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authorRussell King <rmk+kernel@arm.linux.org.uk>2015-07-07 12:35:33 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2015-07-07 12:35:33 +0100
commit06be5eefe1192eb8ce8d07497f67595b6bfe9741 (patch)
tree80f1987d4970f8079681f8be0c135cafc8d6329a /Documentation/filesystems
parentARM: fix lockdep unannotated irqs-off warning (diff)
parentARM: avoid unwanted GCC memset()/memcpy() optimisations for IO variants (diff)
downloadlinux-dev-06be5eefe1192eb8ce8d07497f67595b6bfe9741.tar.xz
linux-dev-06be5eefe1192eb8ce8d07497f67595b6bfe9741.zip
Merge branches 'fixes' and 'ioremap' into for-linus
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/Locking4
-rw-r--r--Documentation/filesystems/automount-support.txt51
-rw-r--r--Documentation/filesystems/nfs/knfsd-stats.txt44
-rw-r--r--Documentation/filesystems/porting25
-rw-r--r--Documentation/filesystems/proc.txt3
-rw-r--r--Documentation/filesystems/quota.txt5
-rw-r--r--Documentation/filesystems/vfs.txt39
-rw-r--r--Documentation/filesystems/xfs.txt12
8 files changed, 75 insertions, 108 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 0a926e2ba3ab..6a34a0f4d37c 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -50,8 +50,8 @@ prototypes:
int (*rename2) (struct inode *, struct dentry *,
struct inode *, struct dentry *, unsigned int);
int (*readlink) (struct dentry *, char __user *,int);
- void * (*follow_link) (struct dentry *, struct nameidata *);
- void (*put_link) (struct dentry *, struct nameidata *, void *);
+ const char *(*follow_link) (struct dentry *, void **);
+ void (*put_link) (struct inode *, void *);
void (*truncate) (struct inode *);
int (*permission) (struct inode *, int, unsigned int);
int (*get_acl)(struct inode *, int);
diff --git a/Documentation/filesystems/automount-support.txt b/Documentation/filesystems/automount-support.txt
index 7cac200e2a85..7eb762eb3136 100644
--- a/Documentation/filesystems/automount-support.txt
+++ b/Documentation/filesystems/automount-support.txt
@@ -1,41 +1,15 @@
-Support is available for filesystems that wish to do automounting support (such
-as kAFS which can be found in fs/afs/). This facility includes allowing
-in-kernel mounts to be performed and mountpoint degradation to be
-requested. The latter can also be requested by userspace.
+Support is available for filesystems that wish to do automounting
+support (such as kAFS which can be found in fs/afs/ and NFS in
+fs/nfs/). This facility includes allowing in-kernel mounts to be
+performed and mountpoint degradation to be requested. The latter can
+also be requested by userspace.
======================
IN-KERNEL AUTOMOUNTING
======================
-A filesystem can now mount another filesystem on one of its directories by the
-following procedure:
-
- (1) Give the directory a follow_link() operation.
-
- When the directory is accessed, the follow_link op will be called, and
- it will be provided with the location of the mountpoint in the nameidata
- structure (vfsmount and dentry).
-
- (2) Have the follow_link() op do the following steps:
-
- (a) Call vfs_kern_mount() to call the appropriate filesystem to set up a
- superblock and gain a vfsmount structure representing it.
-
- (b) Copy the nameidata provided as an argument and substitute the dentry
- argument into it the copy.
-
- (c) Call do_add_mount() to install the new vfsmount into the namespace's
- mountpoint tree, thus making it accessible to userspace. Use the
- nameidata set up in (b) as the destination.
-
- If the mountpoint will be automatically expired, then do_add_mount()
- should also be given the location of an expiration list (see further
- down).
-
- (d) Release the path in the nameidata argument and substitute in the new
- vfsmount and its root dentry. The ref counts on these will need
- incrementing.
+See section "Mount Traps" of Documentation/filesystems/autofs4.txt
Then from userspace, you can just do something like:
@@ -61,17 +35,18 @@ AUTOMATIC MOUNTPOINT EXPIRY
===========================
Automatic expiration of mountpoints is easy, provided you've mounted the
-mountpoint to be expired in the automounting procedure outlined above.
+mountpoint to be expired in the automounting procedure outlined separately.
To do expiration, you need to follow these steps:
- (3) Create at least one list off which the vfsmounts to be expired can be
- hung. Access to this list will be governed by the vfsmount_lock.
+ (1) Create at least one list off which the vfsmounts to be expired can be
+ hung.
- (4) In step (2c) above, the call to do_add_mount() should be provided with a
- pointer to this list. It will hang the vfsmount off of it if it succeeds.
+ (2) When a new mountpoint is created in the ->d_automount method, add
+ the mnt to the list using mnt_set_expiry()
+ mnt_set_expiry(newmnt, &afs_vfsmounts);
- (5) When you want mountpoints to be expired, call mark_mounts_for_expiry()
+ (3) When you want mountpoints to be expired, call mark_mounts_for_expiry()
with a pointer to this list. This will process the list, marking every
vfsmount thereon for potential expiry on the next call.
diff --git a/Documentation/filesystems/nfs/knfsd-stats.txt b/Documentation/filesystems/nfs/knfsd-stats.txt
index 64ced5149d37..1a5d82180b84 100644
--- a/Documentation/filesystems/nfs/knfsd-stats.txt
+++ b/Documentation/filesystems/nfs/knfsd-stats.txt
@@ -68,16 +68,10 @@ sockets-enqueued
rate of change for this counter is zero; significantly non-zero
values may indicate a performance limitation.
- This can happen either because there are too few nfsd threads in the
- thread pool for the NFS workload (the workload is thread-limited),
- or because the NFS workload needs more CPU time than is available in
- the thread pool (the workload is CPU-limited). In the former case,
- configuring more nfsd threads will probably improve the performance
- of the NFS workload. In the latter case, the sunrpc server layer is
- already choosing not to wake idle nfsd threads because there are too
- many nfsd threads which want to run but cannot, so configuring more
- nfsd threads will make no difference whatsoever. The overloads-avoided
- statistic (see below) can be used to distinguish these cases.
+ This can happen because there are too few nfsd threads in the thread
+ pool for the NFS workload (the workload is thread-limited), in which
+ case configuring more nfsd threads will probably improve the
+ performance of the NFS workload.
threads-woken
Counts how many times an idle nfsd thread is woken to try to
@@ -88,36 +82,6 @@ threads-woken
thing. The ideal rate of change for this counter will be close
to but less than the rate of change of the packets-arrived counter.
-overloads-avoided
- Counts how many times the sunrpc server layer chose not to wake an
- nfsd thread, despite the presence of idle nfsd threads, because
- too many nfsd threads had been recently woken but could not get
- enough CPU time to actually run.
-
- This statistic counts a circumstance where the sunrpc layer
- heuristically avoids overloading the CPU scheduler with too many
- runnable nfsd threads. The ideal rate of change for this counter
- is zero. Significant non-zero values indicate that the workload
- is CPU limited. Usually this is associated with heavy CPU usage
- on all the CPUs in the nfsd thread pool.
-
- If a sustained large overloads-avoided rate is detected on a pool,
- the top(1) utility should be used to check for the following
- pattern of CPU usage on all the CPUs associated with the given
- nfsd thread pool.
-
- - %us ~= 0 (as you're *NOT* running applications on your NFS server)
-
- - %wa ~= 0
-
- - %id ~= 0
-
- - %sy + %hi + %si ~= 100
-
- If this pattern is seen, configuring more nfsd threads will *not*
- improve the performance of the workload. If this patten is not
- seen, then something more subtle is wrong.
-
threads-timedout
Counts how many times an nfsd thread triggered an idle timeout,
i.e. was not woken to handle any incoming network packets for
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index e69274de8d0c..68f1c9106573 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -379,10 +379,10 @@ may now be called in rcu-walk mode (nd->flags & LOOKUP_RCU). -ECHILD should be
returned if the filesystem cannot handle rcu-walk. See
Documentation/filesystems/vfs.txt for more details.
- permission and check_acl are inode permission checks that are called
-on many or all directory inodes on the way down a path walk (to check for
-exec permission). These must now be rcu-walk aware (flags & IPERM_FLAG_RCU).
-See Documentation/filesystems/vfs.txt for more details.
+ permission is an inode permission check that is called on many or all
+directory inodes on the way down a path walk (to check for exec permission). It
+must now be rcu-walk aware (mask & MAY_NOT_BLOCK). See
+Documentation/filesystems/vfs.txt for more details.
--
[mandatory]
@@ -483,3 +483,20 @@ in your dentry operations instead.
--
[mandatory]
->aio_read/->aio_write are gone. Use ->read_iter/->write_iter.
+---
+[recommended]
+ for embedded ("fast") symlinks just set inode->i_link to wherever the
+ symlink body is and use simple_follow_link() as ->follow_link().
+--
+[mandatory]
+ calling conventions for ->follow_link() have changed. Instead of returning
+ cookie and using nd_set_link() to store the body to traverse, we return
+ the body to traverse and store the cookie using explicit void ** argument.
+ nameidata isn't passed at all - nd_jump_link() doesn't need it and
+ nd_[gs]et_link() is gone.
+--
+[mandatory]
+ calling conventions for ->put_link() have changed. It gets inode instead of
+ dentry, it does not get nameidata at all and it gets called only when cookie
+ is non-NULL. Note that link body isn't available anymore, so if you need it,
+ store it as cookie.
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index c3b6b301d8b0..6f7fafde0884 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -205,7 +205,7 @@ asynchronous manner and the value may not be very precise. To see a precise
snapshot of a moment, you can see /proc/<pid>/smaps file and scan page table.
It's slow but very precise.
-Table 1-2: Contents of the status files (as of 3.20.0)
+Table 1-2: Contents of the status files (as of 4.1)
..............................................................................
Field Content
Name filename of the executable
@@ -235,6 +235,7 @@ Table 1-2: Contents of the status files (as of 3.20.0)
VmExe size of text segment
VmLib size of shared library code
VmPTE size of page table entries
+ VmPMD size of second level page tables
VmSwap size of swap usage (the number of referred swapents)
Threads number of threads
SigQ number of signals queued/max. number for queue
diff --git a/Documentation/filesystems/quota.txt b/Documentation/filesystems/quota.txt
index 5e8de25bf0f1..29fc01552646 100644
--- a/Documentation/filesystems/quota.txt
+++ b/Documentation/filesystems/quota.txt
@@ -32,7 +32,10 @@ The interface uses generic netlink framework (see
http://lwn.net/Articles/208755/ and http://people.suug.ch/~tgr/libnl/ for more
details about this layer). The name of the quota generic netlink interface
is "VFS_DQUOT". Definitions of constants below are in <linux/quota.h>.
- Currently, the interface supports only one message type QUOTA_NL_C_WARNING.
+Since the quota netlink protocol is not namespace aware, quota netlink messages
+are sent only in initial network namespace.
+
+Currently, the interface supports only one message type QUOTA_NL_C_WARNING.
This command is used to send a notification about any of the above mentioned
events. Each message has six attributes. These are (type of the argument is
in parentheses):
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 5d833b32bbcd..5eb8456fc41e 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -350,8 +350,8 @@ struct inode_operations {
int (*rename2) (struct inode *, struct dentry *,
struct inode *, struct dentry *, unsigned int);
int (*readlink) (struct dentry *, char __user *,int);
- void * (*follow_link) (struct dentry *, struct nameidata *);
- void (*put_link) (struct dentry *, struct nameidata *, void *);
+ const char *(*follow_link) (struct dentry *, void **);
+ void (*put_link) (struct inode *, void *);
int (*permission) (struct inode *, int);
int (*get_acl)(struct inode *, int);
int (*setattr) (struct dentry *, struct iattr *);
@@ -436,16 +436,18 @@ otherwise noted.
follow_link: called by the VFS to follow a symbolic link to the
inode it points to. Only required if you want to support
- symbolic links. This method returns a void pointer cookie
- that is passed to put_link().
+ symbolic links. This method returns the symlink body
+ to traverse (and possibly resets the current position with
+ nd_jump_link()). If the body won't go away until the inode
+ is gone, nothing else is needed; if it needs to be otherwise
+ pinned, the data needed to release whatever we'd grabbed
+ is to be stored in void * variable passed by address to
+ follow_link() instance.
put_link: called by the VFS to release resources allocated by
- follow_link(). The cookie returned by follow_link() is passed
- to this method as the last parameter. It is used by
- filesystems such as NFS where page cache is not stable
- (i.e. page that was installed when the symbolic link walk
- started might not be in the page cache at the end of the
- walk).
+ follow_link(). The cookie stored by follow_link() is passed
+ to this method as the last parameter; only called when
+ cookie isn't NULL.
permission: called by the VFS to check for access rights on a POSIX-like
filesystem.
@@ -797,7 +799,7 @@ struct file_operations
----------------------
This describes how the VFS can manipulate an open file. As of kernel
-3.12, the following members are defined:
+4.1, the following members are defined:
struct file_operations {
struct module *owner;
@@ -811,8 +813,9 @@ struct file_operations {
long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
int (*mmap) (struct file *, struct vm_area_struct *);
+ int (*mremap)(struct file *, struct vm_area_struct *);
int (*open) (struct inode *, struct file *);
- int (*flush) (struct file *);
+ int (*flush) (struct file *, fl_owner_t id);
int (*release) (struct inode *, struct file *);
int (*fsync) (struct file *, loff_t, loff_t, int datasync);
int (*aio_fsync) (struct kiocb *, int datasync);
@@ -822,11 +825,15 @@ struct file_operations {
unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
int (*check_flags)(int);
int (*flock) (struct file *, int, struct file_lock *);
- ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, size_t, unsigned int);
- ssize_t (*splice_read)(struct file *, struct pipe_inode_info *, size_t, unsigned int);
- int (*setlease)(struct file *, long arg, struct file_lock **, void **);
- long (*fallocate)(struct file *, int mode, loff_t offset, loff_t len);
+ ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
+ ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
+ int (*setlease)(struct file *, long, struct file_lock **, void **);
+ long (*fallocate)(struct file *file, int mode, loff_t offset,
+ loff_t len);
void (*show_fdinfo)(struct seq_file *m, struct file *f);
+#ifndef CONFIG_MMU
+ unsigned (*mmap_capabilities)(struct file *);
+#endif
};
Again, all methods are called without any locks being held, unless
diff --git a/Documentation/filesystems/xfs.txt b/Documentation/filesystems/xfs.txt
index 5a5a05582b58..8146e9fd5ffc 100644
--- a/Documentation/filesystems/xfs.txt
+++ b/Documentation/filesystems/xfs.txt
@@ -236,10 +236,10 @@ Removed Mount Options
Name Removed
---- -------
- delaylog/nodelaylog v3.20
- ihashsize v3.20
- irixsgid v3.20
- osyncisdsync/osyncisosync v3.20
+ delaylog/nodelaylog v4.0
+ ihashsize v4.0
+ irixsgid v4.0
+ osyncisdsync/osyncisosync v4.0
sysctls
@@ -346,5 +346,5 @@ Removed Sysctls
Name Removed
---- -------
- fs.xfs.xfsbufd_centisec v3.20
- fs.xfs.age_buffer_centisecs v3.20
+ fs.xfs.xfsbufd_centisec v4.0
+ fs.xfs.age_buffer_centisecs v4.0