Changes in Kconfig

f91a704f - fs: prepare for stackable filesystems backing file helpers

Mon, 02 Oct 2023 14:19:46 +0000

fs: prepare for stackable filesystems backing file helpersIn preparation for factoring out some backing file io helpers fromoverlayfs, move backing_file_open() into a new file fs/backing-file.cand header.Add a MAINTAINERS entry for stackable filesystems and add a KconfigFS_STACK which stackable filesystems need to select.For now, the backing_file struct, the backing_file alloc/free functionsand the backing_file_real_path() accessor remain internal to file_table.c.We may change that in the future.Signed-off-by: Amir Goldstein List of files: /linux-6.15/fs/overlayfs/Kconfig

36295542 - ovl: Kconfig: introduce CONFIG_OVERLAY_FS_DEBUG

Sun, 21 May 2023 08:28:11 +0000

ovl: Kconfig: introduce CONFIG_OVERLAY_FS_DEBUGProvide a Kconfig option to enable extra debugging checks for overlayfs.Reviewed-by: Amir Goldstein Signed-off-by: Andrea Righi Signed-off-by: Amir Goldstein List of files: /linux-6.15/fs/overlayfs/Kconfig

637d13b5 - ovl: Kconfig: Fix spelling mistake "undelying" -> "underlying"

Fri, 07 Oct 2022 20:40:54 +0000

ovl: Kconfig: Fix spelling mistake "undelying" -> "underlying"There is a spelling mistake in a Kconfig description. Fix it.Signed-off-by: Colin Ian King Signed-off-by: Miklos Szeredi List of files: /linux-6.15/fs/overlayfs/Kconfig

72ef5e52 - docs: fix broken references to text files

Tue, 14 Apr 2020 16:48:35 +0000

docs: fix broken references to text filesSeveral references got broken due to txt to ReST conversion.Several of them can be automatically fixed with: scripts/documentation-file-ref-check --fixReviewed-by: Mathieu Poirier # hwtracing/coresight/KconfigReviewed-by: Paul E. McKenney # memory-barrier.txtAcked-by: Alex Shi # translations/zh_CNAcked-by: Federico Vaga # translations/it_ITAcked-by: Marc Zyngier # kvm/arm64Signed-off-by: Mauro Carvalho Chehab Link: https://lore.kernel.org/r/6f919ddb83a33b5f2a63b6b5f0575737bb2b36aa.1586881715.git.mchehab+huawei@kernel.orgSigned-off-by: Jonathan Corbet List of files: /linux-6.15/fs/overlayfs/Kconfig

53afcd31 - ovl: fix some xino configurations

Fri, 21 Feb 2020 14:34:42 +0000

ovl: fix some xino configurationsFix up two bugs in the coversion to xino_mode:1. xino=off does not always end up in disabled mode2. xino=auto on 32bit arch should end up in disabled modeTake a proactive approach to disabling xino on 32bit kernel:1. Disable XINO_AUTO config during build time2. Disable xino with a warning on mount timeAs a by product, xino=on on 32bit arch also ends up in disabled mode.We never intended to enable xino on 32bit arch and this will make therest of the logic simpler.Fixes: 0f831ec85eda ("ovl: simplify ovl_same_sb() helper")Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi List of files: /linux-6.15/fs/overlayfs/Kconfig

ec8f24b7 - treewide: Add SPDX license identifier - Makefile/Kconfig

Sun, 19 May 2019 12:07:45 +0000

treewide: Add SPDX license identifier - Makefile/KconfigAdd SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any formThese files fall under the project license, GPL v2 only. The resulting SPDXlicense identifier is: GPL-2.0-onlySigned-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman List of files: /linux-6.15/fs/overlayfs/Kconfig

d5791044 - ovl: Provide a mount option metacopy=on/off for metadata copyup

Fri, 11 May 2018 15:49:27 +0000

ovl: Provide a mount option metacopy=on/off for metadata copyupBy default metadata only copy up is disabled. Provide a mount option sothat users can choose one way or other.Also provide a kernel config and module option to enable/disable metacopyfeature.metacopy feature requires redirect_dir=on when upper is present.Otherwise, it requires redirect_dir=follow atleast.As of now, metacopy does not work with nfs_export=on. So if bothmetacopy=on and nfs_export=on then nfs_export is disabled.Signed-off-by: Vivek Goyal Reviewed-by: Amir Goldstein Signed-off-by: Miklos Szeredi List of files: /linux-6.15/fs/overlayfs/Kconfig

4280f74a - ovl: Kconfig documentation fixes

Thu, 31 May 2018 09:06:10 +0000

ovl: Kconfig documentation fixesReported-by: Randy Dunlap Signed-off-by: Miklos Szeredi List of files: /linux-6.15/fs/overlayfs/Kconfig

795939a9 - ovl: add support for "xino" mount and config options

Thu, 29 Mar 2018 06:08:18 +0000

ovl: add support for "xino" mount and config optionsWith mount option "xino=on", mounter declares that there are enoughfree high bits in underlying fs to hold the layer fsid.If overlayfs does encounter underlying inodes using the high xinobits reserved for layer fsid, a warning will be emitted and the originalinode number will be used.The mount option name "xino" goes after a similar meaning mount optionof aufs, but in overlayfs case, the mapping is stateless.An example for a use case of "xino=on" is when upper/lower is on an xfsfilesystem. xfs uses 64bit inode numbers, but it currently never uses theupper 8bit for inode numbers exposed via stat(2) and that is not likely tochange in the future without user opting-in for a new xfs feature. Theactual number of unused upper bit is much larger and determined by the xfsfilesystem geometry (64 - agno_log - agblklog - inopblog). That meansthat for all practical purpose, there are enough unused bits in xfsinode numbers for more than OVL_MAX_STACK unique fsid's.Another use case of "xino=on" is when upper/lower is on tmpfs. tmpfs inodenumbers are allocated sequentially since boot, so they will practiallynever use the high inode number bits.For compatibility with applications that expect 32bit inodes, the featurecan be disabled with "xino=off". The option "xino=auto" automaticallydetects underlying filesystem that use 32bit inodes and enables thefeature. The Kconfig option OVERLAY_FS_XINO_AUTO and module parameter ofthe same name, determine if the default mode for overlayfs mount is"xino=auto" or "xino=off".Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi List of files: /linux-6.15/fs/overlayfs/Kconfig

36cd95df - ovl: update Kconfig texts

Wed, 07 Mar 2018 10:47:15 +0000

ovl: update Kconfig textsAdd some hints about overlayfs kernel config options.Enabling NFS export by default is especially recommended against, as itincurs a performance penalty even if the filesystem is not actuallyexported.Signed-off-by: Miklos Szeredi List of files: /linux-6.15/fs/overlayfs/Kconfig

f168f109 - ovl: add support for "nfs_export" configuration

Fri, 19 Jan 2018 09:26:53 +0000

ovl: add support for "nfs_export" configurationIntroduce the "nfs_export" config, module and mount options.The NFS export feature depends on the "index" feature and enables twoimplicit overlayfs features: "index_all" and "verify_lower".The "index_all" feature creates an index on copy up of every file anddirectory. The "verify_lower" feature uses the full index to detectoverlay filesystems inconsistencies on lookup, like redirect frommultiple upper dirs to the same lower dir.NFS export can be enabled for non-upper mount with no index. However,because lower layer redirects cannot be verified with the index, enablingNFS export support on an overlay with no upper layer requires turning offredirect follow (e.g. "redirect_dir=nofollow").The full index may incur some overhead on mount time, especially whenverifying that lower directory file handles are not stale.NFS export support, full index and consistency verification will beimplemented by following patches.Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi List of files: /linux-6.15/fs/overlayfs/Kconfig

60b86642 - ovl: update documentation of inodes index feature

Wed, 10 Jan 2018 21:15:21 +0000

ovl: update documentation of inodes index featureDocument that inode index feature solves breaking hard links oncopy up.Simplify Kconfig backward compatibility disclaimer.Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi List of files: /linux-6.15/fs/overlayfs/Kconfig

438c84c2 - ovl: don't follow redirects if redirect_dir=off

Mon, 11 Dec 2017 10:28:10 +0000

ovl: don't follow redirects if redirect_dir=offOverlayfs is following redirects even when redirects are disabled. If thisis unintentional (probably the majority of cases) then this can be aproblem. E.g. upper layer comes from untrusted USB drive, and attackercrafts a redirect to enable read access to otherwise unreadabledirectories.If "redirect_dir=off", then turn off following as well as creation ofredirects. If "redirect_dir=follow", then turn on following, but turn offcreation of redirects (which is what "redirect_dir=off" does now).This is a backward incompatible change, so make it dependent on a configoption.Reported-by: David Howells Signed-off-by: Miklos Szeredi List of files: /linux-6.15/fs/overlayfs/Kconfig

02bcd157 - ovl: introduce the inodes index dir feature

Wed, 21 Jun 2017 12:28:36 +0000

ovl: introduce the inodes index dir featureCreate the index dir on mount. The index dir will contain hardlinks toupper inodes, named after the hex representation of their origin lowerinodes.The index dir is going to be used to prevent breaking lower hardlinkson copy up and to implement overlayfs NFS export.Because the feature is not fully backward compat, enabling the featureis opt-in by config/module/mount option.Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi List of files: /linux-6.15/fs/overlayfs/Kconfig

72d42504 - ovl: select EXPORTFS

Thu, 11 May 2017 11:34:29 +0000

ovl: select EXPORTFSWe get a link error when EXPORTFS is not enabled:ERROR: "exportfs_encode_fh" [fs/overlayfs/overlay.ko] undefined!ERROR: "exportfs_decode_fh" [fs/overlayfs/overlay.ko] undefined!This adds a Kconfig 'select' statement for overlayfs, the same way thatit is done for the other users of exportfs.Fixes: 3a1e819b4e80 ("ovl: store file handle of lower inode on copy up")Signed-off-by: Arnd Bergmann Signed-off-by: Miklos Szeredi List of files: /linux-6.15/fs/overlayfs/Kconfig

688ea0e5 - ovl: allow redirect_dir to default to "on"

Fri, 16 Dec 2016 10:02:57 +0000

ovl: allow redirect_dir to default to "on"This patch introduces a kernel config option and a module param. Both canbe used independently to turn the default value of redirect_dir on or off.Signed-off-by: Miklos Szeredi List of files: /linux-6.15/fs/overlayfs/Kconfig

ef94b186 - ovl: rename filesystem type to "overlay"

Thu, 20 Nov 2014 15:39:59 +0000

ovl: rename filesystem type to "overlay"Some distributions carry an "old" format of overlayfs while mainline has a"new" format.The distros will possibly want to keep the old overlayfs alongside the newfor compatibility reasons.To make it possible to differentiate the two versions change the name ofthe new one from "overlayfs" to "overlay".Signed-off-by: Miklos Szeredi Reported-by: Serge Hallyn Cc: Andy Whitcroft List of files: /linux-6.15/fs/overlayfs/Kconfig

e9be9d5e - overlay filesystem

Thu, 23 Oct 2014 22:14:38 +0000

overlay filesystemOverlayfs allows one, usually read-write, directory tree to beoverlaid onto another, read-only directory tree. All modificationsgo to the upper, writable layer.This type of mechanism is most often used for live CDs but there's awide variety of other uses.The implementation differs from other "union filesystem"implementations in that after a file is opened all operations godirectly to the underlying, lower or upper, filesystems. Thissimplifies the implementation and allows native performance in thesecases.The dentry tree is duplicated from the underlying filesystems, thisenables fast cached lookups without adding special support into theVFS. This uses slightly more memory than union mounts, but dentriesare relatively small.Currently inodes are duplicated as well, but it is a possibleoptimization to share inodes for non-directories.Opening non directories results in the open forwarded to theunderlying filesystem. This makes the behavior very similar to unionmounts (with the same limitations vs. fchmod/fchown on O_RDONLY filedescriptors).Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlayThe following cotributions have been folded into this patch:Neil Brown : - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_readFelix Fietkau : - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteoutsErez Zadok - fix cleanup after WARN_ONSedat Dilek - fix up permission to confirm to new APIRobin Dong - fix possible leak in ovl_new_inode - create new inode in ovl_linkAndy Whitcroft - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inodeAV: - 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 renameAlso thanks to the following people for testing and reporting bugs: Jordi Pujol Andy Whitcroft Michal Suchanek Felix Fietkau Erez Zadok Randy Dunlap Signed-off-by: Miklos Szeredi List of files: /linux-6.15/fs/overlayfs/Kconfig