ext2_block_to_path(9)

🎀 NAME 🎀

okay so bestie, this is ext2_block_to_path(9) from the Kernel API Manual, and it is literally here to parse the block number into an array of offsets. periodt 💅

✨ SYNOPSIS ✨

int ext2_block_to_path (struct inode *inode , long i_block , int
       offsets[4] , int *boundary );

💅 ARGUMENTS 💅

• inode — the inode in question, but bestie we are only interested in its superblock 👀
• i_block — the block number to be parsed, no cap
• offsets — the array where the offsets get stored 🎀
• boundary — set this non-zero if the referred-to block is likely to be followed (on disk) by an indirect block. To store the locations of file's data ext2 uses a data structure common for UNIX filesystems - tree of pointers anchored in the inode, with data blocks at leaves and indirect blocks in intermediate nodes. This function translates the block number into path in that tree - return value is the path length and offsets[n] is the offset of pointer to (n+1)th node in the nth one. If block is out of range (negative or too large) warning is printed and zero returned. 🫶

🫶 NOTE 🫶

function doesn't find node addresses, so no IO is needed. All we need to know is the capacity of indirect blocks (taken from the inode->i_sb). lowkey iconic that it stays IO-free ✨

👀 SEE ALSO 👀

Kernel file ./fs/ext2/inode.c:

• ext2_get_branch(9)
• ext2_find_near(9)
• ext2_find_goal(9)
• ext2_blks_to_allocate(9)
• ext2_alloc_blocks(9)
• ext2_alloc_branch(9)
• ext2_splice_branch(9)
• ext2_find_shared(9)
• ext2_free_data(9)
• ext2_free_branches(9)

this cutie comes from ./fs/ext2 and is dated October 2026 — mwah 💖🌸