How about the following fix?
@@ -2665,11 +2665,7 @@ static void get_new_segment(struct f2fs_sb_info *sbi,
         if (secno >= MAIN_SECS(sbi)) {
                 secno = find_first_zero_bit(free_i->free_secmap,
                                                         MAIN_SECS(sbi));
-               if (secno >= MAIN_SECS(sbi)) {
-                       f2fs_stop_checkpoint(sbi, false,
-                               STOP_CP_REASON_NO_SEGMENT);
-                       f2fs_bug_on(sbi, 1);
-               }
+               f2fs_bug_on(sbi, secno >= MAIN_SECS(sbi));
         }
         segno = GET_SEG_FROM_SEC(sbi, secno);
         zoneno = GET_ZONE_FROM_SEC(sbi, secno);
@@ -2700,6 +2696,8 @@ static void get_new_segment(struct f2fs_sb_info *sbi,
         __set_inuse(sbi, segno);
         *newseg = segno;
         spin_unlock(&free_i->segmap_lock);
+       if (secno >= MAIN_SECS(sbi))
+               f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_NO_SEGMENT);

How about this?

---
 fs/f2fs/segment.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index d0209ea77dd2..8edc42071e6f 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2646,6 +2646,7 @@ static void get_new_segment(struct f2fs_sb_info *sbi,
        unsigned int old_zoneno = GET_ZONE_FROM_SEG(sbi, *newseg);
        bool init = true;
        int i;
+       int ret = 0;

        spin_lock(&free_i->segmap_lock);

@@ -2671,9 +2672,8 @@ static void get_new_segment(struct f2fs_sb_info *sbi,
                secno = find_first_zero_bit(free_i->free_secmap,
                                                        MAIN_SECS(sbi));
                if (secno >= MAIN_SECS(sbi)) {
-                       f2fs_stop_checkpoint(sbi, false,
-                               STOP_CP_REASON_NO_SEGMENT);
-                       f2fs_bug_on(sbi, 1);
+                       ret = -ENOSPC;
+                       goto out_unlock;
                }
        }
        segno = GET_SEG_FROM_SEC(sbi, secno);
@@ -2704,7 +2704,13 @@ static void get_new_segment(struct f2fs_sb_info *sbi,
        f2fs_bug_on(sbi, test_bit(segno, free_i->free_segmap));
        __set_inuse(sbi, segno);
        *newseg = segno;
+out_unlock:
        spin_unlock(&free_i->segmap_lock);
+
+       if (ret) {
+               f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_NO_SEGMENT);
+               f2fs_bug_on(sbi, 1);
+       }
 }

 static void reset_curseg(struct f2fs_sb_info *sbi, int type, int modified)
--
2.40.1


    Thanks,

     > +                     f2fs_bug_on(sbi, 1);
     > +             }
     > +
     >       }
     >       segno = GET_SEG_FROM_SEC(sbi, secno);
     >       zoneno = GET_ZONE_FROM_SEC(sbi, secno);
     > diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
     > index 9b69c50..755e9a4 100644
     > --- a/include/linux/f2fs_fs.h
     > +++ b/include/linux/f2fs_fs.h
     > @@ -75,6 +75,7 @@ enum stop_cp_reason {
     >       STOP_CP_REASON_CORRUPTED_SUMMARY,
     >       STOP_CP_REASON_UPDATE_INODE,
     >       STOP_CP_REASON_FLUSH_FAIL,
     > +     STOP_CP_REASON_NO_SEGMENT,
     >       STOP_CP_REASON_MAX,
     >   };
     >



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