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-rw-r--r--Documentation/filesystems/00-INDEX6
-rw-r--r--Documentation/filesystems/quota.txt59
-rw-r--r--Documentation/filesystems/ramfs-rootfs-initramfs.txt14
3 files changed, 72 insertions, 7 deletions
diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX
index 599593a..1de155e 100644
--- a/Documentation/filesystems/00-INDEX
+++ b/Documentation/filesystems/00-INDEX
@@ -44,10 +44,16 @@ files.txt
- info on file management in the Linux kernel.
fuse.txt
- info on the Filesystem in User SpacE including mount options.
+gfs2.txt
+ - info on the Global File System 2.
hfs.txt
- info on the Macintosh HFS Filesystem for Linux.
+hfsplus.txt
+ - info on the Macintosh HFSPlus Filesystem for Linux.
hpfs.txt
- info and mount options for the OS/2 HPFS.
+inotify.txt
+ - info on the powerful yet simple file change notification system.
isofs.txt
- info and mount options for the ISO 9660 (CDROM) filesystem.
jfs.txt
diff --git a/Documentation/filesystems/quota.txt b/Documentation/filesystems/quota.txt
new file mode 100644
index 0000000..a590c40
--- /dev/null
+++ b/Documentation/filesystems/quota.txt
@@ -0,0 +1,59 @@
+
+Quota subsystem
+===============
+
+Quota subsystem allows system administrator to set limits on used space and
+number of used inodes (inode is a filesystem structure which is associated
+with each file or directory) for users and/or groups. For both used space and
+number of used inodes there are actually two limits. The first one is called
+softlimit and the second one hardlimit. An user can never exceed a hardlimit
+for any resource. User is allowed to exceed softlimit but only for limited
+period of time. This period is called "grace period" or "grace time". When
+grace time is over, user is not able to allocate more space/inodes until he
+frees enough of them to get below softlimit.
+
+Quota limits (and amount of grace time) are set independently for each
+filesystem.
+
+For more details about quota design, see the documentation in quota-tools package
+(http://sourceforge.net/projects/linuxquota).
+
+Quota netlink interface
+=======================
+When user exceeds a softlimit, runs out of grace time or reaches hardlimit,
+quota subsystem traditionally printed a message to the controlling terminal of
+the process which caused the excess. This method has the disadvantage that
+when user is using a graphical desktop he usually cannot see the message.
+Thus quota netlink interface has been designed to pass information about
+the above events to userspace. There they can be captured by an application
+and processed accordingly.
+
+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.
+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):
+ QUOTA_NL_A_QTYPE (u32)
+ - type of quota being exceeded (one of USRQUOTA, GRPQUOTA)
+ QUOTA_NL_A_EXCESS_ID (u64)
+ - UID/GID (depends on quota type) of user / group whose limit
+ is being exceeded.
+ QUOTA_NL_A_CAUSED_ID (u64)
+ - UID of a user who caused the event
+ QUOTA_NL_A_WARNING (u32)
+ - what kind of limit is exceeded:
+ QUOTA_NL_IHARDWARN - inode hardlimit
+ QUOTA_NL_ISOFTLONGWARN - inode softlimit is exceeded longer
+ than given grace period
+ QUOTA_NL_ISOFTWARN - inode softlimit
+ QUOTA_NL_BHARDWARN - space (block) hardlimit
+ QUOTA_NL_BSOFTLONGWARN - space (block) softlimit is exceeded
+ longer than given grace period.
+ QUOTA_NL_BSOFTWARN - space (block) softlimit
+ QUOTA_NL_A_DEV_MAJOR (u32)
+ - major number of a device with the affected filesystem
+ QUOTA_NL_A_DEV_MINOR (u32)
+ - minor number of a device with the affected filesystem
diff --git a/Documentation/filesystems/ramfs-rootfs-initramfs.txt b/Documentation/filesystems/ramfs-rootfs-initramfs.txt
index 25981e2..339c6a4 100644
--- a/Documentation/filesystems/ramfs-rootfs-initramfs.txt
+++ b/Documentation/filesystems/ramfs-rootfs-initramfs.txt
@@ -8,7 +8,7 @@ What is ramfs?
Ramfs is a very simple filesystem that exports Linux's disk caching
mechanisms (the page cache and dentry cache) as a dynamically resizable
-ram-based filesystem.
+RAM-based filesystem.
Normally all files are cached in memory by Linux. Pages of data read from
backing store (usually the block device the filesystem is mounted on) are kept
@@ -34,7 +34,7 @@ ramfs and ramdisk:
------------------
The older "ram disk" mechanism created a synthetic block device out of
-an area of ram and used it as backing store for a filesystem. This block
+an area of RAM and used it as backing store for a filesystem. This block
device was of fixed size, so the filesystem mounted on it was of fixed
size. Using a ram disk also required unnecessarily copying memory from the
fake block device into the page cache (and copying changes back out), as well
@@ -46,8 +46,8 @@ unnecessary work for the CPU, and pollutes the CPU caches. (There are tricks
to avoid this copying by playing with the page tables, but they're unpleasantly
complicated and turn out to be about as expensive as the copying anyway.)
More to the point, all the work ramfs is doing has to happen _anyway_,
-since all file access goes through the page and dentry caches. The ram
-disk is simply unnecessary, ramfs is internally much simpler.
+since all file access goes through the page and dentry caches. The RAM
+disk is simply unnecessary; ramfs is internally much simpler.
Another reason ramdisks are semi-obsolete is that the introduction of
loopback devices offered a more flexible and convenient way to create
@@ -103,7 +103,7 @@ All this differs from the old initrd in several ways:
initramfs archive is a gzipped cpio archive (like tar only simpler,
see cpio(1) and Documentation/early-userspace/buffer-format.txt). The
kernel's cpio extraction code is not only extremely small, it's also
- __init data that can be discarded during the boot process.
+ __init text and data that can be discarded during the boot process.
- The program run by the old initrd (which was called /initrd, not /init) did
some setup and then returned to the kernel, while the init program from
@@ -220,7 +220,7 @@ device) but the separate packaging of initrd (which is nice if you have
non-GPL code you'd like to run from initramfs, without conflating it with
the GPL licensed Linux kernel binary).
-It can also be used to supplement the kernel's built-in initamfs image. The
+It can also be used to supplement the kernel's built-in initramfs image. The
files in the external archive will overwrite any conflicting files in
the built-in initramfs archive. Some distributors also prefer to customize
a single kernel image with task-specific initramfs images, without recompiling.
@@ -339,7 +339,7 @@ smooth transition and allowing early boot functionality to gradually move to
The move to early userspace is necessary because finding and mounting the real
root device is complex. Root partitions can span multiple devices (raid or
separate journal). They can be out on the network (requiring dhcp, setting a
-specific mac address, logging into a server, etc). They can live on removable
+specific MAC address, logging into a server, etc). They can live on removable
media, with dynamically allocated major/minor numbers and persistent naming
issues requiring a full udev implementation to sort out. They can be
compressed, encrypted, copy-on-write, loopback mounted, strangely partitioned,