diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/autofs4-mount-control.txt | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/caching/netfs-api.txt | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/debugfs.txt | 158 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4.txt | 6 | ||||
| -rw-r--r-- | Documentation/filesystems/fiemap.txt | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/nfs-rdma.txt | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/proc.txt | 4 | ||||
| -rw-r--r-- | Documentation/filesystems/sysfs-pci.txt | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/vfat.txt | 8 |
9 files changed, 172 insertions, 14 deletions
diff --git a/Documentation/filesystems/autofs4-mount-control.txt b/Documentation/filesystems/autofs4-mount-control.txt index c6341745df3..8f78ded4b64 100644 --- a/Documentation/filesystems/autofs4-mount-control.txt +++ b/Documentation/filesystems/autofs4-mount-control.txt @@ -369,7 +369,7 @@ The call requires an initialized struct autofs_dev_ioctl. There are two possible variations. Both use the path field set to the path of the mount point to check and the size field adjusted appropriately. One uses the ioctlfd field to identify a specific mount point to check while the other -variation uses the path and optionaly arg1 set to an autofs mount type. +variation uses the path and optionally arg1 set to an autofs mount type. The call returns 1 if this is a mount point and sets arg1 to the device number of the mount and field arg2 to the relevant super block magic number (described below) or 0 if it isn't a mountpoint. In both cases diff --git a/Documentation/filesystems/caching/netfs-api.txt b/Documentation/filesystems/caching/netfs-api.txt index 4db125b3a5c..2666b1ed5e9 100644 --- a/Documentation/filesystems/caching/netfs-api.txt +++ b/Documentation/filesystems/caching/netfs-api.txt @@ -184,7 +184,7 @@ This has the following fields: have index children. If this function is not supplied or if it returns NULL then the first - cache in the parent's list will be chosed, or failing that, the first + cache in the parent's list will be chosen, or failing that, the first cache in the master list. (4) A function to retrieve an object's key from the netfs [mandatory]. diff --git a/Documentation/filesystems/debugfs.txt b/Documentation/filesystems/debugfs.txt new file mode 100644 index 00000000000..ed52af60c2d --- /dev/null +++ b/Documentation/filesystems/debugfs.txt @@ -0,0 +1,158 @@ +Copyright 2009 Jonathan Corbet <corbet@lwn.net> + +Debugfs exists as a simple way for kernel developers to make information +available to user space. Unlike /proc, which is only meant for information +about a process, or sysfs, which has strict one-value-per-file rules, +debugfs has no rules at all. Developers can put any information they want +there. The debugfs filesystem is also intended to not serve as a stable +ABI to user space; in theory, there are no stability constraints placed on +files exported there. The real world is not always so simple, though [1]; +even debugfs interfaces are best designed with the idea that they will need +to be maintained forever. + +Debugfs is typically mounted with a command like: + + mount -t debugfs none /sys/kernel/debug + +(Or an equivalent /etc/fstab line). + +Note that the debugfs API is exported GPL-only to modules. + +Code using debugfs should include <linux/debugfs.h>. Then, the first order +of business will be to create at least one directory to hold a set of +debugfs files: + + struct dentry *debugfs_create_dir(const char *name, struct dentry *parent); + +This call, if successful, will make a directory called name underneath the +indicated parent directory. If parent is NULL, the directory will be +created in the debugfs root. On success, the return value is a struct +dentry pointer which can be used to create files in the directory (and to +clean it up at the end). A NULL return value indicates that something went +wrong. If ERR_PTR(-ENODEV) is returned, that is an indication that the +kernel has been built without debugfs support and none of the functions +described below will work. + +The most general way to create a file within a debugfs directory is with: + + struct dentry *debugfs_create_file(const char *name, mode_t mode, + struct dentry *parent, void *data, + const struct file_operations *fops); + +Here, name is the name of the file to create, mode describes the access +permissions the file should have, parent indicates the directory which +should hold the file, data will be stored in the i_private field of the +resulting inode structure, and fops is a set of file operations which +implement the file's behavior. At a minimum, the read() and/or write() +operations should be provided; others can be included as needed. Again, +the return value will be a dentry pointer to the created file, NULL for +error, or ERR_PTR(-ENODEV) if debugfs support is missing. + +In a number of cases, the creation of a set of file operations is not +actually necessary; the debugfs code provides a number of helper functions +for simple situations. Files containing a single integer value can be +created with any of: + + struct dentry *debugfs_create_u8(const char *name, mode_t mode, + struct dentry *parent, u8 *value); + struct dentry *debugfs_create_u16(const char *name, mode_t mode, + struct dentry *parent, u16 *value); + struct dentry *debugfs_create_u32(const char *name, mode_t mode, + struct dentry *parent, u32 *value); + struct dentry *debugfs_create_u64(const char *name, mode_t mode, + struct dentry *parent, u64 *value); + +These files support both reading and writing the given value; if a specific +file should not be written to, simply set the mode bits accordingly. The +values in these files are in decimal; if hexadecimal is more appropriate, +the following functions can be used instead: + + struct dentry *debugfs_create_x8(const char *name, mode_t mode, + struct dentry *parent, u8 *value); + struct dentry *debugfs_create_x16(const char *name, mode_t mode, + struct dentry *parent, u16 *value); + struct dentry *debugfs_create_x32(const char *name, mode_t mode, + struct dentry *parent, u32 *value); + +Note that there is no debugfs_create_x64(). + +These functions are useful as long as the developer knows the size of the +value to be exported. Some types can have different widths on different +architectures, though, complicating the situation somewhat. There is a +function meant to help out in one special case: + + struct dentry *debugfs_create_size_t(const char *name, mode_t mode, + struct dentry *parent, + size_t *value); + +As might be expected, this function will create a debugfs file to represent +a variable of type size_t. + +Boolean values can be placed in debugfs with: + + struct dentry *debugfs_create_bool(const char *name, mode_t mode, + struct dentry *parent, u32 *value); + +A read on the resulting file will yield either Y (for non-zero values) or +N, followed by a newline. If written to, it will accept either upper- or +lower-case values, or 1 or 0. Any other input will be silently ignored. + +Finally, a block of arbitrary binary data can be exported with: + + struct debugfs_blob_wrapper { + void *data; + unsigned long size; + }; + + struct dentry *debugfs_create_blob(const char *name, mode_t mode, + struct dentry *parent, + struct debugfs_blob_wrapper *blob); + +A read of this file will return the data pointed to by the +debugfs_blob_wrapper structure. Some drivers use "blobs" as a simple way +to return several lines of (static) formatted text output. This function +can be used to export binary information, but there does not appear to be +any code which does so in the mainline. Note that all files created with +debugfs_create_blob() are read-only. + +There are a couple of other directory-oriented helper functions: + + struct dentry *debugfs_rename(struct dentry *old_dir, + struct dentry *old_dentry, + struct dentry *new_dir, + const char *new_name); + + struct dentry *debugfs_create_symlink(const char *name, + struct dentry *parent, + const char *target); + +A call to debugfs_rename() will give a new name to an existing debugfs +file, possibly in a different directory. The new_name must not exist prior +to the call; the return value is old_dentry with updated information. +Symbolic links can be created with debugfs_create_symlink(). + +There is one important thing that all debugfs users must take into account: +there is no automatic cleanup of any directories created in debugfs. If a +module is unloaded without explicitly removing debugfs entries, the result +will be a lot of stale pointers and no end of highly antisocial behavior. +So all debugfs users - at least those which can be built as modules - must +be prepared to remove all files and directories they create there. A file +can be removed with: + + void debugfs_remove(struct dentry *dentry); + +The dentry value can be NULL, in which case nothing will be removed. + +Once upon a time, debugfs users were required to remember the dentry +pointer for every debugfs file they created so that all files could be +cleaned up. We live in more civilized times now, though, and debugfs users +can call: + + void debugfs_remove_recursive(struct dentry *dentry); + +If this function is passed a pointer for the dentry corresponding to the +top-level directory, the entire hierarchy below that directory will be +removed. + +Notes: + [1] http://lwn.net/Articles/309298/ diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index 97882df0486..608fdba97b7 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt @@ -294,7 +294,7 @@ max_batch_time=usec Maximum amount of time ext4 should wait for amount of time (on average) that it takes to finish committing a transaction. Call this time the "commit time". If the time that the - transactoin has been running is less than the + transaction has been running is less than the commit time, ext4 will try sleeping for the commit time to see if other operations will join the transaction. The commit time is capped by @@ -328,7 +328,7 @@ noauto_da_alloc replacing existing files via patterns such as journal commit, in the default data=ordered mode, the data blocks of the new file are forced to disk before the rename() operation is - commited. This provides roughly the same level + committed. This provides roughly the same level of guarantees as ext3, and avoids the "zero-length" problem that can happen when a system crashes before the delayed allocation @@ -358,7 +358,7 @@ written to the journal first, and then to its final location. In the event of a crash, the journal can be replayed, bringing both data and metadata into a consistent state. This mode is the slowest except when data needs to be read from and written to disk at the same time where it -outperforms all others modes. Curently ext4 does not have delayed +outperforms all others modes. Currently ext4 does not have delayed allocation support if this data journalling mode is selected. References diff --git a/Documentation/filesystems/fiemap.txt b/Documentation/filesystems/fiemap.txt index 1e3defcfe50..606233cd461 100644 --- a/Documentation/filesystems/fiemap.txt +++ b/Documentation/filesystems/fiemap.txt @@ -204,7 +204,7 @@ fiemap_check_flags() helper: int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags); -The struct fieinfo should be passed in as recieved from ioctl_fiemap(). The +The struct fieinfo should be passed in as received from ioctl_fiemap(). The set of fiemap flags which the fs understands should be passed via fs_flags. If fiemap_check_flags finds invalid user flags, it will place the bad values in fieinfo->fi_flags and return -EBADR. If the file system gets -EBADR, from diff --git a/Documentation/filesystems/nfs-rdma.txt b/Documentation/filesystems/nfs-rdma.txt index 85eaeaddd27..e386f7e4bce 100644 --- a/Documentation/filesystems/nfs-rdma.txt +++ b/Documentation/filesystems/nfs-rdma.txt @@ -100,7 +100,7 @@ Installation $ sudo cp utils/mount/mount.nfs /sbin/mount.nfs In this location, mount.nfs will be invoked automatically for NFS mounts - by the system mount commmand. + by the system mount command. NOTE: mount.nfs and therefore nfs-utils-1.1.2 or greater is only needed on the NFS client machine. You do not need this specific version of diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index ce84cfc9eae..cd8717a3627 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -366,7 +366,7 @@ just those considered 'most important'. The new vectors are: RES, CAL, TLB -- rescheduling, call and TLB flush interrupts are sent from one CPU to another per the needs of the OS. Typically, their statistics are used by kernel developers and interested users to - determine the occurance of interrupt of the given type. + determine the occurrence of interrupts of the given type. The above IRQ vectors are displayed only when relevent. For example, the threshold vector does not exist on x86_64 platforms. Others are @@ -551,7 +551,7 @@ Committed_AS: The amount of memory presently allocated on the system. memory once that memory has been successfully allocated. VmallocTotal: total size of vmalloc memory area VmallocUsed: amount of vmalloc area which is used -VmallocChunk: largest contigious block of vmalloc area which is free +VmallocChunk: largest contiguous block of vmalloc area which is free .............................................................................. diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt index 26e4b8bc53e..85354b32d73 100644 --- a/Documentation/filesystems/sysfs-pci.txt +++ b/Documentation/filesystems/sysfs-pci.txt @@ -72,7 +72,7 @@ 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 succesfully. +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. diff --git a/Documentation/filesystems/vfat.txt b/Documentation/filesystems/vfat.txt index 3a5ddc96901..5147be5e13c 100644 --- a/Documentation/filesystems/vfat.txt +++ b/Documentation/filesystems/vfat.txt @@ -124,10 +124,10 @@ sys_immutable -- If set, ATTR_SYS attribute on FAT is handled as flush -- If set, the filesystem will try to flush to disk more early than normal. Not set by default. -rodir -- FAT has the ATTR_RO (read-only) attribute. But on Windows, - the ATTR_RO of the directory will be just ignored actually, - and is used by only applications as flag. E.g. it's setted - for the customized folder. +rodir -- FAT has the ATTR_RO (read-only) attribute. On Windows, + the ATTR_RO of the directory will just be ignored, + and is used only by applications as a flag (e.g. it's set + for the customized folder). If you want to use ATTR_RO as read-only flag even for the directory, set this option. |