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* Merge branch 'for-4.2' of ↵Linus Torvalds2015-06-261-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: - threadgroup_lock got reorganized so that its users can pick the actual locking mechanism to use. Its only user - cgroups - is updated to use a percpu_rwsem instead of per-process rwsem. This makes things a bit lighter on hot paths and allows cgroups to perform and fail multi-task (a process) migrations atomically. Multi-task migrations are used in several places including the unified hierarchy. - Delegation rule and documentation added to unified hierarchy. This will likely be the last interface update from the cgroup core side for unified hierarchy before lifting the devel mask. - Some groundwork for the pids controller which is scheduled to be merged in the coming devel cycle. * 'for-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: add delegation section to unified hierarchy documentation cgroup: require write perm on common ancestor when moving processes on the default hierarchy cgroup: separate out cgroup_procs_write_permission() from __cgroup_procs_write() kernfs: make kernfs_get_inode() public MAINTAINERS: add a cgroup core co-maintainer cgroup: fix uninitialised iterator in for_each_subsys_which cgroup: replace explicit ss_mask checking with for_each_subsys_which cgroup: use bitmask to filter for_each_subsys cgroup: add seq_file forward declaration for struct cftype cgroup: simplify threadgroup locking sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsem sched, cgroup: reorganize threadgroup locking cgroup: switch to unsigned long for bitmasks cgroup: reorganize include/linux/cgroup.h cgroup: separate out include/linux/cgroup-defs.h cgroup: fix some comment typos
| * kernfs: make kernfs_get_inode() publicTejun Heo2015-06-181-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | Move kernfs_get_inode() prototype from fs/kernfs/kernfs-internal.h to include/linux/kernfs.h. It obtains the matching inode for a kernfs_node. It will be used by cgroup for inode based permission checks for now but is generally useful. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | Merge tag 'driver-core-4.2-rc1' of ↵Linus Torvalds2015-06-263-5/+4
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here is the driver core / firmware changes for 4.2-rc1. A number of small changes all over the place in the driver core, and in the firmware subsystem. Nothing really major, full details in the shortlog. Some of it is a bit of churn, given that the platform driver probing changes was found to not work well, so they were reverted. All of these have been in linux-next for a while with no reported issues" * tag 'driver-core-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (31 commits) Revert "base/platform: Only insert MEM and IO resources" Revert "base/platform: Continue on insert_resource() error" Revert "of/platform: Use platform_device interface" Revert "base/platform: Remove code duplication" firmware: add missing kfree for work on async call fs: sysfs: don't pass count == 0 to bin file readers base:dd - Fix for typo in comment to function driver_deferred_probe_trigger(). base/platform: Remove code duplication of/platform: Use platform_device interface base/platform: Continue on insert_resource() error base/platform: Only insert MEM and IO resources firmware: use const for remaining firmware names firmware: fix possible use after free on name on asynchronous request firmware: check for file truncation on direct firmware loading firmware: fix __getname() missing failure check drivers: of/base: move of_init to driver_init drivers/base: cacheinfo: fix annoying typo when DT nodes are absent sysfs: disambiguate between "error code" and "failure" in comments driver-core: fix build for !CONFIG_MODULES driver-core: make __device_attach() static ...
| * \ Merge 4.1-rc7 into driver-core-nextGreg Kroah-Hartman2015-06-0834-179/+407
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | We want the fixes in this branch as well for testing and merge resolution. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | fs: sysfs: don't pass count == 0 to bin file readersVladimir Zapolskiy2015-06-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If count == 0 bytes are requested by a reader, sysfs_kf_bin_read() deliberately returns 0 without passing a potentially harmful value to some externally defined underlying battr->read() function. However in case of (pos == size && count) the next clause always sets count to 0 and this value is handed over to battr->read(). The change intends to make obsolete (and remove later) a redundant sanity check in battr->read(), if it is present, or add more protection to struct bin_attribute users, who does not care about input arguments. Signed-off-by: Vladimir Zapolskiy <vz@mleia.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | sysfs: disambiguate between "error code" and "failure" in commentsAntonio Ospite2015-05-241-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The sentence "Returns 0 on success or error" might be misinterpreted as "the function will always returns 0", make it less ambiguous. Also, use the word "failure" as the contrary of "success". Signed-off-by: Antonio Ospite <ao2@ao2.it> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-doc@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | | kernfs: remove outdated and confusing commentWolfram Sang2015-05-241-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Grabbing the parent is not happening anymore since 2010 (e72ceb8ccac5f7 "sysfs: Remove sysfs_get/put_active_two"). Remove this confusing comment. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | Merge branch 'akpm' (patches from Andrew)Linus Torvalds2015-06-2611-39/+227
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge second patchbomb from Andrew Morton: - most of the rest of MM - lots of misc things - procfs updates - printk feature work - updates to get_maintainer, MAINTAINERS, checkpatch - lib/ updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (96 commits) exit,stats: /* obey this comment */ coredump: add __printf attribute to cn_*printf functions coredump: use from_kuid/kgid when formatting corename fs/reiserfs: remove unneeded cast NILFS2: support NFSv2 export fs/befs/btree.c: remove unneeded initializations fs/minix: remove unneeded cast init/do_mounts.c: add create_dev() failure log kasan: remove duplicate definition of the macro KASAN_FREE_PAGE fs/efs: femove unneeded cast checkpatch: emit "NOTE: <types>" message only once after multiple files checkpatch: emit an error when there's a diff in a changelog checkpatch: validate MODULE_LICENSE content checkpatch: add multi-line handling for PREFER_ETHER_ADDR_COPY checkpatch: suggest using eth_zero_addr() and eth_broadcast_addr() checkpatch: fix processing of MEMSET issues checkpatch: suggest using ether_addr_equal*() checkpatch: avoid NOT_UNIFIED_DIFF errors on cover-letter.patch files checkpatch: remove local from codespell path checkpatch: add --showfile to allow input via pipe to show filenames ...
| * | | | coredump: add __printf attribute to cn_*printf functionsNicolas Iooss2015-06-251-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This allows detecting improper format string at build time, like: fs/coredump.c:225:5: warning: format '%ld' expects argument of type 'long int', but argument 3 has type 'int' [-Wformat=] err = cn_printf(cn, "%ld", cprm->siginfo->si_signo); ^ As si_signo is always an int, the format should be %d here. Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | coredump: use from_kuid/kgid when formatting corenameNicolas Iooss2015-06-251-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When adding __printf attribute to cn_printf, gcc reports some issues: fs/coredump.c:213:5: warning: format '%d' expects argument of type 'int', but argument 3 has type 'kuid_t' [-Wformat=] err = cn_printf(cn, "%d", cred->uid); ^ fs/coredump.c:217:5: warning: format '%d' expects argument of type 'int', but argument 3 has type 'kgid_t' [-Wformat=] err = cn_printf(cn, "%d", cred->gid); ^ These warnings come from the fact that the value of uid/gid needs to be extracted from the kuid_t/kgid_t structure before being used as an integer. More precisely, cred->uid and cred->gid need to be converted to either user-namespace uid/gid or to init_user_ns uid/gid. Use init_user_ns in order not to break existing ABI, and document this in Documentation/sysctl/kernel.txt. While at it, format uid and gid values with %u instead of %d because uid_t/__kernel_uid32_t and gid_t/__kernel_gid32_t are unsigned int. Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | fs/reiserfs: remove unneeded castFiro Yang2015-06-251-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kmem_cache_alloc() returns void*. Signed-off-by: Firo Yang <firogm@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | NILFS2: support NFSv2 exportNeilBrown2015-06-251-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The "fh_len" passed to ->fh_to_* is not guaranteed to be that same as that returned by encode_fh - it may be larger. With NFSv2, the filehandle is fixed length, so it may appear longer than expected and be zero-padded. So we must test that fh_len is at least some value, not exactly equal to it. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | fs/befs/btree.c: remove unneeded initializationsFabian Frederick2015-06-251-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | bh, od_sup and this_node are unconditionally initialized in befs_bt_read_super() and befs_btree_find() Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | fs/minix: remove unneeded castFiro Yang2015-06-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kmem_cache_alloc() returns void*. Signed-off-by: Firo Yang <firogm@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | fs/efs: femove unneeded castFiro Yang2015-06-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kmem_cache_alloc() returns void*. Signed-off-by: Firo Yang <firogm@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | fs/ext4/super.c: use strreplace() in ext4_fill_super()Rasmus Villemoes2015-06-251-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This makes a very large function a little smaller. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | fs/jbd2/journal.c: use strreplace()Rasmus Villemoes2015-06-251-8/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In one case, we eliminate a local variable; in the other a strlen() call and some .text. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | fs, proc: introduce CONFIG_PROC_CHILDRENIago López Galeiras2015-06-253-3/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 818411616baf ("fs, proc: introduce /proc/<pid>/task/<tid>/children entry") introduced the children entry for checkpoint restore and the file is only available on kernels configured with CONFIG_EXPERT and CONFIG_CHECKPOINT_RESTORE. This is available in most distributions (Fedora, Debian, Ubuntu, CoreOS) because they usually enable CONFIG_EXPERT and CONFIG_CHECKPOINT_RESTORE. But Arch does not enable CONFIG_EXPERT or CONFIG_CHECKPOINT_RESTORE. However, the children proc file is useful outside of checkpoint restore. I would like to use it in rkt. The rkt process exec() another program it does not control, and that other program will fork()+exec() a child process. I would like to find the pid of the child process from an external tool without iterating in /proc over all processes to find which one has a parent pid equal to rkt. This commit introduces CONFIG_PROC_CHILDREN and makes CONFIG_CHECKPOINT_RESTORE select it. This allows enabling /proc/<pid>/task/<tid>/children without needing to enable CONFIG_CHECKPOINT_RESTORE and CONFIG_EXPERT. Alban tested that /proc/<pid>/task/<tid>/children is present when the kernel is configured with CONFIG_PROC_CHILDREN=y but without CONFIG_CHECKPOINT_RESTORE Signed-off-by: Iago López Galeiras <iago@endocode.com> Tested-by: Alban Crequy <alban@endocode.com> Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Serge Hallyn <serge.hallyn@canonical.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Djalal Harouni <djalal@endocode.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | proc: fix PAGE_SIZE limit of /proc/$PID/cmdlineAlexey Dobriyan2015-06-251-9/+196
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | /proc/$PID/cmdline truncates output at PAGE_SIZE. It is easy to see with $ cat /proc/self/cmdline $(seq 1037) 2>/dev/null However, command line size was never limited to PAGE_SIZE but to 128 KB and relatively recently limitation was removed altogether. People noticed and ask questions: http://stackoverflow.com/questions/199130/how-do-i-increase-the-proc-pid-cmdline-4096-byte-limit seq file interface is not OK, because it kmalloc's for whole output and open + read(, 1) + sleep will pin arbitrary amounts of kernel memory. To not do that, limit must be imposed which is incompatible with arbitrary sized command lines. I apologize for hairy code, but this it direct consequence of command line layout in memory and hacks to support things like "init [3]". The loops are "unrolled" otherwise it is either macros which hide control flow or functions with 7-8 arguments with equal line count. There should be real setproctitle(2) or something. [akpm@linux-foundation.org: fix a billion min() warnings] Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Tested-by: Jarod Wilson <jarod@redhat.com> Acked-by: Jarod Wilson <jarod@redhat.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Jan Stancek <jstancek@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | | Merge branch 'for-4.2/writeback' of git://git.kernel.dk/linux-blockLinus Torvalds2015-06-2527-274/+1079
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull cgroup writeback support from Jens Axboe: "This is the big pull request for adding cgroup writeback support. This code has been in development for a long time, and it has been simmering in for-next for a good chunk of this cycle too. This is one of those problems that has been talked about for at least half a decade, finally there's a solution and code to go with it. Also see last weeks writeup on LWN: http://lwn.net/Articles/648292/" * 'for-4.2/writeback' of git://git.kernel.dk/linux-block: (85 commits) writeback, blkio: add documentation for cgroup writeback support vfs, writeback: replace FS_CGROUP_WRITEBACK with SB_I_CGROUPWB writeback: do foreign inode detection iff cgroup writeback is enabled v9fs: fix error handling in v9fs_session_init() bdi: fix wrong error return value in cgwb_create() buffer: remove unusued 'ret' variable writeback: disassociate inodes from dying bdi_writebacks writeback: implement foreign cgroup inode bdi_writeback switching writeback: add lockdep annotation to inode_to_wb() writeback: use unlocked_inode_to_wb transaction in inode_congested() writeback: implement unlocked_inode_to_wb transaction and use it for stat updates writeback: implement [locked_]inode_to_wb_and_lock_list() writeback: implement foreign cgroup inode detection writeback: make writeback_control track the inode being written back writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb() mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback support is in use writeback: implement memcg writeback domain based throttling writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changes writeback: implement memcg wb_domain writeback: update wb_over_bg_thresh() to use wb_domain aware operations ...
| * | | | | vfs, writeback: replace FS_CGROUP_WRITEBACK with SB_I_CGROUPWBTejun Heo2015-06-171-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | FS_CGROUP_WRITEBACK indicates whether a file_system_type supports cgroup writeback; however, different super_blocks of the same file_system_type may or may not support cgroup writeback depending on filesystem options. This patch replaces FS_CGROUP_WRITEBACK with a per-super_block flag. super_block->s_flags carries some internal flags in the high bits but it's exposd to userland through uapi header and running out of space anyway. This patch adds a new field super_block->s_iflags to carry kernel-internal flags. It is currently only used by the new SB_I_CGROUPWB flag whose concatenated and abbreviated name is for consistency with other super_block flags. ext2_fill_super() is updated to set SB_I_CGROUPWB. v2: Added super_block->s_iflags instead of stealing another high bit from sb->s_flags as suggested by Christoph and Jan. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Cc: Christoph Hellwig <hch@infradead.org> Cc: Jan Kara <jack@suse.cz> Cc: linux-ext4@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: do foreign inode detection iff cgroup writeback is enabledTejun Heo2015-06-171-3/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, even when a filesystem doesn't set the FS_CGROUP_WRITEBACK flag, if the filesystem uses wbc_init_bio() and wbc_account_io(), the foreign inode detection and migration logic still ends up activating cgroup writeback which is unexpected. This patch ensures that the foreign inode detection logic stays disabled when inode_cgwb_enabled() is false by not associating writeback_control's with bdi_writeback's. This also avoids unnecessary operations in wbc_init_bio(), wbc_account_io() and wbc_detach_inode() for filesystems which don't support cgroup writeback. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | v9fs: fix error handling in v9fs_session_init()Tejun Heo2015-06-082-34/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On failure, v9fs_session_init() returns with the v9fs_session_info struct partially initialized and expects the caller to invoke v9fs_session_close() to clean it up; however, it doesn't track whether the bdi is initialized or not and curiously invokes bdi_destroy() in both vfs_session_init() failure path too. A. If v9fs_session_init() fails before the bdi is initialized, the follow-up v9fs_session_close() will invoke bdi_destroy() on an uninitialized bdi. B. If v9fs_session_init() fails after the bdi is initialized, bdi_destroy() will be called twice on the same bdi - once in the failure path of v9fs_session_init() and then by v9fs_session_close(). A is broken no matter what. B used to be okay because bdi_destroy() allowed being invoked multiple times on the same bdi, which BTW was broken in its own way - if bdi_destroy() was invoked on an initialiezd but !registered bdi, it'd fail to free percpu counters. Since f0054bb1e1f3 ("writeback: move backing_dev_info->wb_lock and ->worklist into bdi_writeback"), this no longer work - bdi_destroy() on an initialized but not registered bdi works correctly but multiple invocations of bdi_destroy() is no longer allowed. The obvious culprit here is v9fs_session_init()'s odd and broken error behavior. It should simply clean up after itself on failures. This patch makes the following updates to v9fs_session_init(). * @rc -> @retval error return propagation removed. It didn't serve any purpose. Just use @rc. * Move addition to v9fs_sessionlist to the end of the function so that incomplete sessions are not put on the list or iterated and error path doesn't have to worry about it. * Update error handling so that it cleans up after itself. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | buffer: remove unusued 'ret' variableJens Axboe2015-06-021-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge hickup on my part, due to a clash between the writeback changes and the EOPNOTSUPP removal in _submit_bh(). Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: disassociate inodes from dying bdi_writebacksTejun Heo2015-06-021-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For the purpose of foreign inode detection, wb's (bdi_writeback's) are identified by the associated memcg ID. As we create a separate wb for each memcg, this is enough to identify the active wb's; however, when blkcg is enabled or disabled higher up in the hierarchy, the mapping between memcg and blkcg changes which in turn creates a new wb to service the new mapping. The old wb is unlinked from index and released after all references are drained. The foreign inode detection logic can't detect this condition because both the old and new wb's point to the same memcg and thus never decides to move inodes attached to the old wb to the new one. This patch adds logic to initiate switching immediately in wbc_attach_and_unlock_inode() if the associated wb is dying. We can make the usual foreign detection logic to distinguish the different wb's mapped to the memcg but the dying wb is never gonna be in active service again and there's no point in tracking the usage history and reaching the switch verdict after enough data points are collected. It's already known that the wb has to be switched. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: implement foreign cgroup inode bdi_writeback switchingTejun Heo2015-06-021-2/+84
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As concurrent write sharing of an inode is expected to be very rare and memcg only tracks page ownership on first-use basis severely confining the usefulness of such sharing, cgroup writeback tracks ownership per-inode. While the support for concurrent write sharing of an inode is deemed unnecessary, an inode being written to by different cgroups at different points in time is a lot more common, and, more importantly, charging only by first-use can too readily lead to grossly incorrect behaviors (single foreign page can lead to gigabytes of writeback to be incorrectly attributed). To resolve this issue, cgroup writeback detects the majority dirtier of an inode and transfers the ownership to it. The previous patches implemented the foreign condition detection mechanism and laid the groundwork. This patch implements the actual switching. With the previously implemented [unlocked_]inode_to_wb_and_list_lock() and wb stat transaction, grabbing wb->list_lock, inode->i_lock and mapping->tree_lock gives us full exclusion against all wb operations on the target inode. inode_switch_wb_work_fn() grabs all the locks and transfers the inode atomically along with its RECLAIMABLE and WRITEBACK stats. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: add lockdep annotation to inode_to_wb()Tejun Heo2015-06-021-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the previous three patches, all operations which acquire wb from inode are either under one of inode->i_lock, mapping->tree_lock or wb->list_lock or protected by unlocked_inode_to_wb transaction. This will be depended upon by foreign inode wb switching. This patch adds lockdep assertion to inode_to_wb() so that usages outside the above list locks can be caught easily. There are three exceptions. * locked_inode_to_wb_and_lock_list() is holding wb->list_lock but the wb may not be the inode's. Ensuring that is the function's role after all. Updated to deref inode->i_wb directly. * inode_wb_stat_unlocked_begin() is usually protected by combination of !I_WB_SWITCH and rcu_read_lock(). Updated to deref inode->i_wb directly. * inode_congested() wants to test whether inode->i_wb is set before starting the transaction. Added inode_to_wb_is_valid() which tests inode->i_wb directly. v5: might_lock() removed. It annotates that the lock is grabbed w/ irq enabled which isn't the case and triggering lockdep warning spuriously. v4: might_lock() added to unlocked_inode_to_wb_begin(). v3: inode_congested() conversion added. v2: locked_inode_to_wb_and_lock_list() was missing in the first version. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: use unlocked_inode_to_wb transaction in inode_congested()Tejun Heo2015-06-021-4/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Similar to wb stat updates, inode_congested() accesses the associated wb of an inode locklessly, which will break with foreign inode wb switching. This path updates inode_congested() to use unlocked inode wb access transaction introduced by the previous patch. Combined with the previous two patches, this makes all wb list and access operations to be protected by either of inode->i_lock, wb->list_lock, or mapping->tree_lock while wb switching is in progress. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: implement unlocked_inode_to_wb transaction and use it for stat ↵Tejun Heo2015-06-021-6/+111
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | updates The mechanism for detecting whether an inode should switch its wb (bdi_writeback) association is now in place. This patch build the framework for the actual switching. This patch adds a new inode flag I_WB_SWITCHING, which has two functions. First, the easy one, it ensures that there's only one switching in progress for a give inode. Second, it's used as a mechanism to synchronize wb stat updates. The two stats, WB_RECLAIMABLE and WB_WRITEBACK, aren't event counters but track the current number of dirty pages and pages under writeback respectively. As such, when an inode is moved from one wb to another, the inode's portion of those stats have to be transferred together; unfortunately, this is a bit tricky as those stat updates are percpu operations which are performed without holding any lock in some places. This patch solves the problem in a similar way as memcg. Each such lockless stat updates are wrapped in transaction surrounded by unlocked_inode_to_wb_begin/end(). During normal operation, they map to rcu_read_lock/unlock(); however, if I_WB_SWITCHING is asserted, mapping->tree_lock is grabbed across the transaction. In turn, the switching path sets I_WB_SWITCHING and waits for a RCU grace period to pass before actually starting to switch, which guarantees that all stat update paths are synchronizing against mapping->tree_lock. This patch still doesn't implement the actual switching. v3: Updated on top of the recent cancel_dirty_page() updates. unlocked_inode_to_wb_begin() now nests inside mem_cgroup_begin_page_stat() to match the locking order. v2: The i_wb access transaction will be used for !stat accesses too. Function names and comments updated accordingly. s/inode_wb_stat_unlocked_{begin|end}/unlocked_inode_to_wb_{begin|end}/ s/switch_wb/switch_wbs/ Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: implement [locked_]inode_to_wb_and_lock_list()Tejun Heo2015-06-021-5/+75
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup writeback currently assumes that inode to wb association doesn't change; however, with the planned foreign inode wb switching mechanism, the association will change dynamically. When an inode needs to be put on one of the IO lists of its wb, the current code simply calls inode_to_wb() and locks the returned wb; however, with the planned wb switching, the association may change before locking the wb and may even get released. This patch implements [locked_]inode_to_wb_and_lock_list() which pins the associated wb while holding i_lock, releases it, acquires wb->list_lock and verifies that the association hasn't changed inbetween. As the association will be protected by both locks among other things, this guarantees that the wb is the inode's associated wb until the list_lock is released. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: implement foreign cgroup inode detectionTejun Heo2015-06-023-3/+179
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As concurrent write sharing of an inode is expected to be very rare and memcg only tracks page ownership on first-use basis severely confining the usefulness of such sharing, cgroup writeback tracks ownership per-inode. While the support for concurrent write sharing of an inode is deemed unnecessary, an inode being written to by different cgroups at different points in time is a lot more common, and, more importantly, charging only by first-use can too readily lead to grossly incorrect behaviors (single foreign page can lead to gigabytes of writeback to be incorrectly attributed). To resolve this issue, cgroup writeback detects the majority dirtier of an inode and will transfer the ownership to it. To avoid unnnecessary oscillation, the detection mechanism keeps track of history and gives out the switch verdict only if the foreign usage pattern is stable over a certain amount of time and/or writeback attempts. The detection mechanism has fairly low space and computation overhead. It adds 8 bytes to struct inode (one int and two u16's) and minimal amount of calculation per IO. The detection mechanism converges to the correct answer usually in several seconds of IO time when there's a clear majority dirtier. Even when there isn't, it can reach an acceptable answer fairly quickly under most circumstances. Please see wb_detach_inode() for more details. This patch only implements detection. Following patches will implement actual switching. v2: wbc_account_io() now checks whether the wbc is associated with a wb before dereferencing it. This can happen when pageout() is writing pages directly without going through the usual writeback path. As pageout() path is single-threaded, we don't want it to be blocked behind a slow cgroup and ultimately want it to delegate actual writing to the usual writeback path. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make writeback_control track the inode being written backTejun Heo2015-06-023-16/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, for cgroup writeback, the IO submission paths directly associate the bio's with the blkcg from inode_to_wb_blkcg_css(); however, it'd be necessary to keep more writeback context to implement foreign inode writeback detection. wbc (writeback_control) is the natural fit for the extra context - it persists throughout the writeback of each inode and is passed all the way down to IO submission paths. This patch adds wbc_attach_and_unlock_inode(), wbc_detach_inode(), and wbc_attach_fdatawrite_inode() which are used to associate wbc with the inode being written back. IO submission paths now use wbc_init_bio() instead of directly associating bio's with blkcg themselves. This leaves inode_to_wb_blkcg_css() w/o any user. The function is removed. wbc currently only tracks the associated wb (bdi_writeback). Future patches will add more for foreign inode detection. The association is established under i_lock which will be depended upon when migrating foreign inodes to other wb's. As currently, once established, inode to wb association never changes, going through wbc when initializing bio's doesn't cause any behavior changes. v2: submit_blk_blkcg() now checks whether the wbc is associated with a wb before dereferencing it. This can happen when pageout() is writing pages directly without going through the usual writeback path. As pageout() path is single-threaded, we don't want it to be blocked behind a slow cgroup and ultimately want it to delegate actual writing to the usual writeback path. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb()Tejun Heo2015-06-021-0/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, majority of cgroup writeback support including all the above functions are implemented in include/linux/backing-dev.h and mm/backing-dev.c; however, the portion closely related to writeback logic implemented in include/linux/writeback.h and mm/page-writeback.c will expand to support foreign writeback detection and correction. This patch moves wb[_try]_get() and wb_put() to include/linux/backing-dev-defs.h so that they can be used from writeback.h and inode_{attach|detach}_wb() to writeback.h and page-writeback.c. This is pure reorganization and doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: move over_bground_thresh() to mm/page-writeback.cTejun Heo2015-06-021-18/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | and rename it to wb_over_bg_thresh(). The function is closely tied to the dirty throttling mechanism implemented in page-writeback.c. This relocation will allow future updates necessary for cgroup writeback support. While at it, add function comment. This is pure reorganization and doesn't introduce any behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: move global_dirty_limit into wb_domainTejun Heo2015-06-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is a part of the series to define wb_domain which represents a domain that wb's (bdi_writeback's) belong to and are measured against each other in. This will enable IO backpressure propagation for cgroup writeback. global_dirty_limit exists to regulate the global dirty threshold which is a property of the wb_domain. This patch moves hard_dirty_limit, dirty_lock, and update_time into wb_domain. This is pure reorganization and doesn't introduce any behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: reorganize [__]wb_update_bandwidth()Tejun Heo2015-06-021-10/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __wb_update_bandwidth() is called from two places - fs/fs-writeback.c::balance_dirty_pages() and mm/page-writeback.c::wb_writeback(). The latter updates only the write bandwidth while the former also deals with the dirty ratelimit. The two callsites are distinguished by whether @thresh parameter is zero or not, which is cryptic. In addition, the two files define their own different versions of wb_update_bandwidth() on top of __wb_update_bandwidth(), which is confusing to say the least. This patch cleans up [__]wb_update_bandwidth() in the following ways. * __wb_update_bandwidth() now takes explicit @update_ratelimit parameter to gate dirty ratelimit handling. * mm/page-writeback.c::wb_update_bandwidth() is flattened into its caller - balance_dirty_pages(). * fs/fs-writeback.c::wb_update_bandwidth() is moved to mm/page-writeback.c and __wb_update_bandwidth() is made static. * While at it, add a lockdep assertion to __wb_update_bandwidth(). Except for the lockdep addition, this is pure reorganization and doesn't introduce any behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: clean up wb_dirty_limit()Tejun Heo2015-06-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The function name wb_dirty_limit(), its argument @dirty and the local variable @wb_dirty are mortally confusing given that the function calculates per-wb threshold value not dirty pages, especially given that @dirty and @wb_dirty are used elsewhere for dirty pages. Let's rename the function to wb_calc_thresh() and wb_dirty to wb_thresh. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | ext2: enable cgroup writeback supportTejun Heo2015-06-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Writeback now supports cgroup writeback and the generic writeback, buffer, libfs, and mpage helpers that ext2 uses are all updated to work with cgroup writeback. This patch enables cgroup writeback for ext2 by adding FS_CGROUP_WRITEBACK to its ->fs_flags. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: linux-ext4@vger.kernel.org Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | mpage: make __mpage_writepage() honor cgroup writebackTejun Heo2015-06-021-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __mpage_writepage() is used to implement mpage_writepages() which in turn is used for ->writepages() of various filesystems. All writeback logic is now updated to handle cgroup writeback and the block cgroup to issue IOs for is encoded in writeback_control and can be retrieved from the inode; however, __mpage_writepage() currently ignores the blkcg indicated by the inode and issues all bio's without explicit blkcg association. This patch updates __mpage_writepage() so that the issued bio's are associated with inode_to_writeback_blkcg_css(inode). v2: Updated for per-inode wb association. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | buffer, writeback: make __block_write_full_page() honor cgroup writebackTejun Heo2015-06-021-6/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [__]block_write_full_page() is used to implement ->writepage in various filesystems. All writeback logic is now updated to handle cgroup writeback and the block cgroup to issue IOs for is encoded in writeback_control and can be retrieved from the inode; however, [__]block_write_full_page() currently ignores the blkcg indicated by inode and issues all bio's without explicit blkcg association. This patch adds submit_bh_blkcg() which associates the bio with the specified blkio cgroup before issuing and uses it in __block_write_full_page() so that the issued bio's are associated with inode_to_wb_blkcg_css(inode). v2: Updated for per-inode wb association. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: dirty inodes against their matching cgroup bdi_writeback'sTejun Heo2015-06-021-12/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __mark_inode_dirty() always dirtied the inode against the root wb (bdi_writeback). The previous patches added all the infrastructure necessary to attribute an inode against the wb of the dirtying cgroup. This patch updates __mark_inode_dirty() so that it uses the wb associated with the inode instead of unconditionally using the root one. Currently, none of the filesystems has FS_CGROUP_WRITEBACK and all pages will keep being dirtied against the root wb. v2: Updated for per-inode wb association. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make writeback initiation functions handle multiple bdi_writeback'sTejun Heo2015-06-021-5/+91
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [try_]writeback_inodes_sb[_nr]() and sync_inodes_sb() currently only handle dirty inodes on the root wb (bdi_writeback) of the target bdi. This patch implements bdi_split_work_to_wbs() and use it to make these functions handle multiple wb's. bdi_split_work_to_wbs() takes a base wb_writeback_work and create clones of it and issue them to the wb's of the target bdi. The base work's nr_pages is distributed using wb_split_bdi_pages() - ie. according to each wb's write bandwidth's proportion in the bdi. Cloning a bdi involves memory allocation which may fail. In such cases, bdi_split_work_to_wbs() issues the base work directly and waits for its completion before proceeding to the next wb to guarantee forward progress and correctness under memory pressure. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: restructure try_writeback_inodes_sb[_nr]()Tejun Heo2015-06-021-23/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | try_writeback_inodes_sb_nr() wraps writeback_inodes_sb_nr() so that it handles s_umount locking and skips if writeback is already in progress. The in progress test is performed on the root wb (bdi_writeback) which isn't sufficient for cgroup writeback support. The test must be done per-wb. To prepare for the change, this patch factors out __writeback_inodes_sb_nr() from writeback_inodes_sb_nr() and adds @skip_if_busy and moves the in progress test right before queueing the wb_writeback_work. try_writeback_inodes_sb_nr() now just grabs s_umount and invokes __writeback_inodes_sb_nr() with asserted @skip_if_busy. This way, later addition of multiple wb handling can skip only the wb's which already have writeback in progress. This swaps the order between in progress test and s_umount test which can flip the return value when writeback is in progress and s_umount is being held by someone else but this shouldn't cause any meaningful difference. It's a fringe condition and the return value is an unsynchronized hint anyway. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: implement wb_wait_for_single_work()Tejun Heo2015-06-021-2/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For cgroup writeback, multiple wb_writeback_work items may need to be issuedto accomplish a single task. The previous patch updated the waiting mechanism such that wb_wait_for_completion() can wait for multiple work items. Issuing mulitple work items involves memory allocation which may fail. As most writeback operations can't fail or blocked on memory allocation, in such cases, we'll fall back to sequential issuing of an on-stack work item, which would need to be waited upon sequentially. This patch implements wb_wait_for_single_work() which waits for a single work item independently from wb_completion waiting so that such fallback mechanism can be used without getting tangled with the usual issuing / completion operation. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: implement bdi_wait_for_completion()Tejun Heo2015-06-021-12/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the completion of a wb_writeback_work can be waited upon by setting its ->done to a struct completion and waiting on it; however, for cgroup writeback support, it's necessary to issue multiple work items to multiple bdi_writebacks and wait for the completion of all. This patch implements wb_completion which can wait for multiple work items and replaces the struct completion with it. It can be defined using DEFINE_WB_COMPLETION_ONSTACK(), used for multiple work items and waited for by wb_wait_for_completion(). Nobody currently issues multiple work items and this patch doesn't introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: add wb_writeback_work->auto_freeTejun Heo2015-06-021-7/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, a wb_writeback_work is freed automatically on completion if it doesn't have ->done set. Add wb_writeback_work->auto_free to make the switch explicit. This will help cgroup writeback support where waiting for completion and whether to free automatically don't necessarily move together. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make wakeup_dirtytime_writeback() handle multiple bdi_writeback'sTejun Heo2015-06-021-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | wakeup_dirtytime_writeback() currently only starts writeback on the root wb (bdi_writeback). For cgroup writeback support, update the function to check all wbs. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make wakeup_flusher_threads() handle multiple bdi_writeback'sTejun Heo2015-06-021-2/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | wakeup_flusher_threads() currently only starts writeback on the root wb (bdi_writeback). For cgroup writeback support, update the function to wake up all wbs and distribute the number of pages to write according to the proportion of each wb's write bandwidth, which is implemented in wb_split_bdi_pages(). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make bdi_start_background_writeback() take bdi_writeback instead ↵Tejun Heo2015-06-021-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | of backing_dev_info bdi_start_background_writeback() currently takes @bdi and kicks the root wb (bdi_writeback). In preparation for cgroup writeback support, make it take wb instead. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make writeback_in_progress() take bdi_writeback instead of ↵Tejun Heo2015-06-021-14/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | backing_dev_info writeback_in_progress() currently takes @bdi and returns whether writeback is in progress on its root wb (bdi_writeback). In preparation for cgroup writeback support, make it take wb instead. While at it, make it an inline function. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>