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* kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERTDavid Rientjes2011-01-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The meaning of CONFIG_EMBEDDED has long since been obsoleted; the option is used to configure any non-standard kernel with a much larger scope than only small devices. This patch renames the option to CONFIG_EXPERT in init/Kconfig and fixes references to the option throughout the kernel. A new CONFIG_EMBEDDED option is added that automatically selects CONFIG_EXPERT when enabled and can be used in the future to isolate options that should only be considered for embedded systems (RISC architectures, SLOB, etc). Calling the option "EXPERT" more accurately represents its intention: only expert users who understand the impact of the configuration changes they are making should enable it. Reviewed-by: Ingo Molnar <mingo@elte.hu> Acked-by: David Woodhouse <david.woodhouse@intel.com> Signed-off-by: David Rientjes <rientjes@google.com> Cc: Greg KH <gregkh@suse.de> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jens Axboe <axboe@kernel.dk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Robin Holt <holt@sgi.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: FS_POSIX_ACL does not depend on BLOCKRandy Dunlap2011-01-171-9/+8
| | | | | | | | | | | | | | | - Fix a kconfig unmet dependency warning. - Remove the comment that identifies which filesystems use POSIX ACL utility routines. - Move the FS_POSIX_ACL symbol outside of the BLOCK symbol if/endif block because its functions do not depend on BLOCK and some of the filesystems that use it do not depend on BLOCK. warning: (GENERIC_ACL && JFFS2_FS_POSIX_ACL && NFSD_V4 && NFS_ACL_SUPPORT && 9P_FS_POSIX_ACL) selects FS_POSIX_ACL which has unmet direct dependencies (BLOCK) Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge 'staging-next' to Linus's treeGreg Kroah-Hartman2010-10-281-2/+0
|\ | | | | | | | | | | | | | | This merges the staging-next tree to Linus's tree and resolves some conflicts that were present due to changes in other trees that were affected by files here. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * smbfs: move to drivers/stagingArnd Bergmann2010-10-051-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | smbfs has been scheduled for removal in 2.6.27, so maybe we can now move it to drivers/staging on the way out. smbfs still uses the big kernel lock and nobody is going to fix that, so we should be getting rid of it soon. This removes the 32 bit compat mount and ioctl handling code, which is implemented in common fs code, and moves all smbfs related files into drivers/staging/smbfs. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * autofs3: move to drivers/stagingArnd Bergmann2010-10-051-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Nobody appears to be interested in fixing autofs3 bugs any more and it uses the BKL, which is going away. Move this to staging for retirement. Unless someone complains until 2.6.38, we can remove it for good. The include/linux/auto_fs.h header file is still used by autofs4, so it remains in place. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Ian Kent <raven@themaw.net> Cc: autofs@linux.kernel.org Cc: "H. Peter Anvin" <hpa@zytor.com> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | Merge branch 'flock' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bklLinus Torvalds2010-10-271-1/+0
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | * 'flock' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl: locks: turn lock_flocks into a spinlock fasync: re-organize fasync entry insertion to allow it under a spinlock locks/nfsd: allocate file lock outside of spinlock lockd: fix nlmsvc_notify_blocked locking lockd: push lock_flocks down
| * | locks: turn lock_flocks into a spinlockArnd Bergmann2010-10-271-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | Nothing depends on lock_flocks using the BKL any more, so we can do the switch over to a private spinlock. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* | | fs: move exportfs since it is not a networking filesystemRandy Dunlap2010-10-261-3/+3
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the EXPORTFS kconfig symbol out of the NETWORK_FILESYSTEMS block since it provides a library function that can be (and is) used by other (non-network) filesystems. This also eliminates a kconfig dependency warning: warning: (XFS_FS && BLOCK || NFSD && NETWORK_FILESYSTEMS && INET && FILE_LOCKING && BKL) selects EXPORTFS which has unmet direct dependencies (NETWORK_FILESYSTEMS) Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alex Elder <aelder@sgi.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* / BKL: introduce CONFIG_BKL.Arnd Bergmann2010-10-211-0/+1
|/ | | | | | | | | | | | | | | | | | | With all the patches we have queued in the BKL removal tree, only a few dozen modules are left that actually rely on the BKL, and even there are lots of low-hanging fruit. We need to decide what to do about them, this patch illustrates one of the options: Every user of the BKL is marked as 'depends on BKL' in Kconfig, and the CONFIG_BKL becomes a user-visible option. If it gets disabled, no BKL using module can be built any more and the BKL code itself is compiled out. The one exception is file locking, which is practically always enabled and does a 'select BKL' instead. This effectively forces CONFIG_BKL to be enabled until we have solved the fs/lockd mess and can apply the patch that removes the BKL from fs/locks.c. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* fs/Kconfig: Fix typo Userpace -> UserspaceStephen Boyd2010-07-201-1/+1
| | | | | Signed-off-by: Stephen Boyd <bebarino@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* Merge branch 'for-linus' of ↵Linus Torvalds2010-03-191-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (205 commits) ceph: update for write_inode API change ceph: reset osd after relevant messages timed out ceph: fix flush_dirty_caps race with caps migration ceph: include migrating caps in issued set ceph: fix osdmap decoding when pools include (removed) snaps ceph: return EBADF if waiting for caps on closed file ceph: set osd request message front length correctly ceph: reset front len on return to msgpool; BUG on mismatched front iov ceph: fix snaptrace decoding on cap migration between mds ceph: use single osd op reply msg ceph: reset bits on connection close ceph: remove bogus mds forward warning ceph: remove fragile __map_osds optimization ceph: fix connection fault STANDBY check ceph: invalidate_authorizer without con->mutex held ceph: don't clobber write return value when using O_SYNC ceph: fix client_request_forward decoding ceph: drop messages on unregistered mds sessions; cleanup ceph: fix comments, locking in destroy_inode ceph: move dereference after NULL test ... Fix trivial conflicts in Documentation/ioctl/ioctl-number.txt
| * ceph: Kconfig, MakefileSage Weil2009-10-061-0/+1
| | | | | | | | | | | | Kconfig options and Makefile. Signed-off-by: Sage Weil <sage@newdream.net>
* | [LogFS] add new flash file systemJoern Engel2009-11-201-0/+1
| | | | | | | | | | | | | | This is a new flash file system. See Documentation/filesystems/logfs.txt Signed-off-by: Joern Engel <joern@logfs.org>
* | powerpc: Cleanup Kconfig selection of hugetlbfs supportBenjamin Herrenschmidt2009-10-301-1/+1
| | | | | | | | Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* | Merge branch 'sh/for-2.6.32' of ↵Linus Torvalds2009-10-291-2/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6 * 'sh/for-2.6.32' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: sh: Fix hugetlbfs dependencies for SH-3 && MMU configurations. sh: Document uImage.bin target in archhelp. sh: add uImage.bin target sh: rsk7203 CONFIG_MTD=n fix sh: Check for return_to_handler when unwinding the stack sh: Build fix: define more __movmem* symbols sh: __irq_entry annotate do_IRQ(). Fix up sh/powerpc conflicts in fs/Kconfig
| * | sh: Fix hugetlbfs dependencies for SH-3 && MMU configurations.Paul Mundt2009-10-271-2/+2
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The hugetlb dependencies presently depend on SUPERH && MMU while the hugetlb page size definitions depend on CPU_SH4 or CPU_SH5. This unfortunately allows SH-3 + MMU configurations to enable hugetlbfs without a corresponding HPAGE_SHIFT definition, resulting in the build blowing up. As SH-3 doesn't support variable page sizes, we tighten up the dependenies a bit to prevent hugetlbfs from being enabled. These days we also have a shiny new SYS_SUPPORTS_HUGETLBFS, so switch to using that rather than adding to the list of corner cases in fs/Kconfig. Reported-by: Kristoffer Ericson <kristoffer.ericson@gmail.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* / powerpc: Limit hugetlbfs support to PPC64 Book-3S machinesKumar Gala2009-10-271-1/+1
|/ | | | | Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* tmpfs: depend on shmemHugh Dickins2009-09-221-0/+1
| | | | | | | | | | | | | | | | | | | | | CONFIG_SHMEM off gives you (ramfs masquerading as) tmpfs, even when CONFIG_TMPFS is off: that's a little anomalous, and I'd intended to make more sense of it by removing CONFIG_TMPFS altogether, always enabling its code when CONFIG_SHMEM; but so many defconfigs have CONFIG_SHMEM on CONFIG_TMPFS off that we'd better leave that as is. But there is no point in asking for CONFIG_TMPFS if CONFIG_SHMEM is off: make TMPFS depend on SHMEM, which also prevents TMPFS_POSIX_ACL shmem_acl.o being pointlessly built into the kernel when SHMEM is off. And a selfish change, to prevent the world from being rebuilt when I switch between CONFIG_SHMEM on and off: the only CONFIG_SHMEM in the header files is mm.h shmem_lock() - give that a shmem.c stub instead. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Acked-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs/Kconfig: move nilfs2 outside misc filesystemsRyusuke Konishi2009-09-141-1/+1
| | | | | | | | | | | | | | | | | | Some people asked me questions like the following: On Wed, 15 Jul 2009 13:11:21 +0200, Leon Woestenberg wrote: > just wondering, any reasons why NILFS2 is one of the miscellaneous > filesystems and, for example, btrfs, is not in Kconfig? Actually, nilfs is NOT a filesystem came from other operating systems, but a filesystem created purely for Linux. Nor is it a flash filesystem but that for generic block devices. So, this moves nilfs outside the misc category as I responded in LKML "Re: Why does NILFS2 hide under Miscellaneous filesystems?" (Message-Id: <20090716.002526.93465395.ryusuke@osrg.net>). Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
* fs/Kconfig: move nilfs2 outRyusuke Konishi2009-07-141-26/+1
| | | | | | | | | fs/Kconfig file was split into individual fs/*/Kconfig files before nilfs was merged. I've found the current config entry of nilfs is tainting the work. Sorry, I didn't notice. This fixes the violation. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: Alexey Dobriyan <adobriyan@gmail.com>
* Merge branch 'for-2.6.31' of git://fieldses.org/git/linux-nfsdLinus Torvalds2009-06-221-0/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-2.6.31' of git://fieldses.org/git/linux-nfsd: (60 commits) SUNRPC: Fix the TCP server's send buffer accounting nfsd41: Backchannel: minorversion support for the back channel nfsd41: Backchannel: cleanup nfs4.0 callback encode routines nfsd41: Remove ip address collision detection case nfsd: optimise the starting of zero threads when none are running. nfsd: don't take nfsd_mutex twice when setting number of threads. nfsd41: sanity check client drc maxreqs nfsd41: move channel attributes from nfsd4_session to a nfsd4_channel_attr struct NFS: kill off complicated macro 'PROC' sunrpc: potential memory leak in function rdma_read_xdr nfsd: minor nfsd_vfs_write cleanup nfsd: Pull write-gathering code out of nfsd_vfs_write nfsd: track last inode only in use_wgather case sunrpc: align cache_clean work's timer nfsd: Use write gathering only with NFSv2 NFSv4: kill off complicated macro 'PROC' NFSv4: do exact check about attribute specified knfsd: remove unreported filehandle stats counters knfsd: fix reply cache memory corruption knfsd: reply cache cleanups ...
| * lockd: fix FILE_LOCKING=n build errorRandy Dunlap2009-05-131-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | lockd/svclock.c is missing a header file <linux/fs.h>. <linux/fs.h> is missing a definition of locks_release_private() for the config case of FILE_LOCKING=n, causing a build error: fs/lockd/svclock.c:330: error: implicit declaration of function 'locks_release_private' lockd without FILE_LOCKING doesn't make sense, so make LOCKD and LOCKD_V4 depend on FILE_LOCKING, and make NFS depend on FILE_LOCKING. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
* | Hugetlbfs: Enable hugetlbfs for more systems in Kconfig.David Daney2009-06-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | As part of adding hugetlbfs support for MIPS, I am adding a new kconfig variable 'SYS_SUPPORTS_HUGETLBFS'. Since some mips cpu varients don't yet support it, we can enable selection of HUGETLBFS on a system by system basis from the arch/mips/Kconfig. Signed-off-by: David Daney <ddaney@caviumnetworks.com> CC: William Irwin <wli@holomorphy.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* | CONFIG_FILE_LOCKING should not depend on CONFIG_BLOCKTomas Szepe2009-06-161-7/+7
| | | | | | | | | | | | | | | | | | | | | | CONFIG_FILE_LOCKING should not depend on CONFIG_BLOCK. This makes it possible to run complete systems out of a CONFIG_BLOCK=n initramfs on current kernels again (this last worked on 2.6.27.*). Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | CUSE: implement CUSE - Character device in UserspaceTejun Heo2009-06-091-0/+10
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | CUSE enables implementing character devices in userspace. With recent additions of ioctl and poll support, FUSE already has most of what's necessary to implement character devices. All CUSE has to do is bonding all those components - FUSE, chardev and the driver model - nicely. When client opens /dev/cuse, kernel starts conversation with CUSE_INIT. The client tells CUSE which device it wants to create. As the previous patch made fuse_file usable without associated fuse_inode, CUSE doesn't create super block or inodes. It attaches fuse_file to cdev file->private_data during open and set ff->fi to NULL. The rest of the operation is almost identical to FUSE direct IO case. Each CUSE device has a corresponding directory /sys/class/cuse/DEVNAME (which is symlink to /sys/devices/virtual/class/DEVNAME if SYSFS_DEPRECATED is turned off) which hosts "waiting" and "abort" among other things. Those two files have the same meaning as the FUSE control files. The only notable lacking feature compared to in-kernel implementation is mmap support. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* nilfs2: update makefile and KconfigRyusuke Konishi2009-04-071-1/+26
| | | | | | | | | This adds a Makefile for the nilfs2 file system, and updates the makefile and Kconfig file in the file system directory. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-fscacheLinus Torvalds2009-04-031-0/+7
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-fscache: (41 commits) NFS: Add mount options to enable local caching on NFS NFS: Display local caching state NFS: Store pages from an NFS inode into a local cache NFS: Read pages from FS-Cache into an NFS inode NFS: nfs_readpage_async() needs to be accessible as a fallback for local caching NFS: Add read context retention for FS-Cache to call back with NFS: FS-Cache page management NFS: Add some new I/O counters for FS-Cache doing things for NFS NFS: Invalidate FsCache page flags when cache removed NFS: Use local disk inode cache NFS: Define and create inode-level cache objects NFS: Define and create superblock-level objects NFS: Define and create server-level objects NFS: Register NFS for caching and retrieve the top-level index NFS: Permit local filesystem caching to be enabled for NFS NFS: Add FS-Cache option bit and debug bit NFS: Add comment banners to some NFS functions FS-Cache: Make kAFS use FS-Cache CacheFiles: A cache that backs onto a mounted filesystem CacheFiles: Export things for CacheFiles ...
| * CacheFiles: A cache that backs onto a mounted filesystemDavid Howells2009-04-031-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * FS-Cache: Add main configuration option, module entry points and debuggingDavid Howells2009-04-031-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the main configuration option, allowing FS-Cache to be selected; the module entry and exit functions and the debugging stuff used by these patches. The two configuration options added are: CONFIG_FSCACHE CONFIG_FSCACHE_DEBUG The first enables the facility, and the second makes the debugging statements enableable through the "debug" module parameter. The value of this parameter is a bitmask as described in: Documentation/filesystems/caching/fscache.txt The module can be loaded at this point, but all it will do at this point in the patch series is to start up the slow work facility and shut it down again. 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>
* | fs: Add exofs to Kernel buildBoaz Harrosh2009-03-311-0/+2
|/ | | | | | | - Add exofs to fs/Kconfig under "menu 'Miscellaneous filesystems'" - Add exofs to fs/Makefile Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
* quota: Move quota files into separate directoryJan Kara2009-03-261-55/+1
| | | | | | Quota subsystem has more and more files. It's time to create a dir for it. Signed-off-by: Jan Kara <jack@suse.cz>
* fs/Kconfig: move 9p outAlexey Dobriyan2009-01-221-11/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move afs outAlexey Dobriyan2009-01-221-22/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move coda outAlexey Dobriyan2009-01-221-22/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move the rest of ncpfs outAlexey Dobriyan2009-01-221-22/+0
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move smbfs outAlexey Dobriyan2009-01-221-57/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move sunrpc outAlexey Dobriyan2009-01-221-79/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move nfsd outAlexey Dobriyan2009-01-221-81/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move nfs outAlexey Dobriyan2009-01-221-86/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move ufs outAlexey Dobriyan2009-01-221-44/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move sysv outAlexey Dobriyan2009-01-221-38/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move romfs outAlexey Dobriyan2009-01-221-18/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move qnx4 outAlexey Dobriyan2009-01-221-26/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move hpfs outAlexey Dobriyan2009-01-221-16/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move omfs outAlexey Dobriyan2009-01-221-14/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move minix outAlexey Dobriyan2009-01-221-18/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move vxfs outAlexey Dobriyan2009-01-221-17/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move squashfs outAlexey Dobriyan2009-01-221-52/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move cramfs outAlexey Dobriyan2009-01-221-20/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* fs/Kconfig: move efs outAlexey Dobriyan2009-01-221-16/+1
| | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-17 01:22:38 +0000