Tag
ext4
- Jul 28, 2026 Mounting: From Device Node to a Live Superblock The sequence a filesystem driver follows when it is handed a block device, the checks that must pass before the volume becomes writable, and what a failed mount must unwind. filesystems
- Mar 19, 2026 Delayed Allocation and the Reservation Window Why holding back the block-allocation decision until writeback makes layout better and failure later, and how a per-file reservation prevents the space from being promised twice. filesystems
- Mar 7, 2026 Inode Tables and the Arithmetic of Inode Numbers How a fixed-size inode record is found from its number with one division, why the table is preallocated rather than grown, and what happens when the number of inodes runs out before the space does. filesystems
- May 20, 2025 Block Groups and the Cost of Metadata Locality Why a filesystem carves itself into groups with their own bitmaps and inode tables, what the descriptor table records, and how allocation policy turns locality into seek distance. filesystems
- Jan 16, 2025 The Superblock: Magic Number, Geometry, and Feature Flags How a filesystem announces its own layout at a fixed disk offset, why its feature bits are split into three classes with different contracts, and what a driver does when it meets a bit it does not understand. filesystems
- Nov 25, 2024 Extent Trees and the Replacement of Indirect Block Maps What an extent record actually encodes, why the inode-sized root makes small files free of external metadata, and how the tree splits when a file fragments. filesystems
- Mar 14, 2023 Directory Hash Trees: Indexing Names Without Breaking Enumeration How a hashed b-tree stores directory entries in blocks while preserving the linear order readdir requires, and how a fake dirent hides the interior nodes from a reader that does not know about them. filesystems