.. SPDX-License-Identifier: GPL-2.0 ================================================= incfs: A stacked incremental filesystem for Linux ================================================= /sys/fs interface ================= Please update Documentation/ABI/testing/sysfs-fs-incfs if you update this section. incfs creates the following files in /sys/fs. Features -------- /sys/fs/incremental-fs/features/corefs Reads 'supported'. Always present. /sys/fs/incremental-fs/features/v2 Reads 'supported'. Present if all v2 features of incfs are supported. These are: fs-verity support inotify support ioclts: INCFS_IOC_SET_READ_TIMEOUTS INCFS_IOC_GET_READ_TIMEOUTS INCFS_IOC_GET_BLOCK_COUNT INCFS_IOC_CREATE_MAPPED_FILE .incomplete folder .blocks_written pseudo file report_uid mount option /sys/fs/incremental-fs/features/zstd Reads 'supported'. Present if zstd compression is supported for data blocks. Optional per mount ------------------ For each incfs mount, the mount option sysfs_name=[name] creates a /sys/fs node called: /sys/fs/incremental-fs/instances/[name] This will contain the following files: /sys/fs/incremental-fs/instances/[name]/reads_delayed_min Returns a count of the number of reads that were delayed as a result of the per UID read timeouts min time setting. /sys/fs/incremental-fs/instances/[name]/reads_delayed_min_us Returns total delay time for all files since first mount as a result of the per UID read timeouts min time setting. /sys/fs/incremental-fs/instances/[name]/reads_delayed_pending Returns a count of the number of reads that were delayed as a result of waiting for a pending read. /sys/fs/incremental-fs/instances/[name]/reads_delayed_pending_us Returns total delay time for all files since first mount as a result of waiting for a pending read. /sys/fs/incremental-fs/instances/[name]/reads_failed_hash_verification Returns number of reads that failed because of hash verification failures. /sys/fs/incremental-fs/instances/[name]/reads_failed_other Returns number of reads that failed for reasons other than timing out or hash failures. /sys/fs/incremental-fs/instances/[name]/reads_failed_timed_out Returns number of reads that timed out. For reads_delayed_*** settings, note that a file can count for both reads_delayed_min and reads_delayed_pending if incfs first waits for a pending read then has to wait further for the min time. In that case, the time spent waiting is split between reads_delayed_pending_us, which is increased by the time spent waiting for the pending read, and reads_delayed_min_us, which is increased by the remainder of the time spent waiting. Reads that timed out are not added to the reads_delayed_pending or the reads_delayed_pending_us counters.