Commit 3558d4f8 ("btrfs: Deprecate userspace transaction ioctls")
marked the beginning of the end of userspace transaction. This commit
finishes the job! There are no known users and ceph does not use the
ioctl anymore.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Acked-by: NSage Weil <sage@redhat.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The called function name is self explanatory.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Now that nothing uses the root arg of btrfs_log_dentry_safe it can be
safely removed. No functional changes.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The __cold functions are placed to a special section, as they're
expected to be called rarely. This could help i-cache prefetches or help
compiler to decide which branches are more/less likely to be taken
without any other annotations needed.

Though we can't add more __exit annotations, it's still possible to add
__cold (that's also added with __exit). That way the following function
categories are tagged:

- printf wrappers, error messages
- exit helpers
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Add a documentation blob that explains what the i_version field is, how
it is expected to work, and how it is currently implemented by various
filesystems.

We already have inode_inc_iversion. Add several other functions for
manipulating and accessing the i_version counter. For now, the
implementation is trivial and basically works the way that all of the
open-coded i_version accesses work today.

Future patches will convert existing users of i_version to use the new
API, and then convert the backend implementation to do things more
efficiently.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Reviewed-by: NJan Kara <jack@suse.cz>

If we do a buffered write after a zero range operation that has an
unaligned (with the filesystem's sector size) end which also falls within
an unwritten (prealloc) extent that is currently beyond the inode's
i_size, and the zero range operation has the flag FALLOC_FL_KEEP_SIZE,
we end up leaking data and metadata space. This happens because when
zeroing a range we call btrfs_truncate_block(), which does delalloc
(loads the page and partially zeroes its content), and in the buffered
write path we only clear existing delalloc space reservation for the
range we are writing into if that range starts at an offset smaller then
the inode's i_size, which makes sense since we can not have delalloc
extents beyond the i_size, only unwritten extents are allowed.

Example reproducer:

 $ mkfs.btrfs -f /dev/sdb
 $ mount /dev/sdb /mnt
 $ xfs_io -f -c "falloc -k 428K 4K" /mnt/foobar
 $ xfs_io -c "fzero -k 0 430K" /mnt/foobar
 $ xfs_io -c "pwrite -S 0xaa 428K 4K" /mnt/foobar
 $ umount /mnt

After the unmount we get the metadata and data space leaks reported in
dmesg/syslog:

 [95794.602253] ------------[ cut here ]------------
 [95794.603322] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9561 btrfs_destroy_inode+0x4e/0x206 [btrfs]
 [95794.605167] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs]
 [95794.613000] CPU: 0 PID: 31496 Comm: umount Tainted: G        W       4.14.0-rc6-btrfs-next-54+ #1
 [95794.614448] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
 [95794.615972] task: ffff880075aa0240 task.stack: ffffc90001734000
 [95794.617114] RIP: 0010:btrfs_destroy_inode+0x4e/0x206 [btrfs]
 [95794.618001] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202
 [95794.618721] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c
 [95794.619645] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418
 [95794.620711] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000
 [95794.621932] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000
 [95794.623124] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0
 [95794.624188] FS:  00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000
 [95794.625578] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 [95794.626522] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0
 [95794.627647] Call Trace:
 [95794.628128]  destroy_inode+0x3d/0x55
 [95794.628573]  evict+0x177/0x17e
 [95794.629010]  dispose_list+0x50/0x71
 [95794.629478]  evict_inodes+0x132/0x141
 [95794.630289]  generic_shutdown_super+0x3f/0x10b
 [95794.630864]  kill_anon_super+0x12/0x1c
 [95794.631383]  btrfs_kill_super+0x16/0x21 [btrfs]
 [95794.631930]  deactivate_locked_super+0x30/0x68
 [95794.632539]  deactivate_super+0x36/0x39
 [95794.633200]  cleanup_mnt+0x49/0x67
 [95794.633818]  __cleanup_mnt+0x12/0x14
 [95794.634416]  task_work_run+0x82/0xa6
 [95794.634902]  prepare_exit_to_usermode+0xe1/0x10c
 [95794.635525]  syscall_return_slowpath+0x18c/0x1af
 [95794.636122]  entry_SYSCALL_64_fastpath+0xab/0xad
 [95794.636834] RIP: 0033:0x7fa678cb99a7
 [95794.637370] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
 [95794.638672] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7
 [95794.639596] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90
 [95794.640703] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015
 [95794.641773] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64
 [95794.643150] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160
 [95794.644249] Code: ff 4c 8b a8 80 06 00 00 48 8b 87 c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 <0f> ff 83 bb 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00
 [95794.646929] ---[ end trace e95877675c6ec007 ]---
 [95794.647751] ------------[ cut here ]------------
 [95794.648509] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9562 btrfs_destroy_inode+0x59/0x206 [btrfs]
 [95794.649842] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs]
 [95794.654659] CPU: 0 PID: 31496 Comm: umount Tainted: G        W       4.14.0-rc6-btrfs-next-54+ #1
 [95794.655894] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
 [95794.657546] task: ffff880075aa0240 task.stack: ffffc90001734000
 [95794.658433] RIP: 0010:btrfs_destroy_inode+0x59/0x206 [btrfs]
 [95794.659279] RSP: 0018:ffffc90001737d00 EFLAGS: 00010202
 [95794.660054] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c
 [95794.660753] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418
 [95794.661513] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000
 [95794.662289] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000
 [95794.663393] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0
 [95794.664342] FS:  00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000
 [95794.665673] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 [95794.666593] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0
 [95794.667629] Call Trace:
 [95794.668065]  destroy_inode+0x3d/0x55
 [95794.668637]  evict+0x177/0x17e
 [95794.669179]  dispose_list+0x50/0x71
 [95794.669830]  evict_inodes+0x132/0x141
 [95794.670416]  generic_shutdown_super+0x3f/0x10b
 [95794.671103]  kill_anon_super+0x12/0x1c
 [95794.671786]  btrfs_kill_super+0x16/0x21 [btrfs]
 [95794.672552]  deactivate_locked_super+0x30/0x68
 [95794.673393]  deactivate_super+0x36/0x39
 [95794.674107]  cleanup_mnt+0x49/0x67
 [95794.674706]  __cleanup_mnt+0x12/0x14
 [95794.675279]  task_work_run+0x82/0xa6
 [95794.675795]  prepare_exit_to_usermode+0xe1/0x10c
 [95794.676507]  syscall_return_slowpath+0x18c/0x1af
 [95794.677275]  entry_SYSCALL_64_fastpath+0xab/0xad
 [95794.678006] RIP: 0033:0x7fa678cb99a7
 [95794.678600] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
 [95794.679739] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7
 [95794.680779] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90
 [95794.681837] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015
 [95794.682867] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64
 [95794.683891] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160
 [95794.684843] Code: c0 01 00 00 48 85 c0 74 02 0f ff 48 83 bb e0 02 00 00 00 74 02 0f ff 83 bb 3c ff ff ff 00 74 02 0f ff 83 bb 40 ff ff ff 00 74 02 <0f> ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff
 [95794.687156] ---[ end trace e95877675c6ec008 ]---
 [95794.687876] ------------[ cut here ]------------
 [95794.688579] WARNING: CPU: 0 PID: 31496 at fs/btrfs/inode.c:9565 btrfs_destroy_inode+0x7d/0x206 [btrfs]
 [95794.689735] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs]
 [95794.695015] CPU: 0 PID: 31496 Comm: umount Tainted: G        W       4.14.0-rc6-btrfs-next-54+ #1
 [95794.696396] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
 [95794.697956] task: ffff880075aa0240 task.stack: ffffc90001734000
 [95794.698925] RIP: 0010:btrfs_destroy_inode+0x7d/0x206 [btrfs]
 [95794.699763] RSP: 0018:ffffc90001737d00 EFLAGS: 00010206
 [95794.700434] RAX: 0000000000000000 RBX: ffff880070fa1418 RCX: ffffc90001737c7c
 [95794.701445] RDX: 0000000175aa0240 RSI: 0000000000000001 RDI: ffff880070fa1418
 [95794.702448] RBP: ffffc90001737d38 R08: 0000000000000000 R09: 0000000000000000
 [95794.703557] R10: ffffc90001737c48 R11: ffff88007123e158 R12: ffff880075b6a000
 [95794.704441] R13: ffff88006145c000 R14: ffff880070fa1418 R15: ffff880070c3b4a0
 [95794.705270] FS:  00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000
 [95794.706341] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 [95794.707001] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0
 [95794.708030] Call Trace:
 [95794.708466]  destroy_inode+0x3d/0x55
 [95794.709071]  evict+0x177/0x17e
 [95794.709497]  dispose_list+0x50/0x71
 [95794.709973]  evict_inodes+0x132/0x141
 [95794.710564]  generic_shutdown_super+0x3f/0x10b
 [95794.711200]  kill_anon_super+0x12/0x1c
 [95794.711633]  btrfs_kill_super+0x16/0x21 [btrfs]
 [95794.712139]  deactivate_locked_super+0x30/0x68
 [95794.712608]  deactivate_super+0x36/0x39
 [95794.713093]  cleanup_mnt+0x49/0x67
 [95794.713514]  __cleanup_mnt+0x12/0x14
 [95794.713933]  task_work_run+0x82/0xa6
 [95794.714543]  prepare_exit_to_usermode+0xe1/0x10c
 [95794.715247]  syscall_return_slowpath+0x18c/0x1af
 [95794.715952]  entry_SYSCALL_64_fastpath+0xab/0xad
 [95794.716653] RIP: 0033:0x7fa678cb99a7
 [95794.721100] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
 [95794.722052] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7
 [95794.722856] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90
 [95794.723698] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015
 [95794.724736] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64
 [95794.725928] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160
 [95794.726728] Code: 40 ff ff ff 00 74 02 0f ff 48 83 bb f8 fe ff ff 00 74 02 0f ff 48 83 bb 00 ff ff ff 00 74 02 0f ff 48 83 bb 30 ff ff ff 00 74 02 <0f> ff 48 83 bb 08 ff ff ff 00 74 02 0f ff 4d 85 e4 0f 84 52 01
 [95794.729203] ---[ end trace e95877675c6ec009 ]---
 [95794.841054] ------------[ cut here ]------------
 [95794.841829] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5831 btrfs_free_block_groups+0x235/0x36a [btrfs]
 [95794.843425] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs]
 [95794.850658] CPU: 0 PID: 31496 Comm: umount Tainted: G        W       4.14.0-rc6-btrfs-next-54+ #1
 [95794.852590] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
 [95794.854752] task: ffff880075aa0240 task.stack: ffffc90001734000
 [95794.855812] RIP: 0010:btrfs_free_block_groups+0x235/0x36a [btrfs]
 [95794.856811] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206
 [95794.857805] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001
 [95794.859014] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff
 [95794.860270] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9
 [95794.861525] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000
 [95794.862700] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100
 [95794.863810] FS:  00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000
 [95794.865149] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 [95794.866099] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0
 [95794.867198] Call Trace:
 [95794.867626]  close_ctree+0x1db/0x2b8 [btrfs]
 [95794.868188]  ? evict_inodes+0x132/0x141
 [95794.869037]  btrfs_put_super+0x15/0x17 [btrfs]
 [95794.870400]  generic_shutdown_super+0x6a/0x10b
 [95794.871262]  kill_anon_super+0x12/0x1c
 [95794.872046]  btrfs_kill_super+0x16/0x21 [btrfs]
 [95794.872746]  deactivate_locked_super+0x30/0x68
 [95794.873687]  deactivate_super+0x36/0x39
 [95794.874639]  cleanup_mnt+0x49/0x67
 [95794.875504]  __cleanup_mnt+0x12/0x14
 [95794.876126]  task_work_run+0x82/0xa6
 [95794.876788]  prepare_exit_to_usermode+0xe1/0x10c
 [95794.877777]  syscall_return_slowpath+0x18c/0x1af
 [95794.878381]  entry_SYSCALL_64_fastpath+0xab/0xad
 [95794.878888] RIP: 0033:0x7fa678cb99a7
 [95794.879307] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
 [95794.880204] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7
 [95794.881640] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90
 [95794.882690] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015
 [95794.883538] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64
 [95794.884562] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160
 [95794.885664] Code: 89 ef e8 07 ec 32 e1 e8 9d c0 ea e0 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 <0f> ff 48 83 bb 88 02 00 00 00 74 02 0f ff 48 83 bb d8 02 00 00
 [95794.887980] ---[ end trace e95877675c6ec00a ]---
 [95794.888739] ------------[ cut here ]------------
 [95794.889405] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:5832 btrfs_free_block_groups+0x241/0x36a [btrfs]
 [95794.891020] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs]
 [95794.897551] CPU: 0 PID: 31496 Comm: umount Tainted: G        W       4.14.0-rc6-btrfs-next-54+ #1
 [95794.898509] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
 [95794.899685] task: ffff880075aa0240 task.stack: ffffc90001734000
 [95794.900592] RIP: 0010:btrfs_free_block_groups+0x241/0x36a [btrfs]
 [95794.901387] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206
 [95794.902300] RAX: 0000000080000000 RBX: ffff88006145c000 RCX: 0000000000000001
 [95794.903260] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff
 [95794.904332] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9
 [95794.905300] R10: ffffc90001737c80 R11: 00000000000337fd R12: 0000000000000000
 [95794.906439] R13: ffff88006145c0c0 R14: ffff88021b61a800 R15: ffff88006145c100
 [95794.907459] FS:  00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000
 [95794.908625] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 [95794.909511] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0
 [95794.910630] Call Trace:
 [95794.911153]  close_ctree+0x1db/0x2b8 [btrfs]
 [95794.911837]  ? evict_inodes+0x132/0x141
 [95794.912344]  btrfs_put_super+0x15/0x17 [btrfs]
 [95794.912975]  generic_shutdown_super+0x6a/0x10b
 [95794.913788]  kill_anon_super+0x12/0x1c
 [95794.914424]  btrfs_kill_super+0x16/0x21 [btrfs]
 [95794.915142]  deactivate_locked_super+0x30/0x68
 [95794.915831]  deactivate_super+0x36/0x39
 [95794.916433]  cleanup_mnt+0x49/0x67
 [95794.917045]  __cleanup_mnt+0x12/0x14
 [95794.917665]  task_work_run+0x82/0xa6
 [95794.918309]  prepare_exit_to_usermode+0xe1/0x10c
 [95794.919021]  syscall_return_slowpath+0x18c/0x1af
 [95794.919722]  entry_SYSCALL_64_fastpath+0xab/0xad
 [95794.920426] RIP: 0033:0x7fa678cb99a7
 [95794.921039] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
 [95794.922303] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7
 [95794.923335] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90
 [95794.924364] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015
 [95794.925435] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64
 [95794.926533] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160
 [95794.927557] Code: 48 8d b3 28 02 00 00 48 83 c9 ff 31 d2 48 89 df e8 29 c5 ff ff 48 83 bb 80 02 00 00 00 74 02 0f ff 48 83 bb 88 02 00 00 00 74 02 <0f> ff 48 83 bb d8 02 00 00 00 74 02 0f ff 48 83 bb e0 02 00 00
 [95794.930166] ---[ end trace e95877675c6ec00b ]---
 [95794.930961] ------------[ cut here ]------------
 [95794.931727] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs]
 [95794.932729] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs]
 [95794.938394] CPU: 0 PID: 31496 Comm: umount Tainted: G        W       4.14.0-rc6-btrfs-next-54+ #1
 [95794.939842] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
 [95794.941455] task: ffff880075aa0240 task.stack: ffffc90001734000
 [95794.942336] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs]
 [95794.943268] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206
 [95794.944127] RAX: ffff8802004fd0e8 RBX: ffff88006145c000 RCX: 0000000000000001
 [95794.945211] RDX: 00000001810af668 RSI: 0000000000000002 RDI: 00000000ffffffff
 [95794.946316] RBP: ffffc90001737d98 R08: 0000000000000000 R09: ffffffff817e22b9
 [95794.947271] R10: ffffc90001737c80 R11: 00000000000337fd R12: ffff8802004fd0e8
 [95794.948219] R13: ffff88006145c0c0 R14: ffff88006145e598 R15: ffff88006145c100
 [95794.949193] FS:  00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000
 [95794.950495] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 [95794.951338] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0
 [95794.952361] Call Trace:
 [95794.952811]  close_ctree+0x1db/0x2b8 [btrfs]
 [95794.953522]  ? evict_inodes+0x132/0x141
 [95794.954543]  btrfs_put_super+0x15/0x17 [btrfs]
 [95794.955231]  generic_shutdown_super+0x6a/0x10b
 [95794.955916]  kill_anon_super+0x12/0x1c
 [95794.956414]  btrfs_kill_super+0x16/0x21 [btrfs]
 [95794.956953]  deactivate_locked_super+0x30/0x68
 [95794.957635]  deactivate_super+0x36/0x39
 [95794.958256]  cleanup_mnt+0x49/0x67
 [95794.958701]  __cleanup_mnt+0x12/0x14
 [95794.959181]  task_work_run+0x82/0xa6
 [95794.959635]  prepare_exit_to_usermode+0xe1/0x10c
 [95794.960182]  syscall_return_slowpath+0x18c/0x1af
 [95794.960731]  entry_SYSCALL_64_fastpath+0xab/0xad
 [95794.961438] RIP: 0033:0x7fa678cb99a7
 [95794.961990] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
 [95794.963111] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7
 [95794.963975] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90
 [95794.964680] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015
 [95794.965763] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64
 [95794.966868] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160
 [95794.967800] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff
 [95794.970629] ---[ end trace e95877675c6ec00c ]---
 [95794.971451] BTRFS info (device sdi): space_info 1 has 7680000 free, is not full
 [95794.972351] BTRFS info (device sdi): space_info total=8388608, used=704512, pinned=0, reserved=0, may_use=4096, readonly=0
 [95794.973595] ------------[ cut here ]------------
 [95794.974353] WARNING: CPU: 0 PID: 31496 at fs/btrfs/extent-tree.c:9953 btrfs_free_block_groups+0x2bc/0x36a [btrfs]
 [95794.980163] Modules linked in: btrfs xfs ppdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper parport_pc psmouse sg i2c_piix4 parport i2c_core evdev pcspkr button serio_raw sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod virtio_scsi ata_generic crc32c_intel ata_piix floppy virtio_pci virtio_ring virtio libata scsi_mod e1000 [last unloaded: btrfs]
 [95794.986461] CPU: 0 PID: 31496 Comm: umount Tainted: G        W       4.14.0-rc6-btrfs-next-54+ #1
 [95794.987591] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
 [95794.988929] task: ffff880075aa0240 task.stack: ffffc90001734000
 [95794.989922] RIP: 0010:btrfs_free_block_groups+0x2bc/0x36a [btrfs]
 [95794.990715] RSP: 0018:ffffc90001737d70 EFLAGS: 00010206
 [95794.991431] RAX: ffff88020f6e70e8 RBX: ffff88006145c000 RCX: ffffffff8115a906
 [95794.992455] RDX: ffffffff8115a902 RSI: ffff880075aa0b40 RDI: ffff880075aa0b40
 [95794.993535] RBP: ffffc90001737d98 R08: 0000000000000020 R09: fffffffffffffff7
 [95794.994573] R10: 00000000ffffffc4 R11: ffff8800633b1bc0 R12: ffff88020f6e70e8
 [95794.996250] R13: 0000000000000038 R14: ffff88006145e598 R15: 0000000000000000
 [95794.997233] FS:  00007fa6793c92c0(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000
 [95794.998592] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 [95794.999484] CR2: 000056338670d048 CR3: 00000000610dc005 CR4: 00000000001606f0
 [95795.000542] Call Trace:
 [95795.001138]  close_ctree+0x1db/0x2b8 [btrfs]
 [95795.001885]  ? evict_inodes+0x132/0x141
 [95795.002407]  btrfs_put_super+0x15/0x17 [btrfs]
 [95795.003093]  generic_shutdown_super+0x6a/0x10b
 [95795.003720]  kill_anon_super+0x12/0x1c
 [95795.004353]  btrfs_kill_super+0x16/0x21 [btrfs]
 [95795.005095]  deactivate_locked_super+0x30/0x68
 [95795.005716]  deactivate_super+0x36/0x39
 [95795.006388]  cleanup_mnt+0x49/0x67
 [95795.006939]  __cleanup_mnt+0x12/0x14
 [95795.007512]  task_work_run+0x82/0xa6
 [95795.008124]  prepare_exit_to_usermode+0xe1/0x10c
 [95795.008994]  syscall_return_slowpath+0x18c/0x1af
 [95795.009831]  entry_SYSCALL_64_fastpath+0xab/0xad
 [95795.010610] RIP: 0033:0x7fa678cb99a7
 [95795.011193] RSP: 002b:00007ffccf0aaed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
 [95795.012327] RAX: 0000000000000000 RBX: 0000563386706030 RCX: 00007fa678cb99a7
 [95795.013432] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000056338670ca90
 [95795.014558] RBP: 000056338670ca90 R08: 000056338670c740 R09: 0000000000000015
 [95795.015577] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007fa6791bae64
 [95795.016569] R13: 0000000000000000 R14: 0000563386706210 R15: 00007ffccf0ab160
 [95795.017662] Code: 00 00 00 4c 8b a3 98 25 00 00 49 83 bc 24 60 ff ff ff 00 75 16 49 83 bc 24 68 ff ff ff 00 75 0b 49 83 bc 24 70 ff ff ff 00 74 16 <0f> ff 49 8d b4 24 18 ff ff ff 31 c9 31 d2 48 89 df e8 93 7a ff
 [95795.020538] ---[ end trace e95877675c6ec00d ]---
 [95795.021259] BTRFS info (device sdi): space_info 4 has 1072775168 free, is not full
 [95795.022390] BTRFS info (device sdi): space_info total=1073741824, used=114688, pinned=0, reserved=0, may_use=786432, readonly=65536

Fix this by ensuring the zero range operation does not call
btrfs_truncate_block() if the corresponding extent is an unwritten one
(it's pointless anyway, since reading from an unwritten extent yields
zeroes).
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Tested-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

For a fallocate's zero range operation that targets a range with an end
that is not aligned to the sector size, we can end up not updating the
inode's i_size. This happens when the last page of the range maps to an
unwritten (prealloc) extent and before that last page we have either a
hole or a written extent. This is because in this scenario we relied
on a call to btrfs_prealloc_file_range() to update the inode's i_size,
however it can only update the i_size to the "down aligned" end of the
range.

Example:

 $ mkfs.btrfs -f /dev/sdc
 $ mount /dev/sdc /mnt
 $ xfs_io -f -c "pwrite -S 0xff 0 428K" /mnt/foobar
 $ xfs_io -c "falloc -k 428K 4K" /mnt/foobar
 $ xfs_io -c "fzero 0 430K" /mnt/foobar
 $ du --bytes /mnt/foobar
 438272	/mnt/foobar

The inode's i_size was left as 428Kb (438272 bytes) when it should have
been updated to 430Kb (440320 bytes).
Fix this by always updating the inode's i_size explicitly after zeroing
the range.

Fixes: ba6d5887946ff86d93dc ("Btrfs: add support for fallocate's zero range operation")
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

During a buffered IO write, we can have an extent state that we got when
we locked the range (if the range starts at an offset lower than eof), so
always pass it to btrfs_dirty_pages() so that setting the delalloc bit
in the range does not need to do a full search in the inode's io tree,
saving time and reducing the amount of time we hold the io tree's lock.
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This implements support the zero range operation of fallocate. For now
at least it's as simple as possible while reusing most of the existing
fallocate and hole punching infrastructure.
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

All callers pass either GFP_NOFS or GFP_KERNEL now, so we can sink the
parameter to the function, though we lose some of the slightly better
semantics of GFP_KERNEL in some places, it's worth cleaning up the
callchains.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Setting plug can merge adjacent IOs before dispatching IOs to the disk
driver.

Without plug, it'd not be a problem for single disk usecases, but for
multiple disks using raid profile, a large IO can be split to several
IOs of stripe length, and plug can be helpful to bring them together
for each disk so that we can save several disk access.

Moreover, fsync issues synchronous writes, so plug can really take
effect.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

All callers use GFP_NOFS, we don't have to pass it as an argument. The
built-in tests pass GFP_KERNEL, but they run only at module load time
and NOFS works there as well.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Adding __init macro gives kernel a hint that this function is only used
during the initialization phase and its memory resources can be freed up
after.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Right before we go into this loop locked_end is set to alloc_end - 1 and
is being used in nearby functions, no need to have exceptions. This just
makes the code consistent, no functional changes.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Fallocating a file in btrfs goes through several stages. The one before
actually inserting the fallocated extents is to create a qgroup
reservation, covering the desired range. To this end there is a loop in
btrfs_fallocate which checks to see if there are holes in the fallocated
range or !PREALLOC extents past EOF and if so create qgroup reservations
for them. Unfortunately, the main condition of the loop is burried right
at the end of its body rather than in the actual while statement which
makes it non-obvious. Fix this by moving the condition in the while
statement where it belongs. No functional changes.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Xfstests btrfs/146 revealed this corruption,

[   58.138831] Buffer I/O error on dev dm-0, logical block 2621424, async page read
[   58.151233] BTRFS error (device sdf): bdev /dev/mapper/error-test errs: wr 1, rd 0, flush 0, corrupt 0, gen 0
[   58.152403] list_add corruption. prev->next should be next (ffff88005e6775d8), but was ffffc9000189be88. (prev=ffffc9000189be88).
[   58.153518] ------------[ cut here ]------------
[   58.153892] WARNING: CPU: 1 PID: 1287 at lib/list_debug.c:31 __list_add_valid+0x169/0x1f0
...
[   58.157379] RIP: 0010:__list_add_valid+0x169/0x1f0
...
[   58.161956] Call Trace:
[   58.162264]  btrfs_log_inode_parent+0x5bd/0xfb0 [btrfs]
[   58.163583]  btrfs_log_dentry_safe+0x60/0x80 [btrfs]
[   58.164003]  btrfs_sync_file+0x4c2/0x6f0 [btrfs]
[   58.164393]  vfs_fsync_range+0x5f/0xd0
[   58.164898]  do_fsync+0x5a/0x90
[   58.165170]  SyS_fsync+0x10/0x20
[   58.165395]  entry_SYSCALL_64_fastpath+0x1f/0xbe
...

It turns out that we could record btrfs_log_ctx:io_err in
log_one_extents when IO fails, but make log_one_extents() return '0'
instead of -EIO, so the IO error is not acknowledged by the callers,
i.e.  btrfs_log_inode_parent(), which would remove btrfs_log_ctx:list
from list head 'root->log_ctxs'.  Since btrfs_log_ctx is allocated
from stack memory, it'd get freed with a object alive on the
list. then a future list_add will throw the above warning.

This returns the correct error in the above case.

Jeff also reported this while testing against his fsync error
patch set[1].

[1]: https://www.spinics.net/lists/linux-btrfs/msg65308.html
"btrfs list corruption and soft lockups while testing writeback error handling"

Fixes: 8407f553 ("Btrfs: fix data corruption after fast fsync and writeback error")
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The patch from commit a7e3b975 ("Btrfs: fix reported number of inode
blocks") introduced a regression where if we do a buffered write starting
at position equal to or greater than the file's size and then stat(2) the
file before writeback is triggered, the number of used blocks does not
change (unless there's a prealloc/unwritten extent). Example:

  $ xfs_io -f -c "pwrite -S 0xab 0 64K" foobar
  $ du -h foobar
  0	foobar
  $ sync
  $ du -h foobar
  64K	foobar

The first version of that patch didn't had this regression and the second
version, which was the one committed, was made only to address some
performance regression detected by the intel test robots using fs_mark.

This fixes the regression by setting the new delaloc bit in the range, and
doing it at btrfs_dirty_pages() while setting the regular dealloc bit as
well, so that this way we set both bits at once avoiding navigation of the
inode's io tree twice. Doing it at btrfs_dirty_pages() is also the most
meaninful place, as we should set the new dellaloc bit when if we set the
delalloc bit, which happens only if we copied bytes into the pages at
__btrfs_buffered_write().

This was making some of LTP's du tests fail, which can be quickly run
using a command line like the following:

  $ ./runltp -q -p -l /ltp.log -f commands -s du -d /mnt

Fixes: a7e3b975 ("Btrfs: fix reported number of inode blocks")
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Move the definition of the function btrfs_find_new_delalloc_bytes() closer
to the function btrfs_dirty_pages(), because in a future commit it will be
used exclusively by btrfs_dirty_pages(). This just moves the function's
definition, with no functional changes at all.
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Right now we do a lot of weird hoops around outstanding_extents in order
to keep the extent count consistent.  This is because we logically
transfer the outstanding_extent count from the initial reservation
through the set_delalloc_bits.  This makes it pretty difficult to get a
handle on how and when we need to mess with outstanding_extents.

Fix this by revamping the rules of how we deal with outstanding_extents.
Now instead everybody that is holding on to a delalloc extent is
required to increase the outstanding extents count for itself.  This
means we'll have something like this

btrfs_delalloc_reserve_metadata	- outstanding_extents = 1
 btrfs_set_extent_delalloc	- outstanding_extents = 2
btrfs_release_delalloc_extents	- outstanding_extents = 1

for an initial file write.  Now take the append write where we extend an
existing delalloc range but still under the maximum extent size

btrfs_delalloc_reserve_metadata - outstanding_extents = 2
  btrfs_set_extent_delalloc
    btrfs_set_bit_hook		- outstanding_extents = 3
    btrfs_merge_extent_hook	- outstanding_extents = 2
btrfs_delalloc_release_extents	- outstanding_extnets = 1

In order to make the ordered extent transition we of course must now
make ordered extents carry their own outstanding_extent reservation, so
for cow_file_range we end up with

btrfs_add_ordered_extent	- outstanding_extents = 2
clear_extent_bit		- outstanding_extents = 1
btrfs_remove_ordered_extent	- outstanding_extents = 0

This makes all manipulations of outstanding_extents much more explicit.
Every successful call to btrfs_delalloc_reserve_metadata _must_ now be
combined with btrfs_release_delalloc_extents, even in the error case, as
that is the only function that actually modifies the
outstanding_extents counter.

The drawback to this is now we are much more likely to have transient
cases where outstanding_extents is much larger than it actually should
be.  This could happen before as we manipulated the delalloc bits, but
now it happens basically at every write.  This may put more pressure on
the ENOSPC flushing code, but I think making this code simpler is worth
the cost.  I have another change coming to mitigate this side-effect
somewhat.

I also added trace points for the counter manipulation.  These were used
by a bpf script I wrote to help track down leak issues.
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Code cleanup for better understanding:
Variable needs_unlock to be called extent_locked to show state as
opposed to action. Changed the type to int, to reduce code in the
critical path.
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

We need the actual root for the ref verifier tool to work, so change
these functions to pass the root around instead.  This will be used in
a subsequent patch.
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Bool initializations should use true and false. Bool tests don't need
comparisons.
Signed-off-by: NThomas Meyer <thomas@m3y3r.de>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This is based on the old idea and code from Milosz Tanski.  With the aio
nowait code it becomes mostly trivial now.  Buffered writes continue to
return -EOPNOTSUPP if RWF_NOWAIT is passed.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Readdir does dir_emit while under the btree lock.  dir_emit can trigger
the page fault which means we can deadlock.  Fix this by allocating a
buffer on opening a directory and copying the readdir into this buffer
and doing dir_emit from outside of the tree lock.

Thread A
readdir  <holding tree lock>
  dir_emit
    <page fault>
      down_read(mmap_sem)

Thread B
mmap write
  down_write(mmap_sem)
    page_mkwrite
      wait_ordered_extents

Process C
finish_ordered_extent
  insert_reserved_file_extent
   try to lock leaf <hang>
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
[ copy the deadlock scenario to changelog ]
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Signed-off-by: NDavid Sterba <dsterba@suse.com>

Assigning pos for usage early messes up in append mode, where the pos is
re-assigned in generic_write_checks(). Assign pos later to get the
correct position to write from iocb->ki_pos.

Since check_can_nocow also uses the value of pos, we shift
generic_write_checks() before check_can_nocow(). Checks with IOCB_DIRECT
are present in generic_write_checks(), so checking for IOCB_NOWAIT is
enough.

Also, put locking sequence in the fast path.

This fixes a user visible bug, as reported:

"apparently breaks several shell related features on my system.
In zsh history stopped working, because no new entries are added
anymore.
I fist noticed the issue when I tried to build mplayer. It uses a shell
script to generate a help_mp.h file:
[...]

Here is a simple testcase:

 % echo "foo" >> test
 % echo "foo" >> test
 % cat test
 foo
 %
"

Fixes: edf064e7 ("btrfs: nowait aio support")
CC: Jens Axboe <axboe@kernel.dk>
Reported-by: NMarkus Trippelsdorf <markus@trippelsdorf.de>
Link: https://lkml.kernel.org/r/20170704042306.GA274@x4Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Just check and advance the errseq_t in the file before returning, and
use an errseq_t based check for writeback errors.

Other internal callers of filemap_* functions are left as-is.
Signed-off-by: NJeff Layton <jlayton@redhat.com>

[BUG]
For the following case, btrfs can underflow qgroup reserved space
at an error path:
(Page size 4K, function name without "btrfs_" prefix)

         Task A                  |             Task B
----------------------------------------------------------------------
Buffered_write [0, 2K)           |
|- check_data_free_space()       |
|  |- qgroup_reserve_data()      |
|     Range aligned to page      |
|     range [0, 4K)          <<< |
|     4K bytes reserved      <<< |
|- copy pages to page cache      |
                                 | Buffered_write [2K, 4K)
                                 | |- check_data_free_space()
                                 | |  |- qgroup_reserved_data()
                                 | |     Range alinged to page
                                 | |     range [0, 4K)
                                 | |     Already reserved by A <<<
                                 | |     0 bytes reserved      <<<
                                 | |- delalloc_reserve_metadata()
                                 | |  And it *FAILED* (Maybe EQUOTA)
                                 | |- free_reserved_data_space()
                                      |- qgroup_free_data()
                                         Range aligned to page range
                                         [0, 4K)
                                         Freeing 4K
(Special thanks to Chandan for the detailed report and analyse)

[CAUSE]
Above Task B is freeing reserved data range [0, 4K) which is actually
reserved by Task A.

And at writeback time, page dirty by Task A will go through writeback
routine, which will free 4K reserved data space at file extent insert
time, causing the qgroup underflow.

[FIX]
For btrfs_qgroup_free_data(), add @reserved parameter to only free
data ranges reserved by previous btrfs_qgroup_reserve_data().
So in above case, Task B will try to free 0 byte, so no underflow.
Reported-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
Tested-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Introduce a new parameter, struct extent_changeset for
btrfs_qgroup_reserved_data() and its callers.

Such extent_changeset was used in btrfs_qgroup_reserve_data() to record
which range it reserved in current reserve, so it can free it in error
paths.

The reason we need to export it to callers is, at buffered write error
path, without knowing what exactly which range we reserved in current
allocation, we can free space which is not reserved by us.

This will lead to qgroup reserved space underflow.
Reviewed-by: NChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

While punching a hole in a range that is not aligned with the sector size
(currently the same as the page size) we can end up leaving an extent map
in memory with a length that is smaller then the sector size or with a
start offset that is not aligned to the sector size. Both cases are not
expected and can lead to problems. This issue is easily detected
after the patch from commit a7e3b975 ("Btrfs: fix reported number of
inode blocks"), introduced in kernel 4.12-rc1, in a scenario like the
following for example:

  $ mkfs.btrfs -f /dev/sdb
  $ mount /dev/sdb /mnt
  $ xfs_io -c "pwrite -S 0xaa -b 100K 0 100K" /mnt/foo
  $ xfs_io -c "fpunch 60K 90K" /mnt/foo
  $ xfs_io -c "pwrite -S 0xbb -b 100K 50K 100K" /mnt/foo
  $ xfs_io -c "pwrite -S 0xcc -b 50K 100K 50K" /mnt/foo
  $ umount /mnt

After the unmount operation we can see several warnings emmitted due to
underflows related to space reservation counters:

[ 2837.443299] ------------[ cut here ]------------
[ 2837.447395] WARNING: CPU: 8 PID: 2474 at fs/btrfs/inode.c:9444 btrfs_destroy_inode+0xe8/0x27e [btrfs]
[ 2837.452108] Modules linked in: dm_flakey dm_mod ppdev parport_pc psmouse parport sg pcspkr acpi_cpufreq tpm_tis tpm_tis_core i2c_piix4 i2c_core evdev tpm button se
rio_raw sunrpc loop autofs4 ext4 crc16 jbd2 mbcache btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_gene
ric raid1 raid0 multipath linear md_mod sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring virtio e1000 scsi_mod floppy
[ 2837.458389] CPU: 8 PID: 2474 Comm: umount Tainted: G        W       4.10.0-rc8-btrfs-next-43+ #1
[ 2837.459754] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014
[ 2837.462379] Call Trace:
[ 2837.462379]  dump_stack+0x68/0x92
[ 2837.462379]  __warn+0xc2/0xdd
[ 2837.462379]  warn_slowpath_null+0x1d/0x1f
[ 2837.462379]  btrfs_destroy_inode+0xe8/0x27e [btrfs]
[ 2837.462379]  destroy_inode+0x3d/0x55
[ 2837.462379]  evict+0x177/0x17e
[ 2837.462379]  dispose_list+0x50/0x71
[ 2837.462379]  evict_inodes+0x132/0x141
[ 2837.462379]  generic_shutdown_super+0x3f/0xeb
[ 2837.462379]  kill_anon_super+0x12/0x1c
[ 2837.462379]  btrfs_kill_super+0x16/0x21 [btrfs]
[ 2837.462379]  deactivate_locked_super+0x30/0x68
[ 2837.462379]  deactivate_super+0x36/0x39
[ 2837.462379]  cleanup_mnt+0x58/0x76
[ 2837.462379]  __cleanup_mnt+0x12/0x14
[ 2837.462379]  task_work_run+0x77/0x9b
[ 2837.462379]  prepare_exit_to_usermode+0x9d/0xc5
[ 2837.462379]  syscall_return_slowpath+0x196/0x1b9
[ 2837.462379]  entry_SYSCALL_64_fastpath+0xab/0xad
[ 2837.462379] RIP: 0033:0x7f3ef3e6b9a7
[ 2837.462379] RSP: 002b:00007ffdd0d8de58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
[ 2837.462379] RAX: 0000000000000000 RBX: 0000556f76a39060 RCX: 00007f3ef3e6b9a7
[ 2837.462379] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000556f76a3f910
[ 2837.462379] RBP: 0000556f76a3f910 R08: 0000556f76a3e670 R09: 0000000000000015
[ 2837.462379] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f3ef436ce64
[ 2837.462379] R13: 0000000000000000 R14: 0000556f76a39240 R15: 00007ffdd0d8e0e0
[ 2837.519355] ---[ end trace e79345fe24b30b8d ]---
[ 2837.596256] ------------[ cut here ]------------
[ 2837.597625] WARNING: CPU: 8 PID: 2474 at fs/btrfs/extent-tree.c:5699 btrfs_free_block_groups+0x246/0x3eb [btrfs]
[ 2837.603547] Modules linked in: dm_flakey dm_mod ppdev parport_pc psmouse parport sg pcspkr acpi_cpufreq tpm_tis tpm_tis_core i2c_piix4 i2c_core evdev tpm button serio_raw sunrpc loop autofs4 ext4 crc16 jbd2 mbcache btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring virtio e1000 scsi_mod floppy
[ 2837.659372] CPU: 8 PID: 2474 Comm: umount Tainted: G        W       4.10.0-rc8-btrfs-next-43+ #1
[ 2837.663359] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014
[ 2837.663359] Call Trace:
[ 2837.663359]  dump_stack+0x68/0x92
[ 2837.663359]  __warn+0xc2/0xdd
[ 2837.663359]  warn_slowpath_null+0x1d/0x1f
[ 2837.663359]  btrfs_free_block_groups+0x246/0x3eb [btrfs]
[ 2837.663359]  close_ctree+0x1dd/0x2e1 [btrfs]
[ 2837.663359]  ? evict_inodes+0x132/0x141
[ 2837.663359]  btrfs_put_super+0x15/0x17 [btrfs]
[ 2837.663359]  generic_shutdown_super+0x6a/0xeb
[ 2837.663359]  kill_anon_super+0x12/0x1c
[ 2837.663359]  btrfs_kill_super+0x16/0x21 [btrfs]
[ 2837.663359]  deactivate_locked_super+0x30/0x68
[ 2837.663359]  deactivate_super+0x36/0x39
[ 2837.663359]  cleanup_mnt+0x58/0x76
[ 2837.663359]  __cleanup_mnt+0x12/0x14
[ 2837.663359]  task_work_run+0x77/0x9b
[ 2837.663359]  prepare_exit_to_usermode+0x9d/0xc5
[ 2837.663359]  syscall_return_slowpath+0x196/0x1b9
[ 2837.663359]  entry_SYSCALL_64_fastpath+0xab/0xad
[ 2837.663359] RIP: 0033:0x7f3ef3e6b9a7
[ 2837.663359] RSP: 002b:00007ffdd0d8de58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
[ 2837.663359] RAX: 0000000000000000 RBX: 0000556f76a39060 RCX: 00007f3ef3e6b9a7
[ 2837.663359] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000556f76a3f910
[ 2837.663359] RBP: 0000556f76a3f910 R08: 0000556f76a3e670 R09: 0000000000000015
[ 2837.663359] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f3ef436ce64
[ 2837.663359] R13: 0000000000000000 R14: 0000556f76a39240 R15: 00007ffdd0d8e0e0
[ 2837.739445] ---[ end trace e79345fe24b30b8e ]---
[ 2837.745595] ------------[ cut here ]------------
[ 2837.746412] WARNING: CPU: 8 PID: 2474 at fs/btrfs/extent-tree.c:5700 btrfs_free_block_groups+0x261/0x3eb [btrfs]
[ 2837.747955] Modules linked in: dm_flakey dm_mod ppdev parport_pc psmouse parport sg pcspkr acpi_cpufreq tpm_tis tpm_tis_core i2c_piix4 i2c_core evdev tpm button serio_raw sunrpc loop autofs4 ext4 crc16 jbd2 mbcache btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring virtio e1000 scsi_mod floppy
[ 2837.755395] CPU: 8 PID: 2474 Comm: umount Tainted: G        W       4.10.0-rc8-btrfs-next-43+ #1
[ 2837.756769] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014
[ 2837.758526] Call Trace:
[ 2837.758925]  dump_stack+0x68/0x92
[ 2837.759383]  __warn+0xc2/0xdd
[ 2837.759383]  warn_slowpath_null+0x1d/0x1f
[ 2837.759383]  btrfs_free_block_groups+0x261/0x3eb [btrfs]
[ 2837.759383]  close_ctree+0x1dd/0x2e1 [btrfs]
[ 2837.759383]  ? evict_inodes+0x132/0x141
[ 2837.759383]  btrfs_put_super+0x15/0x17 [btrfs]
[ 2837.759383]  generic_shutdown_super+0x6a/0xeb
[ 2837.759383]  kill_anon_super+0x12/0x1c
[ 2837.759383]  btrfs_kill_super+0x16/0x21 [btrfs]
[ 2837.759383]  deactivate_locked_super+0x30/0x68
[ 2837.759383]  deactivate_super+0x36/0x39
[ 2837.759383]  cleanup_mnt+0x58/0x76
[ 2837.759383]  __cleanup_mnt+0x12/0x14
[ 2837.759383]  task_work_run+0x77/0x9b
[ 2837.759383]  prepare_exit_to_usermode+0x9d/0xc5
[ 2837.759383]  syscall_return_slowpath+0x196/0x1b9
[ 2837.759383]  entry_SYSCALL_64_fastpath+0xab/0xad
[ 2837.759383] RIP: 0033:0x7f3ef3e6b9a7
[ 2837.759383] RSP: 002b:00007ffdd0d8de58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
[ 2837.759383] RAX: 0000000000000000 RBX: 0000556f76a39060 RCX: 00007f3ef3e6b9a7
[ 2837.759383] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000556f76a3f910
[ 2837.759383] RBP: 0000556f76a3f910 R08: 0000556f76a3e670 R09: 0000000000000015
[ 2837.759383] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f3ef436ce64
[ 2837.759383] R13: 0000000000000000 R14: 0000556f76a39240 R15: 00007ffdd0d8e0e0
[ 2837.777063] ---[ end trace e79345fe24b30b8f ]---
[ 2837.778235] ------------[ cut here ]------------
[ 2837.778856] WARNING: CPU: 8 PID: 2474 at fs/btrfs/extent-tree.c:9825 btrfs_free_block_groups+0x348/0x3eb [btrfs]
[ 2837.791385] Modules linked in: dm_flakey dm_mod ppdev parport_pc psmouse parport sg pcspkr acpi_cpufreq tpm_tis tpm_tis_core i2c_piix4 i2c_core evdev tpm button serio_raw sunrpc loop autofs4 ext4 crc16 jbd2 mbcache btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring virtio e1000 scsi_mod floppy
[ 2837.797711] CPU: 8 PID: 2474 Comm: umount Tainted: G        W       4.10.0-rc8-btrfs-next-43+ #1
[ 2837.798594] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014
[ 2837.800118] Call Trace:
[ 2837.800515]  dump_stack+0x68/0x92
[ 2837.801015]  __warn+0xc2/0xdd
[ 2837.801471]  warn_slowpath_null+0x1d/0x1f
[ 2837.801698]  btrfs_free_block_groups+0x348/0x3eb [btrfs]
[ 2837.801698]  close_ctree+0x1dd/0x2e1 [btrfs]
[ 2837.801698]  ? evict_inodes+0x132/0x141
[ 2837.801698]  btrfs_put_super+0x15/0x17 [btrfs]
[ 2837.801698]  generic_shutdown_super+0x6a/0xeb
[ 2837.801698]  kill_anon_super+0x12/0x1c
[ 2837.801698]  btrfs_kill_super+0x16/0x21 [btrfs]
[ 2837.801698]  deactivate_locked_super+0x30/0x68
[ 2837.801698]  deactivate_super+0x36/0x39
[ 2837.801698]  cleanup_mnt+0x58/0x76
[ 2837.801698]  __cleanup_mnt+0x12/0x14
[ 2837.801698]  task_work_run+0x77/0x9b
[ 2837.801698]  prepare_exit_to_usermode+0x9d/0xc5
[ 2837.801698]  syscall_return_slowpath+0x196/0x1b9
[ 2837.801698]  entry_SYSCALL_64_fastpath+0xab/0xad
[ 2837.801698] RIP: 0033:0x7f3ef3e6b9a7
[ 2837.801698] RSP: 002b:00007ffdd0d8de58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
[ 2837.801698] RAX: 0000000000000000 RBX: 0000556f76a39060 RCX: 00007f3ef3e6b9a7
[ 2837.801698] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000556f76a3f910
[ 2837.801698] RBP: 0000556f76a3f910 R08: 0000556f76a3e670 R09: 0000000000000015
[ 2837.801698] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f3ef436ce64
[ 2837.801698] R13: 0000000000000000 R14: 0000556f76a39240 R15: 00007ffdd0d8e0e0
[ 2837.818441] ---[ end trace e79345fe24b30b90 ]---
[ 2837.818991] BTRFS info (device sdc): space_info 1 has 7974912 free, is not full
[ 2837.819830] BTRFS info (device sdc): space_info total=8388608, used=417792, pinned=0, reserved=0, may_use=18446744073709547520, readonly=0

What happens in the above example is the following:

1) When punching the hole, at btrfs_punch_hole(), the variable tail_len
   is set to 2048 (as tail_start is 148Kb + 1 and offset + len is 150Kb).
   This results in the creation of an extent map with a length of 2Kb
   starting at file offset 148Kb, through find_first_non_hole() ->
   btrfs_get_extent().

2) The second write (first write after the hole punch operation), sets
   the range [50Kb, 152Kb[ to delalloc.

3) The third write, at btrfs_find_new_delalloc_bytes(), sees the extent
   map covering the range [148Kb, 150Kb[ and ends up calling
   set_extent_bit() for the same range, which results in splitting an
   existing extent state record, covering the range [148Kb, 152Kb[ into
   two 2Kb extent state records, covering the ranges [148Kb, 150Kb[ and
   [150Kb, 152Kb[.

4) Finally at lock_and_cleanup_extent_if_need(), immediately after calling
   btrfs_find_new_delalloc_bytes() we clear the delalloc bit from the
   range [100Kb, 152Kb[ which results in the btrfs_clear_bit_hook()
   callback being invoked against the two 2Kb extent state records that
   cover the ranges [148Kb, 150Kb[ and [150Kb, 152Kb[. When called against
   the first 2Kb extent state, it calls btrfs_delalloc_release_metadata()
   with a length argument of 2048 bytes. That function rounds up the length
   to a sector size aligned length, so it ends up considering a length of
   4096 bytes, and then calls calc_csum_metadata_size() which results in
   decrementing the inode's csum_bytes counter by 4096 bytes, so after
   it stays a value of 0 bytes. Then the same happens when
   btrfs_clear_bit_hook() is called against the second extent state that
   has a length of 2Kb, covering the range [150Kb, 152Kb[, the length is
   rounded up to 4096 and calc_csum_metadata_size() ends up being called
   to decrement 4096 bytes from the inode's csum_bytes counter, which
   at that time has a value of 0, leading to an underflow, which is
   exactly what triggers the first warning, at btrfs_destroy_inode().
   All the other warnings relate to several space accounting counters
   that underflow as well due to similar reasons.

A similar case but where the hole punching operation creates an extent map
with a start offset not aligned to the sector size is the following:

  $ mkfs.btrfs -f /dev/sdb
  $ mount /dev/sdb /mnt
  $ xfs_io -f -c "fpunch 695K 820K" $SCRATCH_MNT/bar
  $ xfs_io -c "pwrite -S 0xaa 1008K 307K" $SCRATCH_MNT/bar
  $ xfs_io -c "pwrite -S 0xbb -b 630K 1073K 630K" $SCRATCH_MNT/bar
  $ xfs_io -c "pwrite -S 0xcc -b 459K 1068K 459K" $SCRATCH_MNT/bar
  $ umount /mnt

During the unmount operation we get similar traces for the same reasons as
in the first example.

So fix the hole punching operation to make sure it never creates extent
maps with a length that is not aligned to the sector size nor with a start
offset that is not aligned to the sector size, as this breaks all
assumptions and it's a land mine.

Fixes: d7781546 ("btrfs: Avoid trucating page or punching hole in a already existed hole.")
Cc: <stable@vger.kernel.org>
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Return EAGAIN if any of the following checks fail
 + i_rwsem is not lockable
 + NODATACOW or PREALLOC is not set
 + Cannot nocow at the desired location
 + Writing beyond end of file which is not allocated
Acked-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Currently when there are buffered writes that were not yet flushed and
they fall within allocated ranges of the file (that is, not in holes or
beyond eof assuming there are no prealloc extents beyond eof), btrfs
simply reports an incorrect number of used blocks through the stat(2)
system call (or any of its variants), regardless of mount options or
inode flags (compress, compress-force, nodatacow). This is because the
number of blocks used that is reported is based on the current number
of bytes in the vfs inode plus the number of dealloc bytes in the btrfs
inode. The later covers bytes that both fall within allocated regions
of the file and holes.

Example scenarios where the number of reported blocks is wrong while the
buffered writes are not flushed:

  $ mkfs.btrfs -f /dev/sdc
  $ mount /dev/sdc /mnt/sdc

  $ xfs_io -f -c "pwrite -S 0xaa 0 64K" /mnt/sdc/foo1
  wrote 65536/65536 bytes at offset 0
  64 KiB, 16 ops; 0.0000 sec (259.336 MiB/sec and 66390.0415 ops/sec)

  $ sync

  $ xfs_io -c "pwrite -S 0xbb 0 64K" /mnt/sdc/foo1
  wrote 65536/65536 bytes at offset 0
  64 KiB, 16 ops; 0.0000 sec (192.308 MiB/sec and 49230.7692 ops/sec)

  # The following should have reported 64K...
  $ du -h /mnt/sdc/foo1
  128K	/mnt/sdc/foo1

  $ sync

  # After flushing the buffered write, it now reports the correct value.
  $ du -h /mnt/sdc/foo1
  64K	/mnt/sdc/foo1

  $ xfs_io -f -c "falloc -k 0 128K" -c "pwrite -S 0xaa 0 64K" /mnt/sdc/foo2
  wrote 65536/65536 bytes at offset 0
  64 KiB, 16 ops; 0.0000 sec (520.833 MiB/sec and 133333.3333 ops/sec)

  $ sync

  $ xfs_io -c "pwrite -S 0xbb 64K 64K" /mnt/sdc/foo2
  wrote 65536/65536 bytes at offset 65536
  64 KiB, 16 ops; 0.0000 sec (260.417 MiB/sec and 66666.6667 ops/sec)

  # The following should have reported 128K...
  $ du -h /mnt/sdc/foo2
  192K	/mnt/sdc/foo2

  $ sync

  # After flushing the buffered write, it now reports the correct value.
  $ du -h /mnt/sdc/foo2
  128K	/mnt/sdc/foo2

So the number of used file blocks is simply incorrect, unlike in other
filesystems such as ext4 and xfs for example, but only while the buffered
writes are not flushed.

Fix this by tracking the number of delalloc bytes that fall within holes
and beyond eof of a file, and use instead this new counter when reporting
the number of used blocks for an inode.

Another different problem that exists is that the delalloc bytes counter
is reset when writeback starts (by clearing the EXTENT_DEALLOC flag from
the respective range in the inode's iotree) and the vfs inode's bytes
counter is only incremented when writeback finishes (through
insert_reserved_file_extent()). Therefore while writeback is ongoing we
simply report a wrong number of blocks used by an inode if the write
operation covers a range previously unallocated. While this change does
not fix this problem, it does minimizes it a lot by shortening that time
window, as the new dealloc bytes counter (new_delalloc_bytes) is only
decremented when writeback finishes right before updating the vfs inode's
bytes counter. Fully fixing this second problem is not trivial and will
be addressed later by a different patch.
Signed-off-by: NFilipe Manana <fdmanana@suse.com>

If the call to btrfs_qgroup_reserve_data() failed, we were leaking an
extent map structure. The failure can happen either due to an -ENOMEM
condition or, when quotas are enabled, due to -EDQUOT for example.
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>

btrfs_get_extent() never returns NULL pointers, so this code introduces
a static checker warning.

The btrfs_get_extent() is a bit complex, but trust me that it doesn't
return NULLs and also if it did we would trigger the BUG_ON(!em) before
the last return statement.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
[ updated subject ]
Signed-off-by: NDavid Sterba <dsterba@suse.com>

In addition to changing the signature, this patch also switches
all the functions which are used as an argument to also take btrfs_inode.
Namely those are: btrfs_get_extent and btrfs_get_extent_filemap.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>