2005-04-17 06:20:36 +08:00
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#
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# Makefile for the Linux filesystems.
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#
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# 14 Sep 2000, Christoph Hellwig <hch@infradead.org>
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# Rewritten to use lists instead of if-statements.
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#
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[PATCH] BLOCK: Make it possible to disable the block layer [try #6]
Make it possible to disable the block layer. Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.
This patch does the following:
(*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
support.
(*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
an item that uses the block layer. This includes:
(*) Block I/O tracing.
(*) Disk partition code.
(*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.
(*) The SCSI layer. As far as I can tell, even SCSI chardevs use the
block layer to do scheduling. Some drivers that use SCSI facilities -
such as USB storage - end up disabled indirectly from this.
(*) Various block-based device drivers, such as IDE and the old CDROM
drivers.
(*) MTD blockdev handling and FTL.
(*) JFFS - which uses set_bdev_super(), something it could avoid doing by
taking a leaf out of JFFS2's book.
(*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
linux/elevator.h contingent on CONFIG_BLOCK being set. sector_div() is,
however, still used in places, and so is still available.
(*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
parts of linux/fs.h.
(*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.
(*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.
(*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
is not enabled.
(*) fs/no-block.c is created to hold out-of-line stubs and things that are
required when CONFIG_BLOCK is not set:
(*) Default blockdev file operations (to give error ENODEV on opening).
(*) Makes some /proc changes:
(*) /proc/devices does not list any blockdevs.
(*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.
(*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.
(*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
given command other than Q_SYNC or if a special device is specified.
(*) In init/do_mounts.c, no reference is made to the blockdev routines if
CONFIG_BLOCK is not defined. This does not prohibit NFS roots or JFFS2.
(*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
error ENOSYS by way of cond_syscall if so).
(*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
CONFIG_BLOCK is not set, since they can't then happen.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-10-01 02:45:40 +08:00
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obj-y := open.o read_write.o file_table.o super.o \
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char_dev.o stat.o exec.o pipe.o namei.o fcntl.o \
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2013-03-12 21:46:27 +08:00
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ioctl.o readdir.o select.o dcache.o inode.o \
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2008-10-16 13:05:12 +08:00
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attr.o bad_inode.o file.o filesystems.o namespace.o \
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[PATCH] BLOCK: Make it possible to disable the block layer [try #6]
Make it possible to disable the block layer. Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.
This patch does the following:
(*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
support.
(*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
an item that uses the block layer. This includes:
(*) Block I/O tracing.
(*) Disk partition code.
(*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.
(*) The SCSI layer. As far as I can tell, even SCSI chardevs use the
block layer to do scheduling. Some drivers that use SCSI facilities -
such as USB storage - end up disabled indirectly from this.
(*) Various block-based device drivers, such as IDE and the old CDROM
drivers.
(*) MTD blockdev handling and FTL.
(*) JFFS - which uses set_bdev_super(), something it could avoid doing by
taking a leaf out of JFFS2's book.
(*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
linux/elevator.h contingent on CONFIG_BLOCK being set. sector_div() is,
however, still used in places, and so is still available.
(*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
parts of linux/fs.h.
(*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.
(*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.
(*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
is not enabled.
(*) fs/no-block.c is created to hold out-of-line stubs and things that are
required when CONFIG_BLOCK is not set:
(*) Default blockdev file operations (to give error ENODEV on opening).
(*) Makes some /proc changes:
(*) /proc/devices does not list any blockdevs.
(*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.
(*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.
(*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
given command other than Q_SYNC or if a special device is specified.
(*) In init/do_mounts.c, no reference is made to the blockdev routines if
CONFIG_BLOCK is not defined. This does not prohibit NFS roots or JFFS2.
(*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
error ENOSYS by way of cond_syscall if so).
(*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
CONFIG_BLOCK is not set, since they can't then happen.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-10-01 02:45:40 +08:00
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seq_file.o xattr.o libfs.o fs-writeback.o \
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2013-04-30 06:07:22 +08:00
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pnode.o splice.o sync.o utimes.o \
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2014-08-07 20:39:04 +08:00
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stack.o fs_struct.o statfs.o fs_pin.o
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[PATCH] BLOCK: Make it possible to disable the block layer [try #6]
Make it possible to disable the block layer. Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.
This patch does the following:
(*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
support.
(*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
an item that uses the block layer. This includes:
(*) Block I/O tracing.
(*) Disk partition code.
(*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.
(*) The SCSI layer. As far as I can tell, even SCSI chardevs use the
block layer to do scheduling. Some drivers that use SCSI facilities -
such as USB storage - end up disabled indirectly from this.
(*) Various block-based device drivers, such as IDE and the old CDROM
drivers.
(*) MTD blockdev handling and FTL.
(*) JFFS - which uses set_bdev_super(), something it could avoid doing by
taking a leaf out of JFFS2's book.
(*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
linux/elevator.h contingent on CONFIG_BLOCK being set. sector_div() is,
however, still used in places, and so is still available.
(*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
parts of linux/fs.h.
(*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.
(*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.
(*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
is not enabled.
(*) fs/no-block.c is created to hold out-of-line stubs and things that are
required when CONFIG_BLOCK is not set:
(*) Default blockdev file operations (to give error ENODEV on opening).
(*) Makes some /proc changes:
(*) /proc/devices does not list any blockdevs.
(*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.
(*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.
(*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
given command other than Q_SYNC or if a special device is specified.
(*) In init/do_mounts.c, no reference is made to the blockdev routines if
CONFIG_BLOCK is not defined. This does not prohibit NFS roots or JFFS2.
(*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
error ENOSYS by way of cond_syscall if so).
(*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
CONFIG_BLOCK is not set, since they can't then happen.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-10-01 02:45:40 +08:00
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ifeq ($(CONFIG_BLOCK),y)
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2014-05-20 01:02:18 +08:00
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obj-y += buffer.o block_dev.o direct-io.o mpage.o
|
[PATCH] BLOCK: Make it possible to disable the block layer [try #6]
Make it possible to disable the block layer. Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.
This patch does the following:
(*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
support.
(*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
an item that uses the block layer. This includes:
(*) Block I/O tracing.
(*) Disk partition code.
(*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.
(*) The SCSI layer. As far as I can tell, even SCSI chardevs use the
block layer to do scheduling. Some drivers that use SCSI facilities -
such as USB storage - end up disabled indirectly from this.
(*) Various block-based device drivers, such as IDE and the old CDROM
drivers.
(*) MTD blockdev handling and FTL.
(*) JFFS - which uses set_bdev_super(), something it could avoid doing by
taking a leaf out of JFFS2's book.
(*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
linux/elevator.h contingent on CONFIG_BLOCK being set. sector_div() is,
however, still used in places, and so is still available.
(*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
parts of linux/fs.h.
(*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.
(*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.
(*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
is not enabled.
(*) fs/no-block.c is created to hold out-of-line stubs and things that are
required when CONFIG_BLOCK is not set:
(*) Default blockdev file operations (to give error ENODEV on opening).
(*) Makes some /proc changes:
(*) /proc/devices does not list any blockdevs.
(*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.
(*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.
(*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
given command other than Q_SYNC or if a special device is specified.
(*) In init/do_mounts.c, no reference is made to the blockdev routines if
CONFIG_BLOCK is not defined. This does not prohibit NFS roots or JFFS2.
(*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
error ENOSYS by way of cond_syscall if so).
(*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
CONFIG_BLOCK is not set, since they can't then happen.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-10-01 02:45:40 +08:00
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else
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obj-y += no-block.o
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endif
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2005-04-17 06:20:36 +08:00
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2011-12-07 01:21:54 +08:00
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obj-$(CONFIG_PROC_FS) += proc_namespace.o
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2008-12-18 02:59:41 +08:00
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obj-y += notify/
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2005-04-17 06:20:36 +08:00
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obj-$(CONFIG_EPOLL) += eventpoll.o
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2007-05-11 13:23:11 +08:00
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obj-$(CONFIG_ANON_INODES) += anon_inodes.o
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signal/timer/event: signalfd core
This patch series implements the new signalfd() system call.
I took part of the original Linus code (and you know how badly it can be
broken :), and I added even more breakage ;) Signals are fetched from the same
signal queue used by the process, so signalfd will compete with standard
kernel delivery in dequeue_signal(). If you want to reliably fetch signals on
the signalfd file, you need to block them with sigprocmask(SIG_BLOCK). This
seems to be working fine on my Dual Opteron machine. I made a quick test
program for it:
http://www.xmailserver.org/signafd-test.c
The signalfd() system call implements signal delivery into a file descriptor
receiver. The signalfd file descriptor if created with the following API:
int signalfd(int ufd, const sigset_t *mask, size_t masksize);
The "ufd" parameter allows to change an existing signalfd sigmask, w/out going
to close/create cycle (Linus idea). Use "ufd" == -1 if you want a brand new
signalfd file.
The "mask" allows to specify the signal mask of signals that we are interested
in. The "masksize" parameter is the size of "mask".
The signalfd fd supports the poll(2) and read(2) system calls. The poll(2)
will return POLLIN when signals are available to be dequeued. As a direct
consequence of supporting the Linux poll subsystem, the signalfd fd can use
used together with epoll(2) too.
The read(2) system call will return a "struct signalfd_siginfo" structure in
the userspace supplied buffer. The return value is the number of bytes copied
in the supplied buffer, or -1 in case of error. The read(2) call can also
return 0, in case the sighand structure to which the signalfd was attached,
has been orphaned. The O_NONBLOCK flag is also supported, and read(2) will
return -EAGAIN in case no signal is available.
If the size of the buffer passed to read(2) is lower than sizeof(struct
signalfd_siginfo), -EINVAL is returned. A read from the signalfd can also
return -ERESTARTSYS in case a signal hits the process. The format of the
struct signalfd_siginfo is, and the valid fields depends of the (->code &
__SI_MASK) value, in the same way a struct siginfo would:
struct signalfd_siginfo {
__u32 signo; /* si_signo */
__s32 err; /* si_errno */
__s32 code; /* si_code */
__u32 pid; /* si_pid */
__u32 uid; /* si_uid */
__s32 fd; /* si_fd */
__u32 tid; /* si_fd */
__u32 band; /* si_band */
__u32 overrun; /* si_overrun */
__u32 trapno; /* si_trapno */
__s32 status; /* si_status */
__s32 svint; /* si_int */
__u64 svptr; /* si_ptr */
__u64 utime; /* si_utime */
__u64 stime; /* si_stime */
__u64 addr; /* si_addr */
};
[akpm@linux-foundation.org: fix signalfd_copyinfo() on i386]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 13:23:13 +08:00
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obj-$(CONFIG_SIGNALFD) += signalfd.o
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signal/timer/event: timerfd core
This patch introduces a new system call for timers events delivered though
file descriptors. This allows timer event to be used with standard POSIX
poll(2), select(2) and read(2). As a consequence of supporting the Linux
f_op->poll subsystem, they can be used with epoll(2) too.
The system call is defined as:
int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr);
The "ufd" parameter allows for re-use (re-programming) of an existing timerfd
w/out going through the close/open cycle (same as signalfd). If "ufd" is -1,
s new file descriptor will be created, otherwise the existing "ufd" will be
re-programmed.
The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME. The time
specified in the "utmr->it_value" parameter is the expiry time for the timer.
If the TFD_TIMER_ABSTIME flag is set in "flags", this is an absolute time,
otherwise it's a relative time.
If the time specified in the "utmr->it_interval" is not zero (.tv_sec == 0,
tv_nsec == 0), this is the period at which the following ticks should be
generated.
The "utmr->it_interval" should be set to zero if only one tick is requested.
Setting the "utmr->it_value" to zero will disable the timer, or will create a
timerfd without the timer enabled.
The function returns the new (or same, in case "ufd" is a valid timerfd
descriptor) file, or -1 in case of error.
As stated before, the timerfd file descriptor supports poll(2), select(2) and
epoll(2). When a timer event happened on the timerfd, a POLLIN mask will be
returned.
The read(2) call can be used, and it will return a u32 variable holding the
number of "ticks" that happened on the interface since the last call to
read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN will
be returned if no ticks happened.
A quick test program, shows timerfd working correctly on my amd64 box:
http://www.xmailserver.org/timerfd-test.c
[akpm@linux-foundation.org: add sys_timerfd to sys_ni.c]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 13:23:16 +08:00
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obj-$(CONFIG_TIMERFD) += timerfd.o
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signal/timer/event: eventfd core
This is a very simple and light file descriptor, that can be used as event
wait/dispatch by userspace (both wait and dispatch) and by the kernel
(dispatch only). It can be used instead of pipe(2) in all cases where those
would simply be used to signal events. Their kernel overhead is much lower
than pipes, and they do not consume two fds. When used in the kernel, it can
offer an fd-bridge to enable, for example, functionalities like KAIO or
syslets/threadlets to signal to an fd the completion of certain operations.
But more in general, an eventfd can be used by the kernel to signal readiness,
in a POSIX poll/select way, of interfaces that would otherwise be incompatible
with it. The API is:
int eventfd(unsigned int count);
The eventfd API accepts an initial "count" parameter, and returns an eventfd
fd. It supports poll(2) (POLLIN, POLLOUT, POLLERR), read(2) and write(2).
The POLLIN flag is raised when the internal counter is greater than zero.
The POLLOUT flag is raised when at least a value of "1" can be written to the
internal counter.
The POLLERR flag is raised when an overflow in the counter value is detected.
The write(2) operation can never overflow the counter, since it blocks (unless
O_NONBLOCK is set, in which case -EAGAIN is returned).
But the eventfd_signal() function can do it, since it's supposed to not sleep
during its operation.
The read(2) function reads the __u64 counter value, and reset the internal
value to zero. If the value read is equal to (__u64) -1, an overflow happened
on the internal counter (due to 2^64 eventfd_signal() posts that has never
been retired - unlickely, but possible).
The write(2) call writes an __u64 count value, and adds it to the current
counter. The eventfd fd supports O_NONBLOCK also.
On the kernel side, we have:
struct file *eventfd_fget(int fd);
int eventfd_signal(struct file *file, unsigned int n);
The eventfd_fget() should be called to get a struct file* from an eventfd fd
(this is an fget() + check of f_op being an eventfd fops pointer).
The kernel can then call eventfd_signal() every time it wants to post an event
to userspace. The eventfd_signal() function can be called from any context.
An eventfd() simple test and bench is available here:
http://www.xmailserver.org/eventfd-bench.c
This is the eventfd-based version of pipetest-4 (pipe(2) based):
http://www.xmailserver.org/pipetest-4.c
Not that performance matters much in the eventfd case, but eventfd-bench
shows almost as double as performance than pipetest-4.
[akpm@linux-foundation.org: fix i386 build]
[akpm@linux-foundation.org: add sys_eventfd to sys_ni.c]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 13:23:19 +08:00
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obj-$(CONFIG_EVENTFD) += eventfd.o
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2008-10-16 13:05:12 +08:00
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obj-$(CONFIG_AIO) += aio.o
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2008-08-06 21:12:22 +08:00
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obj-$(CONFIG_FILE_LOCKING) += locks.o
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2006-01-10 12:52:14 +08:00
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obj-$(CONFIG_COMPAT) += compat.o compat_ioctl.o
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2005-04-17 06:20:36 +08:00
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obj-$(CONFIG_BINFMT_AOUT) += binfmt_aout.o
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obj-$(CONFIG_BINFMT_EM86) += binfmt_em86.o
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obj-$(CONFIG_BINFMT_MISC) += binfmt_misc.o
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2013-05-01 06:27:44 +08:00
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obj-$(CONFIG_BINFMT_SCRIPT) += binfmt_script.o
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2005-04-17 06:20:36 +08:00
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obj-$(CONFIG_BINFMT_ELF) += binfmt_elf.o
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2008-01-30 20:31:46 +08:00
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obj-$(CONFIG_COMPAT_BINFMT_ELF) += compat_binfmt_elf.o
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2005-04-17 06:20:36 +08:00
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obj-$(CONFIG_BINFMT_ELF_FDPIC) += binfmt_elf_fdpic.o
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obj-$(CONFIG_BINFMT_SOM) += binfmt_som.o
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obj-$(CONFIG_BINFMT_FLAT) += binfmt_flat.o
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obj-$(CONFIG_FS_MBCACHE) += mbcache.o
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2013-12-20 21:16:37 +08:00
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obj-$(CONFIG_FS_POSIX_ACL) += posix_acl.o
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2005-06-23 01:16:26 +08:00
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obj-$(CONFIG_NFS_COMMON) += nfs_common/
|
2012-10-05 08:15:23 +08:00
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obj-$(CONFIG_COREDUMP) += coredump.o
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2013-04-30 06:07:22 +08:00
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obj-$(CONFIG_SYSCTL) += drop_caches.o
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2005-04-17 06:20:36 +08:00
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2011-01-29 21:13:26 +08:00
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obj-$(CONFIG_FHANDLE) += fhandle.o
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2009-01-26 22:28:09 +08:00
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obj-y += quota/
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2005-04-17 06:20:36 +08:00
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obj-$(CONFIG_PROC_FS) += proc/
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2014-02-04 03:09:17 +08:00
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obj-$(CONFIG_KERNFS) += kernfs/
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obj-$(CONFIG_SYSFS) += sysfs/
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2006-05-04 02:38:53 +08:00
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obj-$(CONFIG_CONFIGFS_FS) += configfs/
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2005-04-17 06:20:36 +08:00
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obj-y += devpts/
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obj-$(CONFIG_PROFILING) += dcookies.o
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2006-01-18 17:30:29 +08:00
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obj-$(CONFIG_DLM) += dlm/
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2005-04-17 06:20:36 +08:00
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# Do not add any filesystems before this line
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2009-04-03 23:42:36 +08:00
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obj-$(CONFIG_FSCACHE) += fscache/
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2005-04-17 06:20:36 +08:00
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obj-$(CONFIG_REISERFS_FS) += reiserfs/
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obj-$(CONFIG_EXT3_FS) += ext3/ # Before ext2 so root fs can be ext3
|
ext4: Reorder fs/Makefile so that ext2 root fs's are mounted using ext2
In fs/Makefile, ext3 was placed before ext2 so that a root filesystem
that possessed a journal, it would be mounted as ext3 instead of ext2.
This was necessary because a cleanly unmounted ext3 filesystem was
fully backwards compatible with ext2, and could be mounted by ext2 ---
but it was desirable that it be mounted with ext3 so that the
journaling would be enabled.
The ext4 filesystem supports new incompatible features, so there is no
danger of an ext4 filesystem being mistaken for an ext2 filesystem.
At that point, the relative ordering of ext4 with respect to ext2
didn't matter until ext4 gained the ability to mount filesystems
without a journal starting in 2.6.29-rc1. Now that this is the case,
given that ext4 is before ext2, it means that root filesystems that
were using the plain-jane ext2 format are getting mounted using the
ext4 filesystem driver, which is a change in behavior which could be
surprising to users.
It's doubtful that there are that many ext2-only root filesystem users
that would also have ext4 compiled into the kernel, but to adhere to
the principle of least surprise, the correct ordering in fs/Makefile
is ext3, followed by ext2, and finally ext4.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2009-02-28 22:50:01 +08:00
|
|
|
obj-$(CONFIG_EXT2_FS) += ext2/
|
|
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|
|
# We place ext4 after ext2 so plain ext2 root fs's are mounted using ext2
|
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|
# unless explicitly requested by rootfstype
|
|
|
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|
obj-$(CONFIG_EXT4_FS) += ext4/
|
2005-04-17 06:20:36 +08:00
|
|
|
obj-$(CONFIG_JBD) += jbd/
|
2006-10-11 16:21:01 +08:00
|
|
|
obj-$(CONFIG_JBD2) += jbd2/
|
2005-04-17 06:20:36 +08:00
|
|
|
obj-$(CONFIG_CRAMFS) += cramfs/
|
2009-01-05 16:46:27 +08:00
|
|
|
obj-$(CONFIG_SQUASHFS) += squashfs/
|
2007-10-17 14:29:27 +08:00
|
|
|
obj-y += ramfs/
|
2005-04-17 06:20:36 +08:00
|
|
|
obj-$(CONFIG_HUGETLBFS) += hugetlbfs/
|
|
|
|
|
obj-$(CONFIG_CODA_FS) += coda/
|
|
|
|
|
obj-$(CONFIG_MINIX_FS) += minix/
|
|
|
|
|
obj-$(CONFIG_FAT_FS) += fat/
|
|
|
|
|
obj-$(CONFIG_BFS_FS) += bfs/
|
|
|
|
|
obj-$(CONFIG_ISO9660_FS) += isofs/
|
|
|
|
|
obj-$(CONFIG_HFSPLUS_FS) += hfsplus/ # Before hfs to find wrapped HFS+
|
|
|
|
|
obj-$(CONFIG_HFS_FS) += hfs/
|
2006-10-04 17:16:22 +08:00
|
|
|
obj-$(CONFIG_ECRYPT_FS) += ecryptfs/
|
2005-04-17 06:20:36 +08:00
|
|
|
obj-$(CONFIG_VXFS_FS) += freevxfs/
|
|
|
|
|
obj-$(CONFIG_NFS_FS) += nfs/
|
|
|
|
|
obj-$(CONFIG_EXPORTFS) += exportfs/
|
|
|
|
|
obj-$(CONFIG_NFSD) += nfsd/
|
|
|
|
|
obj-$(CONFIG_LOCKD) += lockd/
|
|
|
|
|
obj-$(CONFIG_NLS) += nls/
|
|
|
|
|
obj-$(CONFIG_SYSV_FS) += sysv/
|
|
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|
|
obj-$(CONFIG_CIFS) += cifs/
|
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|
obj-$(CONFIG_NCP_FS) += ncpfs/
|
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|
obj-$(CONFIG_HPFS_FS) += hpfs/
|
|
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|
obj-$(CONFIG_NTFS_FS) += ntfs/
|
|
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|
|
obj-$(CONFIG_UFS_FS) += ufs/
|
|
|
|
|
obj-$(CONFIG_EFS_FS) += efs/
|
|
|
|
|
obj-$(CONFIG_JFFS2_FS) += jffs2/
|
2009-11-21 03:13:39 +08:00
|
|
|
obj-$(CONFIG_LOGFS) += logfs/
|
2008-07-15 00:08:38 +08:00
|
|
|
obj-$(CONFIG_UBIFS_FS) += ubifs/
|
2005-04-17 06:20:36 +08:00
|
|
|
obj-$(CONFIG_AFFS_FS) += affs/
|
|
|
|
|
obj-$(CONFIG_ROMFS_FS) += romfs/
|
|
|
|
|
obj-$(CONFIG_QNX4FS_FS) += qnx4/
|
2012-02-17 12:59:20 +08:00
|
|
|
obj-$(CONFIG_QNX6FS_FS) += qnx6/
|
2005-04-17 06:20:36 +08:00
|
|
|
obj-$(CONFIG_AUTOFS4_FS) += autofs4/
|
|
|
|
|
obj-$(CONFIG_ADFS_FS) += adfs/
|
2005-09-10 04:10:22 +08:00
|
|
|
obj-$(CONFIG_FUSE_FS) += fuse/
|
overlay filesystem
Overlayfs allows one, usually read-write, directory tree to be
overlaid onto another, read-only directory tree. All modifications
go to the upper, writable layer.
This type of mechanism is most often used for live CDs but there's a
wide variety of other uses.
The implementation differs from other "union filesystem"
implementations in that after a file is opened all operations go
directly to the underlying, lower or upper, filesystems. This
simplifies the implementation and allows native performance in these
cases.
The dentry tree is duplicated from the underlying filesystems, this
enables fast cached lookups without adding special support into the
VFS. This uses slightly more memory than union mounts, but dentries
are relatively small.
Currently inodes are duplicated as well, but it is a possible
optimization to share inodes for non-directories.
Opening non directories results in the open forwarded to the
underlying filesystem. This makes the behavior very similar to union
mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file
descriptors).
Usage:
mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay
The following cotributions have been folded into this patch:
Neil Brown <neilb@suse.de>:
- minimal remount support
- use correct seek function for directories
- initialise is_real before use
- rename ovl_fill_cache to ovl_dir_read
Felix Fietkau <nbd@openwrt.org>:
- fix a deadlock in ovl_dir_read_merged
- fix a deadlock in ovl_remove_whiteouts
Erez Zadok <ezk@fsl.cs.sunysb.edu>
- fix cleanup after WARN_ON
Sedat Dilek <sedat.dilek@googlemail.com>
- fix up permission to confirm to new API
Robin Dong <hao.bigrat@gmail.com>
- fix possible leak in ovl_new_inode
- create new inode in ovl_link
Andy Whitcroft <apw@canonical.com>
- switch to __inode_permission()
- copy up i_uid/i_gid from the underlying inode
AV:
- ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits
- ovl_clear_empty() - one failure exit forgetting to do unlock_rename(),
lack of check for udir being the parent of upper, dropping and regaining
the lock on udir (which would require _another_ check for parent being
right).
- bogus d_drop() in copyup and rename [fix from your mail]
- copyup/remove and copyup/rename races [fix from your mail]
- ovl_dir_fsync() leaving ERR_PTR() in ->realfile
- ovl_entry_free() is pointless - it's just a kfree_rcu()
- fold ovl_do_lookup() into ovl_lookup()
- manually assigning ->d_op is wrong. Just use ->s_d_op.
[patches picked from Miklos]:
* copyup/remove and copyup/rename races
* bogus d_drop() in copyup and rename
Also thanks to the following people for testing and reporting bugs:
Jordi Pujol <jordipujolp@gmail.com>
Andy Whitcroft <apw@canonical.com>
Michal Suchanek <hramrach@centrum.cz>
Felix Fietkau <nbd@openwrt.org>
Erez Zadok <ezk@fsl.cs.sunysb.edu>
Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
|
|
|
obj-$(CONFIG_OVERLAYFS_FS) += overlayfs/
|
2005-04-17 06:20:36 +08:00
|
|
|
obj-$(CONFIG_UDF_FS) += udf/
|
|
|
|
|
obj-$(CONFIG_SUN_OPENPROMFS) += openpromfs/
|
2008-07-26 10:45:17 +08:00
|
|
|
obj-$(CONFIG_OMFS_FS) += omfs/
|
2005-04-17 06:20:36 +08:00
|
|
|
obj-$(CONFIG_JFS_FS) += jfs/
|
|
|
|
|
obj-$(CONFIG_XFS_FS) += xfs/
|
[PATCH] v9fs: Documentation, Makefiles, Configuration
OVERVIEW
V9FS is a distributed file system for Linux which provides an
implementation of the Plan 9 resource sharing protocol 9P. It can be
used to share all sorts of resources: static files, synthetic file servers
(such as /proc or /sys), devices, and application file servers (such as
FUSE).
BACKGROUND
Plan 9 (http://plan9.bell-labs.com/plan9) is a research operating
system and associated applications suite developed by the Computing
Science Research Center of AT&T Bell Laboratories (now a part of
Lucent Technologies), the same group that developed UNIX , C, and C++.
Plan 9 was initially released in 1993 to universities, and then made
generally available in 1995. Its core operating systems code laid the
foundation for the Inferno Operating System released as a product by
Lucent Bell-Labs in 1997. The Inferno venture was the only commercial
embodiment of Plan 9 and is currently maintained as a product by Vita
Nuova (http://www.vitanuova.com). After updated releases in 2000 and
2002, Plan 9 was open-sourced under the OSI approved Lucent Public
License in 2003.
The Plan 9 project was started by Ken Thompson and Rob Pike in 1985.
Their intent was to explore potential solutions to some of the
shortcomings of UNIX in the face of the widespread use of high-speed
networks to connect machines. In UNIX, networking was an afterthought
and UNIX clusters became little more than a network of stand-alone
systems. Plan 9 was designed from first principles as a seamless
distributed system with integrated secure network resource sharing.
Applications and services were architected in such a way as to allow
for implicit distribution across a cluster of systems. Configuring an
environment to use remote application components or services in place
of their local equivalent could be achieved with a few simple command
line instructions. For the most part, application implementations
operated independent of the location of their actual resources.
Commercial operating systems haven't changed much in the 20 years
since Plan 9 was conceived. Network and distributed systems support is
provided by a patchwork of middle-ware, with an endless number of
packages supplying pieces of the puzzle. Matters are complicated by
the use of different complicated protocols for individual services,
and separate implementations for kernel and application resources.
The V9FS project (http://v9fs.sourceforge.net) is an attempt to bring
Plan 9's unified approach to resource sharing to Linux and other
operating systems via support for the 9P2000 resource sharing
protocol.
V9FS HISTORY
V9FS was originally developed by Ron Minnich and Maya Gokhale at Los
Alamos National Labs (LANL) in 1997. In November of 2001, Greg Watson
setup a SourceForge project as a public repository for the code which
supported the Linux 2.4 kernel.
About a year ago, I picked up the initial attempt Ron Minnich had
made to provide 2.6 support and got the code integrated into a 2.6.5
kernel. I then went through a line-for-line re-write attempting to
clean-up the code while more closely following the Linux Kernel style
guidelines. I co-authored a paper with Ron Minnich on the V9FS Linux
support including performance comparisons to NFSv3 using Bonnie and
PostMark - this paper appeared at the USENIX/FREENIX 2005
conference in April 2005:
( http://www.usenix.org/events/usenix05/tech/freenix/hensbergen.html ).
CALL FOR PARTICIPATION/REQUEST FOR COMMENTS
Our 2.6 kernel support is stabilizing and we'd like to begin pursuing
its integration into the official kernel tree. We would appreciate any
review, comments, critiques, and additions from this community and are
actively seeking people to join our project and help us produce
something that would be acceptable and useful to the Linux community.
STATUS
The code is reasonably stable, although there are no doubt corner cases
our regression tests haven't discovered yet. It is in regular use by several
of the developers and has been tested on x86 and PowerPC
(32-bit and 64-bit) in both small and large (LANL cluster) deployments.
Our current regression tests include fsx, bonnie, and postmark.
It was our intention to keep things as simple as possible for this
release -- trying to focus on correctness within the core of the
protocol support versus a rich set of features. For example: a more
complete security model and cache layer are in the road map, but
excluded from this release. Additionally, we have removed support for
mmap operations at Al Viro's request.
PERFORMANCE
Detailed performance numbers and analysis are included in the FREENIX
paper, but we show comparable performance to NFSv3 for large file
operations based on the Bonnie benchmark, and superior performance for
many small file operations based on the PostMark benchmark. Somewhat
preliminary graphs (from the FREENIX paper) are available
(http://v9fs.sourceforge.net/perf/index.html).
RESOURCES
The source code is available in a few different forms:
tarballs: http://v9fs.sf.net
CVSweb: http://cvs.sourceforge.net/viewcvs.py/v9fs/linux-9p/
CVS: :pserver:anonymous@cvs.sourceforge.net:/cvsroot/v9fs/linux-9p
Git: rsync://v9fs.graverobber.org/v9fs (webgit: http://v9fs.graverobber.org)
9P: tcp!v9fs.graverobber.org!6564
The user-level server is available from either the Plan 9 distribution
or from http://v9fs.sf.net
Other support applications are still being developed, but preliminary
version can be downloaded from sourceforge.
Documentation on the protocol has historically been the Plan 9 Man
pages (http://plan9.bell-labs.com/sys/man/5/INDEX.html), but there is
an effort under way to write a more complete Internet-Draft style
specification (http://v9fs.sf.net/rfc).
There are a couple of mailing lists supporting v9fs, but the most used
is v9fs-developer@lists.sourceforge.net -- please direct/cc your
comments there so the other v9fs contibutors can participate in the
conversation. There is also an IRC channel: irc://freenode.net/#v9fs
This part of the patch contains Documentation, Makefiles, and configuration
file changes.
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-10 04:04:18 +08:00
|
|
|
obj-$(CONFIG_9P_FS) += 9p/
|
2005-04-17 06:20:36 +08:00
|
|
|
obj-$(CONFIG_AFS_FS) += afs/
|
2009-04-07 10:01:41 +08:00
|
|
|
obj-$(CONFIG_NILFS2_FS) += nilfs2/
|
2005-04-17 06:20:36 +08:00
|
|
|
obj-$(CONFIG_BEFS_FS) += befs/
|
|
|
|
|
obj-$(CONFIG_HOSTFS) += hostfs/
|
|
|
|
|
obj-$(CONFIG_HPPFS) += hppfs/
|
CacheFiles: A cache that backs onto a mounted filesystem
Add an FS-Cache cache-backend that permits a mounted filesystem to be used as a
backing store for the cache.
CacheFiles uses a userspace daemon to do some of the cache management - such as
reaping stale nodes and culling. This is called cachefilesd and lives in
/sbin. The source for the daemon can be downloaded from:
http://people.redhat.com/~dhowells/cachefs/cachefilesd.c
And an example configuration from:
http://people.redhat.com/~dhowells/cachefs/cachefilesd.conf
The filesystem and data integrity of the cache are only as good as those of the
filesystem providing the backing services. Note that CacheFiles does not
attempt to journal anything since the journalling interfaces of the various
filesystems are very specific in nature.
CacheFiles creates a misc character device - "/dev/cachefiles" - that is used
to communication with the daemon. Only one thing may have this open at once,
and whilst it is open, a cache is at least partially in existence. The daemon
opens this and sends commands down it to control the cache.
CacheFiles is currently limited to a single cache.
CacheFiles attempts to maintain at least a certain percentage of free space on
the filesystem, shrinking the cache by culling the objects it contains to make
space if necessary - see the "Cache Culling" section. This means it can be
placed on the same medium as a live set of data, and will expand to make use of
spare space and automatically contract when the set of data requires more
space.
============
REQUIREMENTS
============
The use of CacheFiles and its daemon requires the following features to be
available in the system and in the cache filesystem:
- dnotify.
- extended attributes (xattrs).
- openat() and friends.
- bmap() support on files in the filesystem (FIBMAP ioctl).
- The use of bmap() to detect a partial page at the end of the file.
It is strongly recommended that the "dir_index" option is enabled on Ext3
filesystems being used as a cache.
=============
CONFIGURATION
=============
The cache is configured by a script in /etc/cachefilesd.conf. These commands
set up cache ready for use. The following script commands are available:
(*) brun <N>%
(*) bcull <N>%
(*) bstop <N>%
(*) frun <N>%
(*) fcull <N>%
(*) fstop <N>%
Configure the culling limits. Optional. See the section on culling
The defaults are 7% (run), 5% (cull) and 1% (stop) respectively.
The commands beginning with a 'b' are file space (block) limits, those
beginning with an 'f' are file count limits.
(*) dir <path>
Specify the directory containing the root of the cache. Mandatory.
(*) tag <name>
Specify a tag to FS-Cache to use in distinguishing multiple caches.
Optional. The default is "CacheFiles".
(*) debug <mask>
Specify a numeric bitmask to control debugging in the kernel module.
Optional. The default is zero (all off). The following values can be
OR'd into the mask to collect various information:
1 Turn on trace of function entry (_enter() macros)
2 Turn on trace of function exit (_leave() macros)
4 Turn on trace of internal debug points (_debug())
This mask can also be set through sysfs, eg:
echo 5 >/sys/modules/cachefiles/parameters/debug
==================
STARTING THE CACHE
==================
The cache is started by running the daemon. The daemon opens the cache device,
configures the cache and tells it to begin caching. At that point the cache
binds to fscache and the cache becomes live.
The daemon is run as follows:
/sbin/cachefilesd [-d]* [-s] [-n] [-f <configfile>]
The flags are:
(*) -d
Increase the debugging level. This can be specified multiple times and
is cumulative with itself.
(*) -s
Send messages to stderr instead of syslog.
(*) -n
Don't daemonise and go into background.
(*) -f <configfile>
Use an alternative configuration file rather than the default one.
===============
THINGS TO AVOID
===============
Do not mount other things within the cache as this will cause problems. The
kernel module contains its own very cut-down path walking facility that ignores
mountpoints, but the daemon can't avoid them.
Do not create, rename or unlink files and directories in the cache whilst the
cache is active, as this may cause the state to become uncertain.
Renaming files in the cache might make objects appear to be other objects (the
filename is part of the lookup key).
Do not change or remove the extended attributes attached to cache files by the
cache as this will cause the cache state management to get confused.
Do not create files or directories in the cache, lest the cache get confused or
serve incorrect data.
Do not chmod files in the cache. The module creates things with minimal
permissions to prevent random users being able to access them directly.
=============
CACHE CULLING
=============
The cache may need culling occasionally to make space. This involves
discarding objects from the cache that have been used less recently than
anything else. Culling is based on the access time of data objects. Empty
directories are culled if not in use.
Cache culling is done on the basis of the percentage of blocks and the
percentage of files available in the underlying filesystem. There are six
"limits":
(*) brun
(*) frun
If the amount of free space and the number of available files in the cache
rises above both these limits, then culling is turned off.
(*) bcull
(*) fcull
If the amount of available space or the number of available files in the
cache falls below either of these limits, then culling is started.
(*) bstop
(*) fstop
If the amount of available space or the number of available files in the
cache falls below either of these limits, then no further allocation of
disk space or files is permitted until culling has raised things above
these limits again.
These must be configured thusly:
0 <= bstop < bcull < brun < 100
0 <= fstop < fcull < frun < 100
Note that these are percentages of available space and available files, and do
_not_ appear as 100 minus the percentage displayed by the "df" program.
The userspace daemon scans the cache to build up a table of cullable objects.
These are then culled in least recently used order. A new scan of the cache is
started as soon as space is made in the table. Objects will be skipped if
their atimes have changed or if the kernel module says it is still using them.
===============
CACHE STRUCTURE
===============
The CacheFiles module will create two directories in the directory it was
given:
(*) cache/
(*) graveyard/
The active cache objects all reside in the first directory. The CacheFiles
kernel module moves any retired or culled objects that it can't simply unlink
to the graveyard from which the daemon will actually delete them.
The daemon uses dnotify to monitor the graveyard directory, and will delete
anything that appears therein.
The module represents index objects as directories with the filename "I..." or
"J...". Note that the "cache/" directory is itself a special index.
Data objects are represented as files if they have no children, or directories
if they do. Their filenames all begin "D..." or "E...". If represented as a
directory, data objects will have a file in the directory called "data" that
actually holds the data.
Special objects are similar to data objects, except their filenames begin
"S..." or "T...".
If an object has children, then it will be represented as a directory.
Immediately in the representative directory are a collection of directories
named for hash values of the child object keys with an '@' prepended. Into
this directory, if possible, will be placed the representations of the child
objects:
INDEX INDEX INDEX DATA FILES
========= ========== ================================= ================
cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400
cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...DB1ry
cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...N22ry
cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...FP1ry
If the key is so long that it exceeds NAME_MAX with the decorations added on to
it, then it will be cut into pieces, the first few of which will be used to
make a nest of directories, and the last one of which will be the objects
inside the last directory. The names of the intermediate directories will have
'+' prepended:
J1223/@23/+xy...z/+kl...m/Epqr
Note that keys are raw data, and not only may they exceed NAME_MAX in size,
they may also contain things like '/' and NUL characters, and so they may not
be suitable for turning directly into a filename.
To handle this, CacheFiles will use a suitably printable filename directly and
"base-64" encode ones that aren't directly suitable. The two versions of
object filenames indicate the encoding:
OBJECT TYPE PRINTABLE ENCODED
=============== =============== ===============
Index "I..." "J..."
Data "D..." "E..."
Special "S..." "T..."
Intermediate directories are always "@" or "+" as appropriate.
Each object in the cache has an extended attribute label that holds the object
type ID (required to distinguish special objects) and the auxiliary data from
the netfs. The latter is used to detect stale objects in the cache and update
or retire them.
Note that CacheFiles will erase from the cache any file it doesn't recognise or
any file of an incorrect type (such as a FIFO file or a device file).
==========================
SECURITY MODEL AND SELINUX
==========================
CacheFiles is implemented to deal properly with the LSM security features of
the Linux kernel and the SELinux facility.
One of the problems that CacheFiles faces is that it is generally acting on
behalf of a process, and running in that process's context, and that includes a
security context that is not appropriate for accessing the cache - either
because the files in the cache are inaccessible to that process, or because if
the process creates a file in the cache, that file may be inaccessible to other
processes.
The way CacheFiles works is to temporarily change the security context (fsuid,
fsgid and actor security label) that the process acts as - without changing the
security context of the process when it the target of an operation performed by
some other process (so signalling and suchlike still work correctly).
When the CacheFiles module is asked to bind to its cache, it:
(1) Finds the security label attached to the root cache directory and uses
that as the security label with which it will create files. By default,
this is:
cachefiles_var_t
(2) Finds the security label of the process which issued the bind request
(presumed to be the cachefilesd daemon), which by default will be:
cachefilesd_t
and asks LSM to supply a security ID as which it should act given the
daemon's label. By default, this will be:
cachefiles_kernel_t
SELinux transitions the daemon's security ID to the module's security ID
based on a rule of this form in the policy.
type_transition <daemon's-ID> kernel_t : process <module's-ID>;
For instance:
type_transition cachefilesd_t kernel_t : process cachefiles_kernel_t;
The module's security ID gives it permission to create, move and remove files
and directories in the cache, to find and access directories and files in the
cache, to set and access extended attributes on cache objects, and to read and
write files in the cache.
The daemon's security ID gives it only a very restricted set of permissions: it
may scan directories, stat files and erase files and directories. It may
not read or write files in the cache, and so it is precluded from accessing the
data cached therein; nor is it permitted to create new files in the cache.
There are policy source files available in:
http://people.redhat.com/~dhowells/fscache/cachefilesd-0.8.tar.bz2
and later versions. In that tarball, see the files:
cachefilesd.te
cachefilesd.fc
cachefilesd.if
They are built and installed directly by the RPM.
If a non-RPM based system is being used, then copy the above files to their own
directory and run:
make -f /usr/share/selinux/devel/Makefile
semodule -i cachefilesd.pp
You will need checkpolicy and selinux-policy-devel installed prior to the
build.
By default, the cache is located in /var/fscache, but if it is desirable that
it should be elsewhere, than either the above policy files must be altered, or
an auxiliary policy must be installed to label the alternate location of the
cache.
For instructions on how to add an auxiliary policy to enable the cache to be
located elsewhere when SELinux is in enforcing mode, please see:
/usr/share/doc/cachefilesd-*/move-cache.txt
When the cachefilesd rpm is installed; alternatively, the document can be found
in the sources.
==================
A NOTE ON SECURITY
==================
CacheFiles makes use of the split security in the task_struct. It allocates
its own task_security structure, and redirects current->act_as to point to it
when it acts on behalf of another process, in that process's context.
The reason it does this is that it calls vfs_mkdir() and suchlike rather than
bypassing security and calling inode ops directly. Therefore the VFS and LSM
may deny the CacheFiles access to the cache data because under some
circumstances the caching code is running in the security context of whatever
process issued the original syscall on the netfs.
Furthermore, should CacheFiles create a file or directory, the security
parameters with that object is created (UID, GID, security label) would be
derived from that process that issued the system call, thus potentially
preventing other processes from accessing the cache - including CacheFiles's
cache management daemon (cachefilesd).
What is required is to temporarily override the security of the process that
issued the system call. We can't, however, just do an in-place change of the
security data as that affects the process as an object, not just as a subject.
This means it may lose signals or ptrace events for example, and affects what
the process looks like in /proc.
So CacheFiles makes use of a logical split in the security between the
objective security (task->sec) and the subjective security (task->act_as). The
objective security holds the intrinsic security properties of a process and is
never overridden. This is what appears in /proc, and is what is used when a
process is the target of an operation by some other process (SIGKILL for
example).
The subjective security holds the active security properties of a process, and
may be overridden. This is not seen externally, and is used whan a process
acts upon another object, for example SIGKILLing another process or opening a
file.
LSM hooks exist that allow SELinux (or Smack or whatever) to reject a request
for CacheFiles to run in a context of a specific security label, or to create
files and directories with another security label.
This documentation is added by the patch to:
Documentation/filesystems/caching/cachefiles.txt
Signed-Off-By: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 23:42:41 +08:00
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obj-$(CONFIG_CACHEFILES) += cachefiles/
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2005-04-17 06:20:36 +08:00
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|
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obj-$(CONFIG_DEBUG_FS) += debugfs/
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2005-12-16 06:31:24 +08:00
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obj-$(CONFIG_OCFS2_FS) += ocfs2/
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2008-09-26 00:25:16 +08:00
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|
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obj-$(CONFIG_BTRFS_FS) += btrfs/
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2006-01-17 00:43:37 +08:00
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|
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obj-$(CONFIG_GFS2_FS) += gfs2/
|
2012-11-02 16:25:27 +08:00
|
|
|
obj-$(CONFIG_F2FS_FS) += f2fs/
|
2011-10-27 09:26:49 +08:00
|
|
|
obj-y += exofs/ # Multiple modules
|
2009-10-07 02:31:15 +08:00
|
|
|
obj-$(CONFIG_CEPH_FS) += ceph/
|
2010-12-29 06:25:21 +08:00
|
|
|
obj-$(CONFIG_PSTORE) += pstore/
|
2013-02-09 00:27:24 +08:00
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|
|
obj-$(CONFIG_EFIVAR_FS) += efivarfs/
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