1. 27 5月, 2016 1 次提交
    • C
      Btrfs: fix handling of faults from btrfs_copy_from_user · 56244ef1
      Chris Mason 提交于
      When btrfs_copy_from_user isn't able to copy all of the pages, we need
      to adjust our accounting to reflect the work that was actually done.
      
      Commit 2e78c927 changed around the decisions a little and we ended up
      skipping the accounting adjustments some of the time.  This commit makes
      sure that when we don't copy anything at all, we still hop into
      the adjustments, and switches to release_bytes instead of write_bytes,
      since write_bytes isn't aligned.
      
      The accounting errors led to warnings during btrfs_destroy_inode:
      
      [   70.847532] WARNING: CPU: 10 PID: 514 at fs/btrfs/inode.c:9350 btrfs_destroy_inode+0x2b3/0x2c0
      [   70.847536] Modules linked in: i2c_piix4 virtio_net i2c_core input_leds button led_class serio_raw acpi_cpufreq sch_fq_codel autofs4 virtio_blk
      [   70.847538] CPU: 10 PID: 514 Comm: umount Tainted: G        W 4.6.0-rc6_00062_g2997da1-dirty #23
      [   70.847539] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.0-1.fc24 04/01/2014
      [   70.847542]  0000000000000000 ffff880ff5cafab8 ffffffff8149d5e9 0000000000000202
      [   70.847543]  0000000000000000 0000000000000000 0000000000000000 ffff880ff5cafb08
      [   70.847547]  ffffffff8107bdfd ffff880ff5cafaf8 000024868120013d ffff880ff5cafb28
      [   70.847547] Call Trace:
      [   70.847550]  [<ffffffff8149d5e9>] dump_stack+0x51/0x78
      [   70.847551]  [<ffffffff8107bdfd>] __warn+0xfd/0x120
      [   70.847553]  [<ffffffff8107be3d>] warn_slowpath_null+0x1d/0x20
      [   70.847555]  [<ffffffff8139c9e3>] btrfs_destroy_inode+0x2b3/0x2c0
      [   70.847556]  [<ffffffff812003a1>] ? __destroy_inode+0x71/0x140
      [   70.847558]  [<ffffffff812004b3>] destroy_inode+0x43/0x70
      [   70.847559]  [<ffffffff810b7b5f>] ? wake_up_bit+0x2f/0x40
      [   70.847560]  [<ffffffff81200c68>] evict+0x148/0x1d0
      [   70.847562]  [<ffffffff81398ade>] ? start_transaction+0x3de/0x460
      [   70.847564]  [<ffffffff81200d49>] dispose_list+0x59/0x80
      [   70.847565]  [<ffffffff81201ba0>] evict_inodes+0x180/0x190
      [   70.847566]  [<ffffffff812191ff>] ? __sync_filesystem+0x3f/0x50
      [   70.847568]  [<ffffffff811e95f8>] generic_shutdown_super+0x48/0x100
      [   70.847569]  [<ffffffff810b75c0>] ? woken_wake_function+0x20/0x20
      [   70.847571]  [<ffffffff811e9796>] kill_anon_super+0x16/0x30
      [   70.847573]  [<ffffffff81365cde>] btrfs_kill_super+0x1e/0x130
      [   70.847574]  [<ffffffff811e99be>] deactivate_locked_super+0x4e/0x90
      [   70.847576]  [<ffffffff811e9e61>] deactivate_super+0x51/0x70
      [   70.847577]  [<ffffffff8120536f>] cleanup_mnt+0x3f/0x80
      [   70.847579]  [<ffffffff81205402>] __cleanup_mnt+0x12/0x20
      [   70.847581]  [<ffffffff81098358>] task_work_run+0x68/0xa0
      [   70.847582]  [<ffffffff810022b6>] exit_to_usermode_loop+0xd6/0xe0
      [   70.847583]  [<ffffffff81002e1d>] do_syscall_64+0xbd/0x170
      [   70.847586]  [<ffffffff817d4dbc>] entry_SYSCALL64_slow_path+0x25/0x25
      
      This is the test program I used to force short returns from
      btrfs_copy_from_user
      
      void *dontneed(void *arg)
      {
      	char *p = arg;
      	int ret;
      
      	while(1) {
      		ret = madvise(p, BUFSIZE/4, MADV_DONTNEED);
      		if (ret) {
      			perror("madvise");
      			exit(1);
      		}
      	}
      }
      
      int main(int ac, char **av) {
      	int ret;
      	int fd;
      	char *filename;
      	unsigned long offset;
      	char *buf;
      	int i;
      	pthread_t tid;
      
      	if (ac != 2) {
      		fprintf(stderr, "usage: dammitdave filename\n");
      		exit(1);
      	}
      
      	buf = mmap(NULL, BUFSIZE, PROT_READ|PROT_WRITE,
      		   MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
      	if (buf == MAP_FAILED) {
      		perror("mmap");
      		exit(1);
      	}
      	memset(buf, 'a', BUFSIZE);
      	filename = av[1];
      
      	ret = pthread_create(&tid, NULL, dontneed, buf);
      	if (ret) {
      		fprintf(stderr, "error %d from pthread_create\n", ret);
      		exit(1);
      	}
      
      	ret = pthread_detach(tid);
      	if (ret) {
      		fprintf(stderr, "pthread detach failed %d\n", ret);
      		exit(1);
      	}
      
      	while (1) {
      		fd = open(filename, O_RDWR | O_CREAT, 0600);
      		if (fd < 0) {
      			perror("open");
      			exit(1);
      		}
      
      		for (i = 0; i < ROUNDS; i++) {
      			int this_write = BUFSIZE;
      
      			offset = rand() % MAXSIZE;
      			ret = pwrite(fd, buf, this_write, offset);
      			if (ret < 0) {
      				perror("pwrite");
      				exit(1);
      			} else if (ret != this_write) {
      				fprintf(stderr, "short write to %s offset %lu ret %d\n",
      					filename, offset, ret);
      				exit(1);
      			}
      			if (i == ROUNDS - 1) {
      				ret = sync_file_range(fd, offset, 4096,
      				    SYNC_FILE_RANGE_WRITE);
      				if (ret < 0) {
      					perror("sync_file_range");
      					exit(1);
      				}
      			}
      		}
      		ret = ftruncate(fd, 0);
      		if (ret < 0) {
      			perror("ftruncate");
      			exit(1);
      		}
      		ret = close(fd);
      		if (ret) {
      			perror("close");
      			exit(1);
      		}
      		ret = unlink(filename);
      		if (ret) {
      			perror("unlink");
      			exit(1);
      		}
      
      	}
      	return 0;
      }
      Signed-off-by: NChris Mason <clm@fb.com>
      Reported-by: NDave Jones <dsj@fb.com>
      Fixes: 2e78c927
      cc: stable@vger.kernel.org # v4.6
      Signed-off-by: NChris Mason <clm@fb.com>
      56244ef1
  2. 26 5月, 2016 1 次提交
  3. 28 4月, 2016 2 次提交
  4. 05 4月, 2016 1 次提交
    • K
      mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros · 09cbfeaf
      Kirill A. Shutemov 提交于
      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: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Acked-by: NMichal Hocko <mhocko@suse.com>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      09cbfeaf
  5. 04 4月, 2016 1 次提交
  6. 31 3月, 2016 1 次提交
    • F
      btrfs: fix crash/invalid memory access on fsync when using overlayfs · de17e793
      Filipe Manana 提交于
      If the lower or upper directory of an overlayfs mount belong to a btrfs
      file system and we fsync the file through the overlayfs' merged directory
      we ended up accessing an inode that didn't belong to btrfs as if it were
      a btrfs inode at btrfs_sync_file() resulting in a crash like the following:
      
      [ 7782.588845] BUG: unable to handle kernel NULL pointer dereference at 0000000000000544
      [ 7782.590624] IP: [<ffffffffa030b7ab>] btrfs_sync_file+0x11b/0x3e9 [btrfs]
      [ 7782.591931] PGD 4d954067 PUD 1e878067 PMD 0
      [ 7782.592016] Oops: 0002 [#6] PREEMPT SMP DEBUG_PAGEALLOC
      [ 7782.592016] Modules linked in: btrfs overlay ppdev crc32c_generic evdev xor raid6_pq psmouse pcspkr sg serio_raw acpi_cpufreq parport_pc parport tpm_tis i2c_piix4 tpm i2c_core processor button loop autofs4 ext4 crc16 mbcache jbd2 sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix virtio_pci libata virtio_ring virtio scsi_mod e1000 floppy [last unloaded: btrfs]
      [ 7782.592016] CPU: 10 PID: 16437 Comm: xfs_io Tainted: G      D         4.5.0-rc6-btrfs-next-26+ #1
      [ 7782.592016] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
      [ 7782.592016] task: ffff88001b8d40c0 ti: ffff880137488000 task.ti: ffff880137488000
      [ 7782.592016] RIP: 0010:[<ffffffffa030b7ab>]  [<ffffffffa030b7ab>] btrfs_sync_file+0x11b/0x3e9 [btrfs]
      [ 7782.592016] RSP: 0018:ffff88013748be40  EFLAGS: 00010286
      [ 7782.592016] RAX: 0000000080000000 RBX: ffff880133b30c88 RCX: 0000000000000001
      [ 7782.592016] RDX: 0000000000000001 RSI: ffffffff8148fec0 RDI: 00000000ffffffff
      [ 7782.592016] RBP: ffff88013748bec0 R08: 0000000000000001 R09: 0000000000000000
      [ 7782.624248] R10: ffff88013748be40 R11: 0000000000000246 R12: 0000000000000000
      [ 7782.624248] R13: 0000000000000000 R14: 00000000009305a0 R15: ffff880015e3be40
      [ 7782.624248] FS:  00007fa83b9cb700(0000) GS:ffff88023ed40000(0000) knlGS:0000000000000000
      [ 7782.624248] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      [ 7782.624248] CR2: 0000000000000544 CR3: 00000001fa652000 CR4: 00000000000006e0
      [ 7782.624248] Stack:
      [ 7782.624248]  ffffffff8108b5cc ffff88013748bec0 0000000000000246 ffff8800b005ded0
      [ 7782.624248]  ffff880133b30d60 8000000000000000 7fffffffffffffff 0000000000000246
      [ 7782.624248]  0000000000000246 ffffffff81074f9b ffffffff8104357c ffff880015e3be40
      [ 7782.624248] Call Trace:
      [ 7782.624248]  [<ffffffff8108b5cc>] ? arch_local_irq_save+0x9/0xc
      [ 7782.624248]  [<ffffffff81074f9b>] ? ___might_sleep+0xce/0x217
      [ 7782.624248]  [<ffffffff8104357c>] ? __do_page_fault+0x3c0/0x43a
      [ 7782.624248]  [<ffffffff811a2351>] vfs_fsync_range+0x8c/0x9e
      [ 7782.624248]  [<ffffffff811a237f>] vfs_fsync+0x1c/0x1e
      [ 7782.624248]  [<ffffffff811a24d6>] do_fsync+0x31/0x4a
      [ 7782.624248]  [<ffffffff811a2700>] SyS_fsync+0x10/0x14
      [ 7782.624248]  [<ffffffff81493617>] entry_SYSCALL_64_fastpath+0x12/0x6b
      [ 7782.624248] Code: 85 c0 0f 85 e2 02 00 00 48 8b 45 b0 31 f6 4c 29 e8 48 ff c0 48 89 45 a8 48 8d 83 d8 00 00 00 48 89 c7 48 89 45 a0 e8 fc 43 18 e1 <f0> 41 ff 84 24 44 05 00 00 48 8b 83 58 ff ff ff 48 c1 e8 07 83
      [ 7782.624248] RIP  [<ffffffffa030b7ab>] btrfs_sync_file+0x11b/0x3e9 [btrfs]
      [ 7782.624248]  RSP <ffff88013748be40>
      [ 7782.624248] CR2: 0000000000000544
      [ 7782.661994] ---[ end trace 721e14960eb939bc ]---
      
      This started happening since commit 4bacc9c9 (overlayfs: Make f_path
      always point to the overlay and f_inode to the underlay) and even though
      after this change we could still access the btrfs inode through
      struct file->f_mapping->host or struct file->f_inode, we would end up
      resulting in more similar issues later on at check_parent_dirs_for_sync()
      because the dentry we got (from struct file->f_path.dentry) was from
      overlayfs and not from btrfs, that is, we had no way of getting the dentry
      that belonged to btrfs (we always got the dentry that belonged to
      overlayfs).
      
      The new patch from Miklos Szeredi, titled "vfs: add file_dentry()" and
      recently submitted to linux-fsdevel, adds a file_dentry() API that allows
      us to get the btrfs dentry from the input file and therefore being able
      to fsync when the upper and lower directories belong to btrfs filesystems.
      
      This issue has been reported several times by users in the mailing list
      and bugzilla. A test case for xfstests is being submitted as well.
      
      Fixes: 4bacc9c9 ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay")
      Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=101951
      Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=109791Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      Cc: stable@vger.kernel.org
      de17e793
  7. 14 3月, 2016 1 次提交
  8. 12 3月, 2016 1 次提交
  9. 02 3月, 2016 1 次提交
    • F
      Btrfs: fix race when checking if we can skip fsync'ing an inode · affc0ff9
      Filipe Manana 提交于
      If we're about to do a fast fsync for an inode and btrfs_inode_in_log()
      returns false, it's possible that we had an ordered extent in progress
      (btrfs_finish_ordered_io() not run yet) when we noticed that the inode's
      last_trans field was not greater than the id of the last committed
      transaction, but shortly after, before we checked if there were any
      ongoing ordered extents, the ordered extent had just completed and
      removed itself from the inode's ordered tree, in which case we end up not
      logging the inode, losing some data if a power failure or crash happens
      after the fsync handler returns and before the transaction is committed.
      
      Fix this by checking first if there are any ongoing ordered extents
      before comparing the inode's last_trans with the id of the last committed
      transaction - when it completes, an ordered extent always updates the
      inode's last_trans before it removes itself from the inode's ordered
      tree (at btrfs_finish_ordered_io()).
      Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      affc0ff9
  10. 18 2月, 2016 3 次提交
  11. 11 2月, 2016 1 次提交
  12. 02 2月, 2016 3 次提交
  13. 23 1月, 2016 1 次提交
    • A
      wrappers for ->i_mutex access · 5955102c
      Al Viro 提交于
      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: NAl Viro <viro@zeniv.linux.org.uk>
      5955102c
  14. 20 1月, 2016 1 次提交
  15. 01 1月, 2016 1 次提交
  16. 16 12月, 2015 1 次提交
    • C
      Btrfs: check prepare_uptodate_page() error code earlier · bb1591b4
      Chris Mason 提交于
      prepare_pages() may end up calling prepare_uptodate_page() twice if our
      write only spans a single page.  But if the first call returns an error,
      our page will be unlocked and its not safe to call it again.
      
      This bug goes all the way back to 2011, and it's not something commonly
      hit.
      
      While we're here, add a more explicit check for the page being truncated
      away.  The bare lock_page() alone is protected only by good thoughts and
      i_mutex, which we're sure to regret eventually.
      Reported-by: NDave Jones <dsj@fb.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      bb1591b4
  17. 08 12月, 2015 1 次提交
    • C
      vfs: pull btrfs clone API to vfs layer · 04b38d60
      Christoph Hellwig 提交于
      The btrfs clone ioctls are now adopted by other file systems, with NFS
      and CIFS already having support for them, and XFS being under active
      development.  To avoid growth of various slightly incompatible
      implementations, add one to the VFS.  Note that clones are different from
      file copies in several ways:
      
       - they are atomic vs other writers
       - they support whole file clones
       - they support 64-bit legth clones
       - they do not allow partial success (aka short writes)
       - clones are expected to be a fast metadata operation
      
      Because of that it would be rather cumbersome to try to piggyback them on
      top of the recent clone_file_range infrastructure.  The converse isn't
      true and the clone_file_range system call could try clone file range as
      a first attempt to copy, something that further patches will enable.
      
      Based on earlier work from Peng Tao.
      Signed-off-by: NChristoph Hellwig <hch@lst.de>
      Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      04b38d60
  18. 03 12月, 2015 1 次提交
  19. 02 12月, 2015 1 次提交
  20. 25 11月, 2015 1 次提交
    • D
      btrfs: fix signed overflows in btrfs_sync_file · 9dcbeed4
      David Sterba 提交于
      The calculation of range length in btrfs_sync_file leads to signed
      overflow. This was caught by PaX gcc SIZE_OVERFLOW plugin.
      
      https://forums.grsecurity.net/viewtopic.php?f=1&t=4284
      
      The fsync call passes 0 and LLONG_MAX, the range length does not fit to
      loff_t and overflows, but the value is converted to u64 so it silently
      works as expected.
      
      The minimal fix is a typecast to u64, switching functions to take
      (start, end) instead of (start, len) would be more intrusive.
      
      Coccinelle script found that there's one more opencoded calculation of
      the length.
      
      <smpl>
      @@
      loff_t start, end;
      @@
      * end - start
      </smpl>
      
      CC: stable@vger.kernel.org
      Signed-off-by: NDavid Sterba <dsterba@suse.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      9dcbeed4
  21. 09 11月, 2015 1 次提交
    • F
      Btrfs: fix race leading to incorrect item deletion when dropping extents · aeafbf84
      Filipe Manana 提交于
      While running a stress test I got the following warning triggered:
      
        [191627.672810] ------------[ cut here ]------------
        [191627.673949] WARNING: CPU: 8 PID: 8447 at fs/btrfs/file.c:779 __btrfs_drop_extents+0x391/0xa50 [btrfs]()
        (...)
        [191627.701485] Call Trace:
        [191627.702037]  [<ffffffff8145f077>] dump_stack+0x4f/0x7b
        [191627.702992]  [<ffffffff81095de5>] ? console_unlock+0x356/0x3a2
        [191627.704091]  [<ffffffff8104b3b0>] warn_slowpath_common+0xa1/0xbb
        [191627.705380]  [<ffffffffa0664499>] ? __btrfs_drop_extents+0x391/0xa50 [btrfs]
        [191627.706637]  [<ffffffff8104b46d>] warn_slowpath_null+0x1a/0x1c
        [191627.707789]  [<ffffffffa0664499>] __btrfs_drop_extents+0x391/0xa50 [btrfs]
        [191627.709155]  [<ffffffff8115663c>] ? cache_alloc_debugcheck_after.isra.32+0x171/0x1d0
        [191627.712444]  [<ffffffff81155007>] ? kmemleak_alloc_recursive.constprop.40+0x16/0x18
        [191627.714162]  [<ffffffffa06570c9>] insert_reserved_file_extent.constprop.40+0x83/0x24e [btrfs]
        [191627.715887]  [<ffffffffa065422b>] ? start_transaction+0x3bb/0x610 [btrfs]
        [191627.717287]  [<ffffffffa065b604>] btrfs_finish_ordered_io+0x273/0x4e2 [btrfs]
        [191627.728865]  [<ffffffffa065b888>] finish_ordered_fn+0x15/0x17 [btrfs]
        [191627.730045]  [<ffffffffa067d688>] normal_work_helper+0x14c/0x32c [btrfs]
        [191627.731256]  [<ffffffffa067d96a>] btrfs_endio_write_helper+0x12/0x14 [btrfs]
        [191627.732661]  [<ffffffff81061119>] process_one_work+0x24c/0x4ae
        [191627.733822]  [<ffffffff810615b0>] worker_thread+0x206/0x2c2
        [191627.734857]  [<ffffffff810613aa>] ? process_scheduled_works+0x2f/0x2f
        [191627.736052]  [<ffffffff810613aa>] ? process_scheduled_works+0x2f/0x2f
        [191627.737349]  [<ffffffff810669a6>] kthread+0xef/0xf7
        [191627.738267]  [<ffffffff810f3b3a>] ? time_hardirqs_on+0x15/0x28
        [191627.739330]  [<ffffffff810668b7>] ? __kthread_parkme+0xad/0xad
        [191627.741976]  [<ffffffff81465592>] ret_from_fork+0x42/0x70
        [191627.743080]  [<ffffffff810668b7>] ? __kthread_parkme+0xad/0xad
        [191627.744206] ---[ end trace bbfddacb7aaada8d ]---
      
        $ cat -n fs/btrfs/file.c
        691  int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
        (...)
        758                  btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
        759                  if (key.objectid > ino ||
        760                      key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
        761                          break;
        762
        763                  fi = btrfs_item_ptr(leaf, path->slots[0],
        764                                      struct btrfs_file_extent_item);
        765                  extent_type = btrfs_file_extent_type(leaf, fi);
        766
        767                  if (extent_type == BTRFS_FILE_EXTENT_REG ||
        768                      extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
        (...)
        774                  } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
        (...)
        778                  } else {
        779                          WARN_ON(1);
        780                          extent_end = search_start;
        781                  }
        (...)
      
      This happened because the item we were processing did not match a file
      extent item (its key type != BTRFS_EXTENT_DATA_KEY), and even on this
      case we cast the item to a struct btrfs_file_extent_item pointer and
      then find a type field value that does not match any of the expected
      values (BTRFS_FILE_EXTENT_[REG|PREALLOC|INLINE]). This scenario happens
      due to a tiny time window where a race can happen as exemplified below.
      For example, consider the following scenario where we're using the
      NO_HOLES feature and we have the following two neighbour leafs:
      
                     Leaf X (has N items)                    Leaf Y
      
      [ ... (257 INODE_ITEM 0) (257 INODE_REF 256) ]  [ (257 EXTENT_DATA 8192), ... ]
                slot N - 2         slot N - 1              slot 0
      
      Our inode 257 has an implicit hole in the range [0, 8K[ (implicit rather
      than explicit because NO_HOLES is enabled). Now if our inode has an
      ordered extent for the range [4K, 8K[ that is finishing, the following
      can happen:
      
                CPU 1                                       CPU 2
      
        btrfs_finish_ordered_io()
          insert_reserved_file_extent()
            __btrfs_drop_extents()
               Searches for the key
                (257 EXTENT_DATA 4096) through
                btrfs_lookup_file_extent()
      
               Key not found and we get a path where
               path->nodes[0] == leaf X and
               path->slots[0] == N
      
               Because path->slots[0] is >=
               btrfs_header_nritems(leaf X), we call
               btrfs_next_leaf()
      
               btrfs_next_leaf() releases the path
      
                                                        inserts key
                                                        (257 INODE_REF 4096)
                                                        at the end of leaf X,
                                                        leaf X now has N + 1 keys,
                                                        and the new key is at
                                                        slot N
      
               btrfs_next_leaf() searches for
               key (257 INODE_REF 256), with
               path->keep_locks set to 1,
               because it was the last key it
               saw in leaf X
      
                 finds it in leaf X again and
                 notices it's no longer the last
                 key of the leaf, so it returns 0
                 with path->nodes[0] == leaf X and
                 path->slots[0] == N (which is now
                 < btrfs_header_nritems(leaf X)),
                 pointing to the new key
                 (257 INODE_REF 4096)
      
               __btrfs_drop_extents() casts the
               item at path->nodes[0], slot
               path->slots[0], to a struct
               btrfs_file_extent_item - it does
               not skip keys for the target
               inode with a type less than
               BTRFS_EXTENT_DATA_KEY
               (BTRFS_INODE_REF_KEY < BTRFS_EXTENT_DATA_KEY)
      
               sees a bogus value for the type
               field triggering the WARN_ON in
               the trace shown above, and sets
               extent_end = search_start (4096)
      
               does the if-then-else logic to
               fixup 0 length extent items created
               by a past bug from hole punching:
      
                 if (extent_end == key.offset &&
                     extent_end >= search_start)
                     goto delete_extent_item;
      
               that evaluates to true and it ends
               up deleting the key pointed to by
               path->slots[0], (257 INODE_REF 4096),
               from leaf X
      
      The same could happen for example for a xattr that ends up having a key
      with an offset value that matches search_start (very unlikely but not
      impossible).
      
      So fix this by ensuring that keys smaller than BTRFS_EXTENT_DATA_KEY are
      skipped, never casted to struct btrfs_file_extent_item and never deleted
      by accident. Also protect against the unexpected case of getting a key
      for a lower inode number by skipping that key and issuing a warning.
      
      Cc: stable@vger.kernel.org
      Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      aeafbf84
  22. 03 11月, 2015 2 次提交
    • F
      Btrfs: fix hole punching when using the no-holes feature · 2959a32a
      Filipe Manana 提交于
      When we are using the no-holes feature, if we punch a hole into a file
      range that already contains a hole which overlaps the range we are passing
      to fallocate(), we end up removing the extent map that represents the
      existing hole without adding a new one. This happens because with the
      no-holes feature we do not have explicit extent items to represent holes
      and therefore the call to __btrfs_drop_extents(), made from
      btrfs_punch_hole(), returns an end offset to the variable drop_end that
      is smaller than the end of the range passed to fallocate(), while it
      drops all existing extent maps in that range.
      Normally having a missing extent map is not a problem, for example for
      a readpages() operation we just end up building the extent map by
      looking at the fs/subvol tree for a matching extent item (or a lack of
      one for implicit holes). However for an fsync that uses the fast path,
      which needs to look at the list of modified extent maps, this means
      the fsync will not record information about the complete hole we had
      before the fallocate() call into the log tree, resulting in a file with
      content/layout that does not match what we had neither before nor after
      the hole punch operation.
      
      The following test case for fstests reproduces the issue. It fails without
      this change because we get a file with a different digest after the fsync
      log replay and also with a different extent/hole layout.
      
        seq=`basename $0`
        seqres=$RESULT_DIR/$seq
        echo "QA output created by $seq"
        tmp=/tmp/$$
        status=1	# failure is the default!
        trap "_cleanup; exit \$status" 0 1 2 3 15
      
        _cleanup()
        {
           _cleanup_flakey
           rm -f $tmp.*
        }
      
        # get standard environment, filters and checks
        . ./common/rc
        . ./common/filter
        . ./common/punch
        . ./common/dmflakey
      
        # real QA test starts here
        _need_to_be_root
        _supported_fs generic
        _supported_os Linux
        _require_scratch
        _require_xfs_io_command "fpunch"
        _require_xfs_io_command "fiemap"
        _require_dm_target flakey
        _require_metadata_journaling $SCRATCH_DEV
      
        # This test was motivated by an issue found in btrfs when the btrfs
        # no-holes feature is enabled (introduced in kernel 3.14). So enable
        # the feature if the fs being tested is btrfs.
        if [ $FSTYP == "btrfs" ]; then
            _require_btrfs_fs_feature "no_holes"
            _require_btrfs_mkfs_feature "no-holes"
            MKFS_OPTIONS="$MKFS_OPTIONS -O no-holes"
        fi
      
        rm -f $seqres.full
      
        _scratch_mkfs >>$seqres.full 2>&1
        _init_flakey
        _mount_flakey
      
        # Create out test file with some data and then fsync it.
        # We do the fsync only to make sure the last fsync we do in this test
        # triggers the fast code path of btrfs' fsync implementation, a
        # condition necessary to trigger the bug btrfs had.
        $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 128K" \
                        -c "fsync"                  \
                        $SCRATCH_MNT/foobar | _filter_xfs_io
      
        # Now punch a hole against the range [96K, 128K[.
        $XFS_IO_PROG -c "fpunch 96K 32K" $SCRATCH_MNT/foobar
      
        # Punch another hole against a range that overlaps the previous range
        # and ends beyond eof.
        $XFS_IO_PROG -c "fpunch 64K 128K" $SCRATCH_MNT/foobar
      
        # Punch another hole against a range that overlaps the first range
        # ([96K, 128K[) and ends at eof.
        $XFS_IO_PROG -c "fpunch 32K 96K" $SCRATCH_MNT/foobar
      
        # Fsync our file. We want to verify that, after a power failure and
        # mounting the filesystem again, the file content reflects all the hole
        # punch operations.
        $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foobar
      
        echo "File digest before power failure:"
        md5sum $SCRATCH_MNT/foobar | _filter_scratch
      
        echo "Fiemap before power failure:"
        $XFS_IO_PROG -c "fiemap -v" $SCRATCH_MNT/foobar | _filter_fiemap
      
        # Silently drop all writes and umount to simulate a crash/power failure.
        _load_flakey_table $FLAKEY_DROP_WRITES
        _unmount_flakey
      
        # Allow writes again, mount to trigger log replay and validate file
        # contents.
        _load_flakey_table $FLAKEY_ALLOW_WRITES
        _mount_flakey
      
        echo "File digest after log replay:"
        # Must match the same digest we got before the power failure.
        md5sum $SCRATCH_MNT/foobar | _filter_scratch
      
        echo "Fiemap after log replay:"
        # Must match the same extent listing we got before the power failure.
        $XFS_IO_PROG -c "fiemap -v" $SCRATCH_MNT/foobar | _filter_fiemap
      
        _unmount_flakey
      
        status=0
        exit
      Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      2959a32a
    • Q
      btrfs: Fix a data space underflow warning · 485290a7
      Qu Wenruo 提交于
      Even with quota disabled, generic/127 will trigger a kernel warning by
      underflow data space info.
      
      The bug is caused by buffered write, which in case of short copy, the
      start parameter for btrfs_delalloc_release_space() is wrong, and
      round_up/down() in btrfs_delalloc_release() extents the range to page
      aligned, decreasing one more page than expected.
      
      This patch will fix it by passing correct start.
      Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      485290a7
  23. 26 10月, 2015 1 次提交
    • F
      Btrfs: fix regression running delayed references when using qgroups · b06c4bf5
      Filipe Manana 提交于
      In the kernel 4.2 merge window we had a big changes to the implementation
      of delayed references and qgroups which made the no_quota field of delayed
      references not used anymore. More specifically the no_quota field is not
      used anymore as of:
      
        commit 0ed4792a ("btrfs: qgroup: Switch to new extent-oriented qgroup mechanism.")
      
      Leaving the no_quota field actually prevents delayed references from
      getting merged, which in turn cause the following BUG_ON(), at
      fs/btrfs/extent-tree.c, to be hit when qgroups are enabled:
      
        static int run_delayed_tree_ref(...)
        {
           (...)
           BUG_ON(node->ref_mod != 1);
           (...)
        }
      
      This happens on a scenario like the following:
      
        1) Ref1 bytenr X, action = BTRFS_ADD_DELAYED_REF, no_quota = 1, added.
      
        2) Ref2 bytenr X, action = BTRFS_DROP_DELAYED_REF, no_quota = 0, added.
           It's not merged with Ref1 because Ref1->no_quota != Ref2->no_quota.
      
        3) Ref3 bytenr X, action = BTRFS_ADD_DELAYED_REF, no_quota = 1, added.
           It's not merged with the reference at the tail of the list of refs
           for bytenr X because the reference at the tail, Ref2 is incompatible
           due to Ref2->no_quota != Ref3->no_quota.
      
        4) Ref4 bytenr X, action = BTRFS_DROP_DELAYED_REF, no_quota = 0, added.
           It's not merged with the reference at the tail of the list of refs
           for bytenr X because the reference at the tail, Ref3 is incompatible
           due to Ref3->no_quota != Ref4->no_quota.
      
        5) We run delayed references, trigger merging of delayed references,
           through __btrfs_run_delayed_refs() -> btrfs_merge_delayed_refs().
      
        6) Ref1 and Ref3 are merged as Ref1->no_quota = Ref3->no_quota and
           all other conditions are satisfied too. So Ref1 gets a ref_mod
           value of 2.
      
        7) Ref2 and Ref4 are merged as Ref2->no_quota = Ref4->no_quota and
           all other conditions are satisfied too. So Ref2 gets a ref_mod
           value of 2.
      
        8) Ref1 and Ref2 aren't merged, because they have different values
           for their no_quota field.
      
        9) Delayed reference Ref1 is picked for running (select_delayed_ref()
           always prefers references with an action == BTRFS_ADD_DELAYED_REF).
           So run_delayed_tree_ref() is called for Ref1 which triggers the
           BUG_ON because Ref1->red_mod != 1 (equals 2).
      
      So fix this by removing the no_quota field, as it's not used anymore as
      of commit 0ed4792a ("btrfs: qgroup: Switch to new extent-oriented
      qgroup mechanism.").
      
      The use of no_quota was also buggy in at least two places:
      
      1) At delayed-refs.c:btrfs_add_delayed_tree_ref() - we were setting
         no_quota to 0 instead of 1 when the following condition was true:
         is_fstree(ref_root) || !fs_info->quota_enabled
      
      2) At extent-tree.c:__btrfs_inc_extent_ref() - we were attempting to
         reset a node's no_quota when the condition "!is_fstree(root_objectid)
         || !root->fs_info->quota_enabled" was true but we did it only in
         an unused local stack variable, that is, we never reset the no_quota
         value in the node itself.
      
      This fixes the remainder of problems several people have been having when
      running delayed references, mostly while a balance is running in parallel,
      on a 4.2+ kernel.
      
      Very special thanks to Stéphane Lesimple for helping debugging this issue
      and testing this fix on his multi terabyte filesystem (which took more
      than one day to balance alone, plus fsck, etc).
      
      Also, this fixes deadlock issue when using the clone ioctl with qgroups
      enabled, as reported by Elias Probst in the mailing list. The deadlock
      happens because after calling btrfs_insert_empty_item we have our path
      holding a write lock on a leaf of the fs/subvol tree and then before
      releasing the path we called check_ref() which did backref walking, when
      qgroups are enabled, and tried to read lock the same leaf. The trace for
      this case is the following:
      
        INFO: task systemd-nspawn:6095 blocked for more than 120 seconds.
        (...)
        Call Trace:
          [<ffffffff86999201>] schedule+0x74/0x83
          [<ffffffff863ef64c>] btrfs_tree_read_lock+0xc0/0xea
          [<ffffffff86137ed7>] ? wait_woken+0x74/0x74
          [<ffffffff8639f0a7>] btrfs_search_old_slot+0x51a/0x810
          [<ffffffff863a129b>] btrfs_next_old_leaf+0xdf/0x3ce
          [<ffffffff86413a00>] ? ulist_add_merge+0x1b/0x127
          [<ffffffff86411688>] __resolve_indirect_refs+0x62a/0x667
          [<ffffffff863ef546>] ? btrfs_clear_lock_blocking_rw+0x78/0xbe
          [<ffffffff864122d3>] find_parent_nodes+0xaf3/0xfc6
          [<ffffffff86412838>] __btrfs_find_all_roots+0x92/0xf0
          [<ffffffff864128f2>] btrfs_find_all_roots+0x45/0x65
          [<ffffffff8639a75b>] ? btrfs_get_tree_mod_seq+0x2b/0x88
          [<ffffffff863e852e>] check_ref+0x64/0xc4
          [<ffffffff863e9e01>] btrfs_clone+0x66e/0xb5d
          [<ffffffff863ea77f>] btrfs_ioctl_clone+0x48f/0x5bb
          [<ffffffff86048a68>] ? native_sched_clock+0x28/0x77
          [<ffffffff863ed9b0>] btrfs_ioctl+0xabc/0x25cb
        (...)
      
      The problem goes away by eleminating check_ref(), which no longer is
      needed as its purpose was to get a value for the no_quota field of
      a delayed reference (this patch removes the no_quota field as mentioned
      earlier).
      Reported-by: NStéphane Lesimple <stephane_btrfs@lesimple.fr>
      Tested-by: NStéphane Lesimple <stephane_btrfs@lesimple.fr>
      Reported-by: NElias Probst <mail@eliasprobst.eu>
      Reported-by: NPeter Becker <floyd.net@gmail.com>
      Reported-by: NMalte Schröder <malte@tnxip.de>
      Reported-by: NDerek Dongray <derek@valedon.co.uk>
      Reported-by: NErkki Seppala <flux-btrfs@inside.org>
      Cc: stable@vger.kernel.org  # 4.2+
      Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      Reviewed-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
      b06c4bf5
  24. 22 10月, 2015 6 次提交
  25. 21 10月, 2015 1 次提交
    • Q
      btrfs: Avoid truncate tailing page if fallocate range doesn't exceed inode size · 0f6925fa
      Qu Wenruo 提交于
      Current code will always truncate tailing page if its alloc_start is
      smaller than inode size.
      
      For example, the file extent layout is like:
      0	4K	8K	16K	32K
      |<-----Extent A---------------->|
      |<--Inode size: 18K---------->|
      
      But if calling fallocate even for range [0,4K), it will cause btrfs to
      re-truncate the range [16,32K), causing COW and a new extent.
      
      0	4K	8K	16K	32K
      |///////|	<- Fallocate call range
      |<-----Extent A-------->|<--B-->|
      
      The cause is quite easy, just a careless btrfs_truncate_inode() in a
      else branch without extra judgment.
      Fix it by add judgment on whether the fallocate range is beyond isize.
      Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      0f6925fa
  26. 24 6月, 2015 1 次提交
  27. 10 6月, 2015 1 次提交
    • F
      Btrfs: avoid syncing log in the fast fsync path when not necessary · b659ef02
      Filipe Manana 提交于
      Commit 3a8b36f3 ("Btrfs: fix data loss in the fast fsync path") added
      a performance regression for that causes an unnecessary sync of the log
      trees (fs/subvol and root log trees) when 2 consecutive fsyncs are done
      against a file, without no writes or any metadata updates to the inode in
      between them and if a transaction is committed before the second fsync is
      called.
      
      Huang Ying reported this to lkml (https://lkml.org/lkml/2015/3/18/99)
      after a test sysbench test that measured a -62% decrease of file io
      requests per second for that tests' workload.
      
      The test is:
      
        echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
        echo performance > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor
        echo performance > /sys/devices/system/cpu/cpu2/cpufreq/scaling_governor
        echo performance > /sys/devices/system/cpu/cpu3/cpufreq/scaling_governor
        mkfs -t btrfs /dev/sda2
        mount -t btrfs /dev/sda2 /fs/sda2
        cd /fs/sda2
        for ((i = 0; i < 1024; i++)); do fallocate -l 67108864 testfile.$i; done
        sysbench --test=fileio --max-requests=0 --num-threads=4 --max-time=600 \
          --file-test-mode=rndwr --file-total-size=68719476736 --file-io-mode=sync \
          --file-num=1024 run
      
      A test on kvm guest, running a debug kernel gave me the following results:
      
      Without 3a8b36f3:             16.01 reqs/sec
      With 3a8b36f3:                 3.39 reqs/sec
      With 3a8b36f3 and this patch: 16.04 reqs/sec
      Reported-by: NHuang Ying <ying.huang@intel.com>
      Tested-by: NHuang, Ying <ying.huang@intel.com>
      Signed-off-by: NFilipe Manana <fdmanana@suse.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      b659ef02
  28. 16 4月, 2015 1 次提交
  29. 13 4月, 2015 1 次提交
    • D
      btrfs: qgroup: do a reservation in a higher level. · e2d1f923
      Dongsheng Yang 提交于
      There are two problems in qgroup:
      
      a). The PAGE_CACHE is 4K, even when we are writing a data of 1K,
      qgroup will reserve a 4K size. It will cause the last 3K in a qgroup
      is not available to user.
      
      b). When user is writing a inline data, qgroup will not reserve it,
      it means this is a window we can exceed the limit of a qgroup.
      
      The main idea of this patch is reserving the data size of write_bytes
      rather than the reserve_bytes. It means qgroup will not care about
      the data size btrfs will reserve for user, but only care about the
      data size user is going to write. Then reserve it when user want to
      write and release it in transaction committed.
      
      In this way, qgroup can be released from the complex procedure in
      btrfs and only do the reserve when user want to write and account
      when the data is written in commit_transaction().
      Signed-off-by: NDongsheng Yang <yangds.fnst@cn.fujitsu.com>
      Signed-off-by: NChris Mason <clm@fb.com>
      e2d1f923