ext4: extend ext4_mb_mark_context to support allocation under journal

Previously, ext4_mb_mark_context is only called under fast commit
replay path, so there is no valid handle when we update block bitmap
and group descriptor. This patch try to extend ext4_mb_mark_context
to be used by code under journal. There are several improvement:
1. Add "handle_t *handle" to struct ext4_mark_context to journal block
bitmap and group descriptor update inside ext4_mb_mark_context (the
added journal code is based on ext4_mb_mark_diskspace_used where
ext4_mb_mark_context is going to be used.)
2. Adds a flag argument to ext4_mb_mark_context() which controls
a. EXT4_MB_BITMAP_MARKED_CHECK - whether block bitmap checking is needed.
b. EXT4_MB_SYNC_UPDATE - whether dirty buffers (bitmap and group
descriptor) needs sync.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20230928160407.142069-5-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 3761934c93989e9ea3392a2c5d262a391e9f7a4f..5b3940e3afeadc13275de9ccf83c0b36b04f89d0 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3943,26 +3943,47 @@ void ext4_exit_mballoc(void)
        ext4_groupinfo_destroy_slabs();
 }
 
+#define EXT4_MB_BITMAP_MARKED_CHECK 0x0001
+#define EXT4_MB_SYNC_UPDATE 0x0002
 static int
-ext4_mb_mark_context(struct super_block *sb, bool state, ext4_group_t group,
-                    ext4_grpblk_t blkoff, ext4_grpblk_t len)
+ext4_mb_mark_context(handle_t *handle, struct super_block *sb, bool state,
+                    ext4_group_t group, ext4_grpblk_t blkoff,
+                    ext4_grpblk_t len, int flags, ext4_grpblk_t *ret_changed)
 {
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct buffer_head *bitmap_bh = NULL;
        struct ext4_group_desc *gdp;
        struct buffer_head *gdp_bh;
        int err;
-       unsigned int i, already, changed;
+       unsigned int i, already, changed = len;
 
+       if (ret_changed)
+               *ret_changed = 0;
        bitmap_bh = ext4_read_block_bitmap(sb, group);
        if (IS_ERR(bitmap_bh))
                return PTR_ERR(bitmap_bh);
 
+       if (handle) {
+               BUFFER_TRACE(bitmap_bh, "getting write access");
+               err = ext4_journal_get_write_access(handle, sb, bitmap_bh,
+                                                   EXT4_JTR_NONE);
+               if (err)
+                       goto out_err;
+       }
+
        err = -EIO;
        gdp = ext4_get_group_desc(sb, group, &gdp_bh);
        if (!gdp)
                goto out_err;
 
+       if (handle) {
+               BUFFER_TRACE(gdp_bh, "get_write_access");
+               err = ext4_journal_get_write_access(handle, sb, gdp_bh,
+                                                   EXT4_JTR_NONE);
+               if (err)
+                       goto out_err;
+       }
+
        ext4_lock_group(sb, group);
        if (ext4_has_group_desc_csum(sb) &&
            (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
@@ -3971,12 +3992,14 @@ ext4_mb_mark_context(struct super_block *sb, bool state, ext4_group_t group,
                        ext4_free_clusters_after_init(sb, group, gdp));
        }
 
-       already = 0;
-       for (i = 0; i < len; i++)
-               if (mb_test_bit(blkoff + i, bitmap_bh->b_data) ==
-                               state)
-                       already++;
-       changed = len - already;
+       if (flags & EXT4_MB_BITMAP_MARKED_CHECK) {
+               already = 0;
+               for (i = 0; i < len; i++)
+                       if (mb_test_bit(blkoff + i, bitmap_bh->b_data) ==
+                                       state)
+                               already++;
+               changed = len - already;
+       }
 
        if (state) {
                mb_set_bits(bitmap_bh->b_data, blkoff, len);
@@ -3991,6 +4014,8 @@ ext4_mb_mark_context(struct super_block *sb, bool state, ext4_group_t group,
        ext4_block_bitmap_csum_set(sb, gdp, bitmap_bh);
        ext4_group_desc_csum_set(sb, group, gdp);
        ext4_unlock_group(sb, group);
+       if (ret_changed)
+               *ret_changed = changed;
 
        if (sbi->s_log_groups_per_flex) {
                ext4_group_t flex_group = ext4_flex_group(sbi, group);
@@ -4003,15 +4028,17 @@ ext4_mb_mark_context(struct super_block *sb, bool state, ext4_group_t group,
                        atomic64_add(changed, &fg->free_clusters);
        }
 
-       err = ext4_handle_dirty_metadata(NULL, NULL, bitmap_bh);
+       err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
        if (err)
                goto out_err;
-       err = ext4_handle_dirty_metadata(NULL, NULL, gdp_bh);
+       err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
        if (err)
                goto out_err;
 
-       sync_dirty_buffer(bitmap_bh);
-       sync_dirty_buffer(gdp_bh);
+       if (flags & EXT4_MB_SYNC_UPDATE) {
+               sync_dirty_buffer(bitmap_bh);
+               sync_dirty_buffer(gdp_bh);
+       }
 
 out_err:
        brelse(bitmap_bh);
@@ -4171,7 +4198,11 @@ void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block,
                        break;
                }
 
-               err = ext4_mb_mark_context(sb, state, group, blkoff, clen);
+               err = ext4_mb_mark_context(NULL, sb, state,
+                                          group, blkoff, clen,
+                                          EXT4_MB_BITMAP_MARKED_CHECK |
+                                          EXT4_MB_SYNC_UPDATE,
+                                          NULL);
                if (err)
                        break;
 
@@ -6363,7 +6394,10 @@ static void ext4_free_blocks_simple(struct inode *inode, ext4_fsblk_t block,
        ext4_grpblk_t blkoff;
 
        ext4_get_group_no_and_offset(sb, block, &group, &blkoff);
-       ext4_mb_mark_context(sb, false, group, blkoff, count);
+       ext4_mb_mark_context(NULL, sb, false, group, blkoff, count,
+                            EXT4_MB_BITMAP_MARKED_CHECK |
+                            EXT4_MB_SYNC_UPDATE,
+                            NULL);
 }
 
 /**