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* Merge branch 'work.misc' of ↵Linus Torvalds2018-06-041-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs updates from Al Viro: "Misc bits and pieces not fitting into anything more specific" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: vfs: delete unnecessary assignment in vfs_listxattr Documentation: filesystems: update filesystem locking documentation vfs: namei: use path_equal() in follow_dotdot() fs.h: fix outdated comment about file flags __inode_security_revalidate() never gets NULL opt_dentry make xattr_getsecurity() static vfat: simplify checks in vfat_lookup() get rid of dead code in d_find_alias() it's SB_BORN, not MS_BORN... msdos_rmdir(): kill BS comment remove rpc_rmdir() fs: avoid fdput() after failed fdget() in vfs_dedupe_file_range()
| * it's SB_BORN, not MS_BORN...Al Viro2018-05-101-1/+1
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | fs: don't scan the inode cache before SB_BORN is setDave Chinner2018-05-111-6/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We recently had an oops reported on a 4.14 kernel in xfs_reclaim_inodes_count() where sb->s_fs_info pointed to garbage and so the m_perag_tree lookup walked into lala land. It produces an oops down this path during the failed mount: radix_tree_gang_lookup_tag+0xc4/0x130 xfs_perag_get_tag+0x37/0xf0 xfs_reclaim_inodes_count+0x32/0x40 xfs_fs_nr_cached_objects+0x11/0x20 super_cache_count+0x35/0xc0 shrink_slab.part.66+0xb1/0x370 shrink_node+0x7e/0x1a0 try_to_free_pages+0x199/0x470 __alloc_pages_slowpath+0x3a1/0xd20 __alloc_pages_nodemask+0x1c3/0x200 cache_grow_begin+0x20b/0x2e0 fallback_alloc+0x160/0x200 kmem_cache_alloc+0x111/0x4e0 The problem is that the superblock shrinker is running before the filesystem structures it depends on have been fully set up. i.e. the shrinker is registered in sget(), before ->fill_super() has been called, and the shrinker can call into the filesystem before fill_super() does it's setup work. Essentially we are exposed to both use-after-free and use-before-initialisation bugs here. To fix this, add a check for the SB_BORN flag in super_cache_count. In general, this flag is not set until ->fs_mount() completes successfully, so we know that it is set after the filesystem setup has completed. This matches the trylock_super() behaviour which will not let super_cache_scan() run if SB_BORN is not set, and hence will not allow the superblock shrinker from entering the filesystem while it is being set up or after it has failed setup and is being torn down. Cc: stable@kernel.org Signed-Off-By: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | mm,vmscan: Allow preallocating memory for register_shrinker().Tetsuo Handa2018-04-161-5/+4
|/ | | | | | | | | | | | | | | | | | | | | | | | | | syzbot is catching so many bugs triggered by commit 9ee332d99e4d5a97 ("sget(): handle failures of register_shrinker()"). That commit expected that calling kill_sb() from deactivate_locked_super() without successful fill_super() is safe, but the reality was different; some callers assign attributes which are needed for kill_sb() after sget() succeeds. For example, [1] is a report where sb->s_mode (which seems to be either FMODE_READ | FMODE_EXCL | FMODE_WRITE or FMODE_READ | FMODE_EXCL) is not assigned unless sget() succeeds. But it does not worth complicate sget() so that register_shrinker() failure path can safely call kill_block_super() via kill_sb(). Making alloc_super() fail if memory allocation for register_shrinker() failed is much simpler. Let's avoid calling deactivate_locked_super() from sget_userns() by preallocating memory for the shrinker and making register_shrinker() in sget_userns() never fail. [1] https://syzkaller.appspot.com/bug?id=588996a25a2587be2e3a54e8646728fb9cae44e7 Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: syzbot <syzbot+5a170e19c963a2e0df79@syzkaller.appspotmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'work.thaw' of ↵Linus Torvalds2018-04-121-27/+78
|\ | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs thaw updates from Al Viro: "An ancient series that has fallen through the cracks in the previous cycle" * 'work.thaw' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: buffer.c: call thaw_super during emergency thaw vfs: factor sb iteration out of do_emergency_remount
| * buffer.c: call thaw_super during emergency thawMateusz Guzik2018-03-191-2/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are 2 distinct freezing mechanisms - one operates on block devices and another one directly on super blocks. Both end up with the same result, but thaw of only one of these does not thaw the other. In particular fsfreeze --freeze uses the ioctl variant going to the super block. Since prior to this patch emergency thaw was not doing a relevant thaw, filesystems frozen with this method remained unaffected. The patch is a hack which adds blind unfreezing. In order to keep the super block write-locked the whole time the code is shuffled around and the newly introduced __iterate_supers is employed. Signed-off-by: Mateusz Guzik <mguzik@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: factor sb iteration out of do_emergency_remountMateusz Guzik2017-10-051-25/+36
| | | | | | | | | | | | | | | | | | | | The intent is to reduce code duplication with other code iterating the list. No functional changes. Signed-off-by: Mateusz Guzik <mguzik@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'work.misc' of ↵Linus Torvalds2018-01-311-1/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs updates from Al Viro: "All kinds of misc stuff, without any unifying topic, from various people. Neil's d_anon patch, several bugfixes, introduction of kvmalloc analogue of kmemdup_user(), extending bitfield.h to deal with fixed-endians, assorted cleanups all over the place..." * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits) alpha: osf_sys.c: use timespec64 where appropriate alpha: osf_sys.c: fix put_tv32 regression jffs2: Fix use-after-free bug in jffs2_iget()'s error handling path dcache: delete unused d_hash_mask dcache: subtract d_hash_shift from 32 in advance fs/buffer.c: fold init_buffer() into init_page_buffers() fs: fold __inode_permission() into inode_permission() fs: add RWF_APPEND sctp: use vmemdup_user() rather than badly open-coding memdup_user() snd_ctl_elem_init_enum_names(): switch to vmemdup_user() replace_user_tlv(): switch to vmemdup_user() new primitive: vmemdup_user() memdup_user(): switch to GFP_USER eventfd: fold eventfd_ctx_get() into eventfd_ctx_fileget() eventfd: fold eventfd_ctx_read() into eventfd_read() eventfd: convert to use anon_inode_getfd() nfs4file: get rid of pointless include of btrfs.h uvc_v4l2: clean copyin/copyout up vme_user: don't use __copy_..._user() usx2y: don't bother with memdup_user() for 16-byte structure ...
| * | VFS: don't keep disconnected dentries on d_anonNeilBrown2017-12-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The original purpose of the per-superblock d_anon list was to keep disconnected dentries in the cache between consecutive requests to the NFS server. Dentries can be disconnected if a client holds a file open and repeatedly performs IO on it, and if the server drops the dentry, whether due to memory pressure, server restart, or "echo 3 > /proc/sys/vm/drop_caches". This purpose was thwarted by commit 75a6f82a0d10 ("freeing unlinked file indefinitely delayed") which caused disconnected dentries to be freed as soon as their refcount reached zero. This means that, when a dentry being used by nfsd gets disconnected, a new one needs to be allocated for every request (unless requests overlap). As the dentry has no name, no parent, and no children, there is little of value to cache. As small memory allocations are typically fast (from per-cpu free lists) this likely has little cost. This means that the original purpose of s_anon is no longer relevant: there is no longer any need to keep disconnected dentries on a list so they appear to be hashed. However, s_anon now has a new use. When you mount an NFS filesystem, the dentry stored in s_root is just a placebo. The "real" root dentry is allocated using d_obtain_root() and so it kept on the s_anon list. I don't know the reason for this, but suspect it related to NFSv4 where a mount of "server:/some/path" require NFS to look up the root filehandle on the server, then walk down "/some" and "/path" to get the filehandle to mount. Whatever the reason, NFS depends on the s_anon list and on shrink_dcache_for_umount() pruning all dentries on this list. So we cannot simply remove s_anon. We could just leave the code unchanged, but apart from that being potentially confusing, the (unfair) bit-spin-lock which protects s_anon can become a bottle neck when lots of disconnected dentries are being created. So this patch renames s_anon to s_roots, and stops storing disconnected dentries on the list. Only dentries obtained with d_obtain_root() are now stored on this list. There are many fewer of these (only NFS and NILFS2 use the call, and only during filesystem mount) so contention on the bit-lock will not be a problem. Possibly an alternate solution should be found for NFS and NILFS2, but that would require understanding their needs first. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | sget(): handle failures of register_shrinker()Al Viro2017-12-181-1/+5
| | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | alloc_super(): do ->s_umount initialization earlierAl Viro2017-12-051-19/+18
|/ / | | | | | | | | | | | | ... so that failure exits could count on it having been done. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'work.misc' of ↵Linus Torvalds2017-11-171-25/+21
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs updates from Al Viro: "Assorted stuff, really no common topic here" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: vfs: grab the lock instead of blocking in __fd_install during resizing vfs: stop clearing close on exec when closing a fd include/linux/fs.h: fix comment about struct address_space fs: make fiemap work from compat_ioctl coda: fix 'kernel memory exposure attempt' in fsync pstore: remove unneeded unlikely() vfs: remove unneeded unlikely() stubs for mount_bdev() and kill_block_super() in !CONFIG_BLOCK case make vfs_ustat() static do_handle_open() should be static elf_fdpic: fix unused variable warning fold destroy_super() into __put_super() new helper: destroy_unused_super() fix address space warnings in ipc/ acct.h: get rid of detritus
| * | fold destroy_super() into __put_super()Al Viro2017-10-111-21/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | There's only one caller of destroy_super() left now. Fold it there, and replace those list_lru_destroy() calls with checks that they had already been done (as they should have, when we were dropping the last active reference). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | new helper: destroy_unused_super()Al Viro2017-10-111-12/+19
| |/ | | | | | | | | | | | | | | Used for disposal of super_block instances that had never been reachable via any shared data structures. No need for RCU delay in there, everything can be called directly. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* / License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2017-11-021-0/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge branch 'work.mount' of ↵Linus Torvalds2017-09-151-37/+37
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 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/\<MS_RDONLY\>/SB_RDONLY/g' \ -e 's/\<MS_NOSUID\>/SB_NOSUID/g' \ -e 's/\<MS_NODEV\>/SB_NODEV/g' \ -e 's/\<MS_NOEXEC\>/SB_NOEXEC/g' \ -e 's/\<MS_SYNCHRONOUS\>/SB_SYNCHRONOUS/g' \ -e 's/\<MS_MANDLOCK\>/SB_MANDLOCK/g' \ -e 's/\<MS_DIRSYNC\>/SB_DIRSYNC/g' \ -e 's/\<MS_NOATIME\>/SB_NOATIME/g' \ -e 's/\<MS_NODIRATIME\>/SB_NODIRATIME/g' \ -e 's/\<MS_SILENT\>/SB_SILENT/g' \ -e 's/\<MS_POSIXACL\>/SB_POSIXACL/g' \ -e 's/\<MS_KERNMOUNT\>/SB_KERNMOUNT/g' \ -e 's/\<MS_I_VERSION\>/SB_I_VERSION/g' \ -e 's/\<MS_LAZYTIME\>/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
| * VFS: Differentiate mount flags (MS_*) from internal superblock flagsDavid Howells2017-07-171-34/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Differentiate the MS_* flags passed to mount(2) from the internal flags set in the super_block's s_flags. s_flags are now called SB_*, with the names and the values for the moment mirroring the MS_* flags that they're equivalent to. In this patch, just the headers are altered and some kernel code where blind automated conversion isn't necessarily correct. Note that this shows up some interesting issues: (1) Some MS_* flags get translated to MNT_* flags (such as MS_NODEV -> MNT_NODEV) without passing this on to the filesystem, but some filesystems set such flags anyway. (2) The ->remount_fs() methods of some filesystems adjust the *flags argument by setting MS_* flags in it, such as MS_NOATIME - but these flags are then scrubbed by do_remount_sb() (only the occupants of MS_RMT_MASK are permitted: MS_RDONLY, MS_SYNCHRONOUS, MS_MANDLOCK, MS_I_VERSION and MS_LAZYTIME) I'm not sure what's the best way to solve all these cases. Suggested-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com>
| * VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)David Howells2017-07-171-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Firstly by applying the following with coccinelle's spatch: @@ expression SB; @@ -SB->s_flags & MS_RDONLY +sb_rdonly(SB) to effect the conversion to sb_rdonly(sb), then by applying: @@ expression A, SB; @@ ( -(!sb_rdonly(SB)) && A +!sb_rdonly(SB) && A | -A != (sb_rdonly(SB)) +A != sb_rdonly(SB) | -A == (sb_rdonly(SB)) +A == sb_rdonly(SB) | -!(sb_rdonly(SB)) +!sb_rdonly(SB) | -A && (sb_rdonly(SB)) +A && sb_rdonly(SB) | -A || (sb_rdonly(SB)) +A || sb_rdonly(SB) | -(sb_rdonly(SB)) != A +sb_rdonly(SB) != A | -(sb_rdonly(SB)) == A +sb_rdonly(SB) == A | -(sb_rdonly(SB)) && A +sb_rdonly(SB) && A | -(sb_rdonly(SB)) || A +sb_rdonly(SB) || A ) @@ expression A, B, SB; @@ ( -(sb_rdonly(SB)) ? 1 : 0 +sb_rdonly(SB) | -(sb_rdonly(SB)) ? A : B +sb_rdonly(SB) ? A : B ) to remove left over excess bracketage and finally by applying: @@ expression A, SB; @@ ( -(A & MS_RDONLY) != sb_rdonly(SB) +(bool)(A & MS_RDONLY) != sb_rdonly(SB) | -(A & MS_RDONLY) == sb_rdonly(SB) +(bool)(A & MS_RDONLY) == sb_rdonly(SB) ) to make comparisons against the result of sb_rdonly() (which is a bool) work correctly. Signed-off-by: David Howells <dhowells@redhat.com>
* | quota: Convert dqio_mutex to rwsemJan Kara2017-08-171-1/+1
|/ | | | | | | Convert dqio_mutex to rwsem and call it dqio_sem. No functional changes yet. Signed-off-by: Jan Kara <jack@suse.cz>
* VFS: Kill off s_options and helpersDavid Howells2017-07-111-1/+0
| | | | | | | | | | Kill off s_options, save/replace_mount_options() and generic_show_options() as all filesystems now implement ->show_options() for themselves. This should make it easier to implement a context-based mount where the mount options can be passed individually over a file descriptor. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* VFS: Clean up whitespace in fs/namespace.c and fs/super.cDavid Howells2017-07-061-2/+2
| | | | | | | Clean up line terminal whitespace in fs/namespace.c and fs/super.c. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* bdi: Drop 'parent' argument from bdi_register[_va]()Jan Kara2017-04-201-1/+1
| | | | | | | | | Drop 'parent' argument of bdi_register() and bdi_register_va(). It is always NULL. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
* fs: Remove SB_I_DYNBDI flagJan Kara2017-04-201-4/+1
| | | | | | | | | Now that all bdi structures filesystems use are properly refcounted, we can remove the SB_I_DYNBDI flag. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
* fs: Get proper reference for s_bdiJan Kara2017-04-201-5/+2
| | | | | | | | | | | | | | So far we just relied on block device to hold a bdi reference for us while the filesystem is mounted. While that works perfectly fine, it is a bit awkward that we have a pointer to a refcounted structure in the superblock without proper reference. So make s_bdi hold a proper reference to block device's BDI. No filesystem using mount_bdev() actually changes s_bdi so this is safe and will make bdev filesystems work the same way as filesystems needing to set up their private bdi. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
* fs: Provide infrastructure for dynamic BDIs in filesystemsJan Kara2017-04-201-0/+49
| | | | | | | | | | | | | | | | | | | | | | | | Provide helper functions for setting up dynamically allocated backing_dev_info structures for filesystems and cleaning them up on superblock destruction. CC: linux-mtd@lists.infradead.org CC: linux-nfs@vger.kernel.org CC: Petr Vandrovec <petr@vandrovec.name> CC: linux-nilfs@vger.kernel.org CC: cluster-devel@redhat.com CC: osd-dev@open-osd.org CC: codalist@coda.cs.cmu.edu CC: linux-afs@lists.infradead.org CC: ecryptfs@vger.kernel.org CC: linux-cifs@vger.kernel.org CC: ceph-devel@vger.kernel.org CC: linux-btrfs@vger.kernel.org CC: v9fs-developer@lists.sourceforge.net CC: lustre-devel@lists.lustre.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
* Merge branch 'for-linus' of ↵Linus Torvalds2017-02-241-3/+10
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull namespace updates from Eric Biederman: "There is a lot here. A lot of these changes result in subtle user visible differences in kernel behavior. I don't expect anything will care but I will revert/fix things immediately if any regressions show up. From Seth Forshee there is a continuation of the work to make the vfs ready for unpriviled mounts. We had thought the previous changes prevented the creation of files outside of s_user_ns of a filesystem, but it turns we missed the O_CREAT path. Ooops. Pavel Tikhomirov and Oleg Nesterov worked together to fix a long standing bug in the implemenation of PR_SET_CHILD_SUBREAPER where only children that are forked after the prctl are considered and not children forked before the prctl. The only known user of this prctl systemd forks all children after the prctl. So no userspace regressions will occur. Holding earlier forked children to the same rules as later forked children creates a semantic that is sane enough to allow checkpoing of processes that use this feature. There is a long delayed change by Nikolay Borisov to limit inotify instances inside a user namespace. Michael Kerrisk extends the API for files used to maniuplate namespaces with two new trivial ioctls to allow discovery of the hierachy and properties of namespaces. Konstantin Khlebnikov with the help of Al Viro adds code that when a network namespace exits purges it's sysctl entries from the dcache. As in some circumstances this could use a lot of memory. Vivek Goyal fixed a bug with stacked filesystems where the permissions on the wrong inode were being checked. I continue previous work on ptracing across exec. Allowing a file to be setuid across exec while being ptraced if the tracer has enough credentials in the user namespace, and if the process has CAP_SETUID in it's own namespace. Proc files for setuid or otherwise undumpable executables are now owned by the root in the user namespace of their mm. Allowing debugging of setuid applications in containers to work better. A bug I introduced with permission checking and automount is now fixed. The big change is to mark the mounts that the kernel initiates as a result of an automount. This allows the permission checks in sget to be safely suppressed for this kind of mount. As the permission check happened when the original filesystem was mounted. Finally a special case in the mount namespace is removed preventing unbounded chains in the mount hash table, and making the semantics simpler which benefits CRIU. The vfs fix along with related work in ima and evm I believe makes us ready to finish developing and merge fully unprivileged mounts of the fuse filesystem. The cleanups of the mount namespace makes discussing how to fix the worst case complexity of umount. The stacked filesystem fixes pave the way for adding multiple mappings for the filesystem uids so that efficient and safer containers can be implemented" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: proc/sysctl: Don't grab i_lock under sysctl_lock. vfs: Use upper filesystem inode in bprm_fill_uid() proc/sysctl: prune stale dentries during unregistering mnt: Tuck mounts under others instead of creating shadow/side mounts. prctl: propagate has_child_subreaper flag to every descendant introduce the walk_process_tree() helper nsfs: Add an ioctl() to return owner UID of a userns fs: Better permission checking for submounts exit: fix the setns() && PR_SET_CHILD_SUBREAPER interaction vfs: open() with O_CREAT should not create inodes with unknown ids nsfs: Add an ioctl() to return the namespace type proc: Better ownership of files for non-dumpable tasks in user namespaces exec: Remove LSM_UNSAFE_PTRACE_CAP exec: Test the ptracer's saved cred to see if the tracee can gain caps exec: Don't reset euid and egid when the tracee has CAP_SETUID inotify: Convert to using per-namespace limits
| * fs: Better permission checking for submountsEric W. Biederman2017-02-011-3/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To support unprivileged users mounting filesystems two permission checks have to be performed: a test to see if the user allowed to create a mount in the mount namespace, and a test to see if the user is allowed to access the specified filesystem. The automount case is special in that mounting the original filesystem grants permission to mount the sub-filesystems, to any user who happens to stumble across the their mountpoint and satisfies the ordinary filesystem permission checks. Attempting to handle the automount case by using override_creds almost works. It preserves the idea that permission to mount the original filesystem is permission to mount the sub-filesystem. Unfortunately using override_creds messes up the filesystems ordinary permission checks. Solve this by being explicit that a mount is a submount by introducing vfs_submount, and using it where appropriate. vfs_submount uses a new mount internal mount flags MS_SUBMOUNT, to let sget and friends know that a mount is a submount so they can take appropriate action. sget and sget_userns are modified to not perform any permission checks on submounts. follow_automount is modified to stop using override_creds as that has proven problemantic. do_mount is modified to always remove the new MS_SUBMOUNT flag so that we know userspace will never by able to specify it. autofs4 is modified to stop using current_real_cred that was put in there to handle the previous version of submount permission checking. cifs is modified to pass the mountpoint all of the way down to vfs_submount. debugfs is modified to pass the mountpoint all of the way down to trace_automount by adding a new parameter. To make this change easier a new typedef debugfs_automount_t is introduced to capture the type of the debugfs automount function. Cc: stable@vger.kernel.org Fixes: 069d5ac9ae0d ("autofs: Fix automounts by using current_real_cred()->uid") Fixes: aeaa4a79ff6a ("fs: Call d_automount with the filesystems creds") Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* | block: Use pointer to backing_dev_info from request_queueJan Kara2017-02-021-1/+1
|/ | | | | | | | | | | We will want to have struct backing_dev_info allocated separately from struct request_queue. As the first step add pointer to backing_dev_info to request_queue and convert all users touching it. No functional changes in this patch. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
* quota: Remove dqonoff_mutexJan Kara2016-11-301-1/+0
| | | | | | | | The only places that were grabbing dqonoff_mutex are functions turning quotas on and off and these are properly serialized using s_umount semaphore. Remove dqonoff_mutex. Signed-off-by: Jan Kara <jack@suse.cz>
* fs: Provide function to get superblock with exclusive s_umountJan Kara2016-11-231-20/+60
| | | | | | | | Quota code will need a variant of get_super_thawed() that returns superblock with s_umount held in exclusive mode to serialize quota on and quota off operations. Provide this functionality. Signed-off-by: Jan Kara <jack@suse.cz>
* fs/super.c: don't fool lockdep in freeze_super() and thaw_super() pathsOleg Nesterov2016-10-151-12/+25
| | | | | | | | | | | | | | | sb_wait_write()->percpu_rwsem_release() fools lockdep to avoid the false-positives. Now that xfs was fixed by Dave's commit dbad7c993053 ("xfs: stop holding ILOCK over filldir callbacks") we can remove it and change freeze_super() and thaw_super() to run with s_writers.rw_sem locks held; we add two trivial helpers for that, lockdep_sb_freeze_release() and lockdep_sb_freeze_acquire(). xfstests-dev/check `grep -il freeze tests/*/???` does not trigger any warning from lockdep. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs/super.c: fix race between freeze_super() and thaw_super()Oleg Nesterov2016-10-151-3/+3
| | | | | | | | | | | | | | | | Change thaw_super() to check frozen != SB_FREEZE_COMPLETE rather than frozen == SB_UNFROZEN, otherwise it can race with freeze_super() which drops sb->s_umount after SB_FREEZE_WRITE to preserve the lock ordering. In this case thaw_super() will wrongly call s_op->unfreeze_fs() before it was actually frozen, and call sb_freeze_unlock() which leads to the unbalanced percpu_up_write(). Unfortunately lockdep can't detect this, so this triggers misc BUG_ON()'s in kernel/rcu/sync.c. Reported-and-tested-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-linus' of ↵Linus Torvalds2016-07-301-8/+61
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull userns vfs updates from Eric Biederman: "This tree contains some very long awaited work on generalizing the user namespace support for mounting filesystems to include filesystems with a backing store. The real world target is fuse but the goal is to update the vfs to allow any filesystem to be supported. This patchset is based on a lot of code review and testing to approach that goal. While looking at what is needed to support the fuse filesystem it became clear that there were things like xattrs for security modules that needed special treatment. That the resolution of those concerns would not be fuse specific. That sorting out these general issues made most sense at the generic level, where the right people could be drawn into the conversation, and the issues could be solved for everyone. At a high level what this patchset does a couple of simple things: - Add a user namespace owner (s_user_ns) to struct super_block. - Teach the vfs to handle filesystem uids and gids not mapping into to kuids and kgids and being reported as INVALID_UID and INVALID_GID in vfs data structures. By assigning a user namespace owner filesystems that are mounted with only user namespace privilege can be detected. This allows security modules and the like to know which mounts may not be trusted. This also allows the set of uids and gids that are communicated to the filesystem to be capped at the set of kuids and kgids that are in the owning user namespace of the filesystem. One of the crazier corner casees this handles is the case of inodes whose i_uid or i_gid are not mapped into the vfs. Most of the code simply doesn't care but it is easy to confuse the inode writeback path so no operation that could cause an inode write-back is permitted for such inodes (aka only reads are allowed). This set of changes starts out by cleaning up the code paths involved in user namespace permirted mounts. Then when things are clean enough adds code that cleanly sets s_user_ns. Then additional restrictions are added that are possible now that the filesystem superblock contains owner information. These changes should not affect anyone in practice, but there are some parts of these restrictions that are changes in behavior. - Andy's restriction on suid executables that does not honor the suid bit when the path is from another mount namespace (think /proc/[pid]/fd/) or when the filesystem was mounted by a less privileged user. - The replacement of the user namespace implicit setting of MNT_NODEV with implicitly setting SB_I_NODEV on the filesystem superblock instead. Using SB_I_NODEV is a stronger form that happens to make this state user invisible. The user visibility can be managed but it caused problems when it was introduced from applications reasonably expecting mount flags to be what they were set to. There is a little bit of work remaining before it is safe to support mounting filesystems with backing store in user namespaces, beyond what is in this set of changes. - Verifying the mounter has permission to read/write the block device during mount. - Teaching the integrity modules IMA and EVM to handle filesystems mounted with only user namespace root and to reduce trust in their security xattrs accordingly. - Capturing the mounters credentials and using that for permission checks in d_automount and the like. (Given that overlayfs already does this, and we need the work in d_automount it make sense to generalize this case). Furthermore there are a few changes that are on the wishlist: - Get all filesystems supporting posix acls using the generic posix acls so that posix_acl_fix_xattr_from_user and posix_acl_fix_xattr_to_user may be removed. [Maintainability] - Reducing the permission checks in places such as remount to allow the superblock owner to perform them. - Allowing the superblock owner to chown files with unmapped uids and gids to something that is mapped so the files may be treated normally. I am not considering even obvious relaxations of permission checks until it is clear there are no more corner cases that need to be locked down and handled generically. Many thanks to Seth Forshee who kept this code alive, and putting up with me rewriting substantial portions of what he did to handle more corner cases, and for his diligent testing and reviewing of my changes" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (30 commits) fs: Call d_automount with the filesystems creds fs: Update i_[ug]id_(read|write) to translate relative to s_user_ns evm: Translate user/group ids relative to s_user_ns when computing HMAC dquot: For now explicitly don't support filesystems outside of init_user_ns quota: Handle quota data stored in s_user_ns in quota_setxquota quota: Ensure qids map to the filesystem vfs: Don't create inodes with a uid or gid unknown to the vfs vfs: Don't modify inodes with a uid or gid unknown to the vfs cred: Reject inodes with invalid ids in set_create_file_as() fs: Check for invalid i_uid in may_follow_link() vfs: Verify acls are valid within superblock's s_user_ns. userns: Handle -1 in k[ug]id_has_mapping when !CONFIG_USER_NS fs: Refuse uid/gid changes which don't map into s_user_ns selinux: Add support for unprivileged mounts from user namespaces Smack: Handle labels consistently in untrusted mounts Smack: Add support for unprivileged mounts from user namespaces fs: Treat foreign mounts as nosuid fs: Limit file caps to the user namespace of the super block userns: Remove the now unnecessary FS_USERNS_DEV_MOUNT flag userns: Remove implicit MNT_NODEV fragility. ...
| * userns: Remove the now unnecessary FS_USERNS_DEV_MOUNT flagEric W. Biederman2016-06-231-2/+1
| | | | | | | | | | | | | | | | | | | | Now that SB_I_NODEV controls the nodev behavior devpts can just clear this flag during mount. Simplifying the code and making it easier to audit how the code works. While still preserving the invariant that s_iflags is only modified during mount. Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * userns: Remove implicit MNT_NODEV fragility.Eric W. Biederman2016-06-231-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace the implict setting of MNT_NODEV on mounts that happen with just user namespace permissions with an implicit setting of SB_I_NODEV in s_iflags. The visibility of the implicit MNT_NODEV has caused problems in the past. With this change the fragile case where an implicit MNT_NODEV needs to be preserved in do_remount is removed. Using SB_I_NODEV is much less fragile as s_iflags are set during the original mount and never changed. In do_new_mount with the implicit setting of MNT_NODEV gone, the only code that can affect mnt_flags is fs_fully_visible so simplify the if statement and reduce the indentation of the code to make that clear. Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * mnt: Move the FS_USERNS_MOUNT check into sget_usernsEric W. Biederman2016-06-231-0/+4
| | | | | | | | | | | | | | | | | | | | Allowing a filesystem to be mounted by other than root in the initial user namespace is a filesystem property not a mount namespace property and as such should be checked in filesystem specific code. Move the FS_USERNS_MOUNT test into super.c:sget_userns(). Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * fs: Add user namespace member to struct super_blockEric W. Biederman2016-06-231-6/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Start marking filesystems with a user namespace owner, s_user_ns. In this change this is only used for permission checks of who may mount a filesystem. Ultimately s_user_ns will be used for translating ids and checking capabilities for filesystems mounted from user namespaces. The default policy for setting s_user_ns is implemented in sget(), which arranges for s_user_ns to be set to current_user_ns() and to ensure that the mounter of the filesystem has CAP_SYS_ADMIN in that user_ns. The guts of sget are split out into another function sget_userns(). The function sget_userns calls alloc_super with the specified user namespace or it verifies the existing superblock that was found has the expected user namespace, and fails with EBUSY when it is not. This failing prevents users with the wrong privileges mounting a filesystem. The reason for the split of sget_userns from sget is that in some cases such as mount_ns and kernfs_mount_ns a different policy for permission checking of mounts and setting s_user_ns is necessary, and the existence of sget_userns() allows those policies to be implemented. The helper mount_ns is expected to be used for filesystems such as proc and mqueuefs which present per namespace information. The function mount_ns is modified to call sget_userns instead of sget to ensure the user namespace owner of the namespace whose information is presented by the filesystem is used on the superblock. For sysfs and cgroup the appropriate permission checks are already in place, and kernfs_mount_ns is modified to call sget_userns so that the init_user_ns is the only user namespace used. For the cgroup filesystem cgroup namespace mounts are bind mounts of a subset of the full cgroup filesystem and as such s_user_ns must be the same for all of them as there is only a single superblock. Mounts of sysfs that vary based on the network namespace could in principle change s_user_ns but it keeps the analysis and implementation of kernfs simpler if that is not supported, and at present there appear to be no benefits from supporting a different s_user_ns on any sysfs mount. Getting the details of setting s_user_ns correct has been a long process. Thanks to Pavel Tikhorirorv who spotted a leak in sget_userns. Thanks to Seth Forshee who has kept the work alive. Thanks-to: Seth Forshee <seth.forshee@canonical.com> Thanks-to: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * vfs: Pass data, ns, and ns->userns to mount_nsEric W. Biederman2016-06-231-3/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Today what is normally called data (the mount options) is not passed to fill_super through mount_ns. Pass the mount options and the namespace separately to mount_ns so that filesystems such as proc that have mount options, can use mount_ns. Pass the user namespace to mount_ns so that the standard permission check that verifies the mounter has permissions over the namespace can be performed in mount_ns instead of in each filesystems .mount method. Thus removing the duplication between mqueuefs and proc in terms of permission checks. The extra permission check does not currently affect the rpc_pipefs filesystem and the nfsd filesystem as those filesystems do not currently allow unprivileged mounts. Without unpvileged mounts it is guaranteed that the caller has already passed capable(CAP_SYS_ADMIN) which guarantees extra permission check will pass. Update rpc_pipefs and the nfsd filesystem to ensure that the network namespace reference is always taken in fill_super and always put in kill_sb so that the logic is simpler and so that errors originating inside of fill_super do not cause a network namespace leak. Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* | fs/fs-writeback.c: add a new writeback list for syncDave Chinner2016-07-271-0/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | wait_sb_inodes() currently does a walk of all inodes in the filesystem to find dirty one to wait on during sync. This is highly inefficient and wastes a lot of CPU when there are lots of clean cached inodes that we don't need to wait on. To avoid this "all inode" walk, we need to track inodes that are currently under writeback that we need to wait for. We do this by adding inodes to a writeback list on the sb when the mapping is first tagged as having pages under writeback. wait_sb_inodes() can then walk this list of "inodes under IO" and wait specifically just for the inodes that the current sync(2) needs to wait for. Define a couple helpers to add/remove an inode from the writeback list and call them when the overall mapping is tagged for or cleared from writeback. Update wait_sb_inodes() to walk only the inodes under writeback due to the sync. With this change, filesystem sync times are significantly reduced for fs' with largely populated inode caches and otherwise no other work to do. For example, on a 16xcpu 2GHz x86-64 server, 10TB XFS filesystem with a ~10m entry inode cache, sync times are reduced from ~7.3s to less than 0.1s when the filesystem is fully clean. Link: http://lkml.kernel.org/r/1466594593-6757-2-git-send-email-bfoster@redhat.com Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Holger Hoffstätte <holger.hoffstaette@applied-asynchrony.com> 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>
* Merge branch 'master' into for-nextJiri Kosina2016-04-181-3/+2
|\ | | | | | | | | | | Sync with Linus' tree so that patches against newer codebase can be applied. Signed-off-by: Jiri Kosina <jkosina@suse.cz>
| * writeback: flush inode cgroup wb switches instead of pinning super_blockTejun Heo2016-03-031-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If cgroup writeback is in use, inodes can be scheduled for asynchronous wb switching. Before 5ff8eaac1636 ("writeback: keep superblock pinned during cgroup writeback association switches"), this could race with umount leading to super_block being destroyed while inodes are pinned for wb switching. 5ff8eaac1636 fixed it by bumping s_active while wb switches are in flight; however, this allowed in-flight wb switches to make umounts asynchronous when the userland expected synchronosity - e.g. fsck immediately following umount may fail because the device is still busy. This patch removes the problematic super_block pinning and instead makes generic_shutdown_super() flush in-flight wb switches. wb switches are now executed on a dedicated isw_wq so that they can be flushed and isw_nr_in_flight keeps track of the number of in-flight wb switches so that flushing can be avoided in most cases. v2: Move cgroup_writeback_umount() further below and add MS_ACTIVE check in inode_switch_wbs() as Jan an Al suggested. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Tahsin Erdogan <tahsin@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Al Viro <viro@ZenIV.linux.org.uk> Link: http://lkml.kernel.org/g/CAAeU0aNCq7LGODvVGRU-oU_o-6enii5ey0p1c26D1ZzYwkDc5A@mail.gmail.com Fixes: 5ff8eaac1636 ("writeback: keep superblock pinned during cgroup writeback association switches") Cc: stable@vger.kernel.org #v4.5 Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Tahsin Erdogan <tahsin@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * Merge branch 'for-linus' of ↵Linus Torvalds2016-01-151-1/+1
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial Pull trivial tree updates from Jiri Kosina. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: floppy: make local variable non-static exynos: fixes an incorrect header guard dt-bindings: fixes some incorrect header guards cpufreq-dt: correct dead link in documentation cpufreq: ARM big LITTLE: correct dead link in documentation treewide: Fix typos in printk Documentation: filesystem: Fix typo in fs/eventfd.c fs/super.c: use && instead of & for warn_on condition Documentation: fix sysfs-ptp lib: scatterlist: fix Kconfig description
| * | fs: use block_device name vsprintf helperDmitry Monakhov2016-01-061-3/+1
| | | | | | | | | | | | | | | Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | Doc: treewide : Fix typos in DocBook/filesystem.xmlMasanari Iida2016-04-181-1/+1
| |/ |/| | | | | | | | | | | | | | | This patch fix spelling typos found in DocBook/filesystem.xml. It is because the file was generated from comments in code, I have to fix the comments in codes, instead of xml file. Signed-off-by: Masanari Iida <standby24x7@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* | fs/super.c: use && instead of & for warn_on conditionVincent Stehlé2015-12-081-1/+1
|/ | | | | | | | | | | | | This fixes the following sparse warning: fs/super.c:1202:9: warning: dubious: x & !y Bitwise and logical and are equivalent here, but logical was intended. The generated code is identical, with and without CONFIG_LOCKDEP. Signed-off-by: Vincent Stehlé <vincent.stehle@freescale.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* Merge branch 'superblock-scaling' of ↵Al Viro2015-08-211-1/+3
|\ | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next into for-next Conflicts: include/linux/fs.h
| * sync: serialise per-superblock sync operationsDave Chinner2015-08-181-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When competing sync(2) calls walk the same filesystem, they need to walk the list of inodes on the superblock to find all the inodes that we need to wait for IO completion on. However, when multiple wait_sb_inodes() calls do this at the same time, they contend on the the inode_sb_list_lock and the contention causes system wide slowdowns. In effect, concurrent sync(2) calls can take longer and burn more CPU than if they were serialised. Stop the worst of the contention by adding a per-sb mutex to wrap around wait_sb_inodes() so that we only execute one sync(2) IO completion walk per superblock superblock at a time and hence avoid contention being triggered by concurrent sync(2) calls. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: Dave Chinner <dchinner@redhat.com>
| * inode: convert inode_sb_list_lock to per-sbDave Chinner2015-08-181-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The process of reducing contention on per-superblock inode lists starts with moving the locking to match the per-superblock inode list. This takes the global lock out of the picture and reduces the contention problems to within a single filesystem. This doesn't get rid of contention as the locks still have global CPU scope, but it does isolate operations on different superblocks form each other. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: Dave Chinner <dchinner@redhat.com>
* | change sb_writers to use percpu_rw_semaphoreOleg Nesterov2015-08-151-81/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We can remove everything from struct sb_writers except frozen and add the array of percpu_rw_semaphore's instead. This patch doesn't remove sb_writers->wait_unfrozen yet, we keep it for get_super_thawed(). We will probably remove it later. This change tries to address the following problems: - Firstly, __sb_start_write() looks simply buggy. It does __sb_end_write() if it sees ->frozen, but if it migrates to another CPU before percpu_counter_dec(), sb_wait_write() can wrongly succeed if there is another task which holds the same "semaphore": sb_wait_write() can miss the result of the previous percpu_counter_inc() but see the result of this percpu_counter_dec(). - As Dave Hansen reports, it is suboptimal. The trivial microbenchmark that writes to a tmpfs file in a loop runs 12% faster if we change this code to rely on RCU and kill the memory barriers. - This code doesn't look simple. It would be better to rely on the generic locking code. According to Dave, this change adds the same performance improvement. Note: with this change both freeze_super() and thaw_super() will do synchronize_sched_expedited() 3 times. This is just ugly. But: - This will be "fixed" by the rcu_sync changes we are going to merge. After that freeze_super()->percpu_down_write() will use synchronize_sched(), and thaw_super() won't use synchronize() at all. This doesn't need any changes in fs/super.c. - Once we merge rcu_sync changes, we can also change super.c so that all wb_write->rw_sem's will share the single ->rss in struct sb_writes, then freeze_super() will need only one synchronize_sched(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jan Kara <jack@suse.com>
* | shift percpu_counter_destroy() into destroy_super_work()Oleg Nesterov2015-08-151-4/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Of course, this patch is ugly as hell. It will be (partially) reverted later. We add it to ensure that other WIP changes in percpu_rw_semaphore won't break fs/super.c. We do not even need this change right now, percpu_free_rwsem() is fine in atomic context. But we are going to change this, it will be might_sleep() after we merge the rcu_sync() patches. And even after that we do not really need destroy_super_work(), we will kill it in any case. Instead, destroy_super_rcu() should just check that rss->cb_state == CB_IDLE and do call_rcu() again in the (very unlikely) case this is not true. So this is just the temporary kludge which helps us to avoid the conflicts with the changes which will be (hopefully) routed via rcu tree. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jan Kara <jack@suse.com>
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