user/sven/linux.git/Documentation/filesystems, branch v4.14.136

mm, proc: be more verbose about unstable VMA flags in /proc//smaps

2019-01-26T08:37:07Z

[ Upstream commit 7550c6079846a24f30d15ac75a941c8515dbedfb ] Patch series "THP eligibility reporting via proc". This series of three patches aims at making THP eligibility reporting much more robust and long term sustainable. The trigger for the change is a regression report [2] and the long follow up discussion. In short the specific application didn't have good API to query whether a particular mapping can be backed by THP so it has used VMA flags to workaround that. These flags represent a deep internal state of VMAs and as such they should be used by userspace with a great deal of caution. A similar has happened for [3] when users complained that VM_MIXEDMAP is no longer set on DAX mappings. Again a lack of a proper API led to an abuse. The first patch in the series tries to emphasise that that the semantic of flags might change and any application consuming those should be really careful. The remaining two patches provide a more suitable interface to address [2] and provide a consistent API to query the THP status both for each VMA and process wide as well. [1] http://lkml.kernel.org/r/20181120103515.25280-1-mhocko@kernel.org [2] http://lkml.kernel.org/r/http://lkml.kernel.org/r/alpine.DEB.2.21.1809241054050.224429@chino.kir.corp.google.com [3] http://lkml.kernel.org/r/20181002100531.GC4135@quack2.suse.cz This patch (of 3): Even though vma flags exported via /proc//smaps are explicitly documented to be not guaranteed for future compatibility the warning doesn't go far enough because it doesn't mention semantic changes to those flags. And they are important as well because these flags are a deep implementation internal to the MM code and the semantic might change at any time. Let's consider two recent examples: http://lkml.kernel.org/r/20181002100531.GC4135@quack2.suse.cz : commit e1fb4a086495 "dax: remove VM_MIXEDMAP for fsdax and device dax" has : removed VM_MIXEDMAP flag from DAX VMAs. Now our testing shows that in the : mean time certain customer of ours started poking into /proc//smaps : and looks at VMA flags there and if VM_MIXEDMAP is missing among the VMA : flags, the application just fails to start complaining that DAX support is : missing in the kernel. http://lkml.kernel.org/r/alpine.DEB.2.21.1809241054050.224429@chino.kir.corp.google.com : Commit 1860033237d4 ("mm: make PR_SET_THP_DISABLE immediately active") : introduced a regression in that userspace cannot always determine the set : of vmas where thp is ineligible. : Userspace relies on the "nh" flag being emitted as part of /proc/pid/smaps : to determine if a vma is eligible to be backed by hugepages. : Previous to this commit, prctl(PR_SET_THP_DISABLE, 1) would cause thp to : be disabled and emit "nh" as a flag for the corresponding vmas as part of : /proc/pid/smaps. After the commit, thp is disabled by means of an mm : flag and "nh" is not emitted. : This causes smaps parsing libraries to assume a vma is eligible for thp : and ends up puzzling the user on why its memory is not backed by thp. In both cases userspace was relying on a semantic of a specific VMA flag. The primary reason why that happened is a lack of a proper interface. While this has been worked on and it will be fixed properly, it seems that our wording could see some refinement and be more vocal about semantic aspect of these flags as well. Link: http://lkml.kernel.org/r/20181211143641.3503-2-mhocko@kernel.org Signed-off-by: Michal Hocko Acked-by: Jan Kara Acked-by: Dan Williams Acked-by: David Rientjes Acked-by: Mike Rapoport Acked-by: Vlastimil Babka Cc: Dan Williams Cc: David Rientjes Cc: Paul Oppenheimer Cc: William Kucharski Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

ext4: correct documentation for grpid mount option

2018-02-22T14:42:26Z

commit 9f0372488cc9243018a812e8cfbf27de650b187b upstream. The grpid option is currently described as being the same as nogrpid. Signed-off-by: Ernesto A. Fernández Signed-off-by: Theodore Ts'o Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

2017-10-06T15:52:53Z

Pull overlayfs fixes from Miklos Szeredi: "Fix a regression in 4.14 and one in 4.13. The latter is a case when Docker is doing something it really shouldn't and gets away with it. We now print a warning instead of erroring out. There are also fixes to several error paths" * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: fix regression caused by exclusive upper/work dir protection ovl: fix missing unlock_rename() in ovl_do_copy_up() ovl: fix dentry leak in ovl_indexdir_cleanup() ovl: fix dput() of ERR_PTR in ovl_cleanup_index() ovl: fix error value printed in ovl_lookup_index() ovl: fix may_write_real() for overlayfs directories

ovl: fix regression caused by exclusive upper/work dir protection

2017-10-05T13:53:18Z

Enforcing exclusive ownership on upper/work dirs caused a docker regression: https://github.com/moby/moby/issues/34672. Euan spotted the regression and pointed to the offending commit. Vivek has brought the regression to my attention and provided this reproducer: Terminal 1: mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none merged/ Terminal 2: unshare -m Terminal 1: umount merged mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none merged/ mount: /root/overlay-testing/merged: none already mounted or mount point busy To fix the regression, I replaced the error with an alarming warning. With index feature enabled, mount does fail, but logs a suggestion to override exclusive dir protection by disabling index. Note that index=off mount does take the inuse locks, so a concurrent index=off will issue the warning and a concurrent index=on mount will fail. Documentation was updated to reflect this change. Fixes: 2cac0c00a6cd ("ovl: get exclusive ownership on upper/work dirs") Cc: # v4.13 Reported-by: Euan Kemp Reported-by: Vivek Goyal Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

Merge tag 'driver-core-4.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2017-10-03T15:57:07Z

Pull driver core fixes from Greg KH: "Here are a few small fixes for 4.14-rc4. The removal of DRIVER_ATTR() was almost completed by 4.14-rc1, but one straggler made it in through some other tree (odds are, one of mine...) So there's a simple removal of the last user, and then finally the macro is removed from the tree. There's a fix for old crazy udev instances that insist on reloading a module when it is removed from the kernel due to the new uevents for bind/unbind. This fixes the reported regression, hopefully some year in the future we can drop the workaround, once users update to the latest version, but I'm not holding my breath. And then there's a build fix for a linker warning, and a buffer overflow fix to match the PCI fixes you took through the PCI tree in the same area. All of these have been in linux-next for a few weeks while I've been traveling, sorry for the delay" * tag 'driver-core-4.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: driver core: remove DRIVER_ATTR fpga: altera-cvp: remove DRIVER_ATTR() usage driver core: platform: Don't read past the end of "driver_override" buffer base: arch_topology: fix section mismatch build warnings driver core: suppress sending MODALIAS in UNBIND uevents

Merge tag '4.14-smb3-multidialect-support-and-fixes-for-stable' of git://git.samba.org/sfrench/cifs-2.6

2017-09-19T15:35:42Z

Pull cifs fixes from Steve French: "Convert default dialect to smb2.1 or later to allow connecting to Windows 7 for example, also includes some fixes for stable" * tag '4.14-smb3-multidialect-support-and-fixes-for-stable' of git://git.samba.org/sfrench/cifs-2.6: Update version of cifs module cifs: hide unused functions SMB3: Add support for multidialect negotiate (SMB2.1 and later) CIFS/SMB3: Update documentation to reflect SMB3 and various changes cifs: check rsp for NULL before dereferencing in SMB2_open

driver core: remove DRIVER_ATTR

2017-09-19T07:20:33Z

DRIVER_ATTR is no longer in use, and driver authors should be using DRIVER_ATTR_RW() or DRIVER_ATTR_RO() or DRIVER_ATTR_WO() instead in order to always get the permissions correct. So remove it so that no one can use it anymore. Acked-by: Alan Tull Reviewed-by: Moritz Fischer Signed-off-by: Greg Kroah-Hartman

CIFS/SMB3: Update documentation to reflect SMB3 and various changes

2017-09-17T15:48:00Z

Signed-off-by: Steve French Reviewed-by: Aurelien Aptel Reviewed-by: Pavel Shilovsky

Merge tag 'for-linus-4.14-ofs2' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux

2017-09-15T19:16:18Z

Pull orangefs updates from Mike Marshall: "Some cleanups and a big bug fix for ACLs. When I was reviewing Jan Kara's ACL patch, I realized that Orangefs ACL code was busted, not just in the kernel module, but in the server as well. I've been working on the code in the server mostly, but here's one kernel patch, there will be more" * tag 'for-linus-4.14-ofs2' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux: orangefs: Adjust three checks for null pointers orangefs: Use kcalloc() in orangefs_prepare_cdm_array() orangefs: Delete error messages for a failed memory allocation in five functions orangefs: constify xattr_handler structure orangefs: don't call filemap_write_and_wait from fsync orangefs: off by ones in xattr size checks orangefs: documentation clean up orangefs: react properly to posix_acl_update_mode's aftermath. orangefs: Don't clear SGID when inheriting ACLs

Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2017-09-15T01:54:01Z

Pull mount flag updates from Al Viro: "Another chunk of fmount preparations from dhowells; only trivial conflicts for that part. It separates MS_... bits (very grotty mount(2) ABI) from the struct super_block ->s_flags (kernel-internal, only a small subset of MS_... stuff). This does *not* convert the filesystems to new constants; only the infrastructure is done here. The next step in that series is where the conflicts would be; that's the conversion of filesystems. It's purely mechanical and it's better done after the merge, so if you could run something like list=$(for i in MS_RDONLY MS_NOSUID MS_NODEV MS_NOEXEC MS_SYNCHRONOUS MS_MANDLOCK MS_DIRSYNC MS_NOATIME MS_NODIRATIME MS_SILENT MS_POSIXACL MS_KERNMOUNT MS_I_VERSION MS_LAZYTIME; do git grep -l $i fs drivers/staging/lustre drivers/mtd ipc mm include/linux; done|sort|uniq|grep -v '^fs/namespace.c$') sed -i -e 's/\/SB_RDONLY/g' \ -e 's/\/SB_NOSUID/g' \ -e 's/\/SB_NODEV/g' \ -e 's/\/SB_NOEXEC/g' \ -e 's/\/SB_SYNCHRONOUS/g' \ -e 's/\/SB_MANDLOCK/g' \ -e 's/\/SB_DIRSYNC/g' \ -e 's/\/SB_NOATIME/g' \ -e 's/\/SB_NODIRATIME/g' \ -e 's/\/SB_SILENT/g' \ -e 's/\/SB_POSIXACL/g' \ -e 's/\/SB_KERNMOUNT/g' \ -e 's/\/SB_I_VERSION/g' \ -e 's/\/SB_LAZYTIME/g' \ $list and commit it with something along the lines of 'convert filesystems away from use of MS_... constants' as commit message, it would save a quite a bit of headache next cycle" * 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: VFS: Differentiate mount flags (MS_*) from internal superblock flags VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb) vfs: Add sb_rdonly(sb) to query the MS_RDONLY flag on s_flags