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* Merge branch 'for-linus' of ↵Linus Torvalds2014-07-0413-47/+108
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs Pull btrfs fixes from Chris Mason: "We've queued up a few fixes in my for-linus branch" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: Btrfs: fix crash when starting transaction Btrfs: fix btrfs_print_leaf for skinny metadata Btrfs: fix race of using total_bytes_pinned btrfs: use E2BIG instead of EIO if compression does not help btrfs: remove stale comment from btrfs_flush_all_pending_stuffs Btrfs: fix use-after-free when cloning a trailing file hole btrfs: fix null pointer dereference in btrfs_show_devname when name is null btrfs: fix null pointer dereference in clone_fs_devices when name is null btrfs: fix nossd and ssd_spread mount option regression Btrfs: fix race between balance recovery and root deletion Btrfs: atomically set inode->i_flags in btrfs_update_iflags btrfs: only unlock block in verify_parent_transid if we locked it Btrfs: assert send doesn't attempt to start transactions btrfs compression: reuse recently used workspace Btrfs: fix crash when mounting raid5 btrfs with missing disks btrfs: create sprout should rename fsid on the sysfs as well btrfs: dev replace should replace the sysfs entry btrfs: dev add should add its sysfs entry btrfs: dev delete should remove sysfs entry btrfs: rename add_device_membership to btrfs_kobj_add_device
| * Btrfs: fix crash when starting transactionFilipe Manana2014-07-031-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Often when starting a transaction we commit the currently running transaction, which can end up writing block group caches when the current process has its journal_info set to NULL (and not to a transaction). This makes our assertion at btrfs_check_data_free_space() (current_journal != NULL) fail, resulting in a crash/hang. Therefore fix it by setting journal_info. Two different traces of this issue follow below. 1) [51502.241936] BTRFS: assertion failed: current->journal_info, file: fs/btrfs/extent-tree.c, line: 3670 [51502.242213] ------------[ cut here ]------------ [51502.242493] kernel BUG at fs/btrfs/ctree.h:3964! [51502.242669] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC (...) [51502.244010] Call Trace: [51502.244010] [<ffffffffa02bc025>] btrfs_check_data_free_space+0x395/0x3a0 [btrfs] [51502.244010] [<ffffffffa02c3bdc>] btrfs_write_dirty_block_groups+0x4ac/0x640 [btrfs] [51502.244010] [<ffffffffa0357a6a>] commit_cowonly_roots+0x164/0x226 [btrfs] [51502.244010] [<ffffffffa02d53cd>] btrfs_commit_transaction+0x4ed/0xab0 [btrfs] [51502.244010] [<ffffffff8168ec7b>] ? _raw_spin_unlock+0x2b/0x40 [51502.244010] [<ffffffffa02d6259>] start_transaction+0x459/0x620 [btrfs] [51502.244010] [<ffffffffa02d67ab>] btrfs_start_transaction+0x1b/0x20 [btrfs] [51502.244010] [<ffffffffa02d73e1>] __unlink_start_trans+0x31/0xe0 [btrfs] [51502.244010] [<ffffffffa02dea67>] btrfs_unlink+0x37/0xc0 [btrfs] [51502.244010] [<ffffffff811bb054>] ? do_unlinkat+0x114/0x2a0 [51502.244010] [<ffffffff811baebc>] vfs_unlink+0xcc/0x150 [51502.244010] [<ffffffff811bb1a0>] do_unlinkat+0x260/0x2a0 [51502.244010] [<ffffffff811a9ef4>] ? filp_close+0x64/0x90 [51502.244010] [<ffffffff810aaea6>] ? trace_hardirqs_on_caller+0x16/0x1e0 [51502.244010] [<ffffffff81349cab>] ? trace_hardirqs_on_thunk+0x3a/0x3f [51502.244010] [<ffffffff811be9eb>] SyS_unlinkat+0x1b/0x40 [51502.244010] [<ffffffff81698452>] system_call_fastpath+0x16/0x1b [51502.244010] Code: 0b 55 48 89 e5 0f 0b 55 48 89 e5 0f 0b 55 89 f1 48 c7 c2 71 13 36 a0 48 89 fe 31 c0 48 c7 c7 b8 43 36 a0 48 89 e5 e8 5d b0 32 e1 <0f> 0b 0f 1f 44 00 00 55 b9 11 00 00 00 48 89 e5 41 55 49 89 f5 [51502.244010] RIP [<ffffffffa03575da>] assfail.constprop.88+0x1e/0x20 [btrfs] 2) [25405.097230] BTRFS: assertion failed: current->journal_info, file: fs/btrfs/extent-tree.c, line: 3670 [25405.097488] ------------[ cut here ]------------ [25405.097767] kernel BUG at fs/btrfs/ctree.h:3964! [25405.097940] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC (...) [25405.100008] Call Trace: [25405.100008] [<ffffffffa02bc025>] btrfs_check_data_free_space+0x395/0x3a0 [btrfs] [25405.100008] [<ffffffffa02c3bdc>] btrfs_write_dirty_block_groups+0x4ac/0x640 [btrfs] [25405.100008] [<ffffffffa035755a>] commit_cowonly_roots+0x164/0x226 [btrfs] [25405.100008] [<ffffffffa02d53cd>] btrfs_commit_transaction+0x4ed/0xab0 [btrfs] [25405.100008] [<ffffffff8109c170>] ? bit_waitqueue+0xc0/0xc0 [25405.100008] [<ffffffffa02d6259>] start_transaction+0x459/0x620 [btrfs] [25405.100008] [<ffffffffa02d67ab>] btrfs_start_transaction+0x1b/0x20 [btrfs] [25405.100008] [<ffffffffa02e3407>] btrfs_create+0x47/0x210 [btrfs] [25405.100008] [<ffffffffa02d74cc>] ? btrfs_permission+0x3c/0x80 [btrfs] [25405.100008] [<ffffffff811bc63b>] vfs_create+0x9b/0x130 [25405.100008] [<ffffffff811bcf19>] do_last+0x849/0xe20 [25405.100008] [<ffffffff811b9409>] ? link_path_walk+0x79/0x820 [25405.100008] [<ffffffff811bd5b5>] path_openat+0xc5/0x690 [25405.100008] [<ffffffff810ab07d>] ? trace_hardirqs_on+0xd/0x10 [25405.100008] [<ffffffff811cdcd2>] ? __alloc_fd+0x32/0x1d0 [25405.100008] [<ffffffff811be2a3>] do_filp_open+0x43/0xa0 [25405.100008] [<ffffffff811cddf1>] ? __alloc_fd+0x151/0x1d0 [25405.100008] [<ffffffff811abcfc>] do_sys_open+0x13c/0x230 [25405.100008] [<ffffffff810aaea6>] ? trace_hardirqs_on_caller+0x16/0x1e0 [25405.100008] [<ffffffff811abe12>] SyS_open+0x22/0x30 [25405.100008] [<ffffffff81698452>] system_call_fastpath+0x16/0x1b [25405.100008] Code: 0b 55 48 89 e5 0f 0b 55 48 89 e5 0f 0b 55 89 f1 48 c7 c2 51 13 36 a0 48 89 fe 31 c0 48 c7 c7 d0 43 36 a0 48 89 e5 e8 6d b5 32 e1 <0f> 0b 0f 1f 44 00 00 55 b9 11 00 00 00 48 89 e5 41 55 49 89 f5 [25405.100008] RIP [<ffffffffa03570ca>] assfail.constprop.88+0x1e/0x20 [btrfs] Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: fix btrfs_print_leaf for skinny metadataJosef Bacik2014-07-031-4/+5
| | | | | | | | | | | | | | | | We wouldn't actuall print the extent information if we had a skinny metadata item, this fixes that. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: fix race of using total_bytes_pinnedLiu Bo2014-07-031-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This percpu counter @total_bytes_pinned is introduced to skip unnecessary operations of 'commit transaction', it accounts for those space we may free but are stuck in delayed refs. And we zero out @space_info->total_bytes_pinned every transaction period so we have a better idea of how much space we'll actually free up by committing this transaction. However, we do the 'zero out' part a little earlier, before we actually unpin space, so we end up returning ENOSPC when we actually have free space that's just unpinned from committing transaction. xfstests/generic/074 complained then. This fixes it by actually accounting the percpu pinned number when 'unpin', and since it's protected by space_info->lock, the race is gone now. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: use E2BIG instead of EIO if compression does not helpDavid Sterba2014-07-031-1/+1
| | | | | | | | | | | | | | | | Return codes got updated in 60e1975acb48fc3d74a3422b21dde74c977ac3d5 (btrfs: return errno instead of -1 from compression) lzo wrapper returns E2BIG in this case, do the same for zlib. Signed-off-by: David Sterba <dsterba@suse.cz>
| * btrfs: remove stale comment from btrfs_flush_all_pending_stuffsDavid Sterba2014-07-031-5/+0
| | | | | | | | | | | | | | Commit fcebe4562dec83b3f8d3088d77584727b09130b2 (Btrfs: rework qgroup accounting) removed the qgroup accounting after delayed refs. Signed-off-by: David Sterba <dsterba@suse.cz>
| * Btrfs: fix use-after-free when cloning a trailing file holeFilipe Manana2014-07-031-11/+9
| | | | | | | | | | | | | | | | The transaction handle was being used after being freed. Cc: Chris Mason <clm@fb.com> Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: fix null pointer dereference in btrfs_show_devname when name is nullAnand Jain2014-07-031-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | dev->name is null but missing flag is not set. Strictly speaking the missing flag should have been set, but there are more places where code just checks if name is null. For now this patch does the same. stack: BUG: unable to handle kernel NULL pointer dereference at 0000000000000064 IP: [<ffffffffa0228908>] btrfs_show_devname+0x58/0xf0 [btrfs] [<ffffffff81198879>] show_vfsmnt+0x39/0x130 [<ffffffff81178056>] m_show+0x16/0x20 [<ffffffff8117d706>] seq_read+0x296/0x390 [<ffffffff8115aa7d>] vfs_read+0x9d/0x160 [<ffffffff8115b549>] SyS_read+0x49/0x90 [<ffffffff817abe52>] system_call_fastpath+0x16/0x1b reproducer: mkfs.btrfs -draid1 -mraid1 /dev/sdg1 /dev/sdg2 btrfstune -S 1 /dev/sdg1 modprobe -r btrfs && modprobe btrfs mount -o degraded /dev/sdg1 /btrfs btrfs dev add /dev/sdg3 /btrfs Signed-off-by: Anand Jain <Anand.Jain@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: fix null pointer dereference in clone_fs_devices when name is nullAnand Jain2014-07-031-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | when one of the device path is missing btrfs_device name is null. So this patch will check for that. stack: BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 IP: [<ffffffff812e18c0>] strlen+0x0/0x30 [<ffffffffa01cd92a>] ? clone_fs_devices+0xaa/0x160 [btrfs] [<ffffffffa01cdcf7>] btrfs_init_new_device+0x317/0xca0 [btrfs] [<ffffffff81155bca>] ? __kmalloc_track_caller+0x15a/0x1a0 [<ffffffffa01d6473>] btrfs_ioctl+0xaa3/0x2860 [btrfs] [<ffffffff81132a6c>] ? handle_mm_fault+0x48c/0x9c0 [<ffffffff81192a61>] ? __blkdev_put+0x171/0x180 [<ffffffff817a784c>] ? __do_page_fault+0x4ac/0x590 [<ffffffff81193426>] ? blkdev_put+0x106/0x110 [<ffffffff81179175>] ? mntput+0x35/0x40 [<ffffffff8116d4b0>] do_vfs_ioctl+0x460/0x4a0 [<ffffffff8115c72e>] ? ____fput+0xe/0x10 [<ffffffff81068033>] ? task_work_run+0xb3/0xd0 [<ffffffff8116d547>] SyS_ioctl+0x57/0x90 [<ffffffff817a793e>] ? do_page_fault+0xe/0x10 [<ffffffff817abe52>] system_call_fastpath+0x16/0x1b reproducer: mkfs.btrfs -draid1 -mraid1 /dev/sdg1 /dev/sdg2 btrfstune -S 1 /dev/sdg1 modprobe -r btrfs && modprobe btrfs mount -o degraded /dev/sdg1 /btrfs btrfs dev add /dev/sdg3 /btrfs Signed-off-by: Anand Jain <Anand.Jain@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: fix nossd and ssd_spread mount option regressionEric Sandeen2014-07-031-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The commit 0780253 btrfs: Cleanup the btrfs_parse_options for remount. broke ssd options quite badly; it stopped making ssd_spread imply ssd, and it made "nossd" unsettable. Put things back at least as well as they were before (though ssd mount option handling is still pretty odd: # mount -o "nossd,ssd_spread" works?) Reported-by: Roman Mamedov <rm@romanrm.net> Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: fix race between balance recovery and root deletionWang Shilong2014-07-032-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Balance recovery is called when RW mounting or remounting from RO to RW, it is called to finish roots merging. When doing balance recovery, relocation root's corresponding fs root(whose root refs is 0) might be destroyed by cleaner thread, this will make btrfs fail to mount. Fix this problem by holding @cleaner_mutex when doing balance recovery. Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: atomically set inode->i_flags in btrfs_update_iflagsFilipe Manana2014-07-031-7/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This change is based on the corresponding recent change for ext4: ext4: atomically set inode->i_flags in ext4_set_inode_flags() That has the following commit message that applies to btrfs as well: "Use cmpxchg() to atomically set i_flags instead of clearing out the S_IMMUTABLE, S_APPEND, etc. flags and then setting them from the EXT4_IMMUTABLE_FL, EXT4_APPEND_FL flags, since this opens up a race where an immutable file has the immutable flag cleared for a brief window of time." Replacing EXT4_IMMUTABLE_FL and EXT4_APPEND_FL with BTRFS_INODE_IMMUTABLE and BTRFS_INODE_APPEND, respectively. Reviewed-by: David Sterba <dsterba@suse.cz> Reviewed-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com> Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: only unlock block in verify_parent_transid if we locked itJosef Bacik2014-06-281-1/+2
| | | | | | | | | | | | | | | | | | | | This is a regression from my patch a26e8c9f75b0bfd8cccc9e8f110737b136eb5994, we need to only unlock the block if we were the one who locked it. Otherwise this will trip BUG_ON()'s in locking.c Thanks, cc: stable@vger.kernel.org Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: assert send doesn't attempt to start transactionsFilipe Manana2014-06-281-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | When starting a transaction just assert that current->journal_info doesn't contain a send transaction stub, since send isn't supposed to start transactions and when it finishes (either successfully or not) it's supposed to set current->journal_info to NULL. This is motivated by the change titled: Btrfs: fix crash when starting transaction Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs compression: reuse recently used workspaceSergey Senozhatsky2014-06-281-1/+1
| | | | | | | | | | | | | | | | | | | | Add compression `workspace' in free_workspace() to `idle_workspace' list head, instead of tail. So we have better chances to reuse most recently used `workspace'. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: fix crash when mounting raid5 btrfs with missing disksLiu Bo2014-06-281-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The reproducer is $ mkfs.btrfs D1 D2 D3 -mraid5 $ mkfs.ext4 D2 && mkfs.ext4 D3 $ mount D1 /btrfs -odegraded ------------------- [ 87.672992] ------------[ cut here ]------------ [ 87.673845] kernel BUG at fs/btrfs/raid56.c:1828! ... [ 87.673845] RIP: 0010:[<ffffffff813efc7e>] [<ffffffff813efc7e>] __raid_recover_end_io+0x4ae/0x4d0 ... [ 87.673845] Call Trace: [ 87.673845] [<ffffffff8116bbc6>] ? mempool_free+0x36/0xa0 [ 87.673845] [<ffffffff813f0255>] raid_recover_end_io+0x75/0xa0 [ 87.673845] [<ffffffff81447c5b>] bio_endio+0x5b/0xa0 [ 87.673845] [<ffffffff81447cb2>] bio_endio_nodec+0x12/0x20 [ 87.673845] [<ffffffff81374621>] end_workqueue_fn+0x41/0x50 [ 87.673845] [<ffffffff813ad2aa>] normal_work_helper+0xca/0x2c0 [ 87.673845] [<ffffffff8108ba2b>] process_one_work+0x1eb/0x530 [ 87.673845] [<ffffffff8108b9c9>] ? process_one_work+0x189/0x530 [ 87.673845] [<ffffffff8108c15b>] worker_thread+0x11b/0x4f0 [ 87.673845] [<ffffffff8108c040>] ? rescuer_thread+0x290/0x290 [ 87.673845] [<ffffffff810939c4>] kthread+0xe4/0x100 [ 87.673845] [<ffffffff810938e0>] ? kthread_create_on_node+0x220/0x220 [ 87.673845] [<ffffffff817e7c7c>] ret_from_fork+0x7c/0xb0 [ 87.673845] [<ffffffff810938e0>] ? kthread_create_on_node+0x220/0x220 ------------------- It's because that we miscalculate @rbio->bbio->error so that it doesn't reach maximum of tolerable errors while it should have. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Tested-by: Satoru Takeuchi<takeuchi_satoru@jp.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: create sprout should rename fsid on the sysfs as wellAnand Jain2014-06-281-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Creating sprout will change the fsid of the mounted root. do the same on the sysfs as well. reproducer: mount /dev/sdb /btrfs (seed disk) btrfs dev add /dev/sdc /btrfs mount -o rw,remount /btrfs btrfs dev del /dev/sdb /btrfs mount /dev/sdb /btrfs Error: kobject_add_internal failed for fe350492-dc28-4051-a601-e017b17e6145 with -EEXIST, don't try to register things with the same name in the same directory. Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: dev replace should replace the sysfs entryAnand Jain2014-06-281-0/+5
| | | | | | | | | | | | | | | | | | when we replace the device its corresponding sysfs entry has to be replaced as well Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: dev add should add its sysfs entryAnand Jain2014-06-283-3/+16
| | | | | | | | | | | | | | | | | | we would need the device links to be created, when device is added. Signed-off-by: Anand Jain <Anand.Jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: dev delete should remove sysfs entryAnand Jain2014-06-283-0/+26
| | | | | | | | | | | | | | | | | | | | when we delete the device from the mounted btrfs, we would need its corresponding sysfs enty to be removed as well. Signed-off-by: Anand Jain <Anand.Jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: rename add_device_membership to btrfs_kobj_add_deviceAnand Jain2014-06-281-2/+2
| | | | | | | | | | | | Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
* | Merge branch 'for-linus' of ↵Linus Torvalds2014-06-2211-172/+359
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs Pull btrfs fixes from Chris Mason: "This fixes some lockups in btrfs reported with rc1. It probably has some performance impact because it is backing off our spinning locks more often and switching to a blocking lock. I'll be able to nail that down next week, but for now I want to get the lockups taken care of. Otherwise some more stack reduction and assorted fixes" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: Btrfs: fix wrong error handle when the device is missing or is not writeable Btrfs: fix deadlock when mounting a degraded fs Btrfs: use bio_endio_nodec instead of open code Btrfs: fix NULL pointer crash when running balance and scrub concurrently btrfs: Skip scrubbing removed chunks to avoid -ENOENT. Btrfs: fix broken free space cache after the system crashed Btrfs: make free space cache write out functions more readable Btrfs: remove unused wait queue in struct extent_buffer Btrfs: fix deadlocks with trylock on tree nodes
| * Btrfs: fix wrong error handle when the device is missing or is not writeableMiao Xie2014-06-191-7/+15
| | | | | | | | | | | | | | | | | | The original bio might be submitted, so we shoud increase bi_remaining to account for it when we deal with the error that the device is missing or is not writeable, or we would skip the endio handle. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: fix deadlock when mounting a degraded fsMiao Xie2014-06-192-1/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The deadlock happened when we mount degraded filesystem, the reproduced steps are following: # mkfs.btrfs -f -m raid1 -d raid1 <dev0> <dev1> # echo 1 > /sys/block/`basename <dev0>`/device/delete # mount -o degraded <dev1> <mnt> The reason was that the counter -- bi_remaining was wrong. If the missing or unwriteable device was the last device in the mapping array, we would not submit the original bio, so we shouldn't increase bi_remaining of it in btrfs_end_bio(), or we would skip the final endio handle. Fix this problem by adding a flag into btrfs bio structure. If we submit the original bio, we will set the flag, and we increase bi_remaining counter, or we don't. Though there is another way to fix it -- decrease bi_remaining counter of the original bio when we make sure the original bio is not submitted, this method need add more check and is easy to make mistake. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: use bio_endio_nodec instead of open codeMiao Xie2014-06-191-8/+1
| | | | | | | | | | Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: fix NULL pointer crash when running balance and scrub concurrentlyWang Shilong2014-06-193-7/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While running balance, scrub, fsstress concurrently we hit the following kernel crash: [56561.448845] BTRFS info (device sde): relocating block group 11005853696 flags 132 [56561.524077] BUG: unable to handle kernel NULL pointer dereference at 0000000000000078 [56561.524237] IP: [<ffffffffa038956d>] scrub_chunk.isra.12+0xdd/0x130 [btrfs] [56561.524297] PGD 9be28067 PUD 7f3dd067 PMD 0 [56561.524325] Oops: 0000 [#1] SMP [....] [56561.527237] Call Trace: [56561.527309] [<ffffffffa038980e>] scrub_enumerate_chunks+0x24e/0x490 [btrfs] [56561.527392] [<ffffffff810abe00>] ? abort_exclusive_wait+0x50/0xb0 [56561.527476] [<ffffffffa038add4>] btrfs_scrub_dev+0x1a4/0x530 [btrfs] [56561.527561] [<ffffffffa0368107>] btrfs_ioctl+0x13f7/0x2a90 [btrfs] [56561.527639] [<ffffffff811c82f0>] do_vfs_ioctl+0x2e0/0x4c0 [56561.527712] [<ffffffff8109c384>] ? vtime_account_user+0x54/0x60 [56561.527788] [<ffffffff810f768c>] ? __audit_syscall_entry+0x9c/0xf0 [56561.527870] [<ffffffff811c8551>] SyS_ioctl+0x81/0xa0 [56561.527941] [<ffffffff815707f7>] tracesys+0xdd/0xe2 [...] [56561.528304] RIP [<ffffffffa038956d>] scrub_chunk.isra.12+0xdd/0x130 [btrfs] [56561.528395] RSP <ffff88004c0f5be8> [56561.528454] CR2: 0000000000000078 This is because in btrfs_relocate_chunk(), we will free @bdev directly while scrub may still hold extent mapping, and may access freed memory. Fix this problem by wrapping freeing @bdev work into free_extent_map() which is based on reference count. Reported-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: Skip scrubbing removed chunks to avoid -ENOENT.Qu Wenruo2014-06-191-10/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When run scrub with balance, sometimes -ENOENT will be returned, since in scrub_enumerate_chunks() will search dev_extent in *COMMIT_ROOT*, but btrfs_lookup_block_group() will search block group in *MEMORY*, so if a chunk is removed but not committed, -ENOENT will be returned. However, there is no need to stop scrubbing since other chunks may be scrubbed without problem. So this patch changes the behavior to skip removed chunks and continue to scrub the rest. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: fix broken free space cache after the system crashedMiao Xie2014-06-194-44/+186
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we mounted the filesystem after the crash, we got the following message: BTRFS error (device xxx): block group xxxx has wrong amount of free space BTRFS error (device xxx): failed to load free space cache for block group xxx It is because we didn't update the metadata of the allocated space (in extent tree) until the file data was written into the disk. During this time, there was no information about the allocated spaces in either the extent tree nor the free space cache. when we wrote out the free space cache at this time (commit transaction), those spaces were lost. In fact, only the free space that is used to store the file data had this problem, the others didn't because the metadata of them is updated in the same transaction context. There are many methods which can fix the above problem - track the allocated space, and write it out when we write out the free space cache - account the size of the allocated space that is used to store the file data, if the size is not zero, don't write out the free space cache. The first one is complex and may make the performance drop down. This patch chose the second method, we use a per-block-group variant to account the size of that allocated space. Besides that, we also introduce a per-block-group read-write semaphore to avoid the race between the allocation and the free space cache write out. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: make free space cache write out functions more readableMiao Xie2014-06-191-66/+93
| | | | | | | | | | | | | | | | | | This patch makes the free space cache write out functions more readable, and beisdes that, it also reduces the stack space that the function -- __btrfs_write_out_cache uses from 194bytes to 144bytes. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: remove unused wait queue in struct extent_bufferFilipe Manana2014-06-191-1/+0
| | | | | | | | | | | | | | | | | | | | The lock_wq wait queue is not used anywhere, therefore just remove it. On a x86_64 system, this reduced sizeof(struct extent_buffer) from 320 bytes down to 296 bytes, which means a 4Kb page can now be used for 13 extent buffers instead of 12. Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: fix deadlocks with trylock on tree nodesChris Mason2014-06-191-34/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | The Btrfs tree trylock function is poorly named. It always takes the spinlock and backs off if the blocking lock is held. This can lead to surprising lockups because people expect it to really be a trylock. This commit makes it a pure trylock, both for the spinlock and the blocking lock. It also reworks the nested lock handling slightly to avoid taking the read lock while a spinning write lock might be held. Signed-off-by: Chris Mason <clm@fb.com>
* | Merge branch 'for-linus' of ↵Linus Torvalds2014-06-158-36/+182
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs Pull more btrfs updates from Chris Mason: "This has a few fixes since our last pull and a new ioctl for doing btree searches from userland. It's very similar to the existing ioctl, but lets us return larger items back down to the app" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: btrfs: fix error handling in create_pending_snapshot btrfs: fix use of uninit "ret" in end_extent_writepage() btrfs: free ulist in qgroup_shared_accounting() error path Btrfs: fix qgroups sanity test crash or hang btrfs: prevent RCU warning when dereferencing radix tree slot Btrfs: fix unfinished readahead thread for raid5/6 degraded mounting btrfs: new ioctl TREE_SEARCH_V2 btrfs: tree_search, search_ioctl: direct copy to userspace btrfs: new function read_extent_buffer_to_user btrfs: tree_search, copy_to_sk: return needed size on EOVERFLOW btrfs: tree_search, copy_to_sk: return EOVERFLOW for too small buffer btrfs: tree_search, search_ioctl: accept varying buffer btrfs: tree_search: eliminate redundant nr_items check
| * btrfs: fix error handling in create_pending_snapshotEric Sandeen2014-06-131-5/+7
| | | | | | | | | | | | | | | | | | | | fcebe456 cut and pasted some code to a later point in create_pending_snapshot(), but didn't switch to the appropriate error handling for this stage of the function. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: fix use of uninit "ret" in end_extent_writepage()Eric Sandeen2014-06-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If this condition in end_extent_writepage() is false: if (tree->ops && tree->ops->writepage_end_io_hook) we will then test an uninitialized "ret" at: ret = ret < 0 ? ret : -EIO; The test for ret is for the case where ->writepage_end_io_hook failed, and we'd choose that ret as the error; but if there is no ->writepage_end_io_hook, nothing sets ret. Initializing ret to 0 should be sufficient; if writepage_end_io_hook wasn't set, (!uptodate) means non-zero err was passed in, so we choose -EIO in that case. Signed-of-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: free ulist in qgroup_shared_accounting() error pathEric Sandeen2014-06-131-1/+3
| | | | | | | | | | | | | | | | | | If tmp = ulist_alloc(GFP_NOFS) fails, we return without freeing the previously allocated qgroups = ulist_alloc(GFP_NOFS) and cause a memory leak. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: fix qgroups sanity test crash or hangFilipe Manana2014-06-131-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Often when running the qgroups sanity test, a crash or a hang happened. This is because the extent buffer the test uses for the root node doesn't have an header level explicitly set, making it have a random level value. This is a problem when it's not zero for the btrfs_search_slot() calls the test ends up doing, resulting in crashes or hangs such as the following: [ 6454.127192] Btrfs loaded, debug=on, assert=on, integrity-checker=on (...) [ 6454.127760] BTRFS: selftest: Running qgroup tests [ 6454.127964] BTRFS: selftest: Running test_test_no_shared_qgroup [ 6454.127966] BTRFS: selftest: Qgroup basic add [ 6480.152005] BUG: soft lockup - CPU#0 stuck for 23s! [modprobe:5383] [ 6480.152005] Modules linked in: btrfs(+) xor raid6_pq binfmt_misc nfsd auth_rpcgss oid_registry nfs_acl nfs lockd fscache sunrpc i2c_piix4 i2c_core pcspkr evbug psmouse serio_raw e1000 [last unloaded: btrfs] [ 6480.152005] irq event stamp: 188448 [ 6480.152005] hardirqs last enabled at (188447): [<ffffffff8168ef5c>] restore_args+0x0/0x30 [ 6480.152005] hardirqs last disabled at (188448): [<ffffffff81698e6a>] apic_timer_interrupt+0x6a/0x80 [ 6480.152005] softirqs last enabled at (188446): [<ffffffff810516cf>] __do_softirq+0x1cf/0x450 [ 6480.152005] softirqs last disabled at (188441): [<ffffffff81051c25>] irq_exit+0xb5/0xc0 [ 6480.152005] CPU: 0 PID: 5383 Comm: modprobe Not tainted 3.15.0-rc8-fdm-btrfs-next-33+ #4 [ 6480.152005] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 6480.152005] task: ffff8802146125a0 ti: ffff8800d0d00000 task.ti: ffff8800d0d00000 [ 6480.152005] RIP: 0010:[<ffffffff81349a63>] [<ffffffff81349a63>] __write_lock_failed+0x13/0x20 [ 6480.152005] RSP: 0018:ffff8800d0d038e8 EFLAGS: 00000287 [ 6480.152005] RAX: 0000000000000000 RBX: ffffffff8168ef5c RCX: 000005deb8525852 [ 6480.152005] RDX: 0000000000000000 RSI: 0000000000001d45 RDI: ffff8802105000b8 [ 6480.152005] RBP: ffff8800d0d038e8 R08: fffffe12710f63db R09: ffffffffa03196fb [ 6480.152005] R10: ffff8802146125a0 R11: ffff880214612e28 R12: ffff8800d0d03858 [ 6480.152005] R13: 0000000000000000 R14: ffff8800d0d00000 R15: ffff8802146125a0 [ 6480.152005] FS: 00007f14ff804700(0000) GS:ffff880215e00000(0000) knlGS:0000000000000000 [ 6480.152005] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 6480.152005] CR2: 00007fff4df0dac8 CR3: 00000000d1796000 CR4: 00000000000006f0 [ 6480.152005] Stack: [ 6480.152005] ffff8800d0d03908 ffffffff810ae967 0000000000000001 ffff8802105000b8 [ 6480.152005] ffff8800d0d03938 ffffffff8168e57e ffffffffa0319c16 0000000000000007 [ 6480.152005] ffff880210500000 ffff880210500100 ffff8800d0d039b8 ffffffffa0319c16 [ 6480.152005] Call Trace: [ 6480.152005] [<ffffffff810ae967>] do_raw_write_lock+0x47/0xa0 [ 6480.152005] [<ffffffff8168e57e>] _raw_write_lock+0x5e/0x80 [ 6480.152005] [<ffffffffa0319c16>] ? btrfs_tree_lock+0x116/0x270 [btrfs] [ 6480.152005] [<ffffffffa0319c16>] btrfs_tree_lock+0x116/0x270 [btrfs] [ 6480.152005] [<ffffffffa02b2acb>] btrfs_lock_root_node+0x3b/0x50 [btrfs] [ 6480.152005] [<ffffffffa02b81a6>] btrfs_search_slot+0x916/0xa20 [btrfs] [ 6480.152005] [<ffffffff811a727f>] ? create_object+0x23f/0x300 [ 6480.152005] [<ffffffffa02b9958>] btrfs_insert_empty_items+0x78/0xd0 [btrfs] [ 6480.152005] [<ffffffffa036041a>] insert_normal_tree_ref.constprop.4+0xa2/0x19a [btrfs] [ 6480.152005] [<ffffffffa03605c3>] test_no_shared_qgroup+0xb1/0x1ca [btrfs] [ 6480.152005] [<ffffffff8108cad6>] ? local_clock+0x16/0x30 [ 6480.152005] [<ffffffffa035ef8e>] btrfs_test_qgroups+0x1ae/0x1d7 [btrfs] [ 6480.152005] [<ffffffffa03a69d2>] ? ftrace_define_fields_btrfs_space_reservation+0xfd/0xfd [btrfs] [ 6480.152005] [<ffffffffa03a6a86>] init_btrfs_fs+0xb4/0x153 [btrfs] [ 6480.152005] [<ffffffff81000352>] do_one_initcall+0x102/0x150 [ 6480.152005] [<ffffffff8103d223>] ? set_memory_nx+0x43/0x50 [ 6480.152005] [<ffffffff81682668>] ? set_section_ro_nx+0x6d/0x74 [ 6480.152005] [<ffffffff810d91cc>] load_module+0x1cdc/0x2630 (...) Therefore initialize the extent buffer as an empty leaf (level 0). Issue easy to reproduce when btrfs is built as a module via: $ for ((i = 1; i <= 1000000; i++)); do rmmod btrfs; modprobe btrfs; done Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: prevent RCU warning when dereferencing radix tree slotSasha Levin2014-06-131-1/+1
| | | | | | | | | | | | | | | | Mark the dereference as protected by lock. Not doing so triggers an RCU warning since the radix tree assumed that RCU is in use. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: fix unfinished readahead thread for raid5/6 degraded mountingWang Shilong2014-06-131-2/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Steps to reproduce: # mkfs.btrfs -f /dev/sd[b-f] -m raid5 -d raid5 # mkfs.ext4 /dev/sdc --->corrupt one of btrfs device # mount /dev/sdb /mnt -o degraded # btrfs scrub start -BRd /mnt This is because readahead would skip missing device, this is not true for RAID5/6, because REQ_GET_READ_MIRRORS return 1 for RAID5/6 block mapping. If expected data locates in missing device, readahead thread would not call __readahead_hook() which makes event @rc->elems=0 wait forever. Fix this problem by checking return value of btrfs_map_block(),we can only skip missing device safely if there are several mirrors. Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
| * btrfs: new ioctl TREE_SEARCH_V2Gerhard Heift2014-06-131-0/+41
| | | | | | | | | | | | | | | | | | | | | | | | This new ioctl call allows the user to supply a buffer of varying size in which a tree search can store its results. This is much more flexible if you want to receive items which are larger than the current fixed buffer of 3992 bytes or if you want to fetch more items at once. Items larger than this buffer are for example some of the type EXTENT_CSUM. Signed-off-by: Gerhard Heift <Gerhard@Heift.Name> Signed-off-by: Chris Mason <clm@fb.com> Acked-by: David Sterba <dsterba@suse.cz>
| * btrfs: tree_search, search_ioctl: direct copy to userspaceGerhard Heift2014-06-131-15/+33
| | | | | | | | | | | | | | | | | | By copying each found item seperatly to userspace, we do not need extra buffer in the kernel. Signed-off-by: Gerhard Heift <Gerhard@Heift.Name> Signed-off-by: Chris Mason <clm@fb.com> Acked-by: David Sterba <dsterba@suse.cz>
| * btrfs: new function read_extent_buffer_to_userGerhard Heift2014-06-132-0/+40
| | | | | | | | | | | | | | | | This new function reads the content of an extent directly to user memory. Signed-off-by: Gerhard Heift <Gerhard@Heift.Name> Signed-off-by: Chris Mason <clm@fb.com> Acked-by: David Sterba <dsterba@suse.cz>
| * btrfs: tree_search, copy_to_sk: return needed size on EOVERFLOWGerhard Heift2014-06-131-9/+15
| | | | | | | | | | | | | | | | | | If an item in tree_search is too large to be stored in the given buffer, return the needed size (including the header). Signed-off-by: Gerhard Heift <Gerhard@Heift.Name> Signed-off-by: Chris Mason <clm@fb.com> Acked-by: David Sterba <dsterba@suse.cz>
| * btrfs: tree_search, copy_to_sk: return EOVERFLOW for too small bufferGerhard Heift2014-06-131-2/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | In copy_to_sk, if an item is too large for the given buffer, it now returns -EOVERFLOW instead of copying a search_header with len = 0. For backward compatibility for the first item it still copies such a header to the buffer, but not any other following items, which could have fitted. tree_search changes -EOVERFLOW back to 0 to behave similiar to the way it behaved before this patch. Signed-off-by: Gerhard Heift <Gerhard@Heift.Name> Signed-off-by: Chris Mason <clm@fb.com> Acked-by: David Sterba <dsterba@suse.cz>
| * btrfs: tree_search, search_ioctl: accept varying bufferGerhard Heift2014-06-131-7/+11
| | | | | | | | | | | | | | | | rewrite search_ioctl to accept a buffer with varying size Signed-off-by: Gerhard Heift <Gerhard@Heift.Name> Signed-off-by: Chris Mason <clm@fb.com> Acked-by: David Sterba <dsterba@suse.cz>
| * btrfs: tree_search: eliminate redundant nr_items checkGerhard Heift2014-06-131-5/+7
| | | | | | | | | | | | | | | | | | | | If the amount of items reached the given limit of nr_items, we can leave copy_to_sk without updating the key. Also by returning 1 we leave the loop in search_ioctl without rechecking if we reached the given limit. Signed-off-by: Gerhard Heift <Gerhard@Heift.Name> Signed-off-by: Chris Mason <clm@fb.com> Acked-by: David Sterba <dsterba@suse.cz>
* | Merge branch 'for-linus' of ↵Linus Torvalds2014-06-122-62/+36
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs updates from Al Viro: "This the bunch that sat in -next + lock_parent() fix. This is the minimal set; there's more pending stuff. In particular, I really hope to get acct.c fixes merged this cycle - we need that to deal sanely with delayed-mntput stuff. In the next pile, hopefully - that series is fairly short and localized (kernel/acct.c, fs/super.c and fs/namespace.c). In this pile: more iov_iter work. Most of prereqs for ->splice_write with sane locking order are there and Kent's dio rewrite would also fit nicely on top of this pile" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (70 commits) lock_parent: don't step on stale ->d_parent of all-but-freed one kill generic_file_splice_write() ceph: switch to iter_file_splice_write() shmem: switch to iter_file_splice_write() nfs: switch to iter_splice_write_file() fs/splice.c: remove unneeded exports ocfs2: switch to iter_file_splice_write() ->splice_write() via ->write_iter() bio_vec-backed iov_iter optimize copy_page_{to,from}_iter() bury generic_file_aio_{read,write} lustre: get rid of messing with iovecs ceph: switch to ->write_iter() ceph_sync_direct_write: stop poking into iov_iter guts ceph_sync_read: stop poking into iov_iter guts new helper: copy_page_from_iter() fuse: switch to ->write_iter() btrfs: switch to ->write_iter() ocfs2: switch to ->write_iter() xfs: switch to ->write_iter() ...
| * \ Merge commit '9f12600fe425bc28f0ccba034a77783c09c15af4' into for-linusAl Viro2014-06-122-2/+6
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Backmerge of dcache.c changes from mainline. It's that, or complete rebase... Conflicts: fs/splice.c Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | btrfs: switch to ->write_iter()Al Viro2014-05-061-14/+10
| | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | switch simple generic_file_aio_read() users to ->read_iter()Al Viro2014-05-061-2/+2
| | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | iov_iter_truncate()Al Viro2014-05-061-9/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now It Can Be Done(tm) - we don't need to do iov_shorten() in generic_file_direct_write() anymore, now that all ->direct_IO() instances are converted to proper iov_iter methods and honour iter->count and iter->iov_offset properly. Get rid of count/ocount arguments of generic_file_direct_write(), while we are at it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>