linux/fs/ext4, branch v4.3

Merge branch 'akpm' (patches from Andrew)

2015-10-16T18:42:37Z

Merge misc fixes from Andrew Morton: "6 fixes" * emailed patches from Andrew Morton : sh: add copy_user_page() alias for __copy_user() lib/Kconfig: ZLIB_DEFLATE must select BITREVERSE mm, dax: fix DAX deadlocks memcg: convert threshold to bytes builddeb: remove debian/files before build mm, fs: obey gfp_mapping for add_to_page_cache()

mm, fs: obey gfp_mapping for add_to_page_cache()

2015-10-16T18:42:28Z

Commit 6afdb859b710 ("mm: do not ignore mapping_gfp_mask in page cache allocation paths") has caught some users of hardcoded GFP_KERNEL used in the page cache allocation paths. This, however, wasn't complete and there were others which went unnoticed. Dave Chinner has reported the following deadlock for xfs on loop device: : With the recent merge of the loop device changes, I'm now seeing : XFS deadlock on my single CPU, 1GB RAM VM running xfs/073. : : The deadlocked is as follows: : : kloopd1: loop_queue_read_work : xfs_file_iter_read : lock XFS inode XFS_IOLOCK_SHARED (on image file) : page cache read (GFP_KERNEL) : radix tree alloc : memory reclaim : reclaim XFS inodes : log force to unpin inodes : : : xfs-cil/loop1: : xlog_cil_push : xlog_write : : xlog_state_get_iclog_space() : : : : kloopd1: loop_queue_write_work : xfs_file_write_iter : lock XFS inode XFS_IOLOCK_EXCL (on image file) : : : i.e. the kloopd, with it's split read and write work queues, has : introduced a dependency through memory reclaim. i.e. that writes : need to be able to progress for reads make progress. : : The problem, fundamentally, is that mpage_readpages() does a : GFP_KERNEL allocation, rather than paying attention to the inode's : mapping gfp mask, which is set to GFP_NOFS. : : The didn't used to happen, because the loop device used to issue : reads through the splice path and that does: : : error = add_to_page_cache_lru(page, mapping, index, : GFP_KERNEL & mapping_gfp_mask(mapping)); This has changed by commit aa4d86163e4 ("block: loop: switch to VFS ITER_BVEC"). This patch changes mpage_readpage{s} to follow gfp mask set for the mapping. There are, however, other places which are doing basically the same. lustre:ll_dir_filler is doing GFP_KERNEL from the function which apparently uses GFP_NOFS for other allocations so let's make this consistent. cifs:readpages_get_pages is called from cifs_readpages and __cifs_readpages_from_fscache called from the same path obeys mapping gfp. ramfs_nommu_expand_for_mapping is hardcoding GFP_KERNEL as well regardless it uses mapping_gfp_mask for the page allocation. ext4_mpage_readpages is the called from the page cache allocation path same as read_pages and read_cache_pages As I've noticed in my previous post I cannot say I would be happy about sprinkling mapping_gfp_mask all over the place and it sounds like we should drop gfp_mask argument altogether and use it internally in __add_to_page_cache_locked that would require all the filesystems to use mapping gfp consistently which I am not sure is the case here. From a quick glance it seems that some file system use it all the time while others are selective. Signed-off-by: Michal Hocko Reported-by: Dave Chinner Cc: "Theodore Ts'o" Cc: Ming Lei Cc: Andreas Dilger Cc: Oleg Drokin Cc: Al Viro Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ext4: Update EXT4_USE_FOR_EXT2 description

2015-09-24T11:27:47Z

Configuration option EXT4_USE_FOR_EXT2 has no effect on ext3 support. Support for ext3 is always included now. Signed-off-by: Jean Delvare Fixes: c290ea01ab ("fs: Remove ext3 filesystem driver") Cc: Jan Kara Cc: Theodore Ts'o Cc: Andreas Dilger Signed-off-by: Jan Kara

ext4: start transaction before calling into DAX

2015-09-08T22:35:28Z

Jan Kara pointed out that in the case where we are writing to a hole, we can end up with a lock inversion between the page lock and the journal lock. We can avoid this by starting the transaction in ext4 before calling into DAX. The journal lock nests inside the superblock pagefault lock, so we have to duplicate that code from dax_fault, like XFS does. Signed-off-by: Matthew Wilcox Cc: Jan Kara Cc: Theodore Ts'o Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ext4: add ext4_get_block_dax()

2015-09-08T22:35:28Z

DAX wants different semantics from any currently-existing ext4 get_block callback. Unlike ext4_get_block_write(), it needs to honour the 'create' flag, and unlike ext4_get_block(), it needs to be able to return unwritten extents. So introduce a new ext4_get_block_dax() which has those semantics. We could also change ext4_get_block_write() to honour the 'create' flag, but that might have consequences on other users that I do not currently understand. Signed-off-by: Matthew Wilcox Cc: Theodore Ts'o Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ext4: use ext4_get_block_write() for DAX

2015-09-08T22:35:28Z

DAX relies on the get_block function either zeroing newly allocated blocks before they're findable by subsequent calls to get_block, or marking newly allocated blocks as unwritten. ext4_get_block() cannot create unwritten extents, but ext4_get_block_write() can. Signed-off-by: Matthew Wilcox Reported-by: Andy Rudoff Cc: Theodore Ts'o Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ext4: huge page fault support

2015-09-08T22:35:28Z

Use DAX to provide support for huge pages. Signed-off-by: Matthew Wilcox Cc: Hillf Danton Cc: "Kirill A. Shutemov" Cc: Theodore Ts'o Cc: Jan Kara Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

dax: move DAX-related functions to a new header

2015-09-08T22:35:28Z

In order to handle the !CONFIG_TRANSPARENT_HUGEPAGES case, we need to return VM_FAULT_FALLBACK from the inlined dax_pmd_fault(), which is defined in linux/mm.h. Given that we don't want to include in , the easiest solution is to move the DAX-related functions to a new header, . We could also have moved VM_FAULT_* definitions to a new header, or a different header that isn't quite such a boil-the-ocean header as , but this felt like the best option. Signed-off-by: Matthew Wilcox Cc: Hillf Danton Cc: "Kirill A. Shutemov" Cc: Theodore Ts'o Cc: Jan Kara Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fs: create and use seq_show_option for escaping

2015-09-04T23:54:41Z

Many file systems that implement the show_options hook fail to correctly escape their output which could lead to unescaped characters (e.g. new lines) leaking into /proc/mounts and /proc/[pid]/mountinfo files. This could lead to confusion, spoofed entries (resulting in things like systemd issuing false d-bus "mount" notifications), and who knows what else. This looks like it would only be the root user stepping on themselves, but it's possible weird things could happen in containers or in other situations with delegated mount privileges. Here's an example using overlay with setuid fusermount trusting the contents of /proc/mounts (via the /etc/mtab symlink). Imagine the use of "sudo" is something more sneaky: $ BASE="ovl" $ MNT="$BASE/mnt" $ LOW="$BASE/lower" $ UP="$BASE/upper" $ WORK="$BASE/work/ 0 0 none /proc fuse.pwn user_id=1000" $ mkdir -p "$LOW" "$UP" "$WORK" $ sudo mount -t overlay -o "lowerdir=$LOW,upperdir=$UP,workdir=$WORK" none /mnt $ cat /proc/mounts none /root/ovl/mnt overlay rw,relatime,lowerdir=ovl/lower,upperdir=ovl/upper,workdir=ovl/work/ 0 0 none /proc fuse.pwn user_id=1000 0 0 $ fusermount -u /proc $ cat /proc/mounts cat: /proc/mounts: No such file or directory This fixes the problem by adding new seq_show_option and seq_show_option_n helpers, and updating the vulnerable show_option handlers to use them as needed. Some, like SELinux, need to be open coded due to unusual existing escape mechanisms. [akpm@linux-foundation.org: add lost chunk, per Kees] [keescook@chromium.org: seq_show_option should be using const parameters] Signed-off-by: Kees Cook Acked-by: Serge Hallyn Acked-by: Jan Kara Acked-by: Paul Moore Cc: J. R. Okajima Signed-off-by: Kees Cook Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

2015-09-03T19:52:19Z

Pull ext4 updates from Ted Ts'o: "Pretty much all bug fixes and clean ups for 4.3, after a lot of features and other churn going into 4.2" * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: Revert "ext4: remove block_device_ejected" ext4: ratelimit the file system mounted message ext4: silence a format string false positive ext4: simplify some code in read_mmp_block() ext4: don't manipulate recovery flag when freezing no-journal fs jbd2: limit number of reserved credits ext4 crypto: remove duplicate header file ext4: update c/mtime on truncate up jbd2: avoid infinite loop when destroying aborted journal ext4, jbd2: add REQ_FUA flag when recording an error in the superblock ext4 crypto: fix spelling typo in comment ext4 crypto: exit cleanly if ext4_derive_key_aes() fails ext4: reject journal options for ext2 mounts ext4: implement cgroup writeback support ext4: replace ext4_io_submit->io_op with ->io_wbc ext4 crypto: check for too-short encrypted file names ext4 crypto: use a jbd2 transaction when adding a crypto policy jbd2: speedup jbd2_journal_dirty_metadata()