ext4_bg_num_gdb(9)

✨ NAME ✨

ext4_bg_num_gdb(9) — from the Kernel API Manual, bestie — is literally the function that gives you the number of blocks used by the group table in a group 💅

✨ SYNOPSIS ✨

unsigned long ext4_bg_num_gdb (struct super_block *sb , ext4_group_t group );

🎀 ARGUMENTS 🎀

• sb — the superblock for the filesystem, aka the main-character context for this whole lookup 🫶
• group — the group number you wanna check 🔍

💅 DESCRIPTION 💅

Okay so this function returns the number of blocks used by the group descriptor table — either the primary one or the backup one — in this group. Periodt 💖

Future tea alert 🫖: there may be a different number of descriptor blocks in each group.

🦋 SEE ALSO 🦋

Kernel file ./fs/ext4/balloc.c — and the whole squad is here too:

• ext4_get_group_desc(9)
• ext4_read_block_bitmap_nowait(9)
• ext4_has_free_clusters(9)
• ext4_should_retry_alloc(9)
• ext4_count_free_clusters(9)
• ext4_bg_has_super(9)
• ext4_inode_to_goal_block(9)

mwah 💖 this page lives in ./fs/ext4 and is dated October 2026 — go off, bestie! 🌈👑