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2014-02-07kernfs: add CONFIG_KERNFSTejun Heo
As sysfs was kernfs's only user, kernfs has been piggybacking on CONFIG_SYSFS; however, kernfs is scheduled to grow a new user very soon. Introduce a separate config option CONFIG_KERNFS which is to be selected by kernfs users. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-28Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs updates from Al Viro: "Assorted stuff; the biggest pile here is Christoph's ACL series. Plus assorted cleanups and fixes all over the place... There will be another pile later this week" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (43 commits) __dentry_path() fixes vfs: Remove second variable named error in __dentry_path vfs: Is mounted should be testing mnt_ns for NULL or error. Fix race when checking i_size on direct i/o read hfsplus: remove can_set_xattr nfsd: use get_acl and ->set_acl fs: remove generic_acl nfs: use generic posix ACL infrastructure for v3 Posix ACLs gfs2: use generic posix ACL infrastructure jfs: use generic posix ACL infrastructure xfs: use generic posix ACL infrastructure reiserfs: use generic posix ACL infrastructure ocfs2: use generic posix ACL infrastructure jffs2: use generic posix ACL infrastructure hfsplus: use generic posix ACL infrastructure f2fs: use generic posix ACL infrastructure ext2/3/4: use generic posix ACL infrastructure btrfs: use generic posix ACL infrastructure fs: make posix_acl_create more useful fs: make posix_acl_chmod more useful ...
2014-01-26fs: remove generic_aclChristoph Hellwig
And instead convert tmpfs to use the new generic ACL code, with two stub methods provided for in-memory filesystems. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-01-25fs: merge xattr_acl.c into posix_acl.cChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-11-27sysfs, kernfs: add skeletons for kernfsTejun Heo
Core sysfs implementation will be separated into kernfs so that it can be used by other non-kobject users. This patch creates fs/kernfs/ directory and makes boilerplate changes. kernfs interface will be directly based on sysfs_dirent and its forward declaration is moved to include/linux/kernfs.h which is included from include/linux/sysfs.h. sysfs core implementation will be gradually separated out and moved to kernfs. This patch doesn't introduce any functional changes. v2: mount.c added. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: linux-fsdevel@vger.kernel.org Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-05-01Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull VFS updates from Al Viro, Misc cleanups all over the place, mainly wrt /proc interfaces (switch create_proc_entry to proc_create(), get rid of the deprecated create_proc_read_entry() in favor of using proc_create_data() and seq_file etc). 7kloc removed. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits) don't bother with deferred freeing of fdtables proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h proc: Make the PROC_I() and PDE() macros internal to procfs proc: Supply a function to remove a proc entry by PDE take cgroup_open() and cpuset_open() to fs/proc/base.c ppc: Clean up scanlog ppc: Clean up rtas_flash driver somewhat hostap: proc: Use remove_proc_subtree() drm: proc: Use remove_proc_subtree() drm: proc: Use minor->index to label things, not PDE->name drm: Constify drm_proc_list[] zoran: Don't print proc_dir_entry data in debug reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show() proc: Supply an accessor for getting the data from a PDE's parent airo: Use remove_proc_subtree() rtl8192u: Don't need to save device proc dir PDE rtl8187se: Use a dir under /proc/net/r8180/ proc: Add proc_mkdir_data() proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h} proc: Move PDE_NET() to fs/proc/proc_net.c ...
2013-05-01Merge branch 'x86-efi-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86/efi changes from Peter Anvin: "The bulk of these changes are cleaning up the efivars handling and breaking it up into a tree of files. There are a number of fixes as well. The entire changeset is pretty big, but most of it is code movement. Several of these commits are quite new; the history got very messed up due to a mismerge with the urgent changes for rc8 which completely broke IA64, and so Ingo requested that we rebase it to straighten it out." * 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: efi: remove "kfree(NULL)" efi: locking fix in efivar_entry_set_safe() efi, pstore: Read data from variable store before memcpy() efi, pstore: Remove entry from list when erasing efi, pstore: Initialise 'entry' before iterating efi: split efisubsystem from efivars efivarfs: Move to fs/efivarfs efivars: Move pstore code into the new EFI directory efivars: efivar_entry API efivars: Keep a private global pointer to efivars efi: move utf16 string functions to efi.h x86, efi: Make efi_memblock_x86_reserve_range more readable efivarfs: convert to use simple_open()
2013-04-30fs: make binfmt support for #! scripts modular and removableJosh Triplett
Add a new configuration option CONFIG_BINFMT_SCRIPT to configure support for interpreted scripts starting with "#!"; allow compiling out that support, or building it as a module. Embedded systems running exclusively compiled binaries could leave this support out, and systems that don't need scripts before mounting the root filesystem can build this as a module. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29fs: don't compile in drop_caches.c when CONFIG_SYSCTL=nJosh Triplett
drop_caches.c provides code only invokable via sysctl, so don't compile it in when CONFIG_SYSCTL=n. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-17efivarfs: Move to fs/efivarfsMatt Fleming
Now that efivarfs uses the efivar API, move it out of efivars.c and into fs/efivarfs where it belongs. This move will eventually allow us to enable the efivarfs code without having to also enable CONFIG_EFI_VARS built, and vice versa. Furthermore, things like, mount -t efivarfs none /sys/firmware/efi/efivars will now work if efivarfs is built as a module without requiring the use of MODULE_ALIAS(), which would have been necessary when the efivarfs code was part of efivars.c. Cc: Matthew Garrett <matthew.garrett@nebula.com> Cc: Jeremy Kerr <jk@ozlabs.org> Reviewed-by: Tom Gundersen <teg@jklm.no> Tested-by: Tom Gundersen <teg@jklm.no> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2013-04-09fold fifo.c into pipe.cAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-12-11f2fs: update Kconfig and MakefileJaegeuk Kim
This adds Makefile and Kconfig for f2fs, and updates Makefile and Kconfig files in the fs directory. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2012-10-06coredump: make core dump functionality optionalAlex Kelly
Adds an expert Kconfig option, CONFIG_COREDUMP, which allows disabling of core dump. This saves approximately 2.6k in the compiled kernel, and complements CONFIG_ELF_CORE, which now depends on it. CONFIG_COREDUMP also disables coredump-related sysctls, except for suid_dumpable and related functions, which are necessary for ptrace. [akpm@linux-foundation.org: fix binfmt_aout.c build] Signed-off-by: Alex Kelly <alex.page.kelly@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-02coredump: move core dump functionality into its own fileAlex Kelly
This prepares for making core dump functionality optional. The variable "suid_dumpable" and associated functions are left in fs/exec.c because they're used elsewhere, such as in ptrace. Signed-off-by: Alex Kelly <alex.page.kelly@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-20fs: initial qnx6fs additionKai Bankett
Adds support for qnx6fs readonly support to the linux kernel. * Mount option The option mmi_fs can be used to mount Harman Becker/Audi MMI 3G HDD qnx6fs filesystems. * Documentation A high level filesystem stucture description can be found in the Documentation/filesystems directory. (qnx6.txt) * Additional features - Active (stable) superblock selection - Superblock checksum check (enforced) - Supports mount of qnx6 filesystems with to host different endianess - Automatic endianess detection - Longfilename support (with non-enfocing crc check) - All blocksizes (512, 1024, 2048 and 4096 supported) Signed-off-by: Kai Bankett <chaosman@ontika.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-06Merge branches 'vfsmount-guts', 'umode_t' and 'partitions' into ZAl Viro
2012-01-03vfs: take /proc/*/mounts and friends to fs/proc_namespace.cAl Viro
rationale: that stuff is far tighter bound to fs/namespace.c than to the guts of procfs proper. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03move fs/partitions to block/Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-10-27fs/Makefile: Stupid typo breakage of exofs inclusionBoaz Harrosh
In my last patch I did a stupid mistake and broke the exofs compilation completely. Fix it ASAP. Instead of obj-y I did obj-$(y) Really Really sorry. Me totally blushing :-{| Signed-off-by: Boaz Harrosh <bharrosh@panasas.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-10-24fs/Makefile: Always inspect exofs/Boaz Harrosh
fs/exofs directory has multiple targets now, of which the ore.ko will be needed by the pnfs-objects-layout-driver (fs/nfs/objlayout). As suggested by: Michal Marek <mmarek@suse.cz> convert inclusion of exofs/ from obj-$(CONFIG_EXOFS_FS) => obj-$(y). So ORE can be selected also from fs/nfs/Kconfig CC: Michal Marek <mmarek@suse.cz> CC: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2011-07-15nfsd: Remove deprecated nfsctl system call and related code.NeilBrown
As promised in feature-removal-schedule.txt it is time to remove the nfsctl system call. Userspace has perferred to not use this call throughout 2.6 and it has been excluded in the default configuration since 2.6.36 (9 months ago). So this patch removes all the code that was being compiled out. There are still references to sys_nfsctl in various arch systemcall tables and related code. These should be cleaned out too, probably in the next merge window. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-03-16Merge branch 'release' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6 * 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6: [IA64] tioca: Fix assignment from incompatible pointer warnings [IA64] mca.c: Fix cast from integer to pointer warning [IA64] setup.c Typo fix "Architechtuallly" [IA64] Add CONFIG_MISC_DEVICES=y to configs that need it. [IA64] disable interrupts at end of ia64_mca_cpe_int_handler() [IA64] Add DMA_ERROR_CODE define. pstore: fix build warning for unused return value from sysfs_create_file pstore: X86 platform interface using ACPI/APEI/ERST pstore: new filesystem interface to platform persistent storage
2011-03-15vfs: Add name to file handle conversion supportAneesh Kumar K.V
The syscall also return mount id which can be used to lookup file system specific information such as uuid in /proc/<pid>/mountinfo Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-12-28pstore: new filesystem interface to platform persistent storageTony Luck
Some platforms have a small amount of non-volatile storage that can be used to store information useful to diagnose the cause of a system crash. This is the generic part of a file system interface that presents information from the crash as a series of files in /dev/pstore. Once the information has been seen, the underlying storage is freed by deleting the files. Signed-off-by: Tony Luck <tony.luck@intel.com>
2010-10-28Merge 'staging-next' to Linus's treeGreg Kroah-Hartman
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>
2010-10-05smbfs: move to drivers/stagingArnd Bergmann
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>
2010-10-05autofs3: move to drivers/stagingArnd Bergmann
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>
2010-09-22nfsd: allow deprecated interface to be compiled out.NeilBrown
Add CONFIG_NFSD_DEPRECATED, default to y. Only include deprecated interface if this is defined. This allows distros to remove this interface before the official removal, and allows developers to test without it. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-05-21Take statfs variants to fs/statfs.cAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-03-19Merge branch 'for-linus' of ↵Linus Torvalds
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
2009-11-20[LogFS] add new flash file systemJoern Engel
This is a new flash file system. See Documentation/filesystems/logfs.txt Signed-off-by: Joern Engel <joern@logfs.org>
2009-10-06ceph: Kconfig, MakefileSage Weil
Kconfig options and Makefile. Signed-off-by: Sage Weil <sage@newdream.net>
2009-04-07nilfs2: update makefile and KconfigRyusuke Konishi
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>
2009-04-03Merge git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-fscacheLinus Torvalds
* 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 ...
2009-04-03Merge branch 'for-linus' of git://git.open-osd.org/linux-open-osdLinus Torvalds
* 'for-linus' of git://git.open-osd.org/linux-open-osd: fs: Add exofs to Kernel build exofs: Documentation exofs: export_operations exofs: super_operations and file_system_type exofs: dir_inode and directory operations exofs: address_space_operations exofs: symlink_inode and fast_symlink_inode operations exofs: file and file_inode operations exofs: Kbuild, Headers and osd utils
2009-04-03CacheFiles: A cache that backs onto a mounted filesystemDavid Howells
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>
2009-04-03FS-Cache: Add main configuration option, module entry points and debuggingDavid Howells
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>
2009-03-31Take fs_struct handling to new file (fs/fs_struct.c)Al Viro
Pure code move; two new helper functions for nfsd and daemonize (unshare_fs_struct() and daemonize_fs_struct() resp.; for now - the same code as used to be in callers). unshare_fs_struct() exported (for nfsd, as copy_fs_struct()/exit_fs() used to be), copy_fs_struct() and exit_fs() don't need exports anymore. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-31fs: Add exofs to Kernel buildBoaz Harrosh
- Add exofs to fs/Kconfig under "menu 'Miscellaneous filesystems'" - Add exofs to fs/Makefile Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2009-03-26quota: Move quota files into separate directoryJan Kara
Quota subsystem has more and more files. It's time to create a dir for it. Signed-off-by: Jan Kara <jack@suse.cz>
2009-02-28ext4: Reorder fs/Makefile so that ext2 root fs's are mounted using ext2Theodore Ts'o
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>
2009-01-09Merge git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linusLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus: MAINTAINERS: squashfs entry Squashfs: documentation Squashfs: initrd support Squashfs: Kconfig entry Squashfs: Makefiles Squashfs: header files Squashfs: block operations Squashfs: cache operations Squashfs: uid/gid lookup operations Squashfs: fragment block operations Squashfs: export operations Squashfs: super block operations Squashfs: symlink operations Squashfs: regular file operations Squashfs: directory readdir operations Squashfs: directory lookup operations Squashfs: inode operations
2009-01-09Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstableLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (864 commits) Btrfs: explicitly mark the tree log root for writeback Btrfs: Drop the hardware crc32c asm code Btrfs: Add Documentation/filesystem/btrfs.txt, remove old COPYING Btrfs: kmap_atomic(KM_USER0) is safe for btrfs_readpage_end_io_hook Btrfs: Don't use kmap_atomic(..., KM_IRQ0) during checksum verifies Btrfs: tree logging checksum fixes Btrfs: don't change file extent's ram_bytes in btrfs_drop_extents Btrfs: Use btrfs_join_transaction to avoid deadlocks during snapshot creation Btrfs: drop remaining LINUX_KERNEL_VERSION checks and compat code Btrfs: drop EXPORT symbols from extent_io.c Btrfs: Fix checkpatch.pl warnings Btrfs: Fix free block discard calls down to the block layer Btrfs: avoid orphan inode caused by log replay Btrfs: avoid potential super block corruption Btrfs: do not call kfree if kmalloc failed in btrfs_sysfs_add_super Btrfs: fix a memory leak in btrfs_get_sb Btrfs: Fix typo in clear_state_cb Btrfs: Fix memset length in btrfs_file_write Btrfs: update directory's size when creating subvol/snapshot Btrfs: add permission checks to the ioctls ...
2009-01-05quota: Split off quota tree handling into a separate fileJan Kara
There is going to be a new version of quota format having 64-bit quota limits and a new quota format for OCFS2. They are both going to use the same tree structure as VFSv0 quota format. So split out tree handling into a separate file and make size of leaf blocks, amount of space usable in each block (needed for checksumming) and structures contained in them configurable so that the code can be shared. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2009-01-05Squashfs: MakefilesPhillip Lougher
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2008-12-31filesystem notification: create fs/notify to contain all fs notificationEric Paris
Creating a generic filesystem notification interface, fsnotify, which will be used by inotify, dnotify, and eventually fanotify is really starting to clutter the fs directory. This patch simply moves inotify and dnotify into fs/notify/inotify and fs/notify/dnotify respectively to make both current fs/ and future notification tidier. Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-11-19Merge branch 'master' of ↵Chris Mason
git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
2008-11-06fat: move fs/vfat/* and fs/msdos/* to fs/fatOGAWA Hirofumi
This just moves those files, but change link order from MSDOS, VFAT to VFAT, MSDOS. Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-17ext4: Remove an old reference to ext4dev in Makefile commentMartin Michlmayr
Remove an old reference to ext4dev. Signed-off-by: Martin Michlmayr <tbm@cyrius.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2008-10-16Configure out AIO supportThomas Petazzoni
This patchs adds the CONFIG_AIO option which allows to remove support for asynchronous I/O operations, that are not necessarly used by applications, particularly on embedded devices. As this is a size-reduction option, it depends on CONFIG_EMBEDDED. It allows to save ~7 kilobytes of kernel code/data: text data bss dec hex filename 1115067 119180 217088 1451335 162547 vmlinux 1108025 119048 217088 1444161 160941 vmlinux.new -7042 -132 0 -7174 -1C06 +/- This patch has been originally written by Matt Mackall <mpm@selenic.com>, and is part of the Linux Tiny project. [randy.dunlap@oracle.com: build fix] Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Zach Brown <zach.brown@oracle.com> Signed-off-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>