[PATCH] Clean up whitespace in vfs.txt
From: Raymond Jennings
Date: Mon Aug 10 2015 - 05:31:16 EST
I noticed that vfs.txt looked kinda funky, so I went ahead and
reformatted it.
Signed-off-by: Raymond Jennings
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
diff --git a/Documentation/filesystems/vfs.txt
b/Documentation/filesystems/vfs.txt
index 5eb8456..8ddfe06 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -114,12 +114,12 @@ members are defined:
struct file_system_type {
const char *name;
int fs_flags;
- struct dentry *(*mount) (struct file_system_type *, int,
- const char *, void *);
- void (*kill_sb) (struct super_block *);
- struct module *owner;
- struct file_system_type * next;
- struct list_head fs_supers;
+ struct dentry *(*mount) (struct file_system_type *, int,
+ const char *, void *);
+ void (*kill_sb) (struct super_block *);
+ struct module *owner;
+ struct file_system_type * next;
+ struct list_head fs_supers;
struct lock_class_key s_lock_key;
struct lock_class_key s_umount_key;
};
@@ -136,7 +136,7 @@ struct file_system_type {
should be shut down
owner: for internal VFS use: you should initialize this to
THIS_MODULE in
- most cases.
+ most cases.
next: for internal VFS use: you should initialize this to NULL
@@ -145,7 +145,7 @@ struct file_system_type {
The mount() method has the following arguments:
struct file_system_type *fs_type: describes the filesystem, partly
initialized
- by the specific filesystem code
+ by the specific filesystem code
int flags: mount flags
@@ -182,12 +182,12 @@ and provides a fill_super() callback instead. The
generic variants are:
mount_nodev: mount a filesystem that is not backed by a device
mount_single: mount a filesystem which shares the instance between
- all mounts
+ all mounts
A fill_super() callback implementation has the following arguments:
struct super_block *sb: the superblock structure. The callback
- must initialize this properly.
+ must initialize this properly.
void *data: arbitrary mount options, usually comes as an ASCII
string (see "Mount Options" section)
@@ -208,26 +208,26 @@ This describes how the VFS can manipulate the
superblock of your
filesystem. As of kernel 2.6.22, the following members are defined:
struct super_operations {
- struct inode *(*alloc_inode)(struct super_block *sb);
- void (*destroy_inode)(struct inode *);
-
- void (*dirty_inode) (struct inode *, int flags);
- int (*write_inode) (struct inode *, int);
- void (*drop_inode) (struct inode *);
- void (*delete_inode) (struct inode *);
- void (*put_super) (struct super_block *);
- int (*sync_fs)(struct super_block *sb, int wait);
- int (*freeze_fs) (struct super_block *);
- int (*unfreeze_fs) (struct super_block *);
- int (*statfs) (struct dentry *, struct kstatfs *);
- int (*remount_fs) (struct super_block *, int *, char *);
- void (*clear_inode) (struct inode *);
- void (*umount_begin) (struct super_block *);
-
- int (*show_options)(struct seq_file *, struct dentry *);
-
- ssize_t (*quota_read)(struct super_block *, int, char *,
size_t, loff_t);
- ssize_t (*quota_write)(struct super_block *, int, const char *,
size_t, loff_t);
+ struct inode *(*alloc_inode)(struct super_block *sb);
+ void (*destroy_inode)(struct inode *);
+
+ void (*dirty_inode) (struct inode *, int flags);
+ int (*write_inode) (struct inode *, int);
+ void (*drop_inode) (struct inode *);
+ void (*delete_inode) (struct inode *);
+ void (*put_super) (struct super_block *);
+ int (*sync_fs)(struct super_block *sb, int wait);
+ int (*freeze_fs) (struct super_block *);
+ int (*unfreeze_fs) (struct super_block *);
+ int (*statfs) (struct dentry *, struct kstatfs *);
+ int (*remount_fs) (struct super_block *, int *, char *);
+ void (*clear_inode) (struct inode *);
+ void (*umount_begin) (struct super_block *);
+
+ int (*show_options)(struct seq_file *, struct dentry *);
+
+ ssize_t (*quota_read)(struct super_block *, int, char *, size_t,
loff_t);
+ ssize_t (*quota_write)(struct super_block *, int, const char *,
size_t, loff_t);
int (*nr_cached_objects)(struct super_block *);
void (*free_cached_objects)(struct super_block *, int);
};
@@ -238,14 +238,14 @@ only called from a process context (i.e. not from
an interrupt handler
or bottom half).
alloc_inode: this method is called by alloc_inode() to allocate
memory
- for struct inode and initialize it. If this function is not
- defined, a simple 'struct inode' is allocated. Normally
- alloc_inode will be used to allocate a larger structure which
- contains a 'struct inode' embedded within it.
+ for struct inode and initialize it. If this function is not
+ defined, a simple 'struct inode' is allocated. Normally
+ alloc_inode will be used to allocate a larger structure which
+ contains a 'struct inode' embedded within it.
destroy_inode: this method is called by destroy_inode() to release
- resources allocated for struct inode. It is only required if
- ->alloc_inode was defined and simply undoes anything done by
+ resources allocated for struct inode. It is only required if
+ ->alloc_inode was defined and simply undoes anything done by
->alloc_inode.
dirty_inode: this method is called by the VFS to mark an inode dirty.
@@ -273,15 +273,15 @@ or bottom half).
(i.e. unmount). This is called with the superblock lock held
sync_fs: called when VFS is writing out all dirty data associated
with
- a superblock. The second parameter indicates whether the method
+ a superblock. The second parameter indicates whether the method
should wait until the write out has been completed. Optional.
freeze_fs: called when VFS is locking a filesystem and
- forcing it into a consistent state. This method is currently
- used by the Logical Volume Manager (LVM).
+ forcing it into a consistent state. This method is currently
+ used by the Logical Volume Manager (LVM).
unfreeze_fs: called when VFS is unlocking a filesystem and making it
writable
- again.
+ again.
statfs: called when the VFS needs to get filesystem statistics.
@@ -346,9 +346,9 @@ struct inode_operations {
int (*rmdir) (struct inode *,struct dentry *);
int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
int (*rename) (struct inode *, struct dentry *,
- struct inode *, struct dentry *);
+ struct inode *, struct dentry *);
int (*rename2) (struct inode *, struct dentry *,
- struct inode *, struct dentry *, unsigned int);
+ struct inode *, struct dentry *, unsigned int);
int (*readlink) (struct dentry *, char __user *,int);
const char *(*follow_link) (struct dentry *, void **);
void (*put_link) (struct inode *, void *);
@@ -362,7 +362,7 @@ struct inode_operations {
int (*removexattr) (struct dentry *, const char *);
void (*update_time)(struct inode *, struct timespec *, int);
int (*atomic_open)(struct inode *, struct dentry *, struct file *,
- unsigned open_flag, umode_t create_mode, int *opened);
+ unsigned open_flag, umode_t create_mode, int *opened);
int (*tmpfile) (struct inode *, struct dentry *, umode_t);
int (*dentry_open)(struct dentry *, struct file *, const struct cred
*);
};
@@ -450,7 +450,7 @@ otherwise noted.
cookie isn't NULL.
permission: called by the VFS to check for access rights on a
POSIX-like
- filesystem.
+ filesystem.
May be called in rcu-walk mode (mask & MAY_NOT_BLOCK). If in rcu-walk
mode, the filesystem must check the permission without blocking
or
@@ -460,33 +460,33 @@ otherwise noted.
-ECHILD and it will be called again in ref-walk mode.
setattr: called by the VFS to set attributes for a file. This method
- is called by chmod(2) and related system calls.
+ is called by chmod(2) and related system calls.
getattr: called by the VFS to get attributes of a file. This method
- is called by stat(2) and related system calls.
+ is called by stat(2) and related system calls.
setxattr: called by the VFS to set an extended attribute for a file.
- Extended attribute is a name:value pair associated with an
- inode. This method is called by setxattr(2) system call.
+ Extended attribute is a name:value pair associated with an
+ inode. This method is called by setxattr(2) system call.
getxattr: called by the VFS to retrieve the value of an extended
- attribute name. This method is called by getxattr(2) function
- call.
+ attribute name. This method is called by getxattr(2) function
+ call.
listxattr: called by the VFS to list all extended attributes for a
- given file. This method is called by listxattr(2) system call.
+ given file. This method is called by listxattr(2) system call.
removexattr: called by the VFS to remove an extended attribute from
- a file. This method is called by removexattr(2) system call.
+ a file. This method is called by removexattr(2) system call.
update_time: called by the VFS to update a specific time or the
i_version of
- an inode. If this is not defined the VFS will update the inode
itself
- and call mark_inode_dirty_sync.
+ an inode. If this is not defined the VFS will update the inode itself
+ and call mark_inode_dirty_sync.
atomic_open: called on the last component of an open. Using this
optional
- method the filesystem can look up, possibly create and open the file
in
- one atomic operation. If it cannot perform this (e.g. the file type
- turned out to be wrong) it may signal this by returning 1 instead of
+ method the filesystem can look up, possibly create and open the file
in
+ one atomic operation. If it cannot perform this (e.g. the file type
+ turned out to be wrong) it may signal this by returning 1 instead of
usual 0 or -ve . This method is only called if the last component is
negative or needs lookup. Cached positive dentries are still handled
by
f_op->open(). If the file was created, the FILE_CREATED flag should
be
@@ -581,13 +581,13 @@ struct address_space_operations {
int (*writepages)(struct address_space *, struct writeback_control *);
int (*set_page_dirty)(struct page *page);
int (*readpages)(struct file *filp, struct address_space *mapping,
- struct list_head *pages, unsigned nr_pages);
+ struct list_head *pages, unsigned nr_pages);
int (*write_begin)(struct file *, struct address_space *mapping,
- loff_t pos, unsigned len, unsigned flags,
- struct page **pagep, void **fsdata);
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata);
int (*write_end)(struct file *, struct address_space *mapping,
- loff_t pos, unsigned len, unsigned copied,
- struct page *page, void *fsdata);
+ loff_t pos, unsigned len, unsigned copied,
+ struct page *page, void *fsdata);
sector_t (*bmap)(struct address_space *, sector_t);
void (*invalidatepage) (struct page *, unsigned int, unsigned int);
int (*releasepage) (struct page *, int);
@@ -597,7 +597,7 @@ struct address_space_operations {
int (*migratepage) (struct page *, struct page *);
int (*launder_page) (struct page *);
int (*is_partially_uptodate) (struct page *, unsigned long,
- unsigned long);
+ unsigned long);
void (*is_dirty_writeback) (struct page *, bool *, bool *);
int (*error_remove_page) (struct mapping *mapping, struct page *page);
int (*swap_activate)(struct file *);
@@ -605,54 +605,54 @@ struct address_space_operations {
};
writepage: called by the VM to write a dirty page to backing store.
- This may happen for data integrity reasons (i.e. 'sync'), or
- to free up memory (flush). The difference can be seen in
- wbc->sync_mode.
- The PG_Dirty flag has been cleared and PageLocked is true.
- writepage should start writeout, should set PG_Writeback,
- and should make sure the page is unlocked, either synchronously
- or asynchronously when the write operation completes.
-
- If wbc->sync_mode is WB_SYNC_NONE, ->writepage doesn't have to
- try too hard if there are problems, and may choose to write out
- other pages from the mapping if that is easier (e.g. due to
- internal dependencies). If it chooses not to start writeout, it
- should return AOP_WRITEPAGE_ACTIVATE so that the VM will not keep
- calling ->writepage on that page.
-
- See the file "Locking" for more details.
+ This may happen for data integrity reasons (i.e. 'sync'), or
+ to free up memory (flush). The difference can be seen in
+ wbc->sync_mode.
+ The PG_Dirty flag has been cleared and PageLocked is true.
+ writepage should start writeout, should set PG_Writeback,
+ and should make sure the page is unlocked, either synchronously
+ or asynchronously when the write operation completes.
+
+ If wbc->sync_mode is WB_SYNC_NONE, ->writepage doesn't have to
+ try too hard if there are problems, and may choose to write out
+ other pages from the mapping if that is easier (e.g. due to
+ internal dependencies). If it chooses not to start writeout, it
+ should return AOP_WRITEPAGE_ACTIVATE so that the VM will not keep
+ calling ->writepage on that page.
+
+ See the file "Locking" for more details.
readpage: called by the VM to read a page from backing store.
- The page will be Locked when readpage is called, and should be
- unlocked and marked uptodate once the read completes.
- If ->readpage discovers that it needs to unlock the page for
- some reason, it can do so, and then return AOP_TRUNCATED_PAGE.
- In this case, the page will be relocated, relocked and if
- that all succeeds, ->readpage will be called again.
+ The page will be Locked when readpage is called, and should be
+ unlocked and marked uptodate once the read completes.
+ If ->readpage discovers that it needs to unlock the page for
+ some reason, it can do so, and then return AOP_TRUNCATED_PAGE.
+ In this case, the page will be relocated, relocked and if
+ that all succeeds, ->readpage will be called again.
writepages: called by the VM to write out pages associated with the
- address_space object. If wbc->sync_mode is WBC_SYNC_ALL, then
- the writeback_control will specify a range of pages that must be
- written out. If it is WBC_SYNC_NONE, then a nr_to_write is given
+ address_space object. If wbc->sync_mode is WBC_SYNC_ALL, then
+ the writeback_control will specify a range of pages that must be
+ written out. If it is WBC_SYNC_NONE, then a nr_to_write is given
and that many pages should be written if possible.
If no ->writepages is given, then mpage_writepages is used
- instead. This will choose pages from the address space that are
- tagged as DIRTY and will pass them to ->writepage.
+ instead. This will choose pages from the address space that are
+ tagged as DIRTY and will pass them to ->writepage.
set_page_dirty: called by the VM to set a page dirty.
- This is particularly needed if an address space attaches
- private data to a page, and that data needs to be updated when
- a page is dirtied. This is called, for example, when a memory
+ This is particularly needed if an address space attaches
+ private data to a page, and that data needs to be updated when
+ a page is dirtied. This is called, for example, when a memory
mapped page gets modified.
If defined, it should set the PageDirty flag, and the
- PAGECACHE_TAG_DIRTY tag in the radix tree.
+ PAGECACHE_TAG_DIRTY tag in the radix tree.
readpages: called by the VM to read pages associated with the
address_space
- object. This is essentially just a vector version of
- readpage. Instead of just one page, several pages are
- requested.
+ object. This is essentially just a vector version of
+ readpage. Instead of just one page, several pages are
+ requested.
readpages is only used for read-ahead, so read errors are
- ignored. If anything goes wrong, feel free to give up.
+ ignored. If anything goes wrong, feel free to give up.
write_begin:
Called by the generic buffered write code to ask the filesystem to
@@ -663,7 +663,7 @@ struct address_space_operations {
storage, then those blocks should be pre-read (if they haven't been
read already) so that the updated blocks can be written out properly.
- The filesystem must return the locked pagecache page for the
specified
+ The filesystem must return the locked pagecache page for the specified
offset, in *pagep, for the caller to write into.
It must be able to cope with short writes (where the length passed to
@@ -672,30 +672,30 @@ struct address_space_operations {
flags is a field for AOP_FLAG_xxx flags, described in
include/linux/fs.h.
- A void * may be returned in fsdata, which then gets passed into
- write_end.
+ A void * may be returned in fsdata, which then gets passed into
+ write_end.
- Returns 0 on success; < 0 on failure (which is the error code),
in
+ Returns 0 on success; < 0 on failure (which is the error code), in
which case write_end is not called.
write_end: After a successful write_begin, and data copy, write_end
must
- be called. len is the original len passed to write_begin, and
copied
- is the amount that was able to be copied (copied == len is
always true
+ be called. len is the original len passed to write_begin, and copied
+ is the amount that was able to be copied (copied == len is always true
if write_begin was called with the AOP_FLAG_UNINTERRUPTIBLE flag).
- The filesystem must take care of unlocking the page and
releasing it
- refcount, and updating i_size.
+ The filesystem must take care of unlocking the page and releasing it
+ refcount, and updating i_size.
- Returns < 0 on failure, otherwise the number of bytes (<=
'copied')
- that were able to be copied into pagecache.
+ Returns < 0 on failure, otherwise the number of bytes (<= 'copied')
+ that were able to be copied into pagecache.
bmap: called by the VFS to map a logical block offset within object
to
- physical block number. This method is used by the FIBMAP
- ioctl and for working with swap-files. To be able to swap to
- a file, the file must have a stable mapping to a block
- device. The swap system does not go through the filesystem
- but instead uses bmap to find out where the blocks in the file
- are and uses those addresses directly.
+ physical block number. This method is used by the FIBMAP
+ ioctl and for working with swap-files. To be able to swap to
+ a file, the file must have a stable mapping to a block
+ device. The swap system does not go through the filesystem
+ but instead uses bmap to find out where the blocks in the file
+ are and uses those addresses directly.
dentry_open: *WARNING: probably going away soon, do not use!* This is
an
alternative to f_op->open(), the difference is that this method may
open
@@ -717,46 +717,46 @@ struct address_space_operations {
release MUST succeed.
releasepage: releasepage is called on PagePrivate pages to indicate
- that the page should be freed if possible. ->releasepage
- should remove any private data from the page and clear the
- PagePrivate flag. If releasepage() fails for some reason, it
must
+ that the page should be freed if possible. ->releasepage
+ should remove any private data from the page and clear the
+ PagePrivate flag. If releasepage() fails for some reason, it must
indicate failure with a 0 return value.
releasepage() is used in two distinct though related cases. The
first is when the VM finds a clean page with no active users and
- wants to make it a free page. If ->releasepage succeeds, the
- page will be removed from the address_space and become free.
+ wants to make it a free page. If ->releasepage succeeds, the
+ page will be removed from the address_space and become free.
The second case is when a request has been made to invalidate
- some or all pages in an address_space. This can happen
- through the fadvice(POSIX_FADV_DONTNEED) system call or by the
- filesystem explicitly requesting it as nfs and 9fs do (when
- they believe the cache may be out of date with storage) by
- calling invalidate_inode_pages2().
+ some or all pages in an address_space. This can happen
+ through the fadvice(POSIX_FADV_DONTNEED) system call or by the
+ filesystem explicitly requesting it as nfs and 9fs do (when
+ they believe the cache may be out of date with storage) by
+ calling invalidate_inode_pages2().
If the filesystem makes such a call, and needs to be certain
- that all pages are invalidated, then its releasepage will
- need to ensure this. Possibly it can clear the PageUptodate
- bit if it cannot free private data yet.
+ that all pages are invalidated, then its releasepage will
+ need to ensure this. Possibly it can clear the PageUptodate
+ bit if it cannot free private data yet.
freepage: freepage is called once the page is no longer visible in
- the page cache in order to allow the cleanup of any private
+ the page cache in order to allow the cleanup of any private
data. Since it may be called by the memory reclaimer, it
should not assume that the original address_space mapping still
exists, and it should not block.
direct_IO: called by the generic read/write routines to perform
- direct_IO - that is IO requests which bypass the page cache
- and transfer data directly between the storage and the
- application's address space.
+ direct_IO - that is IO requests which bypass the page cache
+ and transfer data directly between the storage and the
+ application's address space.
migrate_page: This is used to compact the physical memory usage.
- If the VM wants to relocate a page (maybe off a memory card
- that is signalling imminent failure) it will pass a new page
+ If the VM wants to relocate a page (maybe off a memory card
+ that is signalling imminent failure) it will pass a new page
and an old page to this function. migrate_page should
transfer any private data across and update any references
- that it has to the page.
+ that it has to the page.
launder_page: Called before freeing a page - it writes back the dirty
page. To
- prevent redirtying the page, it is kept locked during the whole
+ prevent redirtying the page, it is kept locked during the whole
operation.
is_partially_uptodate: Called by the VM when reading a file through
the
@@ -858,7 +858,7 @@ otherwise noted.
unlocked_ioctl: called by the ioctl(2) system call.
compat_ioctl: called by the ioctl(2) system call when 32 bit system
calls
- are used on 64 bit kernels.
+ are used on 64 bit kernels.
mmap: called by the mmap(2) system call
@@ -882,7 +882,7 @@ otherwise noted.
(non-blocking) mode is enabled for a file
lock: called by the fcntl(2) system call for F_GETLK, F_SETLK, and
F_SETLKW
- commands
+ commands
get_unmapped_area: called by the mmap(2) system call
@@ -891,14 +891,14 @@ otherwise noted.
flock: called by the flock(2) system call
splice_write: called by the VFS to splice data from a pipe to a file.
This
- method is used by the splice(2) system call
+ method is used by the splice(2) system call
splice_read: called by the VFS to splice data from file to a pipe.
This
- method is used by the splice(2) system call
+ method is used by the splice(2) system call
setlease: called by the VFS to set or release a file lock lease.
setlease
- implementations should call generic_setlease to record or remove
- the lease in the inode after setting it.
+ implementations should call generic_setlease to record or remove
+ the lease in the inode after setting it.
fallocate: called by the VFS to preallocate blocks or punch a hole.
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