diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/affs.rst | 16 | ||||
| -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/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 | 3 | ||||
| -rw-r--r-- | Documentation/filesystems/ubifs-authentication.rst | 6 |
9 files changed, 37 insertions, 206 deletions
diff --git a/Documentation/filesystems/affs.rst b/Documentation/filesystems/affs.rst index 7f1a40dce6d3..5776cbd5fa53 100644 --- a/Documentation/filesystems/affs.rst +++ b/Documentation/filesystems/affs.rst @@ -110,13 +110,15 @@ The Amiga protection flags RWEDRWEDHSPARWED are handled as follows: - R maps to r for user, group and others. On directories, R implies x. - - If both W and D are allowed, w will be set. + - W maps to w. - E maps to x. - - H and P are always retained and ignored under Linux. + - D is ignored. - - A is always reset when a file is written to. + - H, S and P are always retained and ignored under Linux. + + - A is cleared when a file is written to. User id and group id will be used unless set[gu]id are given as mount options. Since most of the Amiga file systems are single user systems @@ -128,11 +130,13 @@ Linux -> Amiga: The Linux rwxrwxrwx file mode is handled as follows: - - r permission will set R for user, group and others. + - r permission will allow R for user, group and others. + + - w permission will allow W for user, group and others. - - w permission will set W and D for user, group and others. + - x permission of the user will allow E for plain files. - - x permission of the user will set E for plain files. + - D will be allowed for user, group and others. - All other flags (suid, sgid, ...) are ignored and will not be retained. 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/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..5a3209a4cebf 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) 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 ============ |