ext2_init_block_alloc_info(9)

🎀 ext2_init_block_alloc_info(9) 🎀

hey hey bestie!! welcome to the ext2_init_block_alloc_info(9) page from the Kernel API Manual — yes, the manual name is folded right here, cute and legal. we are deep in kernel land today and it's giving "niche but powerful." 🫶✨

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🌸 NAME 🌸

ext2_init_block_alloc_info - ... okay so that's the function name, bestie. this entire page is about that one function, no cap. 💅

✨ SYNOPSIS ✨

void ext2_init_block_alloc_info (struct inode *inode );

it returns void, so there's literally no return value to obsess over. 💀

🦋 ARGUMENTS 🦋

• inode — the file inode structure. that's the whole argument description in the original, and we're keeping it 100. 💳✨

💖 DESCRIPTION 💖

okay so what does this icon actually do? it allocates and initializes the reservation window structure, then — at last — links that window to the ext2 inode structure. slay. 🎀

quick lore drop: the reservation window structure is only dynamically allocated and linked to the ext2 inode the first time the open file needs a new block. so before every ext2_new_block(s) call, for regular files, we gotta check whether the reservation window structure exists or not. if it doesn't exist — the latter case — this function is called. if you fail to do that check, block reservation gets turned off for that open file. not the vibe. 😭

where does this function get called from? ext2_get_blocks_handle, and it's also called when setting the reservation window size through ioctl before the file is open for write (needs block allocation). iykyk. 🌀

⚠️ heads up, bestie: this needs truncate_mutex protection prior to calling this function. like, before. not after. okay?? 😤

🌈 SEE ALSO 🌈

the kernel file is ./fs/ext2/balloc.c, and the whole squad is:

• Kernel file ./fs/ext2/balloc.c
• __rsv_window_dump(9)
• goal_in_my_reservation(9)
• search_reserve_window(9)
• rsv_window_remove(9)
• ext2_discard_reservation(9)
• ext2_free_blocks(9)
• bitmap_search_next_usable_block(9)
• find_next_usable_block(9)
• ext2_try_to_allocate(9)
• find_next_reservable_window(9)
• alloc_new_reservation(9)
• try_to_extend_reservation(9)
• ext2_try_to_allocate_with_rsv(9)
• ext2_has_free_blocks(9)
• ext2_bg_has_super(9)
• ext2_bg_num_gdb(9)

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okay that's the whole page, bestie!! 💖 source/version vibe: ./fs/ext2; date vibe: October 2026; page: ext2_init_block_alloc_info(9). periodt. 🌈✨👑