blob: 03ae39ec72dc924f0601a24ba25a20bf2e515ea0 [file] [log] [blame]
.. SPDX-License-Identifier: GPL-2.0
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incfs: A stacked incremental filesystem for Linux
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/sys/fs interface
=================
Please update Documentation/ABI/testing/sys-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.