diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/f2fs.rst | 82 | ||||
| -rw-r--r-- | Documentation/filesystems/fscrypt.rst | 74 | ||||
| -rw-r--r-- | Documentation/filesystems/fsverity.rst | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/fuse.rst | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/index.rst | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/locking.rst | 3 | ||||
| -rw-r--r-- | Documentation/filesystems/mount_api.rst | 7 | ||||
| -rw-r--r-- | Documentation/filesystems/overlayfs.rst | 19 | ||||
| -rw-r--r-- | Documentation/filesystems/seq_file.rst | 20 | ||||
| -rw-r--r-- | Documentation/filesystems/sysfs-pci.rst | 138 | ||||
| -rw-r--r-- | Documentation/filesystems/sysfs-tagging.rst | 48 | ||||
| -rw-r--r-- | Documentation/filesystems/sysfs.rst | 11 | ||||
| -rw-r--r-- | Documentation/filesystems/ubifs-authentication.rst | 6 | ||||
| -rw-r--r-- | Documentation/filesystems/zonefs.rst | 15 |
14 files changed, 169 insertions, 260 deletions
diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst index ec8d99703ecb..b8ee761c9922 100644 --- a/Documentation/filesystems/f2fs.rst +++ b/Documentation/filesystems/f2fs.rst @@ -127,14 +127,14 @@ active_logs=%u Support configuring the number of active logs. In the current design, f2fs supports only 2, 4, and 6 logs. Default number is 6. disable_ext_identify Disable the extension list configured by mkfs, so f2fs - does not aware of cold files such as media files. + is not aware of cold files such as media files. inline_xattr Enable the inline xattrs feature. noinline_xattr Disable the inline xattrs feature. inline_xattr_size=%u Support configuring inline xattr size, it depends on flexible inline xattr feature. -inline_data Enable the inline data feature: New created small(<~3.4k) +inline_data Enable the inline data feature: Newly created small (<~3.4k) files can be written into inode block. -inline_dentry Enable the inline dir feature: data in new created +inline_dentry Enable the inline dir feature: data in newly created directory entries can be written into inode block. The space of inode block which is used to store inline dentries is limited to ~3.4k. @@ -203,9 +203,9 @@ usrjquota=<file> Appoint specified file and type during mount, so that quota grpjquota=<file> information can be properly updated during recovery flow, prjjquota=<file> <quota file>: must be in root directory; jqfmt=<quota type> <quota type>: [vfsold,vfsv0,vfsv1]. -offusrjquota Turn off user journelled quota. -offgrpjquota Turn off group journelled quota. -offprjjquota Turn off project journelled quota. +offusrjquota Turn off user journalled quota. +offgrpjquota Turn off group journalled quota. +offprjjquota Turn off project journalled quota. quota Enable plain user disk quota accounting. noquota Disable all plain disk quota option. whint_mode=%s Control which write hints are passed down to block @@ -266,6 +266,8 @@ inlinecrypt When possible, encrypt/decrypt the contents of encrypted inline encryption hardware. The on-disk format is unaffected. For more details, see Documentation/block/inline-encryption.rst. +atgc Enable age-threshold garbage collection, it provides high + effectiveness and efficiency on background GC. ======================== ============================================================ Debugfs Entries @@ -301,7 +303,7 @@ Usage # insmod f2fs.ko -3. Create a directory trying to mount:: +3. Create a directory to use when mounting:: # mkdir /mnt/f2fs @@ -315,7 +317,7 @@ mkfs.f2fs The mkfs.f2fs is for the use of formatting a partition as the f2fs filesystem, which builds a basic on-disk layout. -The options consist of: +The quick options consist of: =============== =========================================================== ``-l [label]`` Give a volume label, up to 512 unicode name. @@ -337,6 +339,8 @@ The options consist of: 1 is set by default, which conducts discard. =============== =========================================================== +Note: please refer to the manpage of mkfs.f2fs(8) to get full option list. + fsck.f2fs --------- The fsck.f2fs is a tool to check the consistency of an f2fs-formatted @@ -344,10 +348,12 @@ partition, which examines whether the filesystem metadata and user-made data are cross-referenced correctly or not. Note that, initial version of the tool does not fix any inconsistency. -The options consist of:: +The quick options consist of:: -d debug level [default:0] +Note: please refer to the manpage of fsck.f2fs(8) to get full option list. + dump.f2fs --------- The dump.f2fs shows the information of specific inode and dumps SSA and SIT to @@ -371,6 +377,37 @@ Examples:: # dump.f2fs -s 0~-1 /dev/sdx (SIT dump) # dump.f2fs -a 0~-1 /dev/sdx (SSA dump) +Note: please refer to the manpage of dump.f2fs(8) to get full option list. + +sload.f2fs +---------- +The sload.f2fs gives a way to insert files and directories in the exisiting disk +image. This tool is useful when building f2fs images given compiled files. + +Note: please refer to the manpage of sload.f2fs(8) to get full option list. + +resize.f2fs +----------- +The resize.f2fs lets a user resize the f2fs-formatted disk image, while preserving +all the files and directories stored in the image. + +Note: please refer to the manpage of resize.f2fs(8) to get full option list. + +defrag.f2fs +----------- +The defrag.f2fs can be used to defragment scattered written data as well as +filesystem metadata across the disk. This can improve the write speed by giving +more free consecutive space. + +Note: please refer to the manpage of defrag.f2fs(8) to get full option list. + +f2fs_io +------- +The f2fs_io is a simple tool to issue various filesystem APIs as well as +f2fs-specific ones, which is very useful for QA tests. + +Note: please refer to the manpage of f2fs_io(8) to get full option list. + Design ====== @@ -383,7 +420,7 @@ consists of a set of sections. By default, section and zone sizes are set to one segment size identically, but users can easily modify the sizes by mkfs. F2FS splits the entire volume into six areas, and all the areas except superblock -consists of multiple segments as described below:: +consist of multiple segments as described below:: align with the zone size <-| |-> align with the segment size @@ -486,7 +523,7 @@ one inode block (i.e., a file) covers:: `- direct node (1018) `- data (1018) -Note that, all the node blocks are mapped by NAT which means the location of +Note that all the node blocks are mapped by NAT which means the location of each node is translated by the NAT table. In the consideration of the wandering tree problem, F2FS is able to cut off the propagation of node updates caused by leaf data writes. @@ -566,7 +603,7 @@ When F2FS finds a file name in a directory, at first a hash value of the file name is calculated. Then, F2FS scans the hash table in level #0 to find the dentry consisting of the file name and its inode number. If not found, F2FS scans the next hash table in level #1. In this way, F2FS scans hash tables in -each levels incrementally from 1 to N. In each levels F2FS needs to scan only +each levels incrementally from 1 to N. In each level F2FS needs to scan only one bucket determined by the following equation, which shows O(log(# of files)) complexity:: @@ -707,7 +744,7 @@ WRITE_LIFE_LONG " WRITE_LIFE_LONG Fallocate(2) Policy ------------------- -The default policy follows the below posix rule. +The default policy follows the below POSIX rule. Allocating disk space The default operation (i.e., mode is zero) of fallocate() allocates @@ -720,7 +757,7 @@ Allocating disk space as a method of optimally implementing that function. However, once F2FS receives ioctl(fd, F2FS_IOC_SET_PIN_FILE) in prior to -fallocate(fd, DEFAULT_MODE), it allocates on-disk blocks addressess having +fallocate(fd, DEFAULT_MODE), it allocates on-disk block addressess having zero or random data, which is useful to the below scenario where: 1. create(fd) @@ -739,7 +776,7 @@ Compression implementation cluster can be compressed or not. - In cluster metadata layout, one special block address is used to indicate - cluster is compressed one or normal one, for compressed cluster, following + a cluster is a compressed one or normal one; for compressed cluster, following metadata maps cluster to [1, 4 << n - 1] physical blocks, in where f2fs stores data including compress header and compressed data. @@ -772,3 +809,18 @@ Compress metadata layout:: +-------------+-------------+----------+----------------------------+ | data length | data chksum | reserved | compressed data | +-------------+-------------+----------+----------------------------+ + +NVMe Zoned Namespace devices +---------------------------- + +- ZNS defines a per-zone capacity which can be equal or less than the + zone-size. Zone-capacity is the number of usable blocks in the zone. + F2FS checks if zone-capacity is less than zone-size, if it is, then any + segment which starts after the zone-capacity is marked as not-free in + the free segment bitmap at initial mount time. These segments are marked + as permanently used so they are not allocated for writes and + consequently are not needed to be garbage collected. In case the + zone-capacity is not aligned to default segment size(2MB), then a segment + can start before the zone-capacity and span across zone-capacity boundary. + Such spanning segments are also considered as usable segments. All blocks + past the zone-capacity are considered unusable in these segments. diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index 423c5a0daf45..44b67ebd6e40 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -436,9 +436,9 @@ FS_IOC_SET_ENCRYPTION_POLICY The FS_IOC_SET_ENCRYPTION_POLICY ioctl sets an encryption policy on an empty directory or verifies that a directory or regular file already -has the specified encryption policy. It takes in a pointer to a -:c:type:`struct fscrypt_policy_v1` or a :c:type:`struct -fscrypt_policy_v2`, defined as follows:: +has the specified encryption policy. It takes in a pointer to +struct fscrypt_policy_v1 or struct fscrypt_policy_v2, defined as +follows:: #define FSCRYPT_POLICY_V1 0 #define FSCRYPT_KEY_DESCRIPTOR_SIZE 8 @@ -464,11 +464,11 @@ fscrypt_policy_v2`, defined as follows:: This structure must be initialized as follows: -- ``version`` must be FSCRYPT_POLICY_V1 (0) if the struct is - :c:type:`fscrypt_policy_v1` or FSCRYPT_POLICY_V2 (2) if the struct - is :c:type:`fscrypt_policy_v2`. (Note: we refer to the original - policy version as "v1", though its version code is really 0.) For - new encrypted directories, use v2 policies. +- ``version`` must be FSCRYPT_POLICY_V1 (0) if + struct fscrypt_policy_v1 is used or FSCRYPT_POLICY_V2 (2) if + struct fscrypt_policy_v2 is used. (Note: we refer to the original + policy version as "v1", though its version code is really 0.) + For new encrypted directories, use v2 policies. - ``contents_encryption_mode`` and ``filenames_encryption_mode`` must be set to constants from ``<linux/fscrypt.h>`` which identify the @@ -508,9 +508,9 @@ This structure must be initialized as follows: replaced with ``master_key_identifier``, which is longer and cannot be arbitrarily chosen. Instead, the key must first be added using `FS_IOC_ADD_ENCRYPTION_KEY`_. Then, the ``key_spec.u.identifier`` - the kernel returned in the :c:type:`struct fscrypt_add_key_arg` must - be used as the ``master_key_identifier`` in the :c:type:`struct - fscrypt_policy_v2`. + the kernel returned in the struct fscrypt_add_key_arg must + be used as the ``master_key_identifier`` in + struct fscrypt_policy_v2. If the file is not yet encrypted, then FS_IOC_SET_ENCRYPTION_POLICY verifies that the file is an empty directory. If so, the specified @@ -590,7 +590,7 @@ FS_IOC_GET_ENCRYPTION_POLICY_EX The FS_IOC_GET_ENCRYPTION_POLICY_EX ioctl retrieves the encryption policy, if any, for a directory or regular file. No additional permissions are required beyond the ability to open the file. It -takes in a pointer to a :c:type:`struct fscrypt_get_policy_ex_arg`, +takes in a pointer to struct fscrypt_get_policy_ex_arg, defined as follows:: struct fscrypt_get_policy_ex_arg { @@ -637,9 +637,8 @@ The FS_IOC_GET_ENCRYPTION_POLICY ioctl can also retrieve the encryption policy, if any, for a directory or regular file. However, unlike `FS_IOC_GET_ENCRYPTION_POLICY_EX`_, FS_IOC_GET_ENCRYPTION_POLICY only supports the original policy -version. It takes in a pointer directly to a :c:type:`struct -fscrypt_policy_v1` rather than a :c:type:`struct -fscrypt_get_policy_ex_arg`. +version. It takes in a pointer directly to struct fscrypt_policy_v1 +rather than struct fscrypt_get_policy_ex_arg. The error codes for FS_IOC_GET_ENCRYPTION_POLICY are the same as those for FS_IOC_GET_ENCRYPTION_POLICY_EX, except that @@ -680,8 +679,7 @@ the filesystem, making all files on the filesystem which were encrypted using that key appear "unlocked", i.e. in plaintext form. It can be executed on any file or directory on the target filesystem, but using the filesystem's root directory is recommended. It takes in -a pointer to a :c:type:`struct fscrypt_add_key_arg`, defined as -follows:: +a pointer to struct fscrypt_add_key_arg, defined as follows:: struct fscrypt_add_key_arg { struct fscrypt_key_specifier key_spec; @@ -710,17 +708,16 @@ follows:: __u8 raw[]; }; -:c:type:`struct fscrypt_add_key_arg` must be zeroed, then initialized +struct fscrypt_add_key_arg must be zeroed, then initialized as follows: - If the key is being added for use by v1 encryption policies, then ``key_spec.type`` must contain FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR, and ``key_spec.u.descriptor`` must contain the descriptor of the key being added, corresponding to the value in the - ``master_key_descriptor`` field of :c:type:`struct - fscrypt_policy_v1`. To add this type of key, the calling process - must have the CAP_SYS_ADMIN capability in the initial user - namespace. + ``master_key_descriptor`` field of struct fscrypt_policy_v1. + To add this type of key, the calling process must have the + CAP_SYS_ADMIN capability in the initial user namespace. Alternatively, if the key is being added for use by v2 encryption policies, then ``key_spec.type`` must contain @@ -737,12 +734,13 @@ as follows: - ``key_id`` is 0 if the raw key is given directly in the ``raw`` field. Otherwise ``key_id`` is the ID of a Linux keyring key of - type "fscrypt-provisioning" whose payload is a :c:type:`struct - fscrypt_provisioning_key_payload` whose ``raw`` field contains the - raw key and whose ``type`` field matches ``key_spec.type``. Since - ``raw`` is variable-length, the total size of this key's payload - must be ``sizeof(struct fscrypt_provisioning_key_payload)`` plus the - raw key size. The process must have Search permission on this key. + type "fscrypt-provisioning" whose payload is + struct fscrypt_provisioning_key_payload whose ``raw`` field contains + the raw key and whose ``type`` field matches ``key_spec.type``. + Since ``raw`` is variable-length, the total size of this key's + payload must be ``sizeof(struct fscrypt_provisioning_key_payload)`` + plus the raw key size. The process must have Search permission on + this key. Most users should leave this 0 and specify the raw key directly. The support for specifying a Linux keyring key is intended mainly to @@ -860,8 +858,8 @@ The FS_IOC_REMOVE_ENCRYPTION_KEY ioctl removes a claim to a master encryption key from the filesystem, and possibly removes the key itself. It can be executed on any file or directory on the target filesystem, but using the filesystem's root directory is recommended. -It takes in a pointer to a :c:type:`struct fscrypt_remove_key_arg`, -defined as follows:: +It takes in a pointer to struct fscrypt_remove_key_arg, defined +as follows:: struct fscrypt_remove_key_arg { struct fscrypt_key_specifier key_spec; @@ -956,8 +954,8 @@ FS_IOC_GET_ENCRYPTION_KEY_STATUS The FS_IOC_GET_ENCRYPTION_KEY_STATUS ioctl retrieves the status of a master encryption key. It can be executed on any file or directory on the target filesystem, but using the filesystem's root directory is -recommended. It takes in a pointer to a :c:type:`struct -fscrypt_get_key_status_arg`, defined as follows:: +recommended. It takes in a pointer to +struct fscrypt_get_key_status_arg, defined as follows:: struct fscrypt_get_key_status_arg { /* input */ @@ -1148,10 +1146,10 @@ Implementation details Encryption context ------------------ -An encryption policy is represented on-disk by a :c:type:`struct -fscrypt_context_v1` or a :c:type:`struct fscrypt_context_v2`. It is -up to individual filesystems to decide where to store it, but normally -it would be stored in a hidden extended attribute. It should *not* be +An encryption policy is represented on-disk by +struct fscrypt_context_v1 or struct fscrypt_context_v2. It is up to +individual filesystems to decide where to store it, but normally it +would be stored in a hidden extended attribute. It should *not* be exposed by the xattr-related system calls such as getxattr() and setxattr() because of the special semantics of the encryption xattr. (In particular, there would be much confusion if an encryption policy @@ -1249,8 +1247,8 @@ a strong "hash" of the ciphertext filename, along with the optional filesystem-specific hash(es) needed for directory lookups. This allows the filesystem to still, with a high degree of confidence, map the filename given in ->lookup() back to a particular directory entry -that was previously listed by readdir(). See :c:type:`struct -fscrypt_nokey_name` in the source for more details. +that was previously listed by readdir(). See +struct fscrypt_nokey_name in the source for more details. Note that the precise way that filenames are presented to userspace without the key is subject to change in the future. It is only meant diff --git a/Documentation/filesystems/fsverity.rst b/Documentation/filesystems/fsverity.rst index 6c8944f6f0f7..895e9711ed88 100644 --- a/Documentation/filesystems/fsverity.rst +++ b/Documentation/filesystems/fsverity.rst @@ -84,7 +84,7 @@ FS_IOC_ENABLE_VERITY -------------------- The FS_IOC_ENABLE_VERITY ioctl enables fs-verity on a file. It takes -in a pointer to a :c:type:`struct fsverity_enable_arg`, defined as +in a pointer to a struct fsverity_enable_arg, defined as follows:: struct fsverity_enable_arg { diff --git a/Documentation/filesystems/fuse.rst b/Documentation/filesystems/fuse.rst index cd717f9bf940..8120c3c0cb4e 100644 --- a/Documentation/filesystems/fuse.rst +++ b/Documentation/filesystems/fuse.rst @@ -47,7 +47,7 @@ filesystems. A good example is sshfs: a secure network filesystem using the sftp protocol. The userspace library and utilities are available from the -`FUSE homepage: <http://fuse.sourceforge.net/>`_ +`FUSE homepage: <https://github.com/libfuse/>`_ Filesystem type =============== diff --git a/Documentation/filesystems/index.rst b/Documentation/filesystems/index.rst index 4c536e66dc4c..98f59a864242 100644 --- a/Documentation/filesystems/index.rst +++ b/Documentation/filesystems/index.rst @@ -34,8 +34,6 @@ algorithms work. quota seq_file sharedsubtree - sysfs-pci - sysfs-tagging automount-support diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst index 64f94a18d97e..c0f2c7586531 100644 --- a/Documentation/filesystems/locking.rst +++ b/Documentation/filesystems/locking.rst @@ -488,9 +488,6 @@ getgeo: no swap_slot_free_notify: no (see below) ======================= =================== -unlock_native_capacity and revalidate_disk are called only from -check_disk_change(). - swap_slot_free_notify is called with swap_lock and sometimes the page lock held. diff --git a/Documentation/filesystems/mount_api.rst b/Documentation/filesystems/mount_api.rst index 29c169c68961..d7f53d62b5bb 100644 --- a/Documentation/filesystems/mount_api.rst +++ b/Documentation/filesystems/mount_api.rst @@ -1,7 +1,7 @@ .. SPDX-License-Identifier: GPL-2.0 ==================== -fILESYSTEM Mount API +Filesystem Mount API ==================== .. CONTENTS @@ -479,7 +479,7 @@ returned. int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param); - Supply a single mount parameter to the filesystem context. This include + Supply a single mount parameter to the filesystem context. This includes the specification of the source/device which is specified as the "source" parameter (which may be specified multiple times if the filesystem supports that). @@ -592,8 +592,7 @@ The following helpers all wrap sget_fc(): one. -===================== -PARAMETER DESCRIPTION +Parameter Description ===================== Parameters are described using structures defined in linux/fs_parser.h. diff --git a/Documentation/filesystems/overlayfs.rst b/Documentation/filesystems/overlayfs.rst index 8ea83a51c266..580ab9a0fe31 100644 --- a/Documentation/filesystems/overlayfs.rst +++ b/Documentation/filesystems/overlayfs.rst @@ -564,6 +564,25 @@ Note: the mount options index=off,nfs_export=on are conflicting for a read-write mount and will result in an error. +Volatile mount +-------------- + +This is enabled with the "volatile" mount option. Volatile mounts are not +guaranteed to survive a crash. It is strongly recommended that volatile +mounts are only used if data written to the overlay can be recreated +without significant effort. + +The advantage of mounting with the "volatile" option is that all forms of +sync calls to the upper filesystem are omitted. + +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 +can be removed. + Testsuite --------- diff --git a/Documentation/filesystems/seq_file.rst b/Documentation/filesystems/seq_file.rst index 7f7ee06b2693..56856481dc8d 100644 --- a/Documentation/filesystems/seq_file.rst +++ b/Documentation/filesystems/seq_file.rst @@ -129,7 +129,9 @@ also a special value which can be returned by the start() function called SEQ_START_TOKEN; it can be used if you wish to instruct your show() function (described below) to print a header at the top of the output. SEQ_START_TOKEN should only be used if the offset is zero, -however. +however. SEQ_START_TOKEN has no special meaning to the core seq_file +code. It is provided as a convenience for a start() funciton to +communicate with the next() and show() functions. The next function to implement is called, amazingly, next(); its job is to move the iterator forward to the next position in the sequence. The @@ -145,6 +147,22 @@ complete. Here's the example version:: return spos; } +The next() function should set ``*pos`` to a value that start() can use +to find the new location in the sequence. When the iterator is being +stored in the private data area, rather than being reinitialized on each +start(), it might seem sufficient to simply set ``*pos`` to any non-zero +value (zero always tells start() to restart the sequence). This is not +sufficient due to historical problems. + +Historically, many next() functions have *not* updated ``*pos`` at +end-of-file. If the value is then used by start() to initialise the +iterator, this can result in corner cases where the last entry in the +sequence is reported twice in the file. In order to discourage this bug +from being resurrected, the core seq_file code now produces a warning if +a next() function does not change the value of ``*pos``. Consequently a +next() function *must* change the value of ``*pos``, and of course must +set it to a non-zero value. + The stop() function closes a session; its job, of course, is to clean up. If dynamic memory is allocated for the iterator, stop() is the place to free it; if a lock was taken by start(), stop() must release diff --git a/Documentation/filesystems/sysfs-pci.rst b/Documentation/filesystems/sysfs-pci.rst deleted file mode 100644 index 742fbd21dc1f..000000000000 --- a/Documentation/filesystems/sysfs-pci.rst +++ /dev/null @@ -1,138 +0,0 @@ -.. SPDX-License-Identifier: GPL-2.0 - -============================================ -Accessing PCI device resources through sysfs -============================================ - -sysfs, usually mounted at /sys, provides access to PCI resources on platforms -that support it. For example, a given bus might look like this:: - - /sys/devices/pci0000:17 - |-- 0000:17:00.0 - | |-- class - | |-- config - | |-- device - | |-- enable - | |-- irq - | |-- local_cpus - | |-- remove - | |-- resource - | |-- resource0 - | |-- resource1 - | |-- resource2 - | |-- revision - | |-- rom - | |-- subsystem_device - | |-- subsystem_vendor - | `-- vendor - `-- ... - -The topmost element describes the PCI domain and bus number. In this case, -the domain number is 0000 and the bus number is 17 (both values are in hex). -This bus contains a single function device in slot 0. The domain and bus -numbers are reproduced for convenience. Under the device directory are several -files, each with their own function. - - =================== ===================================================== - file function - =================== ===================================================== - class PCI class (ascii, ro) - config PCI config space (binary, rw) - device PCI device (ascii, ro) - enable Whether the device is enabled (ascii, rw) - irq IRQ number (ascii, ro) - local_cpus nearby CPU mask (cpumask, ro) - remove remove device from kernel's list (ascii, wo) - resource PCI resource host addresses (ascii, ro) - resource0..N PCI resource N, if present (binary, mmap, rw\ [1]_) - resource0_wc..N_wc PCI WC map resource N, if prefetchable (binary, mmap) - revision PCI revision (ascii, ro) - rom PCI ROM resource, if present (binary, ro) - subsystem_device PCI subsystem device (ascii, ro) - subsystem_vendor PCI subsystem vendor (ascii, ro) - vendor PCI vendor (ascii, ro) - =================== ===================================================== - -:: - - ro - read only file - rw - file is readable and writable - wo - write only file - mmap - file is mmapable - ascii - file contains ascii text - binary - file contains binary data - cpumask - file contains a cpumask type - -.. [1] rw for IORESOURCE_IO (I/O port) regions only - -The read only files are informational, writes to them will be ignored, with -the exception of the 'rom' file. Writable files can be used to perform -actions on the device (e.g. changing config space, detaching a device). -mmapable files are available via an mmap of the file at offset 0 and can be -used to do actual device programming from userspace. Note that some platforms -don't support mmapping of certain resources, so be sure to check the return -value from any attempted mmap. The most notable of these are I/O port -resources, which also provide read/write access. - -The 'enable' file provides a counter that indicates how many times the device -has been enabled. If the 'enable' file currently returns '4', and a '1' is -echoed into it, it will then return '5'. Echoing a '0' into it will decrease -the count. Even when it returns to 0, though, some of the initialisation -may not be reversed. - -The 'rom' file is special in that it provides read-only access to the device's -ROM file, if available. It's disabled by default, however, so applications -should write the string "1" to the file to enable it before attempting a read -call, and disable it following the access by writing "0" to the file. Note -that the device must be enabled for a rom read to return data successfully. -In the event a driver is not bound to the device, it can be enabled using the -'enable' file, documented above. - -The 'remove' file is used to remove the PCI device, by writing a non-zero -integer to the file. This does not involve any kind of hot-plug functionality, -e.g. powering off the device. The device is removed from the kernel's list of -PCI devices, the sysfs directory for it is removed, and the device will be -removed from any drivers attached to it. Removal of PCI root buses is -disallowed. - -Accessing legacy resources through sysfs ----------------------------------------- - -Legacy I/O port and ISA memory resources are also provided in sysfs if the -underlying platform supports them. They're located in the PCI class hierarchy, -e.g.:: - - /sys/class/pci_bus/0000:17/ - |-- bridge -> ../../../devices/pci0000:17 - |-- cpuaffinity - |-- legacy_io - `-- legacy_mem - -The legacy_io file is a read/write file that can be used by applications to -do legacy port I/O. The application should open the file, seek to the desired -port (e.g. 0x3e8) and do a read or a write of 1, 2 or 4 bytes. The legacy_mem -file should be mmapped with an offset corresponding to the memory offset -desired, e.g. 0xa0000 for the VGA frame buffer. The application can then -simply dereference the returned pointer (after checking for errors of course) -to access legacy memory space. - -Supporting PCI access on new platforms --------------------------------------- - -In order to support PCI resource mapping as described above, Linux platform -code should ideally define ARCH_GENERIC_PCI_MMAP_RESOURCE and use the generic -implementation of that functionality. To support the historical interface of -mmap() through files in /proc/bus/pci, platforms may also set HAVE_PCI_MMAP. - -Alternatively, platforms which set HAVE_PCI_MMAP may provide their own -implementation of pci_mmap_page_range() instead of defining -ARCH_GENERIC_PCI_MMAP_RESOURCE. - -Platforms which support write-combining maps of PCI resources must define -arch_can_pci_mmap_wc() which shall evaluate to non-zero at runtime when -write-combining is permitted. Platforms which support maps of I/O resources -define arch_can_pci_mmap_io() similarly. - -Legacy resources are protected by the HAVE_PCI_LEGACY define. Platforms -wishing to support legacy functionality should define it and provide -pci_legacy_read, pci_legacy_write and pci_mmap_legacy_page_range functions. diff --git a/Documentation/filesystems/sysfs-tagging.rst b/Documentation/filesystems/sysfs-tagging.rst deleted file mode 100644 index 83647e10c207..000000000000 --- a/Documentation/filesystems/sysfs-tagging.rst +++ /dev/null @@ -1,48 +0,0 @@ -.. SPDX-License-Identifier: GPL-2.0 - -============= -Sysfs tagging -============= - -(Taken almost verbatim from Eric Biederman's netns tagging patch -commit msg) - -The problem. Network devices show up in sysfs and with the network -namespace active multiple devices with the same name can show up in -the same directory, ouch! - -To avoid that problem and allow existing applications in network -namespaces to see the same interface that is currently presented in -sysfs, sysfs now has tagging directory support. - -By using the network namespace pointers as tags to separate out -the sysfs directory entries we ensure that we don't have conflicts -in the directories and applications only see a limited set of -the network devices. - -Each sysfs directory entry may be tagged with a namespace via the -``void *ns member`` of its ``kernfs_node``. If a directory entry is tagged, -then ``kernfs_node->flags`` will have a flag between KOBJ_NS_TYPE_NONE -and KOBJ_NS_TYPES, and ns will point to the namespace to which it -belongs. - -Each sysfs superblock's kernfs_super_info contains an array -``void *ns[KOBJ_NS_TYPES]``. When a task in a tagging namespace -kobj_nstype first mounts sysfs, a new superblock is created. It -will be differentiated from other sysfs mounts by having its -``s_fs_info->ns[kobj_nstype]`` set to the new namespace. Note that -through bind mounting and mounts propagation, a task can easily view -the contents of other namespaces' sysfs mounts. Therefore, when a -namespace exits, it will call kobj_ns_exit() to invalidate any -kernfs_node->ns pointers pointing to it. - -Users of this interface: - -- define a type in the ``kobj_ns_type`` enumeration. -- call kobj_ns_type_register() with its ``kobj_ns_type_operations`` which has - - - current_ns() which returns current's namespace - - netlink_ns() which returns a socket's namespace - - initial_ns() which returns the initial namesapce - -- call kobj_ns_exit() when an individual tag is no longer valid diff --git a/Documentation/filesystems/sysfs.rst b/Documentation/filesystems/sysfs.rst index ab0f7795792b..004d490179f3 100644 --- a/Documentation/filesystems/sysfs.rst +++ b/Documentation/filesystems/sysfs.rst @@ -172,14 +172,13 @@ calls the associated methods. To illustrate:: - #define to_dev(obj) container_of(obj, struct device, kobj) #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr) static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { struct device_attribute *dev_attr = to_dev_attr(attr); - struct device *dev = to_dev(kobj); + struct device *dev = kobj_to_dev(kobj); ssize_t ret = -EIO; if (dev_attr->show) @@ -242,12 +241,10 @@ Other notes: is 4096. - show() methods should return the number of bytes printed into the - buffer. This is the return value of scnprintf(). + buffer. -- show() must not use snprintf() when formatting the value to be - returned to user space. If you can guarantee that an overflow - will never happen you can use sprintf() otherwise you must use - scnprintf(). +- show() should only use sysfs_emit() or sysfs_emit_at() when formatting + the value to be returned to user space. - store() should return the number of bytes used from the buffer. If the entire buffer has been used, just return the count argument. diff --git a/Documentation/filesystems/ubifs-authentication.rst b/Documentation/filesystems/ubifs-authentication.rst index 1f39c8cea702..5210aed2afbc 100644 --- a/Documentation/filesystems/ubifs-authentication.rst +++ b/Documentation/filesystems/ubifs-authentication.rst @@ -1,11 +1,13 @@ .. SPDX-License-Identifier: GPL-2.0 -:orphan: - .. UBIFS Authentication .. sigma star gmbh .. 2018 +============================ +UBIFS Authentication Support +============================ + Introduction ============ diff --git a/Documentation/filesystems/zonefs.rst b/Documentation/filesystems/zonefs.rst index 6c18bc8ce332..6b213fe9a33e 100644 --- a/Documentation/filesystems/zonefs.rst +++ b/Documentation/filesystems/zonefs.rst @@ -326,6 +326,21 @@ discover the amount of data that has been written to the zone. In the case of a read-only zone discovered at run-time, as indicated in the previous section. The size of the zone file is left unchanged from its last updated value. +A zoned block device (e.g. an NVMe Zoned Namespace device) may have limits on +the number of zones that can be active, that is, zones that are in the +implicit open, explicit open or closed conditions. This potential limitation +translates into a risk for applications to see write IO errors due to this +limit being exceeded if the zone of a file is not already active when a write +request is issued by the user. + +To avoid these potential errors, the "explicit-open" mount option forces zones +to be made active using an open zone command when a file is opened for writing +for the first time. If the zone open command succeeds, the application is then +guaranteed that write requests can be processed. Conversely, the +"explicit-open" mount option will result in a zone close command being issued +to the device on the last close() of a zone file if the zone is not full nor +empty. + Zonefs User Space Tools ======================= |