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* switch xattr_handler->set() to passing dentry and inode separatelyAl Viro2016-05-271-3/+4
| | | | | | | preparation for similar switch in ->setxattr() (see the next commit for rationale). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* tmpfs: mem_cgroup charge fault to vm_mm not current mmAndres Lagar-Cavilla2016-05-201-27/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | Although shmem_fault() has been careful to count a major fault to vm_mm, shmem_getpage_gfp() has been careless in charging a remote access fault to current->mm owner's memcg instead of to vma->vm_mm owner's memcg: that is inconsistent with all the mem_cgroup charging on remote access faults in mm/memory.c. Fix it by passing fault_mm along with fault_type to shmem_get_page_gfp(); but in that case, now knowing the right mm, it's better for it to handle the PGMAJFAULT updates itself. And let's keep this clutter out of most callers' way: change the common shmem_getpage() wrapper to hide fault_mm and fault_type as well as gfp. Signed-off-by: Andres Lagar-Cavilla <andreslc@google.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Yang Shi <yang.shi@linaro.org> Cc: Ning Qu <quning@gmail.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tmpfs: preliminary minor tidyupsHugh Dickins2016-05-201-43/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make a few cleanups in mm/shmem.c, before going on to complicate it. shmem_alloc_page() will become more complicated: we can't afford to to have that complication duplicated between a CONFIG_NUMA version and a !CONFIG_NUMA version, so rearrange the #ifdef'ery there to yield a single shmem_swapin() and a single shmem_alloc_page(). Yes, it's a shame to inflict the horrid pseudo-vma on non-NUMA configurations, but eliminating it is a larger cleanup: I have an alloc_pages_mpol() patchset not yet ready - mpol handling is subtle and bug-prone, and changed yet again since my last version. Move __SetPageLocked, __SetPageSwapBacked from shmem_getpage_gfp() to shmem_alloc_page(): that SwapBacked flag will be useful in future, to help to distinguish different cases appropriately. And the SGP_DIRTY variant of SGP_CACHE is hard to understand and of little use (IIRC it dates back to when shmem_getpage() returned the page unlocked): kill it and do the necessary in shmem_file_read_iter(). But an arm64 build then complained that info may be uninitialized (where shmem_getpage_gfp() deletes a freshly alloced page beyond eof), and advancing to an "sgp <= SGP_CACHE" test jogged it back to reality. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Yang Shi <yang.shi@linaro.org> Cc: Ning Qu <quning@gmail.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: use __SetPageSwapBacked and dont ClearPageSwapBackedHugh Dickins2016-05-201-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | v3.16 commit 07a427884348 ("mm: shmem: avoid atomic operation during shmem_getpage_gfp") rightly replaced one instance of SetPageSwapBacked by __SetPageSwapBacked, pointing out that the newly allocated page is not yet visible to other users (except speculative get_page_unless_zero- ers, who may not update page flags before their further checks). That was part of a series in which Mel was focused on tmpfs profiles: but almost all SetPageSwapBacked uses can be so optimized, with the same justification. Remove ClearPageSwapBacked from __read_swap_cache_async() error path: it's not an error to free a page with PG_swapbacked set. Follow a convention of __SetPageLocked, __SetPageSwapBacked instead of doing it differently in different places; but that's for tidiness - if the ordering actually mattered, we should not be using the __variants. There's probably scope for further __SetPageFlags in other places, but SwapBacked is the one I'm interested in at the moment. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Yang Shi <yang.shi@linaro.org> Cc: Ning Qu <quning@gmail.com> Reviewed-by: Mel Gorman <mgorman@techsingularity.net> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* parallel lookups machinery, part 2Al Viro2016-05-031-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We'll need to verify that there's neither a hashed nor in-lookup dentry with desired parent/name before adding to in-lookup set. One possible solution would be to hold the parent's ->d_lock through both checks, but while the in-lookup set is relatively small at any time, dcache is not. And holding the parent's ->d_lock through something like __d_lookup_rcu() would suck too badly. So we leave the parent's ->d_lock alone, which means that we watch out for the following scenario: * we verify that there's no hashed match * existing in-lookup match gets hashed by another process * we verify that there's no in-lookup matches and decide that everything's fine. Solution: per-directory kinda-sorta seqlock, bumped around the times we hash something that used to be in-lookup or move (and hash) something in place of in-lookup. Then the above would turn into * read the counter * do dcache lookup * if no matches found, check for in-lookup matches * if there had been none of those either, check if the counter has changed; repeat if it has. The "kinda-sorta" part is due to the fact that we don't have much spare space in inode. There is a spare word (shared with i_bdev/i_cdev/i_pipe), so the counter part is not a problem, but spinlock is a different story. We could use the parent's ->d_lock, and it would be less painful in terms of contention, for __d_add() it would be rather inconvenient to grab; we could do that (using lock_parent()), but... Fortunately, we can get serialization on the counter itself, and it might be a good idea in general; we can use cmpxchg() in a loop to get from even to odd and smp_store_release() from odd to even. This commit adds the counter and updating logics; the readers will be added in the next commit. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge getxattr prototype change into work.lookupsAl Viro2016-05-031-3/+3
|\ | | | | | | The rest of work.xattr stuff isn't needed for this branch
| * xattr_handler: pass dentry and inode as separate arguments of ->get()Al Viro2016-04-111-3/+3
| | | | | | | | | | | | ... and do not assume they are already attached to each other Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macrosKirill A. Shutemov2016-04-041-65/+65
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* radix-tree,shmem: introduce radix_tree_iter_next()Matthew Wilcox2016-03-171-9/+3
| | | | | | | | | | | | | | shmem likes to occasionally drop the lock, schedule, then reacqire the lock and continue with the iteration from the last place it left off. This is currently done with a pretty ugly goto. Introduce radix_tree_iter_next() and use it throughout shmem.c. [koct9i@gmail.com: fix bug in radix_tree_iter_next() for tagged iteration] Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: use radix_tree_iter_retry()Matthew Wilcox2016-03-171-11/+12
| | | | | | | | | | | | | | | Instead of a 'goto restart', we can now use radix_tree_iter_retry() to restart from our current position. This will make a difference when there are more ways to happen across an indirect pointer. And it eliminates some confusing gotos. [vbabka@suse.cz: remove now-obsolete-and-misleading comment] Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: convert printk(KERN_<LEVEL> to pr_<level>Joe Perches2016-03-171-8/+6
| | | | | | | | | | | | | | | | Most of the mm subsystem uses pr_<level> so make it consistent. Miscellanea: - Realign arguments - Add missing newline to format - kmemleak-test.c has a "kmemleak: " prefix added to the "Kmemleak testing" logging message via pr_fmt Signed-off-by: Joe Perches <joe@perches.com> Acked-by: Tejun Heo <tj@kernel.org> [percpu] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: migrate: do not touch page->mem_cgroup of live pagesJohannes Weiner2016-03-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Changing a page's memcg association complicates dealing with the page, so we want to limit this as much as possible. Page migration e.g. does not have to do that. Just like page cache replacement, it can forcibly charge a replacement page, and then uncharge the old page when it gets freed. Temporarily overcharging the cgroup by a single page is not an issue in practice, and charging is so cheap nowadays that this is much preferrable to the headache of messing with live pages. The only place that still changes the page->mem_cgroup binding of live pages is when pages move along with a task to another cgroup. But that path isolates the page from the LRU, takes the page lock, and the move lock (lock_page_memcg()). That means page->mem_cgroup is always stable in callers that have the page isolated from the LRU or locked. Lighter unlocked paths, like writeback accounting, can use lock_page_memcg(). [akpm@linux-foundation.org: fix build] [vdavydov@virtuozzo.com: fix lockdep splat] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* make sure that freeing shmem fast symlinks is RCU-delayedAl Viro2016-01-231-5/+4
| | | | | Cc: stable@vger.kernel.org # v4.2+ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* wrappers for ->i_mutex accessAl Viro2016-01-231-6/+6
| | | | | | | | | | | parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested}, inode_foo(inode) being mutex_foo(&inode->i_mutex). Please, use those for access to ->i_mutex; over the coming cycle ->i_mutex will become rwsem, with ->lookup() done with it held only shared. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* mm: memcontrol: charge swap to cgroup2Vladimir Davydov2016-01-211-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patchset introduces swap accounting to cgroup2. This patch (of 7): In the legacy hierarchy we charge memsw, which is dubious, because: - memsw.limit must be >= memory.limit, so it is impossible to limit swap usage less than memory usage. Taking into account the fact that the primary limiting mechanism in the unified hierarchy is memory.high while memory.limit is either left unset or set to a very large value, moving memsw.limit knob to the unified hierarchy would effectively make it impossible to limit swap usage according to the user preference. - memsw.usage != memory.usage + swap.usage, because a page occupying both swap entry and a swap cache page is charged only once to memsw counter. As a result, it is possible to effectively eat up to memory.limit of memory pages *and* memsw.limit of swap entries, which looks unexpected. That said, we should provide a different swap limiting mechanism for cgroup2. This patch adds mem_cgroup->swap counter, which charges the actual number of swap entries used by a cgroup. It is only charged in the unified hierarchy, while the legacy hierarchy memsw logic is left intact. The swap usage can be monitored using new memory.swap.current file and limited using memory.swap.max. Note, to charge swap resource properly in the unified hierarchy, we have to make swap_entry_free uncharge swap only when ->usage reaches zero, not just ->count, i.e. when all references to a swap entry, including the one taken by swap cache, are gone. This is necessary, because otherwise swap-in could result in uncharging swap even if the page is still in swap cache and hence still occupies a swap entry. At the same time, this shouldn't break memsw counter logic, where a page is never charged twice for using both memory and swap, because in case of legacy hierarchy we uncharge swap on commit (see mem_cgroup_commit_charge). Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: adjust to support new THP refcountingKirill A. Shutemov2016-01-161-9/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As with rmap, with new refcounting we cannot rely on PageTransHuge() to check if we need to charge size of huge page form the cgroup. We need to get information from caller to know whether it was mapped with PMD or PTE. We do uncharge when last reference on the page gone. At that point if we see PageTransHuge() it means we need to unchange whole huge page. The tricky part is partial unmap -- when we try to unmap part of huge page. We don't do a special handing of this situation, meaning we don't uncharge the part of huge page unless last user is gone or split_huge_page() is triggered. In case of cgroup memory pressure happens the partial unmapped page will be split through shrinker. This should be good enough. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* page-flags: define PG_locked behavior on compound pagesKirill A. Shutemov2016-01-161-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | lock_page() must operate on the whole compound page. It doesn't make much sense to lock part of compound page. Change code to use head page's PG_locked, if tail page is passed. This patch also gets rid of custom helper functions -- __set_page_locked() and __clear_page_locked(). They are replaced with helpers generated by __SETPAGEFLAG/__CLEARPAGEFLAG. Tail pages to these helper would trigger VM_BUG_ON(). SLUB uses PG_locked as a bit spin locked. IIUC, tail pages should never appear there. VM_BUG_ON() is added to make sure that this assumption is correct. [akpm@linux-foundation.org: fix fs/cifs/file.c] Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'akpm' (patches from Andrew)Linus Torvalds2016-01-151-1/+82
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge first patch-bomb from Andrew Morton: - A few hotfixes which missed 4.4 becasue I was asleep. cc'ed to -stable - A few misc fixes - OCFS2 updates - Part of MM. Including pretty large changes to page-flags handling and to thp management which have been buffered up for 2-3 cycles now. I have a lot of MM material this time. [ It turns out the THP part wasn't quite ready, so that got dropped from this series - Linus ] * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (117 commits) zsmalloc: reorganize struct size_class to pack 4 bytes hole mm/zbud.c: use list_last_entry() instead of list_tail_entry() zram/zcomp: do not zero out zcomp private pages zram: pass gfp from zcomp frontend to backend zram: try vmalloc() after kmalloc() zram/zcomp: use GFP_NOIO to allocate streams mm: add tracepoint for scanning pages drivers/base/memory.c: fix kernel warning during memory hotplug on ppc64 mm/page_isolation: use macro to judge the alignment mm: fix noisy sparse warning in LIBCFS_ALLOC_PRE() mm: rework virtual memory accounting include/linux/memblock.h: fix ordering of 'flags' argument in comments mm: move lru_to_page to mm_inline.h Documentation/filesystems: describe the shared memory usage/accounting memory-hotplug: don't BUG() in register_memory_resource() hugetlb: make mm and fs code explicitly non-modular mm/swapfile.c: use list_for_each_entry_safe in free_swap_count_continuations mm: /proc/pid/clear_refs: no need to clear VM_SOFTDIRTY in clear_soft_dirty_pmd() mm: make sure isolate_lru_page() is never called for tail page vmstat: make vmstat_updater deferrable again and shut down on idle ...
| * mm, proc: reduce cost of /proc/pid/smaps for unpopulated shmem mappingsVlastimil Babka2016-01-151-27/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Following the previous patch, further reduction of /proc/pid/smaps cost is possible for private writable shmem mappings with unpopulated areas where the page walk invokes the .pte_hole function. We can use radix tree iterator for each such area instead of calling find_get_entry() in a loop. This is possible at the extra maintenance cost of introducing another shmem function shmem_partial_swap_usage(). To demonstrate the diference, I have measured this on a process that creates a private writable 2GB mapping of a partially swapped out /dev/shm/file (which cannot employ the optimizations from the prvious patch) and doesn't populate it at all. I time how long does it take to cat /proc/pid/smaps of this process 100 times. Before this patch: real 0m3.831s user 0m0.180s sys 0m3.212s After this patch: real 0m1.176s user 0m0.180s sys 0m0.684s The time is similar to the case where a radix tree iterator is employed on the whole mapping. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * mm, proc: reduce cost of /proc/pid/smaps for shmem mappingsVlastimil Babka2016-01-151-0/+70
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The previous patch has improved swap accounting for shmem mapping, which however made /proc/pid/smaps more expensive for shmem mappings, as we consult the radix tree for each pte_none entry, so the overal complexity is O(n*log(n)). We can reduce this significantly for mappings that cannot contain COWed pages, because then we can either use the statistics tha shmem object itself tracks (if the mapping contains the whole object, or the swap usage of the whole object is zero), or use the radix tree iterator, which is much more effective than repeated find_get_entry() calls. This patch therefore introduces a function shmem_swap_usage(vma) and makes /proc/pid/smaps use it when possible. Only for writable private mappings of shmem objects (i.e. tmpfs files) with the shmem object itself (partially) swapped outwe have to resort to the find_get_entry() approach. Hopefully such mappings are relatively uncommon. To demonstrate the diference, I have measured this on a process that creates a 2GB mapping and dirties single pages with a stride of 2MB, and time how long does it take to cat /proc/pid/smaps of this process 100 times. Private writable mapping of a /dev/shm/file (the most complex case): real 0m3.831s user 0m0.180s sys 0m3.212s Shared mapping of an almost full mapping of a partially swapped /dev/shm/file (which needs to employ the radix tree iterator). real 0m1.351s user 0m0.096s sys 0m0.768s Same, but with /dev/shm/file not swapped (so no radix tree walk needed) real 0m0.935s user 0m0.128s sys 0m0.344s Private anonymous mapping: real 0m0.949s user 0m0.116s sys 0m0.348s The cost is now much closer to the private anonymous mapping case, unless the shmem mapping is private and writable. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * kmemcg: account certain kmem allocations to memcgVladimir Davydov2016-01-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mark those kmem allocations that are known to be easily triggered from userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to memcg. For the list, see below: - threadinfo - task_struct - task_delay_info - pid - cred - mm_struct - vm_area_struct and vm_region (nommu) - anon_vma and anon_vma_chain - signal_struct - sighand_struct - fs_struct - files_struct - fdtable and fdtable->full_fds_bits - dentry and external_name - inode for all filesystems. This is the most tedious part, because most filesystems overwrite the alloc_inode method. The list is far from complete, so feel free to add more objects. Nevertheless, it should be close to "account everything" approach and keep most workloads within bounds. Malevolent users will be able to breach the limit, but this was possible even with the former "account everything" approach (simply because it did not account everything in fact). [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tejun Heo <tj@kernel.org> Cc: Greg Thelen <gthelen@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Make sure that highmem pages are not added to symlink page cacheAl Viro2016-01-141-1/+1
|/ | | | | | | | | | | | | inode_nohighmem() is sufficient to make sure that page_get_link() won't try to allocate a highmem page. Moreover, it is sufficient to make sure that page_symlink/__page_symlink won't do the same thing. However, any filesystem that manually preseeds the symlink's page cache upon symlink(2) needs to make sure that the page it inserts there won't be a highmem one. Fortunately, only nfs and shmem have run afoul of that... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'work.xattr' of ↵Linus Torvalds2016-01-111-90/+43
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs xattr updates from Al Viro: "Andreas' xattr cleanup series. It's a followup to his xattr work that went in last cycle; -0.5KLoC" * 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: xattr handlers: Simplify list operation ocfs2: Replace list xattr handler operations nfs: Move call to security_inode_listsecurity into nfs_listxattr xfs: Change how listxattr generates synthetic attributes tmpfs: listxattr should include POSIX ACL xattrs tmpfs: Use xattr handler infrastructure btrfs: Use xattr handler infrastructure vfs: Distinguish between full xattr names and proper prefixes posix acls: Remove duplicate xattr name definitions gfs2: Remove gfs2_xattr_acl_chmod vfs: Remove vfs_xattr_cmp
| * tmpfs: listxattr should include POSIX ACL xattrsAndreas Gruenbacher2015-12-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | When a file on tmpfs has an ACL or a Default ACL, listxattr should include the corresponding xattr name. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Reviewed-by: James Morris <james.l.morris@oracle.com> Cc: Hugh Dickins <hughd@google.com> Cc: linux-mm@kvack.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * tmpfs: Use xattr handler infrastructureAndreas Gruenbacher2015-12-071-89/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | Use the VFS xattr handler infrastructure and get rid of similar code in the filesystem. For implementing shmem_xattr_handler_set, we need a version of simple_xattr_set which removes the attribute when value is NULL. Use this to implement kernfs_iop_removexattr as well. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Reviewed-by: James Morris <james.l.morris@oracle.com> Cc: Hugh Dickins <hughd@google.com> Cc: linux-mm@kvack.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'work.symlinks' of ↵Linus Torvalds2016-01-111-20/+28
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs RCU symlink updates from Al Viro: "Replacement of ->follow_link/->put_link, allowing to stay in RCU mode even if the symlink is not an embedded one. No changes since the mailbomb on Jan 1" * 'work.symlinks' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: switch ->get_link() to delayed_call, kill ->put_link() kill free_page_put_link() teach nfs_get_link() to work in RCU mode teach proc_self_get_link()/proc_thread_self_get_link() to work in RCU mode teach shmem_get_link() to work in RCU mode teach page_get_link() to work in RCU mode replace ->follow_link() with new method that could stay in RCU mode don't put symlink bodies in pagecache into highmem namei: page_getlink() and page_follow_link_light() are the same thing ufs: get rid of ->setattr() for symlinks udf: don't duplicate page_symlink_inode_operations logfs: don't duplicate page_symlink_inode_operations switch befs long symlinks to page_symlink_operations
| * | switch ->get_link() to delayed_call, kill ->put_link()Al Viro2015-12-301-10/+9
| | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | teach shmem_get_link() to work in RCU modeAl Viro2015-12-091-6/+14
| | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | replace ->follow_link() with new method that could stay in RCU modeAl Viro2015-12-091-4/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | new method: ->get_link(); replacement of ->follow_link(). The differences are: * inode and dentry are passed separately * might be called both in RCU and non-RCU mode; the former is indicated by passing it a NULL dentry. * when called that way it isn't allowed to block and should return ERR_PTR(-ECHILD) if it needs to be called in non-RCU mode. It's a flagday change - the old method is gone, all in-tree instances converted. Conversion isn't hard; said that, so far very few instances do not immediately bail out when called in RCU mode. That'll change in the next commits. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | don't put symlink bodies in pagecache into highmemAl Viro2015-12-091-6/+3
| |/ | | | | | | | | | | | | | | | | | | | | | | kmap() in page_follow_link_light() needed to go - allowing to hold an arbitrary number of kmaps for long is a great way to deadlocking the system. new helper (inode_nohighmem(inode)) needs to be used for pagecache symlinks inodes; done for all in-tree cases. page_follow_link_light() instrumented to yell about anything missed. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* / tmpfs: fix shmem_evict_inode() warnings on i_blocksHugh Dickins2015-12-121-20/+14
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dmitry Vyukov provides a little program, autogenerated by syzkaller, which races a fault on a mapping of a sparse memfd object, against truncation of that object below the fault address: run repeatedly for a few minutes, it reliably generates shmem_evict_inode()'s WARN_ON(inode->i_blocks). (But there's nothing specific to memfd here, nor to the fstat which it happened to use to generate the fault: though that looked suspicious, since a shmem_recalc_inode() had been added there recently. The same problem can be reproduced with open+unlink in place of memfd_create, and with fstatfs in place of fstat.) v3.7 commit 0f3c42f522dc ("tmpfs: change final i_blocks BUG to WARNING") explains one cause of such a warning (a race with shmem_writepage to swap), and possible solutions; but we never took it further, and this syzkaller incident turns out to have a different cause. shmem_getpage_gfp()'s error recovery, when a freshly allocated page is then found to be beyond eof, looks plausible - decrementing the alloced count that was just before incremented - but in fact can go wrong, if a racing thread (the truncator, for example) gets its shmem_recalc_inode() in just after our delete_from_page_cache(). delete_from_page_cache() decrements nrpages, that shmem_recalc_inode() will balance the books by decrementing alloced itself, then our decrement of alloced take it one too low: leading to the WARNING when the object is finally evicted. Once the new page has been exposed in the page cache, shmem_getpage_gfp() must leave it to shmem_recalc_inode() itself to get the accounting right in all cases (and not fall through from "trunc:" to "decused:"). Adjust that error recovery block; and the reinitialization of info and sbinfo can be removed too. While we're here, fix shmem_writepage() to avoid the original issue: it will be safe against a racing shmem_recalc_inode(), if it merely increments swapped before the shmem_delete_from_page_cache() which decrements nrpages (but it must then do its own shmem_recalc_inode() before that, while still in balance, instead of after). (Aside: why do we shmem_recalc_inode() here in the swap path? Because its raison d'etre is to cope with clean sparse shmem pages being reclaimed behind our back: so here when swapping is a good place to look for that case.) But I've not now managed to reproduce this bug, even without the patch. I don't see why I didn't do that earlier: perhaps inhibited by the preference to eliminate shmem_recalc_inode() altogether. Driven by this incident, I do now have a patch to do so at last; but still want to sit on it for a bit, there's a couple of questions yet to be resolved. Signed-off-by: Hugh Dickins <hughd@google.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: page_alloc: hide some GFP internals and document the bits and flag ↵Mel Gorman2015-11-071-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | combinations Andrew stated the following We have quite a history of remote parts of the kernel using weird/wrong/inexplicable combinations of __GFP_ flags. I tend to think that this is because we didn't adequately explain the interface. And I don't think that gfp.h really improved much in this area as a result of this patchset. Could you go through it some time and decide if we've adequately documented all this stuff? This patches first moves some GFP flag combinations that are part of the MM internals to mm/internal.h. The rest of the patch documents the __GFP_FOO bits under various headings and then documents the flag combinations. It will not help callers that are brain damaged but the clarity might motivate some fixes and avoid future mistakes. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tmpfs: avoid a little creat and stat slowdownHugh Dickins2015-11-061-8/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | LKP reports that v4.2 commit afa2db2fb6f1 ("tmpfs: truncate prealloc blocks past i_size") causes a 14.5% slowdown in the AIM9 creat-clo benchmark. creat-clo does just what you'd expect from the name, and creat's O_TRUNC on 0-length file does indeed get into more overhead now shmem_setattr() tests "0 <= 0" instead of "0 < 0". I'm not sure how much we care, but I think it would not be too VW-like to add in a check for whether any pages (or swap) are allocated: if none are allocated, there's none to remove from the radix_tree. At first I thought that check would be good enough for the unmaps too, but no: we should not skip the unlikely case of unmapping pages beyond the new EOF, which were COWed from holes which have now been reclaimed, leaving none. This gives me an 8.5% speedup: on Haswell instead of LKP's Westmere, and running a debug config before and after: I hope those account for the lesser speedup. And probably someone has a benchmark where a thousand threads keep on stat'ing the same file repeatedly: forestall that report by adjusting v4.3 commit 44a30220bc0a ("shmem: recalculate file inode when fstat") not to take the spinlock in shmem_getattr() when there's no work to do. Signed-off-by: Hugh Dickins <hughd@google.com> Reported-by: Ying Huang <ying.huang@linux.intel.com> Tested-by: Ying Huang <ying.huang@linux.intel.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: rename mem_cgroup_migrate to mem_cgroup_replace_pageHugh Dickins2015-11-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | After v4.3's commit 0610c25daa3e ("memcg: fix dirty page migration") mem_cgroup_migrate() doesn't have much to offer in page migration: convert migrate_misplaced_transhuge_page() to set_page_memcg() instead. Then rename mem_cgroup_migrate() to mem_cgroup_replace_page(), since its remaining callers are replace_page_cache_page() and shmem_replace_page(): both of whom passed lrucare true, so just eliminate that argument. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* shmem: recalculate file inode when fstatYu Zhao2015-09-091-0/+16
| | | | | | | | | | | | | | | | | | | | Shmem uses shmem_recalc_inode to update i_blocks when it allocates page, undoes range or swaps. But mm can drop clean page without notifying shmem. This makes fstat sometimes return out-of-date block size. The problem can be partially solved when we add inode_operations->getattr which calls shmem_recalc_inode to update i_blocks for fstat. shmem_recalc_inode also updates counter used by statfs and vm_committed_as. For them the situation is not changed. They still suffer from the discrepancy after dropping clean page and before the function is called by aforementioned triggers. Signed-off-by: Yu Zhao <yuzhao@google.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: use private shmem or hugetlbfs inodes for shm segments.Stephen Smalley2015-08-071-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The shm implementation internally uses shmem or hugetlbfs inodes for shm segments. As these inodes are never directly exposed to userspace and only accessed through the shm operations which are already hooked by security modules, mark the inodes with the S_PRIVATE flag so that inode security initialization and permission checking is skipped. This was motivated by the following lockdep warning: ====================================================== [ INFO: possible circular locking dependency detected ] 4.2.0-0.rc3.git0.1.fc24.x86_64+debug #1 Tainted: G W ------------------------------------------------------- httpd/1597 is trying to acquire lock: (&ids->rwsem){+++++.}, at: shm_close+0x34/0x130 but task is already holding lock: (&mm->mmap_sem){++++++}, at: SyS_shmdt+0x4b/0x180 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&mm->mmap_sem){++++++}: lock_acquire+0xc7/0x270 __might_fault+0x7a/0xa0 filldir+0x9e/0x130 xfs_dir2_block_getdents.isra.12+0x198/0x1c0 [xfs] xfs_readdir+0x1b4/0x330 [xfs] xfs_file_readdir+0x2b/0x30 [xfs] iterate_dir+0x97/0x130 SyS_getdents+0x91/0x120 entry_SYSCALL_64_fastpath+0x12/0x76 -> #2 (&xfs_dir_ilock_class){++++.+}: lock_acquire+0xc7/0x270 down_read_nested+0x57/0xa0 xfs_ilock+0x167/0x350 [xfs] xfs_ilock_attr_map_shared+0x38/0x50 [xfs] xfs_attr_get+0xbd/0x190 [xfs] xfs_xattr_get+0x3d/0x70 [xfs] generic_getxattr+0x4f/0x70 inode_doinit_with_dentry+0x162/0x670 sb_finish_set_opts+0xd9/0x230 selinux_set_mnt_opts+0x35c/0x660 superblock_doinit+0x77/0xf0 delayed_superblock_init+0x10/0x20 iterate_supers+0xb3/0x110 selinux_complete_init+0x2f/0x40 security_load_policy+0x103/0x600 sel_write_load+0xc1/0x750 __vfs_write+0x37/0x100 vfs_write+0xa9/0x1a0 SyS_write+0x58/0xd0 entry_SYSCALL_64_fastpath+0x12/0x76 ... Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Reported-by: Morten Stevens <mstevens@fedoraproject.org> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Eric Paris <eparis@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tmpfs: truncate prealloc blocks past i_sizeJosef Bacik2015-06-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | One of the rocksdb people noticed that when you do something like this fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, 10M) pwrite(fd, buf, 5M, 0) ftruncate(5M) on tmpfs, the file would still take up 10M: which led to super fun issues because we were getting ENOSPC before we thought we should be getting ENOSPC. This patch fixes the problem, and mirrors what all the other fs'es do (and was agreed to be the correct behaviour at LSF). I tested it locally to make sure it worked properly with the following xfs_io -f -c "falloc -k 0 10M" -c "pwrite 0 5M" -c "truncate 5M" file Without the patch we have "Blocks: 20480", with the patch we have the correct value of "Blocks: 10240". Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus-1' of ↵Linus Torvalds2015-06-221-19/+13
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs updates from Al Viro: "In this pile: pathname resolution rewrite. - recursion in link_path_walk() is gone. - nesting limits on symlinks are gone (the only limit remaining is that the total amount of symlinks is no more than 40, no matter how nested). - "fast" (inline) symlinks are handled without leaving rcuwalk mode. - stack footprint (independent of the nesting) is below kilobyte now, about on par with what it used to be with one level of nested symlinks and ~2.8 times lower than it used to be in the worst case. - struct nameidata is entirely private to fs/namei.c now (not even opaque pointers are being passed around). - ->follow_link() and ->put_link() calling conventions had been changed; all in-tree filesystems converted, out-of-tree should be able to follow reasonably easily. For out-of-tree conversions, see Documentation/filesystems/porting for details (and in-tree filesystems for examples of conversion). That has sat in -next since mid-May, seems to survive all testing without regressions and merges clean with v4.1" * 'for-linus-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (131 commits) turn user_{path_at,path,lpath,path_dir}() into static inlines namei: move saved_nd pointer into struct nameidata inline user_path_create() inline user_path_parent() namei: trim do_last() arguments namei: stash dfd and name into nameidata namei: fold path_cleanup() into terminate_walk() namei: saner calling conventions for filename_parentat() namei: saner calling conventions for filename_create() namei: shift nameidata down into filename_parentat() namei: make filename_lookup() reject ERR_PTR() passed as name namei: shift nameidata inside filename_lookup() namei: move putname() call into filename_lookup() namei: pass the struct path to store the result down into path_lookupat() namei: uninline set_root{,_rcu}() namei: be careful with mountpoint crossings in follow_dotdot_rcu() Documentation: remove outdated information from automount-support.txt get rid of assorted nameidata-related debris lustre: kill unused helper lustre: kill unused macro (LOOKUP_CONTINUE) ...
| * switch ->put_link() from dentry to inodeAl Viro2015-05-111-1/+1
| | | | | | | | | | | | | | only one instance looks at that argument at all; that sole exception wants inode rather than dentry. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * don't pass nameidata to ->follow_link()Al Viro2015-05-111-1/+1
| | | | | | | | | | | | | | its only use is getting passed to nd_jump_link(), which can obtain it from current->nameidata Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * new ->follow_link() and ->put_link() calling conventionsAl Viro2015-05-111-12/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | a) instead of storing the symlink body (via nd_set_link()) and returning an opaque pointer later passed to ->put_link(), ->follow_link() _stores_ that opaque pointer (into void * passed by address by caller) and returns the symlink body. Returning ERR_PTR() on error, NULL on jump (procfs magic symlinks) and pointer to symlink body for normal symlinks. Stored pointer is ignored in all cases except the last one. Storing NULL for opaque pointer (or not storing it at all) means no call of ->put_link(). b) the body used to be passed to ->put_link() implicitly (via nameidata). Now only the opaque pointer is. In the cases when we used the symlink body to free stuff, ->follow_link() now should store it as opaque pointer in addition to returning it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * shmem: switch to simple_follow_link()Al Viro2015-05-111-7/+2
| | | | | | | | | | Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | mm: shmem_zero_setup skip security check and lockdep conflict with XFSHugh Dickins2015-06-181-1/+7
|/ | | | | | | | | | | | | | | | | | | | | | | It appears that, at some point last year, XFS made directory handling changes which bring it into lockdep conflict with shmem_zero_setup(): it is surprising that mmap() can clone an inode while holding mmap_sem, but that has been so for many years. Since those few lockdep traces that I've seen all implicated selinux, I'm hoping that we can use the __shmem_file_setup(,,,S_PRIVATE) which v3.13's commit c7277090927a ("security: shmem: implement kernel private shmem inodes") introduced to avoid LSM checks on kernel-internal inodes: the mmap("/dev/zero") cloned inode is indeed a kernel-internal detail. This also covers the !CONFIG_SHMEM use of ramfs to support /dev/zero (and MAP_SHARED|MAP_ANONYMOUS). I thought there were also drivers which cloned inode in mmap(), but if so, I cannot locate them now. Reported-and-tested-by: Prarit Bhargava <prarit@redhat.com> Reported-and-tested-by: Daniel Wagner <wagi@monom.org> Reported-and-tested-by: Morten Stevens <mstevens@fedoraproject.org> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* VFS: assorted weird filesystems: d_inode() annotationsDavid Howells2015-04-151-15/+15
| | | | | Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* make new_sync_{read,write}() staticAl Viro2015-04-121-2/+0
| | | | | | | | All places outside of core VFS that checked ->read and ->write for being NULL or called the methods directly are gone now, so NULL {read,write} with non-NULL {read,write}_iter will do the right thing in all cases. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'iocb' into for-nextAl Viro2015-04-121-1/+1
|\
| * fs: move struct kiocb to fs.hChristoph Hellwig2015-03-261-1/+1
| | | | | | | | | | | | | | | | struct kiocb now is a generic I/O container, so move it to fs.h. Also do a #include diet for aio.h while we're at it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | mm: shmem: check for mapping owner before dereferencingSasha Levin2015-02-231-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | mapping->host can be NULL and shouldn't be dereferenced before being checked. [ 1295.741844] GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] SMP KASAN [ 1295.746387] Dumping ftrace buffer: [ 1295.748217] (ftrace buffer empty) [ 1295.749527] Modules linked in: [ 1295.750268] CPU: 62 PID: 23410 Comm: trinity-c70 Not tainted 3.19.0-next-20150219-sasha-00045-g9130270f #1939 [ 1295.750268] task: ffff8803a49db000 ti: ffff8803a4dc8000 task.ti: ffff8803a4dc8000 [ 1295.750268] RIP: shmem_mapping (mm/shmem.c:1458) [ 1295.750268] RSP: 0000:ffff8803a4dcfbf8 EFLAGS: 00010206 [ 1295.750268] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 00000000000f2804 [ 1295.750268] RDX: 0000000000000005 RSI: 0400000000000794 RDI: 0000000000000028 [ 1295.750268] RBP: ffff8803a4dcfc08 R08: 0000000000000000 R09: 00000000031de000 [ 1295.750268] R10: dffffc0000000000 R11: 00000000031c1000 R12: 0400000000000794 [ 1295.750268] R13: 00000000031c2000 R14: 00000000031de000 R15: ffff880e3bdc1000 [ 1295.750268] FS: 00007f8703c7e700(0000) GS:ffff881164800000(0000) knlGS:0000000000000000 [ 1295.750268] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1295.750268] CR2: 0000000004e58000 CR3: 00000003a9f3c000 CR4: 00000000000007a0 [ 1295.750268] DR0: ffffffff81000000 DR1: 0000009494949494 DR2: 0000000000000000 [ 1295.750268] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 00000000000d0602 [ 1295.750268] Stack: [ 1295.750268] ffff8803a4dcfec8 ffffffffbb1dc770 ffff8803a4dcfc38 ffffffffad6f230b [ 1295.750268] ffffffffad6f2b0d 0000014100000000 ffff88001e17c08b ffff880d9453fe08 [ 1295.750268] ffff8803a4dcfd18 ffffffffad6f2ce2 ffff8803a49dbcd8 ffff8803a49dbce0 [ 1295.750268] Call Trace: [ 1295.750268] mincore_page (mm/mincore.c:61) [ 1295.750268] ? mincore_pte_range (include/linux/spinlock.h:312 mm/mincore.c:131) [ 1295.750268] mincore_pte_range (mm/mincore.c:151) [ 1295.750268] ? mincore_unmapped_range (mm/mincore.c:113) [ 1295.750268] __walk_page_range (mm/pagewalk.c:51 mm/pagewalk.c:90 mm/pagewalk.c:116 mm/pagewalk.c:204) [ 1295.750268] walk_page_range (mm/pagewalk.c:275) [ 1295.750268] SyS_mincore (mm/mincore.c:191 mm/mincore.c:253 mm/mincore.c:220) [ 1295.750268] ? mincore_pte_range (mm/mincore.c:220) [ 1295.750268] ? mincore_unmapped_range (mm/mincore.c:113) [ 1295.750268] ? __mincore_unmapped_range (mm/mincore.c:105) [ 1295.750268] ? ptlock_free (mm/mincore.c:24) [ 1295.750268] ? syscall_trace_enter (arch/x86/kernel/ptrace.c:1610) [ 1295.750268] ia32_do_call (arch/x86/ia32/ia32entry.S:446) [ 1295.750268] Code: e5 48 c1 ea 03 53 48 89 fb 48 83 ec 08 80 3c 02 00 75 4f 48 b8 00 00 00 00 00 fc ff df 48 8b 1b 48 8d 7b 28 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 3f 48 b8 00 00 00 00 00 fc ff df 48 8b 5b 28 48 All code ======== 0: e5 48 in $0x48,%eax 2: c1 ea 03 shr $0x3,%edx 5: 53 push %rbx 6: 48 89 fb mov %rdi,%rbx 9: 48 83 ec 08 sub $0x8,%rsp d: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) 11: 75 4f jne 0x62 13: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 1a: fc ff df 1d: 48 8b 1b mov (%rbx),%rbx 20: 48 8d 7b 28 lea 0x28(%rbx),%rdi 24: 48 89 fa mov %rdi,%rdx 27: 48 c1 ea 03 shr $0x3,%rdx 2b:* 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction 2f: 75 3f jne 0x70 31: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 38: fc ff df 3b: 48 8b 5b 28 mov 0x28(%rbx),%rbx 3f: 48 rex.W ... Code starting with the faulting instruction =========================================== 0: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) 4: 75 3f jne 0x45 6: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax d: fc ff df 10: 48 8b 5b 28 mov 0x28(%rbx),%rbx 14: 48 rex.W ... [ 1295.750268] RIP shmem_mapping (mm/shmem.c:1458) [ 1295.750268] RSP <ffff8803a4dcfbf8> Fixes: 97b713ba3e ("fs: kill BDI_CAP_SWAP_BACKED") Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* | VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry)David Howells2015-02-221-2/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert the following where appropriate: (1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry). (2) S_ISREG(dentry->d_inode) to d_is_reg(dentry). (3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry). This is actually more complicated than it appears as some calls should be converted to d_can_lookup() instead. The difference is whether the directory in question is a real dir with a ->lookup op or whether it's a fake dir with a ->d_automount op. In some circumstances, we can subsume checks for dentry->d_inode not being NULL into this, provided we the code isn't in a filesystem that expects d_inode to be NULL if the dirent really *is* negative (ie. if we're going to use d_inode() rather than d_backing_inode() to get the inode pointer). Note that the dentry type field may be set to something other than DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS manages the fall-through from a negative dentry to a lower layer. In such a case, the dentry type of the negative union dentry is set to the same as the type of the lower dentry. However, if you know d_inode is not NULL at the call site, then you can use the d_is_xxx() functions even in a filesystem. There is one further complication: a 0,0 chardev dentry may be labelled DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE. Strictly, this was intended for special directory entry types that don't have attached inodes. The following perl+coccinelle script was used: use strict; my @callers; open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') || die "Can't grep for S_ISDIR and co. callers"; @callers = <$fd>; close($fd); unless (@callers) { print "No matches\n"; exit(0); } my @cocci = ( '@@', 'expression E;', '@@', '', '- S_ISLNK(E->d_inode->i_mode)', '+ d_is_symlink(E)', '', '@@', 'expression E;', '@@', '', '- S_ISDIR(E->d_inode->i_mode)', '+ d_is_dir(E)', '', '@@', 'expression E;', '@@', '', '- S_ISREG(E->d_inode->i_mode)', '+ d_is_reg(E)' ); my $coccifile = "tmp.sp.cocci"; open($fd, ">$coccifile") || die $coccifile; print($fd "$_\n") || die $coccifile foreach (@cocci); close($fd); foreach my $file (@callers) { chomp $file; print "Processing ", $file, "\n"; system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 || die "spatch failed"; } [AV: overlayfs parts skipped] Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-3.20/bdi' of git://git.kernel.dk/linux-blockLinus Torvalds2015-02-121-18/+6
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull backing device changes from Jens Axboe: "This contains a cleanup of how the backing device is handled, in preparation for a rework of the life time rules. In this part, the most important change is to split the unrelated nommu mmap flags from it, but also removing a backing_dev_info pointer from the address_space (and inode), and a cleanup of other various minor bits. Christoph did all the work here, I just fixed an oops with pages that have a swap backing. Arnd fixed a missing export, and Oleg killed the lustre backing_dev_info from staging. Last patch was from Al, unexporting parts that are now no longer needed outside" * 'for-3.20/bdi' of git://git.kernel.dk/linux-block: Make super_blocks and sb_lock static mtd: export new mtd_mmap_capabilities fs: make inode_to_bdi() handle NULL inode staging/lustre/llite: get rid of backing_dev_info fs: remove default_backing_dev_info fs: don't reassign dirty inodes to default_backing_dev_info nfs: don't call bdi_unregister ceph: remove call to bdi_unregister fs: remove mapping->backing_dev_info fs: export inode_to_bdi and use it in favor of mapping->backing_dev_info nilfs2: set up s_bdi like the generic mount_bdev code block_dev: get bdev inode bdi directly from the block device block_dev: only write bdev inode on close fs: introduce f_op->mmap_capabilities for nommu mmap support fs: kill BDI_CAP_SWAP_BACKED fs: deduplicate noop_backing_dev_info
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-26 19:01:40 +0100