diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/dax.rst | 1 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/atomic_writes.rst | 10 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/bitmaps.rst | 7 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/blockgroup.rst | 11 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/dynamic.rst | 10 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/globals.rst | 15 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/index.rst | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/inode_table.rst | 9 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/overview.rst | 22 | ||||
| -rw-r--r-- | Documentation/filesystems/f2fs.rst | 4 | ||||
| -rw-r--r-- | Documentation/filesystems/overlayfs.rst | 26 | ||||
| -rw-r--r-- | Documentation/filesystems/proc.rst | 8 | ||||
| -rw-r--r-- | Documentation/filesystems/ubifs-authentication.rst | 2 |
13 files changed, 70 insertions, 57 deletions
diff --git a/Documentation/filesystems/dax.rst b/Documentation/filesystems/dax.rst index 08dd5e254cc5..5b283f3d1eb1 100644 --- a/Documentation/filesystems/dax.rst +++ b/Documentation/filesystems/dax.rst @@ -206,7 +206,6 @@ stall the CPU for an extended period, you should also not attempt to implement direct_access. These block devices may be used for inspiration: -- brd: RAM backed block device driver - pmem: NVDIMM persistent memory driver diff --git a/Documentation/filesystems/ext4/atomic_writes.rst b/Documentation/filesystems/ext4/atomic_writes.rst index f65767df3620..aeb47ace738d 100644 --- a/Documentation/filesystems/ext4/atomic_writes.rst +++ b/Documentation/filesystems/ext4/atomic_writes.rst @@ -148,10 +148,10 @@ reserved during: only required to handle a split extent across leaf blocks. How to ------- +~~~~~~ Creating Filesystems with Atomic Write Support -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ First check the atomic write units supported by block device. See :ref:`atomic_write_bdev_support` for more details. @@ -176,7 +176,7 @@ Where ``-b`` specifies the block size, ``-C`` specifies the cluster size in byte and ``-O bigalloc`` enables the bigalloc feature. Application Interface -~~~~~~~~~~~~~~~~~~~~~ +^^^^^^^^^^^^^^^^^^^^^ Applications can use the ``pwritev2()`` system call with the ``RWF_ATOMIC`` flag to perform atomic writes: @@ -204,7 +204,7 @@ writes are supported. .. _atomic_write_bdev_support: Hardware Support ----------------- +~~~~~~~~~~~~~~~~ The underlying storage device must support atomic write operations. Modern NVMe and SCSI devices often provide this capability. @@ -217,7 +217,7 @@ Nonzero values for these attributes indicate that the device supports atomic writes. See Also --------- +~~~~~~~~ * :doc:`bigalloc` - Documentation on the bigalloc feature * :doc:`allocators` - Documentation on block allocation in ext4 diff --git a/Documentation/filesystems/ext4/bitmaps.rst b/Documentation/filesystems/ext4/bitmaps.rst index 91c45d86e9bb..9d7d7b083a25 100644 --- a/Documentation/filesystems/ext4/bitmaps.rst +++ b/Documentation/filesystems/ext4/bitmaps.rst @@ -19,10 +19,3 @@ necessarily the case that no blocks are in use -- if ``meta_bg`` is set, the bitmaps and group descriptor live inside the group. Unfortunately, ext2fs_test_block_bitmap2() will return '0' for those locations, which produces confusing debugfs output. - -Inode Table ------------ -Inode tables are statically allocated at mkfs time. Each block group -descriptor points to the start of the table, and the superblock records -the number of inodes per group. See the section on inodes for more -information. diff --git a/Documentation/filesystems/ext4/blockgroup.rst b/Documentation/filesystems/ext4/blockgroup.rst index ed5a5cac6d40..7cbf0b2b778e 100644 --- a/Documentation/filesystems/ext4/blockgroup.rst +++ b/Documentation/filesystems/ext4/blockgroup.rst @@ -1,7 +1,10 @@ .. SPDX-License-Identifier: GPL-2.0 +Block Groups +------------ + Layout ------- +~~~~~~ The layout of a standard block group is approximately as follows (each of these fields is discussed in a separate section below): @@ -60,7 +63,7 @@ groups (flex_bg). Leftover space is used for file data blocks, indirect block maps, extent tree blocks, and extended attributes. Flexible Block Groups ---------------------- +~~~~~~~~~~~~~~~~~~~~~ Starting in ext4, there is a new feature called flexible block groups (flex_bg). In a flex_bg, several block groups are tied together as one @@ -78,7 +81,7 @@ if flex_bg is enabled. The number of block groups that make up a flex_bg is given by 2 ^ ``sb.s_log_groups_per_flex``. Meta Block Groups ------------------ +~~~~~~~~~~~~~~~~~ Without the option META_BG, for safety concerns, all block group descriptors copies are kept in the first block group. Given the default @@ -117,7 +120,7 @@ Please see an important note about ``BLOCK_UNINIT`` in the section about block and inode bitmaps. Lazy Block Group Initialization -------------------------------- +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A new feature for ext4 are three block group descriptor flags that enable mkfs to skip initializing other parts of the block group diff --git a/Documentation/filesystems/ext4/dynamic.rst b/Documentation/filesystems/ext4/dynamic.rst index bb0c84333341..bbad439aada2 100644 --- a/Documentation/filesystems/ext4/dynamic.rst +++ b/Documentation/filesystems/ext4/dynamic.rst @@ -6,7 +6,9 @@ Dynamic Structures Dynamic metadata are created on the fly when files and blocks are allocated to files. -.. include:: inodes.rst -.. include:: ifork.rst -.. include:: directory.rst -.. include:: attributes.rst +.. toctree:: + + inodes + ifork + directory + attributes diff --git a/Documentation/filesystems/ext4/globals.rst b/Documentation/filesystems/ext4/globals.rst index b17418974fd3..c6a6abce818a 100644 --- a/Documentation/filesystems/ext4/globals.rst +++ b/Documentation/filesystems/ext4/globals.rst @@ -6,9 +6,12 @@ Global Structures The filesystem is sharded into a number of block groups, each of which have static metadata at fixed locations. -.. include:: super.rst -.. include:: group_descr.rst -.. include:: bitmaps.rst -.. include:: mmp.rst -.. include:: journal.rst -.. include:: orphan.rst +.. toctree:: + + super + group_descr + bitmaps + inode_table + mmp + journal + orphan diff --git a/Documentation/filesystems/ext4/index.rst b/Documentation/filesystems/ext4/index.rst index 705d813d558f..1ff8150c50e9 100644 --- a/Documentation/filesystems/ext4/index.rst +++ b/Documentation/filesystems/ext4/index.rst @@ -5,7 +5,7 @@ ext4 Data Structures and Algorithms =================================== .. toctree:: - :maxdepth: 6 + :maxdepth: 2 :numbered: about diff --git a/Documentation/filesystems/ext4/inode_table.rst b/Documentation/filesystems/ext4/inode_table.rst new file mode 100644 index 000000000000..f7900a52c0d5 --- /dev/null +++ b/Documentation/filesystems/ext4/inode_table.rst @@ -0,0 +1,9 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Inode Table +----------- + +Inode tables are statically allocated at mkfs time. Each block group +descriptor points to the start of the table, and the superblock records +the number of inodes per group. See :doc:`inode documentation <inodes>` +for more information on inode table layout. diff --git a/Documentation/filesystems/ext4/overview.rst b/Documentation/filesystems/ext4/overview.rst index 9d4054c17ecb..171c3963d7f6 100644 --- a/Documentation/filesystems/ext4/overview.rst +++ b/Documentation/filesystems/ext4/overview.rst @@ -16,13 +16,15 @@ All fields in ext4 are written to disk in little-endian order. HOWEVER, all fields in jbd2 (the journal) are written to disk in big-endian order. -.. include:: blocks.rst -.. include:: blockgroup.rst -.. include:: special_inodes.rst -.. include:: allocators.rst -.. include:: checksums.rst -.. include:: bigalloc.rst -.. include:: inlinedata.rst -.. include:: eainode.rst -.. include:: verity.rst -.. include:: atomic_writes.rst +.. toctree:: + + blocks + blockgroup + special_inodes + allocators + checksums + bigalloc + inlinedata + eainode + verity + atomic_writes diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst index 440e4ae74e44..8eeb7ea14f61 100644 --- a/Documentation/filesystems/f2fs.rst +++ b/Documentation/filesystems/f2fs.rst @@ -218,7 +218,7 @@ mode=%s Control block allocation mode which supports "adaptive" fragmentation/after-GC situation itself. The developers use these modes to understand filesystem fragmentation/after-GC condition well, and eventually get some insights to handle them better. - In "fragment:segment", f2fs allocates a new segment in ramdom + In "fragment:segment", f2fs allocates a new segment in random position. With this, we can simulate the after-GC condition. In "fragment:block", we can scatter block allocation with "max_fragment_chunk" and "max_fragment_hole" sysfs nodes. @@ -261,7 +261,7 @@ test_dummy_encryption=%s The argument may be either "v1" or "v2", in order to select the corresponding fscrypt policy version. checkpoint=%s[:%u[%]] Set to "disable" to turn off checkpointing. Set to "enable" - to reenable checkpointing. Is enabled by default. While + to re-enable checkpointing. Is enabled by default. While disabled, any unmounting or unexpected shutdowns will cause the filesystem contents to appear as they did when the filesystem was mounted with that option. diff --git a/Documentation/filesystems/overlayfs.rst b/Documentation/filesystems/overlayfs.rst index 4133a336486d..ab989807a2cb 100644 --- a/Documentation/filesystems/overlayfs.rst +++ b/Documentation/filesystems/overlayfs.rst @@ -9,7 +9,7 @@ Overlay Filesystem This document describes a prototype for a new approach to providing overlay-filesystem functionality in Linux (sometimes referred to as union-filesystems). An overlay-filesystem tries to present a -filesystem which is the result over overlaying one filesystem on top +filesystem which is the result of overlaying one filesystem on top of the other. @@ -61,7 +61,7 @@ Inode properties |Configuration | Persistent | Uniform | st_ino == d_ino | d_ino == i_ino | | | st_ino | st_dev | | [*] | +==============+=====+======+=====+======+========+========+========+=======+ -| | dir | !dir | dir | !dir | dir + !dir | dir | !dir | +| | dir | !dir | dir | !dir | dir | !dir | dir | !dir | +--------------+-----+------+-----+------+--------+--------+--------+-------+ | All layers | Y | Y | Y | Y | Y | Y | Y | Y | | on same fs | | | | | | | | | @@ -425,7 +425,7 @@ of information from up to three different layers: The "lower data" file can be on any lower layer, except from the top most lower layer. -Below the top most lower layer, any number of lower most layers may be defined +Below the topmost lower layer, any number of lowermost layers may be defined as "data-only" lower layers, using double colon ("::") separators. A normal lower layer is not allowed to be below a data-only layer, so single colon separators are not allowed to the right of double colon ("::") separators. @@ -445,8 +445,8 @@ to the absolute path of the "lower data" file in the "data-only" lower layer. Instead of explicitly enabling "metacopy=on" it is sufficient to specify at least one data-only layer to enable redirection of data to a data-only layer. -In this case other forms of metacopy are rejected. Note: this way data-only -layers may be used toghether with "userxattr", in which case careful attention +In this case other forms of metacopy are rejected. Note: this way, data-only +layers may be used together with "userxattr", in which case careful attention must be given to privileges needed to change the "user.overlay.redirect" xattr to prevent misuse. @@ -515,7 +515,7 @@ supports these values: The metacopy digest is never generated or used. This is the default if verity option is not specified. - "on": - Whenever a metacopy files specifies an expected digest, the + Whenever a metacopy file specifies an expected digest, the corresponding data file must match the specified digest. When generating a metacopy file the verity digest will be set in it based on the source file (if it has one). @@ -537,7 +537,7 @@ Using an upper layer path and/or a workdir path that are already used by another overlay mount is not allowed and may fail with EBUSY. Using partially overlapping paths is not allowed and may fail with EBUSY. If files are accessed from two overlayfs mounts which share or overlap the -upper layer and/or workdir path the behavior of the overlay is undefined, +upper layer and/or workdir path, the behavior of the overlay is undefined, though it will not result in a crash or deadlock. Mounting an overlay using an upper layer path, where the upper layer path @@ -778,7 +778,7 @@ controlled by the "uuid" mount option, which supports these values: - "auto": (default) UUID is taken from xattr "trusted.overlay.uuid" if it exists. Upgrade to "uuid=on" on first time mount of new overlay filesystem that - meets the prerequites. + meets the prerequisites. Downgrade to "uuid=null" for existing overlay filesystems that were never mounted with "uuid=on". @@ -794,20 +794,20 @@ without significant effort. The advantage of mounting with the "volatile" option is that all forms of sync calls to the upper filesystem are omitted. -In order to avoid a giving a false sense of safety, the syncfs (and fsync) +In order to avoid giving a false sense of safety, the syncfs (and fsync) semantics of volatile mounts are slightly different than that of the rest of VFS. If any writeback error occurs on the upperdir's filesystem after a volatile mount takes place, all sync functions will return an error. Once this condition is reached, the filesystem will not recover, and every subsequent sync -call will return an error, even if the upperdir has not experience a new error +call will return an error, even if the upperdir has not experienced a new error since the last sync call. When overlay is mounted with "volatile" option, the directory "$workdir/work/incompat/volatile" is created. During next mount, overlay checks for this directory and refuses to mount if present. This is a strong -indicator that user should throw away upper and work directories and create -fresh one. In very limited cases where the user knows that the system has -not crashed and contents of upperdir are intact, The "volatile" directory +indicator that the user should discard upper and work directories and create +fresh ones. In very limited cases where the user knows that the system has +not crashed and contents of upperdir are intact, the "volatile" directory can be removed. diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst index 5236cb52e357..2971551b7235 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -1196,12 +1196,14 @@ SecPageTables Memory consumed by secondary page tables, this currently includes KVM mmu and IOMMU allocations on x86 and arm64. NFS_Unstable - Always zero. Previous counted pages which had been written to + Always zero. Previously counted pages which had been written to the server, but has not been committed to stable storage. Bounce - Memory used for block device "bounce buffers" + Always zero. Previously memory used for block device + "bounce buffers". WritebackTmp - Memory used by FUSE for temporary writeback buffers + Always zero. Previously memory used by FUSE for temporary + writeback buffers. CommitLimit Based on the overcommit ratio ('vm.overcommit_ratio'), this is the total amount of memory currently available to diff --git a/Documentation/filesystems/ubifs-authentication.rst b/Documentation/filesystems/ubifs-authentication.rst index 3d85ee88719a..106bb9c056f6 100644 --- a/Documentation/filesystems/ubifs-authentication.rst +++ b/Documentation/filesystems/ubifs-authentication.rst @@ -443,6 +443,6 @@ References [DM-VERITY] https://www.kernel.org/doc/Documentation/device-mapper/verity.rst -[FSCRYPT-POLICY2] https://www.spinics.net/lists/linux-ext4/msg58710.html +[FSCRYPT-POLICY2] https://lore.kernel.org/r/20171023214058.128121-1-ebiggers3@gmail.com/ [UBIFS-WP] http://www.linux-mtd.infradead.org/doc/ubifs_whitepaper.pdf |