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diff --git a/Documentation/btrfs-mount.asciidoc b/Documentation/btrfs-mount.asciidoc deleted file mode 100644 index 39215a8..0000000 --- a/Documentation/btrfs-mount.asciidoc +++ /dev/null @@ -1,251 +0,0 @@ -btrfs-mount(5) -============== - -NAME ----- -btrfs-mount - mount options and supported file attributes for the btrfs filesystem - -DESCRIPTION ------------ -This document describes mount options specific to the btrfs filesystem. -Other generic mount options are available,and are described in the -`mount`(8) manpage. - -MOUNT OPTIONS -------------- -*alloc_start='bytes'*:: - Debugging option to force all block allocations above a certain - byte threshold on each block device. The value is specified in - bytes, optionally with a K, M, or G suffix, case insensitive. - Default is 1MB. - -*autodefrag*:: -*noautodefrag*:: - (since: 3.0, default: off) + - Disable/enable auto defragmentation. - Auto defragmentation detects small random writes into files and queue - them up for the defrag process. Works best for small files; - Not well suited for large database workloads. - -*check_int*:: -*check_int_data*:: -*check_int_print_mask='value'*:: - (since: 3.0, default: off) + - These debugging options control the behavior of the integrity checking - module (the BTRFS_FS_CHECK_INTEGRITY config option required). + - + - `check_int` enables the integrity checker module, which examines all - block write requests to ensure on-disk consistency, at a large - memory and CPU cost. + - + - `check_int_data` includes extent data in the integrity checks, and - implies the check_int option. + - + - `check_int_print_mask` takes a bitmask of BTRFSIC_PRINT_MASK_* values - as defined in 'fs/btrfs/check-integrity.c', to control the integrity - checker module behavior. + - + - See comments at the top of 'fs/btrfs/check-integrity.c' - for more info. - -*commit='seconds'*:: - (since: 3.12, default: 30) + - Set the interval of periodic commit. Higher - values defer data being synced to permanent storage with obvious - consequences when the system crashes. The upper bound is not forced, - but a warning is printed if it's more than 300 seconds (5 minutes). - -*compress*:: -*compress='type'*:: -*compress-force*:: -*compress-force='type'*:: - (default: off) + - Control BTRFS file data compression. Type may be specified as 'zlib', - 'lzo' or 'no' (for no compression, used for remounting). If no type - is specified, 'zlib' is used. If compress-force is specified, - all files will be compressed, whether or not they compress well. - NOTE: If compression is enabled, 'nodatacow' and 'nodatasum' are disabled. - -*degraded*:: - (default: off) + - Allow mounts to continue with missing devices. A read-write mount may - fail with too many devices missing, for example if a stripe member - is completely missing. - -*device='devicepath'*:: - Specify a device during mount so that ioctls on the control device - can be avoided. Especially useful when trying to mount a multi-device - setup as root. May be specified multiple times for multiple devices. - -*discard*:: -*nodiscard*:: - (default: off) + - Disable/enable discard mount option. - Discard issues frequent commands to let the block device reclaim space - freed by the filesystem. - This is useful for SSD devices, thinly provisioned - LUNs and virtual machine images, but may have a significant - performance impact. (The fstrim command is also available to - initiate batch trims from userspace). - -*enospc_debug*:: - (default: off) + - Disable/enable debugging option to be more verbose in some ENOSPC conditions. - -*fatal_errors='action'*:: - (since: 3.4, default: bug) + - Action to take when encountering a fatal error. + - "bug" - BUG() on a fatal error. + - "panic" - panic() on a fatal error. - -*flushoncommit*:: -*noflushoncommit*:: - (default: on) + - The `flushoncommit` mount option forces any data dirtied by a write in a - prior transaction to commit as part of the current commit. This makes - the committed state a fully consistent view of the file system from the - application's perspective (i.e., it includes all completed file system - operations). This was previously the behavior only when a snapshot is - created. - -*inode_cache*:: -*noinode_cache*:: - (since: 3.0, default: off) + - Enable free inode number caching. Defaults to off due to an overflow - problem when the free space crcs don't fit inside a single page. - -*max_inline='bytes'*:: - (default: min(8192, page size) ) - Specify the maximum amount of space, in bytes, that can be inlined in - a metadata B-tree leaf. The value is specified in bytes, optionally - with a K, M, or G suffix, case insensitive. In practice, this value - is limited by the root sector size, with some space unavailable due - to leaf headers. For a 4k sectorsize, max inline data is ~3900 bytes. - -*metadata_ratio='value'*:: - Specify that 1 metadata chunk should be allocated after every - 'value' data chunks. Off by default. - -*acl*:: -*noacl*:: - (default: on) + - Enable/disable support for Posix Access Control Lists (ACLs). See the - `acl`(5) manual page for more information about ACLs. - -*barrier*:: -*nobarrier*:: - (default: on) + - ensure that certain IOs make it through the device cache and are on - persistent storage. If disabled on a device with a volatile - (non-battery-backed) write-back cache, nobarrier option will lead to - filesystem corruption on a system crash or power loss. - -*datacow*:: -*nodatacow*:: - (default: on) + - Enable/disable data copy-on-write for newly created files. - Nodatacow implies nodatasum, and disables all compression. - -*datasum*:: -*nodatasum*:: - (default: on) + - Enable/disable data checksumming for newly created files. - Datasum implies datacow. - -*treelog*:: -*notreelog*:: - (default: on) + - Enable/disable the tree logging used for fsync and O_SYNC writes. - -*recovery*:: - (since: 3.2, default: off) + - Enable autorecovery attempts if a bad tree root is found at mount time. - Currently this scans a list of several previous tree roots and tries to - use the first readable. - -*rescan_uuid_tree*:: - (since: 3.12, default: off) + - Force check and rebuild procedure of the UUID tree. This should not - normally be needed. - -*skip_balance*:: - (since: 3.3, default: off) + - Skip automatic resume of interrupted balance operation after mount. - May be resumed with "btrfs balance resume." - -*nospace_cache*:: - (since: 3.2) + - Disable freespace cache loading without clearing the cache. - -*clear_cache*:: - Force clearing and rebuilding of the disk space cache if something - has gone wrong. - -*ssd*:: -*nossd*:: -*ssd_spread*:: - Options to control ssd allocation schemes. By default, BTRFS will - enable or disable ssd allocation heuristics depending on whether a - rotational or nonrotational disk is in use. The ssd and nossd options - can override this autodetection. + - The ssd_spread mount option attempts to allocate into big chunks - of unused space, and may perform better on low-end ssds. ssd_spread - implies ssd, enabling all other ssd heuristics as well. - -*subvol='path'*:: - Mount subvolume at 'path' rather than the root subvolume. The - 'path' is relative to the top level subvolume. - -*subvolid='ID'*:: - Mount subvolume specified by an ID number rather than the root subvolume. - This allows mounting of subvolumes which are not in the root of the mounted - filesystem. - You can use "btrfs subvolume list" to see subvolume ID numbers. - -*subvolrootid='objectid'*:: - (deprecated) + - Mount subvolume specified by 'objectid' rather than the root subvolume. - This allows mounting of subvolumes which are not in the root of the mounted - filesystem. - You can use "btrfs subvolume show" to see the object ID for a subvolume. - -*thread_pool='number'*:: - The number of worker threads to allocate. The default number is equal - to the number of CPUs + 2, or 8, whichever is smaller. - -*user_subvol_rm_allowed*:: - (default: off) + - Allow subvolumes to be deleted by a non-root user. Use with caution. - -FILE ATTRIBUTES ---------------- -The btrfs filesystem supports setting the following file -attributes the `chattr`(1) utility - -*a* -- append only - -*A* -- no atime updates - -*c* -- compressed - -*C* -- no copy on write - -*d* -- no dump - -*D* -- synchronous directory updates - -*i* -- immutable - -*S* -- synchronous updates - -*X* -- no compression - -For descriptions of these attribute flags, please refer to the -`chattr`(1) man page. - -SEE ALSO --------- -`chattr`(1), -`mkfs.btrfs`(8), -`mount`(8), -`btrfs`(8) |