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>
Currently, all of the grace period handling is part of lockd. Eventually though we'd like to be able to build v4-only servers, at which point we'll need to put all of this elsewhere. Move the code itself into fs/nfs_common and have it build a grace.ko module. Then, rejigger the Kconfig options so that both nfsd and lockd enable it automatically. Signed-off-by: Jeff Layton <jlayton@primarydata.com>
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>
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>
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>
Given that CUSE depends on FUSE, it only makes sense to move its Kconfig entry into the FUSE Kconfig file. Also, add a few grammatical and semantic touchups. Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Pull new F2FS filesystem from Jaegeuk Kim: "Introduce a new file system, Flash-Friendly File System (F2FS), to Linux 3.8. Highlights: - Add initial f2fs source codes - Fix an endian conversion bug - Fix build failures on random configs - Fix the power-off-recovery routine - Minor cleanup, coding style, and typos patches" From the Kconfig help text: F2FS is based on Log-structured File System (LFS), which supports versatile "flash-friendly" features. The design has been focused on addressing the fundamental issues in LFS, which are snowball effect of wandering tree and high cleaning overhead. Since flash-based storages show different characteristics according to the internal geometry or flash memory management schemes aka FTL, F2FS and tools support various parameters not only for configuring on-disk layout, but also for selecting allocation and cleaning algorithms. and there's an article by Neil Brown about it on lwn.net: http://lwn.net/Articles/518988/ * tag 'for-3.8-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (36 commits) f2fs: fix tracking parent inode number f2fs: cleanup the f2fs_bio_alloc routine f2fs: introduce accessor to retrieve number of dentry slots f2fs: remove redundant call to f2fs_put_page in delete entry f2fs: make use of GFP_F2FS_ZERO for setting gfp_mask f2fs: rewrite f2fs_bio_alloc to make it simpler f2fs: fix a typo in f2fs documentation f2fs: remove unused variable f2fs: move error condition for mkdir at proper place f2fs: remove unneeded initialization f2fs: check read only condition before beginning write out f2fs: remove unneeded memset from init_once f2fs: show error in case of invalid mount arguments f2fs: fix the compiler warning for uninitialized use of variable f2fs: resolve build failures f2fs: adjust kernel coding style f2fs: fix endian conversion bugs reported by sparse f2fs: remove unneeded version.h header file from f2fs.h f2fs: update the f2fs document f2fs: update Kconfig and Makefile ...
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>
Ted has sent out a RFC about removing this feature. Eric and Jan confirmed that both RedHat and SUSE enable this feature in all their product. David also said that "As far as I know, it's enabled in all Android kernels that use ext4." So it seems OK for us. And what's more, as inline data depends its implementation on xattr, and to be frank, I don't run any test again inline data enabled while xattr disabled. So I think we should add inline data and remove this config option in the same release. [ The savings if you disable CONFIG_EXT4_FS_XATTR is only 27k, which isn't much in the grand scheme of things. Since no one seems to be testing this configuration except for some automated compile farms, on balance we are better removing this config option, and so that it is effectively always enabled. -- tytso ] Cc: David Brown <davidb@codeaurora.org> Cc: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Pull vfs pile 1 from Al Viro: "This is _not_ all; in particular, Miklos' and Jan's stuff is not there yet." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (64 commits) ext4: initialization of ext4_li_mtx needs to be done earlier debugfs-related mode_t whack-a-mole hfsplus: add an ioctl to bless files hfsplus: change finder_info to u32 hfsplus: initialise userflags qnx4: new helper - try_extent() qnx4: get rid of qnx4_bread/qnx4_getblk take removal of PF_FORKNOEXEC to flush_old_exec() trim includes in inode.c um: uml_dup_mmap() relies on ->mmap_sem being held, but activate_mm() doesn't hold it um: embed ->stub_pages[] into mmu_context gadgetfs: list_for_each_safe() misuse ocfs2: fix leaks on failure exits in module_init ecryptfs: make register_filesystem() the last potential failure exit ntfs: forgets to unregister sysctls on register_filesystem() failure logfs: missing cleanup on register_filesystem() failure jfs: mising cleanup on register_filesystem() failure make configfs_pin_fs() return root dentry on success configfs: configfs_create_dir() has parent dentry in dentry->d_parent configfs: sanitize configfs_create() ...