Commit Graph

2539 Commits

Author SHA1 Message Date
Filipe Manana
28a36e75d1 btrfs: remove redundant root argument from btrfs_update_inode_fallback()
[ Upstream commit 0a5d0dc55f ]

The root argument for btrfs_update_inode_fallback() always matches the
root of the given inode, so remove the root argument and get it from the
inode argument.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 5f61b96159 ("btrfs: fix inode lookup error handling during log replay")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-17 18:35:16 +02:00
Filipe Manana
ddead3c5ca btrfs: remove noinline from btrfs_update_inode()
[ Upstream commit cddaaacca9 ]

The noinline attribute of btrfs_update_inode() is pointless as the
function is exported and widely used, so remove it.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 5f61b96159 ("btrfs: fix inode lookup error handling during log replay")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-17 18:35:16 +02:00
Filipe Manana
2a7ac29f10 btrfs: use btrfs_record_snapshot_destroy() during rmdir
[ Upstream commit 157501b046 ]

We are setting the parent directory's last_unlink_trans directly which
may result in a concurrent task starting to log the directory not see the
update and therefore can log the directory after we removed a child
directory which had a snapshot within instead of falling back to a
transaction commit. Replaying such a log tree would result in a mount
failure since we can't currently delete snapshots (and subvolumes) during
log replay. This is the type of failure described in commit 1ec9a1ae1e
("Btrfs: fix unreplayable log after snapshot delete + parent dir fsync").

Fix this by using btrfs_record_snapshot_destroy() which updates the
last_unlink_trans field while holding the inode's log_mutex lock.

Fixes: 44f714dae5 ("Btrfs: improve performance on fsync against new inode after rename/unlink")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-10 16:03:08 +02:00
Filipe Manana
d77a168028 btrfs: propagate last_unlink_trans earlier when doing a rmdir
[ Upstream commit c466e33e72 ]

In case the removed directory had a snapshot that was deleted, we are
propagating its inode's last_unlink_trans to the parent directory after
we removed the entry from the parent directory. This leaves a small race
window where someone can log the parent directory after we removed the
entry and before we updated last_unlink_trans, and as a result if we ever
try to replay such a log tree, we will fail since we will attempt to
remove a snapshot during log replay, which is currently not possible and
results in the log replay (and mount) to fail. This is the type of failure
described in commit 1ec9a1ae1e ("Btrfs: fix unreplayable log after
snapshot delete + parent dir fsync").

So fix this by propagating the last_unlink_trans to the parent directory
before we remove the entry from it.

Fixes: 44f714dae5 ("Btrfs: improve performance on fsync against new inode after rename/unlink")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-10 16:03:08 +02:00
Anand Jain
65d7f92db8 btrfs: rename err to ret in btrfs_rmdir()
[ Upstream commit c3a1cc8ff4 ]

Unify naming of return value to the preferred way.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: c466e33e72 ("btrfs: propagate last_unlink_trans earlier when doing a rmdir")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-10 16:03:08 +02:00
Filipe Manana
aeeae8feea btrfs: fix a race between renames and directory logging
commit 3ca864de85 upstream.

We have a race between a rename and directory inode logging that if it
happens and we crash/power fail before the rename completes, the next time
the filesystem is mounted, the log replay code will end up deleting the
file that was being renamed.

This is best explained following a step by step analysis of an interleaving
of steps that lead into this situation.

Consider the initial conditions:

1) We are at transaction N;

2) We have directories A and B created in a past transaction (< N);

3) We have inode X corresponding to a file that has 2 hardlinks, one in
   directory A and the other in directory B, so we'll name them as
   "A/foo_link1" and "B/foo_link2". Both hard links were persisted in a
   past transaction (< N);

4) We have inode Y corresponding to a file that as a single hard link and
   is located in directory A, we'll name it as "A/bar". This file was also
   persisted in a past transaction (< N).

The steps leading to a file loss are the following and for all of them we
are under transaction N:

 1) Link "A/foo_link1" is removed, so inode's X last_unlink_trans field
    is updated to N, through btrfs_unlink() -> btrfs_record_unlink_dir();

 2) Task A starts a rename for inode Y, with the goal of renaming from
    "A/bar" to "A/baz", so we enter btrfs_rename();

 3) Task A inserts the new BTRFS_INODE_REF_KEY for inode Y by calling
    btrfs_insert_inode_ref();

 4) Because the rename happens in the same directory, we don't set the
    last_unlink_trans field of directoty A's inode to the current
    transaction id, that is, we don't cal btrfs_record_unlink_dir();

 5) Task A then removes the entries from directory A (BTRFS_DIR_ITEM_KEY
    and BTRFS_DIR_INDEX_KEY items) when calling __btrfs_unlink_inode()
    (actually the dir index item is added as a delayed item, but the
    effect is the same);

 6) Now before task A adds the new entry "A/baz" to directory A by
    calling btrfs_add_link(), another task, task B is logging inode X;

 7) Task B starts a fsync of inode X and after logging inode X, at
    btrfs_log_inode_parent() it calls btrfs_log_all_parents(), since
    inode X has a last_unlink_trans value of N, set at in step 1;

 8) At btrfs_log_all_parents() we search for all parent directories of
    inode X using the commit root, so we find directories A and B and log
    them. Bu when logging direct A, we don't have a dir index item for
    inode Y anymore, neither the old name "A/bar" nor for the new name
    "A/baz" since the rename has deleted the old name but has not yet
    inserted the new name - task A hasn't called yet btrfs_add_link() to
    do that.

    Note that logging directory A doesn't fallback to a transaction
    commit because its last_unlink_trans has a lower value than the
    current transaction's id (see step 4);

 9) Task B finishes logging directories A and B and gets back to
    btrfs_sync_file() where it calls btrfs_sync_log() to persist the log
    tree;

10) Task B successfully persisted the log tree, btrfs_sync_log() completed
    with success, and a power failure happened.

    We have a log tree without any directory entry for inode Y, so the
    log replay code deletes the entry for inode Y, name "A/bar", from the
    subvolume tree since it doesn't exist in the log tree and the log
    tree is authorative for its index (we logged a BTRFS_DIR_LOG_INDEX_KEY
    item that covers the index range for the dentry that corresponds to
    "A/bar").

    Since there's no other hard link for inode Y and the log replay code
    deletes the name "A/bar", the file is lost.

The issue wouldn't happen if task B synced the log only after task A
called btrfs_log_new_name(), which would update the log with the new name
for inode Y ("A/bar").

Fix this by pinning the log root during renames before removing the old
directory entry, and unpinning after btrfs_log_new_name() is called.

Fixes: 259c4b96d7 ("btrfs: stop doing unnecessary log updates during a rename")
CC: stable@vger.kernel.org # 5.18+
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-06 11:00:13 +02:00
Dave Chen
b364ee98ac btrfs: fix COW handling in run_delalloc_nocow()
commit be3f1938d3 upstream.

In run_delalloc_nocow(), when the found btrfs_key's offset > cur_offset,
it indicates a gap between the current processing region and
the next file extent. The original code would directly jump to
the "must_cow" label, which increments the slot and forces a fallback
to COW. This behavior might skip an extent item and result in an
overestimated COW fallback range.

This patch modifies the logic so that when a gap is detected:

- If no COW range is already being recorded (cow_start is unset),
  cow_start is set to cur_offset.

- cur_offset is then advanced to the beginning of the next extent.

- Instead of jumping to "must_cow", control flows directly to
  "next_slot" so that the same extent item can be reexamined properly.

The change ensures that we accurately account for the extent gap and
avoid accidentally extending the range that needs to fallback to COW.

CC: stable@vger.kernel.org # 6.6+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Dave Chen <davechen@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-05-09 09:43:49 +02:00
Haisu Wang
b6b77ca4c9 btrfs: fix the length of reserved qgroup to free
commit 2b084d8205 upstream.

The dealloc flag may be cleared and the extent won't reach the disk in
cow_file_range when errors path. The reserved qgroup space is freed in
commit 30479f31d4 ("btrfs: fix qgroup reserve leaks in
cow_file_range"). However, the length of untouched region to free needs
to be adjusted with the correct remaining region size.

Fixes: 30479f31d4 ("btrfs: fix qgroup reserve leaks in cow_file_range")
CC: stable@vger.kernel.org # 6.11+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Haisu Wang <haisuwang@tencent.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-25 10:45:58 +02:00
Boris Burkov
84464db2ec btrfs: fix qgroup reserve leaks in cow_file_range
commit 30479f31d4 upstream.

In the buffered write path, the dirty page owns the qgroup reserve until
it creates an ordered_extent.

Therefore, any errors that occur before the ordered_extent is created
must free that reservation, or else the space is leaked. The fstest
generic/475 exercises various IO error paths, and is able to trigger
errors in cow_file_range where we fail to get to allocating the ordered
extent. Note that because we *do* clear delalloc, we are likely to
remove the inode from the delalloc list, so the inodes/pages to not have
invalidate/launder called on them in the commit abort path.

This results in failures at the unmount stage of the test that look like:

  BTRFS: error (device dm-8 state EA) in cleanup_transaction:2018: errno=-5 IO failure
  BTRFS: error (device dm-8 state EA) in btrfs_replace_file_extents:2416: errno=-5 IO failure
  BTRFS warning (device dm-8 state EA): qgroup 0/5 has unreleased space, type 0 rsv 28672
  ------------[ cut here ]------------
  WARNING: CPU: 3 PID: 22588 at fs/btrfs/disk-io.c:4333 close_ctree+0x222/0x4d0 [btrfs]
  Modules linked in: btrfs blake2b_generic libcrc32c xor zstd_compress raid6_pq
  CPU: 3 PID: 22588 Comm: umount Kdump: loaded Tainted: G W          6.10.0-rc7-gab56fde445b8 #21
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
  RIP: 0010:close_ctree+0x222/0x4d0 [btrfs]
  RSP: 0018:ffffb4465283be00 EFLAGS: 00010202
  RAX: 0000000000000001 RBX: ffffa1a1818e1000 RCX: 0000000000000001
  RDX: 0000000000000000 RSI: ffffb4465283bbe0 RDI: ffffa1a19374fcb8
  RBP: ffffa1a1818e13c0 R08: 0000000100028b16 R09: 0000000000000000
  R10: 0000000000000003 R11: 0000000000000003 R12: ffffa1a18ad7972c
  R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
  FS:  00007f9168312b80(0000) GS:ffffa1a4afcc0000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f91683c9140 CR3: 000000010acaa000 CR4: 00000000000006f0
  Call Trace:
   <TASK>
   ? close_ctree+0x222/0x4d0 [btrfs]
   ? __warn.cold+0x8e/0xea
   ? close_ctree+0x222/0x4d0 [btrfs]
   ? report_bug+0xff/0x140
   ? handle_bug+0x3b/0x70
   ? exc_invalid_op+0x17/0x70
   ? asm_exc_invalid_op+0x1a/0x20
   ? close_ctree+0x222/0x4d0 [btrfs]
   generic_shutdown_super+0x70/0x160
   kill_anon_super+0x11/0x40
   btrfs_kill_super+0x11/0x20 [btrfs]
   deactivate_locked_super+0x2e/0xa0
   cleanup_mnt+0xb5/0x150
   task_work_run+0x57/0x80
   syscall_exit_to_user_mode+0x121/0x130
   do_syscall_64+0xab/0x1a0
   entry_SYSCALL_64_after_hwframe+0x77/0x7f
  RIP: 0033:0x7f916847a887
  ---[ end trace 0000000000000000 ]---
  BTRFS error (device dm-8 state EA): qgroup reserved space leaked

Cases 2 and 3 in the out_reserve path both pertain to this type of leak
and must free the reserved qgroup data. Because it is already an error
path, I opted not to handle the possible errors in
btrfs_free_qgroup_data.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
[Minor conflict resolved due to code context change.]
Signed-off-by: Jianqi Ren <jianqi.ren.cn@windriver.com>
Signed-off-by: He Zhe <zhe.he@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-25 10:45:56 +02:00
Filipe Manana
893b28374a btrfs: avoid monopolizing a core when activating a swap file
commit 2c8507c63f upstream.

This commit re-attempts the backport of the change to the linux-6.6.y
branch. Commit 6e1a822593 ("btrfs: avoid monopolizing a core when
activating a swap file") on this branch was reverted.

During swap activation we iterate over the extents of a file and we can
have many thousands of them, so we can end up in a busy loop monopolizing
a core. Avoid this by doing a voluntary reschedule after processing each
extent.

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-17 09:40:42 +01:00
Koichiro Den
b4e355e70e Revert "btrfs: avoid monopolizing a core when activating a swap file"
This reverts commit 6e1a822593.

The backport for linux-6.6.y, commit 6e1a822593 ("btrfs: avoid
monopolizing a core when activating a swap file"), inserted
cond_resched() in the wrong location.

Revert it now; a subsequent commit will re-backport the original patch.

Fixes: 6e1a822593 ("btrfs: avoid monopolizing a core when activating a swap file") # linux-6.6.y
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-17 09:40:42 +01:00
Johannes Thumshirn
6228f13f19 btrfs: fix use-after-free in btrfs_encoded_read_endio()
commit 05b36b04d7 upstream.

Shinichiro reported the following use-after free that sometimes is
happening in our CI system when running fstests' btrfs/284 on a TCMU
runner device:

  BUG: KASAN: slab-use-after-free in lock_release+0x708/0x780
  Read of size 8 at addr ffff888106a83f18 by task kworker/u80:6/219

  CPU: 8 UID: 0 PID: 219 Comm: kworker/u80:6 Not tainted 6.12.0-rc6-kts+ #15
  Hardware name: Supermicro Super Server/X11SPi-TF, BIOS 3.3 02/21/2020
  Workqueue: btrfs-endio btrfs_end_bio_work [btrfs]
  Call Trace:
   <TASK>
   dump_stack_lvl+0x6e/0xa0
   ? lock_release+0x708/0x780
   print_report+0x174/0x505
   ? lock_release+0x708/0x780
   ? __virt_addr_valid+0x224/0x410
   ? lock_release+0x708/0x780
   kasan_report+0xda/0x1b0
   ? lock_release+0x708/0x780
   ? __wake_up+0x44/0x60
   lock_release+0x708/0x780
   ? __pfx_lock_release+0x10/0x10
   ? __pfx_do_raw_spin_lock+0x10/0x10
   ? lock_is_held_type+0x9a/0x110
   _raw_spin_unlock_irqrestore+0x1f/0x60
   __wake_up+0x44/0x60
   btrfs_encoded_read_endio+0x14b/0x190 [btrfs]
   btrfs_check_read_bio+0x8d9/0x1360 [btrfs]
   ? lock_release+0x1b0/0x780
   ? trace_lock_acquire+0x12f/0x1a0
   ? __pfx_btrfs_check_read_bio+0x10/0x10 [btrfs]
   ? process_one_work+0x7e3/0x1460
   ? lock_acquire+0x31/0xc0
   ? process_one_work+0x7e3/0x1460
   process_one_work+0x85c/0x1460
   ? __pfx_process_one_work+0x10/0x10
   ? assign_work+0x16c/0x240
   worker_thread+0x5e6/0xfc0
   ? __pfx_worker_thread+0x10/0x10
   kthread+0x2c3/0x3a0
   ? __pfx_kthread+0x10/0x10
   ret_from_fork+0x31/0x70
   ? __pfx_kthread+0x10/0x10
   ret_from_fork_asm+0x1a/0x30
   </TASK>

  Allocated by task 3661:
   kasan_save_stack+0x30/0x50
   kasan_save_track+0x14/0x30
   __kasan_kmalloc+0xaa/0xb0
   btrfs_encoded_read_regular_fill_pages+0x16c/0x6d0 [btrfs]
   send_extent_data+0xf0f/0x24a0 [btrfs]
   process_extent+0x48a/0x1830 [btrfs]
   changed_cb+0x178b/0x2ea0 [btrfs]
   btrfs_ioctl_send+0x3bf9/0x5c20 [btrfs]
   _btrfs_ioctl_send+0x117/0x330 [btrfs]
   btrfs_ioctl+0x184a/0x60a0 [btrfs]
   __x64_sys_ioctl+0x12e/0x1a0
   do_syscall_64+0x95/0x180
   entry_SYSCALL_64_after_hwframe+0x76/0x7e

  Freed by task 3661:
   kasan_save_stack+0x30/0x50
   kasan_save_track+0x14/0x30
   kasan_save_free_info+0x3b/0x70
   __kasan_slab_free+0x4f/0x70
   kfree+0x143/0x490
   btrfs_encoded_read_regular_fill_pages+0x531/0x6d0 [btrfs]
   send_extent_data+0xf0f/0x24a0 [btrfs]
   process_extent+0x48a/0x1830 [btrfs]
   changed_cb+0x178b/0x2ea0 [btrfs]
   btrfs_ioctl_send+0x3bf9/0x5c20 [btrfs]
   _btrfs_ioctl_send+0x117/0x330 [btrfs]
   btrfs_ioctl+0x184a/0x60a0 [btrfs]
   __x64_sys_ioctl+0x12e/0x1a0
   do_syscall_64+0x95/0x180
   entry_SYSCALL_64_after_hwframe+0x76/0x7e

  The buggy address belongs to the object at ffff888106a83f00
   which belongs to the cache kmalloc-rnd-07-96 of size 96
  The buggy address is located 24 bytes inside of
   freed 96-byte region [ffff888106a83f00, ffff888106a83f60)

  The buggy address belongs to the physical page:
  page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888106a83800 pfn:0x106a83
  flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)
  page_type: f5(slab)
  raw: 0017ffffc0000000 ffff888100053680 ffffea0004917200 0000000000000004
  raw: ffff888106a83800 0000000080200019 00000001f5000000 0000000000000000
  page dumped because: kasan: bad access detected

  Memory state around the buggy address:
   ffff888106a83e00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
   ffff888106a83e80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
  >ffff888106a83f00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                              ^
   ffff888106a83f80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
   ffff888106a84000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ==================================================================

Further analyzing the trace and the crash dump's vmcore file shows that
the wake_up() call in btrfs_encoded_read_endio() is calling wake_up() on
the wait_queue that is in the private data passed to the end_io handler.

Commit 4ff47df40447 ("btrfs: move priv off stack in
btrfs_encoded_read_regular_fill_pages()") moved 'struct
btrfs_encoded_read_private' off the stack.

Before that commit one can see a corruption of the private data when
analyzing the vmcore after a crash:

*(struct btrfs_encoded_read_private *)0xffff88815626eec8 = {
	.wait = (wait_queue_head_t){
		.lock = (spinlock_t){
			.rlock = (struct raw_spinlock){
				.raw_lock = (arch_spinlock_t){
					.val = (atomic_t){
						.counter = (int)-2005885696,
					},
					.locked = (u8)0,
					.pending = (u8)157,
					.locked_pending = (u16)40192,
					.tail = (u16)34928,
				},
				.magic = (unsigned int)536325682,
				.owner_cpu = (unsigned int)29,
				.owner = (void *)__SCT__tp_func_btrfs_transaction_commit+0x0 = 0x0,
				.dep_map = (struct lockdep_map){
					.key = (struct lock_class_key *)0xffff8881575a3b6c,
					.class_cache = (struct lock_class *[2]){ 0xffff8882a71985c0, 0xffffea00066f5d40 },
					.name = (const char *)0xffff88815626f100 = "",
					.wait_type_outer = (u8)37,
					.wait_type_inner = (u8)178,
					.lock_type = (u8)154,
				},
			},
			.__padding = (u8 [24]){ 0, 157, 112, 136, 50, 174, 247, 31, 29 },
			.dep_map = (struct lockdep_map){
				.key = (struct lock_class_key *)0xffff8881575a3b6c,
				.class_cache = (struct lock_class *[2]){ 0xffff8882a71985c0, 0xffffea00066f5d40 },
				.name = (const char *)0xffff88815626f100 = "",
				.wait_type_outer = (u8)37,
				.wait_type_inner = (u8)178,
				.lock_type = (u8)154,
			},
		},
		.head = (struct list_head){
			.next = (struct list_head *)0x112cca,
			.prev = (struct list_head *)0x47,
		},
	},
	.pending = (atomic_t){
		.counter = (int)-1491499288,
	},
	.status = (blk_status_t)130,
}

Here we can see several indicators of in-memory data corruption, e.g. the
large negative atomic values of ->pending or
->wait->lock->rlock->raw_lock->val, as well as the bogus spinlock magic
0x1ff7ae32 (decimal 536325682 above) instead of 0xdead4ead or the bogus
pointer values for ->wait->head.

To fix this, change atomic_dec_return() to atomic_dec_and_test() to fix the
corruption, as atomic_dec_return() is defined as two instructions on
x86_64, whereas atomic_dec_and_test() is defined as a single atomic
operation. This can lead to a situation where counter value is already
decremented but the if statement in btrfs_encoded_read_endio() is not
completely processed, i.e. the 0 test has not completed. If another thread
continues executing btrfs_encoded_read_regular_fill_pages() the
atomic_dec_return() there can see an already updated ->pending counter and
continues by freeing the private data. Continuing in the endio handler the
test for 0 succeeds and the wait_queue is woken up, resulting in a
use-after-free.

Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Suggested-by: Damien Le Moal <Damien.LeMoal@wdc.com>
Fixes: 1881fba89b ("btrfs: add BTRFS_IOC_ENCODED_READ ioctl")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Alva Lan <alvalan9@foxmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-01-09 13:31:54 +01:00
Filipe Manana
6e1a822593 btrfs: avoid monopolizing a core when activating a swap file
commit 2c8507c63f upstream.

During swap activation we iterate over the extents of a file and we can
have many thousands of them, so we can end up in a busy loop monopolizing
a core. Avoid this by doing a voluntary reschedule after processing each
extent.

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-01-02 10:32:10 +01:00
Filipe Manana
2a72d5cc83 btrfs: fix missing snapshot drew unlock when root is dead during swap activation
[ Upstream commit 9c803c474c ]

When activating a swap file we acquire the root's snapshot drew lock and
then check if the root is dead, failing and returning with -EPERM if it's
dead but without unlocking the root's snapshot lock. Fix this by adding
the missing unlock.

Fixes: 60021bd754 ("btrfs: prevent subvol with swapfile from being deleted")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14 20:00:20 +01:00
Yue Haibing
3521754614 btrfs: fix passing 0 to ERR_PTR in btrfs_search_dir_index_item()
commit 75f49c3dc7 upstream.

The ret may be zero in btrfs_search_dir_index_item() and should not
passed to ERR_PTR(). Now btrfs_unlink_subvol() is the only caller to
this, reconstructed it to check ERR_PTR(-ENOENT) while ret >= 0.

This fixes smatch warnings:

fs/btrfs/dir-item.c:353
  btrfs_search_dir_index_item() warn: passing zero to 'ERR_PTR'

Fixes: 9dcbe16fcc ("btrfs: use btrfs_for_each_slot in btrfs_search_dir_index_item")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-01 01:58:32 +01:00
Jeff Layton
5ee7efa629 btrfs: update target inode's ctime on unlink
[ Upstream commit 3bc2ac2f8f ]

Unlink changes the link count on the target inode. POSIX mandates that
the ctime must also change when this occurs.

According to https://pubs.opengroup.org/onlinepubs/9699919799/functions/unlink.html:

"Upon successful completion, unlink() shall mark for update the last data
 modification and last file status change timestamps of the parent
 directory. Also, if the file's link count is not 0, the last file status
 change timestamp of the file shall be marked for update."

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add link to the opengroup docs ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-09-18 19:24:05 +02:00
David Sterba
f1eb69aa85 btrfs: initialize location to fix -Wmaybe-uninitialized in btrfs_lookup_dentry()
[ Upstream commit b8e947e9f6 ]

Some arch + compiler combinations report a potentially unused variable
location in btrfs_lookup_dentry(). This is a false alert as the variable
is passed by value and always valid or there's an error. The compilers
cannot probably reason about that although btrfs_inode_by_name() is in
the same file.

   >  + /kisskb/src/fs/btrfs/inode.c: error: 'location.objectid' may be used
   +uninitialized in this function [-Werror=maybe-uninitialized]:  => 5603:9
   >  + /kisskb/src/fs/btrfs/inode.c: error: 'location.type' may be used
   +uninitialized in this function [-Werror=maybe-uninitialized]:  => 5674:5

   m68k-gcc8/m68k-allmodconfig
   mips-gcc8/mips-allmodconfig
   powerpc-gcc5/powerpc-all{mod,yes}config
   powerpc-gcc5/ppc64_defconfig

Initialize it to zero, this should fix the warnings and won't change the
behaviour as btrfs_inode_by_name() accepts only a root or inode item
types, otherwise returns an error.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/linux-btrfs/bd4e9928-17b3-9257-8ba7-6b7f9bbb639a@linux-m68k.org/
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-09-12 11:11:38 +02:00
David Sterba
1bca9776ed btrfs: replace sb::s_blocksize by fs_info::sectorsize
[ Upstream commit 4e00422ee6 ]

The block size stored in the super block is used by subsystems outside
of btrfs and it's a copy of fs_info::sectorsize. Unify that to always
use our sectorsize, with the exception of mount where we first need to
use fixed values (4K) until we read the super block and can set the
sectorsize.

Replace all uses, in most cases it's fewer pointer indirections.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 46a6e10a1a ("btrfs: send: allow cloning non-aligned extent if it ends at i_size")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-29 17:33:43 +02:00
David Sterba
46ca3ec9b8 btrfs: handle invalid root reference found in may_destroy_subvol()
[ Upstream commit 6fbc6f4ac1 ]

The may_destroy_subvol() looks up a root by a key, allowing to do an
inexact search when key->offset is -1.  It's never expected to find such
item, as it would break the allowed range of a root id.

Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-29 17:33:37 +02:00
David Sterba
6be930556d btrfs: push errors up from add_async_extent()
[ Upstream commit dbe6cda68f ]

The memory allocation error in add_async_extent() is not handled
properly, return an error and push the BUG_ON to the caller. Handling it
there is not trivial so at least make it visible.

Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-29 17:33:37 +02:00
Boris Burkov
570bff14e7 btrfs: make btrfs_clear_delalloc_extent() free delalloc reserve
[ Upstream commit 3c6f0c5ecc ]

Currently, this call site in btrfs_clear_delalloc_extent() only converts
the reservation. We are marking it not delalloc, so I don't think it
makes sense to keep the rsv around.  This is a path where we are not
sure to join a transaction, so it leads to incorrect free-ing during
umount.

Helps with the pass rate of generic/269 and generic/475.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-05-17 12:02:14 +02:00
Sweet Tea Dorminy
5e2239fef6 btrfs: fallback if compressed IO fails for ENOSPC
commit 131a821a24 upstream.

In commit b4ccace878 ("btrfs: refactor submit_compressed_extents()"), if
an async extent compressed but failed to find enough space, we changed
from falling back to an uncompressed write to just failing the write
altogether. The principle was that if there's not enough space to write
the compressed version of the data, there can't possibly be enough space
to write the larger, uncompressed version of the data.

However, this isn't necessarily true: due to fragmentation, there could
be enough discontiguous free blocks to write the uncompressed version,
but not enough contiguous free blocks to write the smaller but
unsplittable compressed version.

This has occurred to an internal workload which relied on write()'s
return value indicating there was space. While rare, it has happened a
few times.

Thus, in order to prevent early ENOSPC, re-add a fallback to
uncompressed writing.

Fixes: b4ccace878 ("btrfs: refactor submit_compressed_extents()")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Co-developed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-05-02 16:32:44 +02:00
Boris Burkov
14431815a4 btrfs: qgroup: fix qgroup prealloc rsv leak in subvolume operations
commit 74e9795812 upstream.

Create subvolume, create snapshot and delete subvolume all use
btrfs_subvolume_reserve_metadata() to reserve metadata for the changes
done to the parent subvolume's fs tree, which cannot be mediated in the
normal way via start_transaction. When quota groups (squota or qgroups)
are enabled, this reserves qgroup metadata of type PREALLOC. Once the
operation is associated to a transaction, we convert PREALLOC to
PERTRANS, which gets cleared in bulk at the end of the transaction.

However, the error paths of these three operations were not implementing
this lifecycle correctly. They unconditionally converted the PREALLOC to
PERTRANS in a generic cleanup step regardless of errors or whether the
operation was fully associated to a transaction or not. This resulted in
error paths occasionally converting this rsv to PERTRANS without calling
record_root_in_trans successfully, which meant that unless that root got
recorded in the transaction by some other thread, the end of the
transaction would not free that root's PERTRANS, leaking it. Ultimately,
this resulted in hitting a WARN in CONFIG_BTRFS_DEBUG builds at unmount
for the leaked reservation.

The fix is to ensure that every qgroup PREALLOC reservation observes the
following properties:

1. any failure before record_root_in_trans is called successfully
   results in freeing the PREALLOC reservation.
2. after record_root_in_trans, we convert to PERTRANS, and now the
   transaction owns freeing the reservation.

This patch enforces those properties on the three operations. Without
it, generic/269 with squotas enabled at mkfs time would fail in ~5-10
runs on my system. With this patch, it ran successfully 1000 times in a
row.

Fixes: e85fde5162 ("btrfs: qgroup: fix qgroup meta rsv leak for subvolume operations")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-04-17 11:19:33 +02:00
Filipe Manana
8cc484e85e btrfs: ensure fiemap doesn't race with writes when FIEMAP_FLAG_SYNC is given
[ Upstream commit 418b090277 ]

When FIEMAP_FLAG_SYNC is given to fiemap the expectation is that that
are no concurrent writes and we get a stable view of the inode's extent
layout.

When the flag is given we flush all IO (and wait for ordered extents to
complete) and then lock the inode in shared mode, however that leaves open
the possibility that a write might happen right after the flushing and
before locking the inode. So fix this by flushing again after locking the
inode - we leave the initial flushing before locking the inode to avoid
holding the lock and blocking other RO operations while waiting for IO
and ordered extents to complete. The second flushing while holding the
inode's lock will most of the time do nothing or very little since the
time window for new writes to have happened is small.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 978b63f746 ("btrfs: fix race when detecting delalloc ranges during fiemap")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-04-10 16:35:46 +02:00
Josef Bacik
7bddf18f47 btrfs: don't drop extent_map for free space inode on write error
commit 5571e41ec6 upstream.

While running the CI for an unrelated change I hit the following panic
with generic/648 on btrfs_holes_spacecache.

assertion failed: block_start != EXTENT_MAP_HOLE, in fs/btrfs/extent_io.c:1385
------------[ cut here ]------------
kernel BUG at fs/btrfs/extent_io.c:1385!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 1 PID: 2695096 Comm: fsstress Kdump: loaded Tainted: G        W          6.8.0-rc2+ #1
RIP: 0010:__extent_writepage_io.constprop.0+0x4c1/0x5c0
Call Trace:
 <TASK>
 extent_write_cache_pages+0x2ac/0x8f0
 extent_writepages+0x87/0x110
 do_writepages+0xd5/0x1f0
 filemap_fdatawrite_wbc+0x63/0x90
 __filemap_fdatawrite_range+0x5c/0x80
 btrfs_fdatawrite_range+0x1f/0x50
 btrfs_write_out_cache+0x507/0x560
 btrfs_write_dirty_block_groups+0x32a/0x420
 commit_cowonly_roots+0x21b/0x290
 btrfs_commit_transaction+0x813/0x1360
 btrfs_sync_file+0x51a/0x640
 __x64_sys_fdatasync+0x52/0x90
 do_syscall_64+0x9c/0x190
 entry_SYSCALL_64_after_hwframe+0x6e/0x76

This happens because we fail to write out the free space cache in one
instance, come back around and attempt to write it again.  However on
the second pass through we go to call btrfs_get_extent() on the inode to
get the extent mapping.  Because this is a new block group, and with the
free space inode we always search the commit root to avoid deadlocking
with the tree, we find nothing and return a EXTENT_MAP_HOLE for the
requested range.

This happens because the first time we try to write the space cache out
we hit an error, and on an error we drop the extent mapping.  This is
normal for normal files, but the free space cache inode is special.  We
always expect the extent map to be correct.  Thus the second time
through we end up with a bogus extent map.

Since we're deprecating this feature, the most straightforward way to
fix this is to simply skip dropping the extent map range for this failed
range.

I shortened the test by using error injection to stress the area to make
it easier to reproduce.  With this patch in place we no longer panic
with my error injection test.

CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:24:48 +01:00
Filipe Manana
2f2d903769 btrfs: reject encoded write if inode has nodatasum flag set
commit 1bd96c92c6 upstream.

Currently we allow an encoded write against inodes that have the NODATASUM
flag set, either because they are NOCOW files or they were created while
the filesystem was mounted with "-o nodatasum". This results in having
compressed extents without corresponding checksums, which is a filesystem
inconsistency reported by 'btrfs check'.

For example, running btrfs/281 with MOUNT_OPTIONS="-o nodatacow" triggers
this and 'btrfs check' errors out with:

   [1/7] checking root items
   [2/7] checking extents
   [3/7] checking free space tree
   [4/7] checking fs roots
   root 256 inode 257 errors 1040, bad file extent, some csum missing
   root 256 inode 258 errors 1040, bad file extent, some csum missing
   ERROR: errors found in fs roots
   (...)

So reject encoded writes if the target inode has NODATASUM set.

CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:24:48 +01:00
Omar Sandoval
3eaf00d2f8 btrfs: avoid copying BTRFS_ROOT_SUBVOL_DEAD flag to snapshot of subvolume being deleted
commit 3324d05478 upstream.

Sweet Tea spotted a race between subvolume deletion and snapshotting
that can result in the root item for the snapshot having the
BTRFS_ROOT_SUBVOL_DEAD flag set. The race is:

Thread 1                                      | Thread 2
----------------------------------------------|----------
btrfs_delete_subvolume                        |
  btrfs_set_root_flags(BTRFS_ROOT_SUBVOL_DEAD)|
                                              |btrfs_mksubvol
                                              |  down_read(subvol_sem)
                                              |  create_snapshot
                                              |    ...
                                              |    create_pending_snapshot
                                              |      copy root item from source
  down_write(subvol_sem)                      |

This flag is only checked in send and swap activate, which this would
cause to fail mysteriously.

create_snapshot() now checks the root refs to reject a deleted
subvolume, so we can fix this by locking subvol_sem earlier so that the
BTRFS_ROOT_SUBVOL_DEAD flag and the root refs are updated atomically.

CC: stable@vger.kernel.org # 4.14+
Reported-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-01-31 16:19:05 -08:00
Boris Burkov
1823491513 btrfs: fix qgroup_free_reserved_data int overflow
commit 9e65bfca24 upstream.

The reserved data counter and input parameter is a u64, but we
inadvertently accumulate it in an int. Overflowing that int results in
freeing the wrong amount of data and breaking reserve accounting.

Unfortunately, this overflow rot spreads from there, as the qgroup
release/free functions rely on returning an int to take advantage of
negative values for error codes.

Therefore, the full fix is to return the "released" or "freed" amount by
a u64 argument and to return 0 or negative error code via the return
value.

Most of the call sites simply ignore the return value, though some
of them handle the error and count the returned bytes. Change all of
them accordingly.

CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-20 17:02:03 +01:00
Naohiro Aota
23c7353875 btrfs: zoned: wait for data BG to be finished on direct IO allocation
commit 776a838f1f upstream.

Running the fio command below on a ZNS device results in "Resource
temporarily unavailable" error.

  $ sudo fio --name=w --directory=/mnt --filesize=1GB --bs=16MB --numjobs=16 \
        --rw=write --ioengine=libaio --iodepth=128 --direct=1

  fio: io_u error on file /mnt/w.2.0: Resource temporarily unavailable: write offset=117440512, buflen=16777216
  fio: io_u error on file /mnt/w.2.0: Resource temporarily unavailable: write offset=134217728, buflen=16777216
  ...

This happens because -EAGAIN error returned from btrfs_reserve_extent()
called from btrfs_new_extent_direct() is spilling over to the userland.

btrfs_reserve_extent() returns -EAGAIN when there is no active zone
available. Then, the caller should wait for some other on-going IO to
finish a zone and retry the allocation.

This logic is already implemented for buffered write in cow_file_range(),
but it is missing for the direct IO counterpart. Implement the same logic
for it.

Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Fixes: 2ce543f478 ("btrfs: zoned: wait until zone is finished when allocation didn't progress")
CC: stable@vger.kernel.org # 6.1+
Tested-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-28 17:20:10 +00:00
Filipe Manana
d5e09e385e btrfs: abort transaction on generation mismatch when marking eb as dirty
[ Upstream commit 50564b651d ]

When marking an extent buffer as dirty, at btrfs_mark_buffer_dirty(),
we check if its generation matches the running transaction and if not we
just print a warning. Such mismatch is an indicator that something really
went wrong and only printing a warning message (and stack trace) is not
enough to prevent a corruption. Allowing a transaction to commit with such
an extent buffer will trigger an error if we ever try to read it from disk
due to a generation mismatch with its parent generation.

So abort the current transaction with -EUCLEAN if we notice a generation
mismatch. For this we need to pass a transaction handle to
btrfs_mark_buffer_dirty() which is always available except in test code,
in which case we can pass NULL since it operates on dummy extent buffers
and all test roots have a single node/leaf (root node at level 0).

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-28 17:19:35 +00:00
Linus Torvalds
a229cf67ab for-6.6-rc2-tag
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Merge tag 'for-6.6-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "A few more followup fixes to the directory listing.

  People have noticed different behaviour compared to other filesystems
  after changes in 6.5. This is now unified to more "logical" and
  expected behaviour while still within POSIX. And a few more fixes for
  stable.

   - change behaviour of readdir()/rewinddir() when new directory
     entries are created after opendir(), properly tracking the last
     entry

   - fix race in readdir when multiple threads can set the last entry
     index for a directory

  Additionally:

   - use exclusive lock when direct io might need to drop privs and call
     notify_change()

   - don't clear uptodate bit on page after an error, this may lead to a
     deadlock in subpage mode

   - fix waiting pattern when multiple readers block on Merkle tree
     data, switch to folios"

* tag 'for-6.6-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix race between reading a directory and adding entries to it
  btrfs: refresh dir last index during a rewinddir(3) call
  btrfs: set last dir index to the current last index when opening dir
  btrfs: don't clear uptodate on write errors
  btrfs: file_remove_privs needs an exclusive lock in direct io write
  btrfs: convert btrfs_read_merkle_tree_page() to use a folio
2023-09-20 11:03:45 -07:00
Filipe Manana
8e7f82deb0 btrfs: fix race between reading a directory and adding entries to it
When opening a directory (opendir(3)) or rewinding it (rewinddir(3)), we
are not holding the directory's inode locked, and this can result in later
attempting to add two entries to the directory with the same index number,
resulting in a transaction abort, with -EEXIST (-17), when inserting the
second delayed dir index. This results in a trace like the following:

  Sep 11 22:34:59 myhostname kernel: BTRFS error (device dm-3): err add delayed dir index item(name: cockroach-stderr.log) into the insertion tree of the delayed node(root id: 5, inode id: 4539217, errno: -17)
  Sep 11 22:34:59 myhostname kernel: ------------[ cut here ]------------
  Sep 11 22:34:59 myhostname kernel: kernel BUG at fs/btrfs/delayed-inode.c:1504!
  Sep 11 22:34:59 myhostname kernel: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
  Sep 11 22:34:59 myhostname kernel: CPU: 0 PID: 7159 Comm: cockroach Not tainted 6.4.15-200.fc38.x86_64 #1
  Sep 11 22:34:59 myhostname kernel: Hardware name: ASUS ESC500 G3/P9D WS, BIOS 2402 06/27/2018
  Sep 11 22:34:59 myhostname kernel: RIP: 0010:btrfs_insert_delayed_dir_index+0x1da/0x260
  Sep 11 22:34:59 myhostname kernel: Code: eb dd 48 (...)
  Sep 11 22:34:59 myhostname kernel: RSP: 0000:ffffa9980e0fbb28 EFLAGS: 00010282
  Sep 11 22:34:59 myhostname kernel: RAX: 0000000000000000 RBX: ffff8b10b8f4a3c0 RCX: 0000000000000000
  Sep 11 22:34:59 myhostname kernel: RDX: 0000000000000000 RSI: ffff8b177ec21540 RDI: ffff8b177ec21540
  Sep 11 22:34:59 myhostname kernel: RBP: ffff8b110cf80888 R08: 0000000000000000 R09: ffffa9980e0fb938
  Sep 11 22:34:59 myhostname kernel: R10: 0000000000000003 R11: ffffffff86146508 R12: 0000000000000014
  Sep 11 22:34:59 myhostname kernel: R13: ffff8b1131ae5b40 R14: ffff8b10b8f4a418 R15: 00000000ffffffef
  Sep 11 22:34:59 myhostname kernel: FS:  00007fb14a7fe6c0(0000) GS:ffff8b177ec00000(0000) knlGS:0000000000000000
  Sep 11 22:34:59 myhostname kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  Sep 11 22:34:59 myhostname kernel: CR2: 000000c00143d000 CR3: 00000001b3b4e002 CR4: 00000000001706f0
  Sep 11 22:34:59 myhostname kernel: Call Trace:
  Sep 11 22:34:59 myhostname kernel:  <TASK>
  Sep 11 22:34:59 myhostname kernel:  ? die+0x36/0x90
  Sep 11 22:34:59 myhostname kernel:  ? do_trap+0xda/0x100
  Sep 11 22:34:59 myhostname kernel:  ? btrfs_insert_delayed_dir_index+0x1da/0x260
  Sep 11 22:34:59 myhostname kernel:  ? do_error_trap+0x6a/0x90
  Sep 11 22:34:59 myhostname kernel:  ? btrfs_insert_delayed_dir_index+0x1da/0x260
  Sep 11 22:34:59 myhostname kernel:  ? exc_invalid_op+0x50/0x70
  Sep 11 22:34:59 myhostname kernel:  ? btrfs_insert_delayed_dir_index+0x1da/0x260
  Sep 11 22:34:59 myhostname kernel:  ? asm_exc_invalid_op+0x1a/0x20
  Sep 11 22:34:59 myhostname kernel:  ? btrfs_insert_delayed_dir_index+0x1da/0x260
  Sep 11 22:34:59 myhostname kernel:  ? btrfs_insert_delayed_dir_index+0x1da/0x260
  Sep 11 22:34:59 myhostname kernel:  btrfs_insert_dir_item+0x200/0x280
  Sep 11 22:34:59 myhostname kernel:  btrfs_add_link+0xab/0x4f0
  Sep 11 22:34:59 myhostname kernel:  ? ktime_get_real_ts64+0x47/0xe0
  Sep 11 22:34:59 myhostname kernel:  btrfs_create_new_inode+0x7cd/0xa80
  Sep 11 22:34:59 myhostname kernel:  btrfs_symlink+0x190/0x4d0
  Sep 11 22:34:59 myhostname kernel:  ? schedule+0x5e/0xd0
  Sep 11 22:34:59 myhostname kernel:  ? __d_lookup+0x7e/0xc0
  Sep 11 22:34:59 myhostname kernel:  vfs_symlink+0x148/0x1e0
  Sep 11 22:34:59 myhostname kernel:  do_symlinkat+0x130/0x140
  Sep 11 22:34:59 myhostname kernel:  __x64_sys_symlinkat+0x3d/0x50
  Sep 11 22:34:59 myhostname kernel:  do_syscall_64+0x5d/0x90
  Sep 11 22:34:59 myhostname kernel:  ? syscall_exit_to_user_mode+0x2b/0x40
  Sep 11 22:34:59 myhostname kernel:  ? do_syscall_64+0x6c/0x90
  Sep 11 22:34:59 myhostname kernel:  entry_SYSCALL_64_after_hwframe+0x72/0xdc

The race leading to the problem happens like this:

1) Directory inode X is loaded into memory, its ->index_cnt field is
   initialized to (u64)-1 (at btrfs_alloc_inode());

2) Task A is adding a new file to directory X, holding its vfs inode lock,
   and calls btrfs_set_inode_index() to get an index number for the entry.

   Because the inode's index_cnt field is set to (u64)-1 it calls
   btrfs_inode_delayed_dir_index_count() which fails because no dir index
   entries were added yet to the delayed inode and then it calls
   btrfs_set_inode_index_count(). This functions finds the last dir index
   key and then sets index_cnt to that index value + 1. It found that the
   last index key has an offset of 100. However before it assigns a value
   of 101 to index_cnt...

3) Task B calls opendir(3), ending up at btrfs_opendir(), where the VFS
   lock for inode X is not taken, so it calls btrfs_get_dir_last_index()
   and sees index_cnt still with a value of (u64)-1. Because of that it
   calls btrfs_inode_delayed_dir_index_count() which fails since no dir
   index entries were added to the delayed inode yet, and then it also
   calls btrfs_set_inode_index_count(). This also finds that the last
   index key has an offset of 100, and before it assigns the value 101
   to the index_cnt field of inode X...

4) Task A assigns a value of 101 to index_cnt. And then the code flow
   goes to btrfs_set_inode_index() where it increments index_cnt from
   101 to 102. Task A then creates a delayed dir index entry with a
   sequence number of 101 and adds it to the delayed inode;

5) Task B assigns 101 to the index_cnt field of inode X;

6) At some later point when someone tries to add a new entry to the
   directory, btrfs_set_inode_index() will return 101 again and shortly
   after an attempt to add another delayed dir index key with index
   number 101 will fail with -EEXIST resulting in a transaction abort.

Fix this by locking the inode at btrfs_get_dir_last_index(), which is only
only used when opening a directory or attempting to lseek on it.

Reported-by: ken <ken@bllue.org>
Link: https://lore.kernel.org/linux-btrfs/CAE6xmH+Lp=Q=E61bU+v9eWX8gYfLvu6jLYxjxjFpo3zHVPR0EQ@mail.gmail.com/
Reported-by: syzbot+d13490c82ad5353c779d@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/00000000000036e1290603e097e0@google.com/
Fixes: 9b378f6ad4 ("btrfs: fix infinite directory reads")
CC: stable@vger.kernel.org # 6.5+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-09-14 23:24:42 +02:00
Filipe Manana
e60aa5da14 btrfs: refresh dir last index during a rewinddir(3) call
When opening a directory we find what's the index of its last entry and
then store it in the directory's file handle private data (struct
btrfs_file_private::last_index), so that in the case new directory entries
are added to a directory after an opendir(3) call we don't end up in an
infinite loop (see commit 9b378f6ad4 ("btrfs: fix infinite directory
reads")) when calling readdir(3).

However once rewinddir(3) is called, POSIX states [1] that any new
directory entries added after the previous opendir(3) call, must be
returned by subsequent calls to readdir(3):

  "The rewinddir() function shall reset the position of the directory
   stream to which dirp refers to the beginning of the directory.
   It shall also cause the directory stream to refer to the current
   state of the corresponding directory, as a call to opendir() would
   have done."

We currently don't refresh the last_index field of the struct
btrfs_file_private associated to the directory, so after a rewinddir(3)
we are not returning any new entries added after the opendir(3) call.

Fix this by finding the current last index of the directory when llseek
is called against the directory.

This can be reproduced by the following C program provided by Ian Johnson:

   #include <dirent.h>
   #include <stdio.h>

   int main(void) {
     DIR *dir = opendir("test");

     FILE *file;
     file = fopen("test/1", "w");
     fwrite("1", 1, 1, file);
     fclose(file);

     file = fopen("test/2", "w");
     fwrite("2", 1, 1, file);
     fclose(file);

     rewinddir(dir);

     struct dirent *entry;
     while ((entry = readdir(dir))) {
        printf("%s\n", entry->d_name);
     }
     closedir(dir);
     return 0;
   }

Reported-by: Ian Johnson <ian@ianjohnson.dev>
Link: https://lore.kernel.org/linux-btrfs/YR1P0S.NGASEG570GJ8@ianjohnson.dev/
Fixes: 9b378f6ad4 ("btrfs: fix infinite directory reads")
CC: stable@vger.kernel.org # 6.5+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-09-14 23:24:42 +02:00
Filipe Manana
357950361c btrfs: set last dir index to the current last index when opening dir
When opening a directory for reading it, we set the last index where we
stop iteration to the value in struct btrfs_inode::index_cnt. That value
does not match the index of the most recently added directory entry but
it's instead the index number that will be assigned the next directory
entry.

This means that if after the call to opendir(3) new directory entries are
added, a readdir(3) call will return the first new directory entry. This
is fine because POSIX says the following [1]:

  "If a file is removed from or added to the directory after the most
   recent call to opendir() or rewinddir(), whether a subsequent call to
   readdir() returns an entry for that file is unspecified."

For example for the test script from commit 9b378f6ad4 ("btrfs: fix
infinite directory reads"), where we have 2000 files in a directory, ext4
doesn't return any new directory entry after opendir(3), while xfs returns
the first 13 new directory entries added after the opendir(3) call.

If we move to a shorter example with an empty directory when opendir(3) is
called, and 2 files added to the directory after the opendir(3) call, then
readdir(3) on btrfs will return the first file, ext4 and xfs return the 2
files (but in a different order). A test program for this, reported by
Ian Johnson, is the following:

   #include <dirent.h>
   #include <stdio.h>

   int main(void) {
     DIR *dir = opendir("test");

     FILE *file;
     file = fopen("test/1", "w");
     fwrite("1", 1, 1, file);
     fclose(file);

     file = fopen("test/2", "w");
     fwrite("2", 1, 1, file);
     fclose(file);

     struct dirent *entry;
     while ((entry = readdir(dir))) {
        printf("%s\n", entry->d_name);
     }
     closedir(dir);
     return 0;
   }

To make this less odd, change the behaviour to never return new entries
that were added after the opendir(3) call. This is done by setting the
last_index field of the struct btrfs_file_private attached to the
directory's file handle with a value matching btrfs_inode::index_cnt
minus 1, since that value always matches the index of the next new
directory entry and not the index of the most recently added entry.

[1] https://pubs.opengroup.org/onlinepubs/007904875/functions/readdir_r.html

Link: https://lore.kernel.org/linux-btrfs/YR1P0S.NGASEG570GJ8@ianjohnson.dev/
CC: stable@vger.kernel.org # 6.5+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-09-14 23:24:42 +02:00
Josef Bacik
b595d25996 btrfs: don't clear uptodate on write errors
We have been consistently seeing hangs with generic/648 in our subpage
GitHub CI setup.  This is a classic deadlock, we are calling
btrfs_read_folio() on a folio, which requires holding the folio lock on
the folio, and then finding a ordered extent that overlaps that range
and calling btrfs_start_ordered_extent(), which then tries to write out
the dirty page, which requires taking the folio lock and then we
deadlock.

The hang happens because we're writing to range [1271750656, 1271767040),
page index [77621, 77622], and page 77621 is !Uptodate.  It is also Dirty,
so we call btrfs_read_folio() for 77621 and which does
btrfs_lock_and_flush_ordered_range() for that range, and we find an ordered
extent which is [1271644160, 1271746560), page index [77615, 77621].
The page indexes overlap, but the actual bytes don't overlap.  We're
holding the page lock for 77621, then call
btrfs_lock_and_flush_ordered_range() which tries to flush the dirty
page, and tries to lock 77621 again and then we deadlock.

The byte ranges do not overlap, but with subpage support if we clear
uptodate on any portion of the page we mark the entire thing as not
uptodate.

We have been clearing page uptodate on write errors, but no other file
system does this, and is in fact incorrect.  This doesn't hurt us in the
!subpage case because we can't end up with overlapped ranges that don't
also overlap on the page.

Fix this by not clearing uptodate when we have a write error.  The only
thing we should be doing in this case is setting the mapping error and
carrying on.  This makes it so we would no longer call
btrfs_read_folio() on the page as it's uptodate and eliminates the
deadlock.

With this patch we're now able to make it through a full fstests run on
our subpage blocksize VMs.

Note for stable backports: this probably goes beyond 6.1 but the code
has been cleaned up and clearing the uptodate bit must be verified on
each version independently.

CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-09-13 18:41:07 +02:00
Linus Torvalds
547635c6ac for-6.6-tag
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Merge tag 'for-6.6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs updates from David Sterba:
 "No new features, the bulk of the changes are fixes, refactoring and
  cleanups. The notable fix is the scrub performance restoration after
  rewrite in 6.4, though still only partial.

  Fixes:

   - scrub performance drop due to rewrite in 6.4 partially restored:
      - do IO grouping by blg_plug/blk_unplug again
      - avoid unnecessary tree searches when processing stripes, in
        extent and checksum trees
      - the drop is noticeable on fast PCIe devices, -66% and restored
        to -33% of the original
      - backports to 6.4 planned

   - handle more corner cases of transaction commit during orphan
     cleanup or delayed ref processing

   - use correct fsid/metadata_uuid when validating super block

   - copy directory permissions and time when creating a stub subvolume

  Core:

   - debugging feature integrity checker deprecated, to be removed in
     6.7

   - in zoned mode, zones are activated just before the write, making
     error handling easier, now the overcommit mechanism can be enabled
     again which improves performance by avoiding more frequent flushing

   - v0 extent handling completely removed, deprecated long time ago

   - error handling improvements

   - tests:
      - extent buffer bitmap tests
      - pinned extent splitting tests

   - cleanups and refactoring:
      - compression writeback
      - extent buffer bitmap
      - space flushing, ENOSPC handling"

* tag 'for-6.6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (110 commits)
  btrfs: zoned: skip splitting and logical rewriting on pre-alloc write
  btrfs: tests: test invalid splitting when skipping pinned drop extent_map
  btrfs: tests: add a test for btrfs_add_extent_mapping
  btrfs: tests: add extent_map tests for dropping with odd layouts
  btrfs: scrub: move write back of repaired sectors to scrub_stripe_read_repair_worker()
  btrfs: scrub: don't go ordered workqueue for dev-replace
  btrfs: scrub: fix grouping of read IO
  btrfs: scrub: avoid unnecessary csum tree search preparing stripes
  btrfs: scrub: avoid unnecessary extent tree search preparing stripes
  btrfs: copy dir permission and time when creating a stub subvolume
  btrfs: remove pointless empty list check when reading delayed dir indexes
  btrfs: drop redundant check to use fs_devices::metadata_uuid
  btrfs: compare the correct fsid/metadata_uuid in btrfs_validate_super
  btrfs: use the correct superblock to compare fsid in btrfs_validate_super
  btrfs: simplify memcpy either of metadata_uuid or fsid
  btrfs: add a helper to read the superblock metadata_uuid
  btrfs: remove v0 extent handling
  btrfs: output extra debug info if we failed to find an inline backref
  btrfs: move the !zoned assert into run_delalloc_cow
  btrfs: consolidate the error handling in run_delalloc_nocow
  ...
2023-08-28 12:26:57 -07:00
Linus Torvalds
615e95831e v6.6-vfs.ctime
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Merge tag 'v6.6-vfs.ctime' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs timestamp updates from Christian Brauner:
 "This adds VFS support for multi-grain timestamps and converts tmpfs,
  xfs, ext4, and btrfs to use them. This carries acks from all relevant
  filesystems.

  The VFS always uses coarse-grained timestamps when updating the ctime
  and mtime after a change. This has the benefit of allowing filesystems
  to optimize away a lot of metadata updates, down to around 1 per
  jiffy, even when a file is under heavy writes.

  Unfortunately, this has always been an issue when we're exporting via
  NFSv3, which relies on timestamps to validate caches. A lot of changes
  can happen in a jiffy, so timestamps aren't sufficient to help the
  client decide to invalidate the cache.

  Even with NFSv4, a lot of exported filesystems don't properly support
  a change attribute and are subject to the same problems with timestamp
  granularity. Other applications have similar issues with timestamps
  (e.g., backup applications).

  If we were to always use fine-grained timestamps, that would improve
  the situation, but that becomes rather expensive, as the underlying
  filesystem would have to log a lot more metadata updates.

  This introduces fine-grained timestamps that are used when they are
  actively queried.

  This uses the 31st bit of the ctime tv_nsec field to indicate that
  something has queried the inode for the mtime or ctime. When this flag
  is set, on the next mtime or ctime update, the kernel will fetch a
  fine-grained timestamp instead of the usual coarse-grained one.

  As POSIX generally mandates that when the mtime changes, the ctime
  must also change the kernel always stores normalized ctime values, so
  only the first 30 bits of the tv_nsec field are ever used.

  Filesytems can opt into this behavior by setting the FS_MGTIME flag in
  the fstype. Filesystems that don't set this flag will continue to use
  coarse-grained timestamps.

  Various preparatory changes, fixes and cleanups are included:

   - Fixup all relevant places where POSIX requires updating ctime
     together with mtime. This is a wide-range of places and all
     maintainers provided necessary Acks.

   - Add new accessors for inode->i_ctime directly and change all
     callers to rely on them. Plain accesses to inode->i_ctime are now
     gone and it is accordingly rename to inode->__i_ctime and commented
     as requiring accessors.

   - Extend generic_fillattr() to pass in a request mask mirroring in a
     sense the statx() uapi. This allows callers to pass in a request
     mask to only get a subset of attributes filled in.

   - Rework timestamp updates so it's possible to drop the @now
     parameter the update_time() inode operation and associated helpers.

   - Add inode_update_timestamps() and convert all filesystems to it
     removing a bunch of open-coding"

* tag 'v6.6-vfs.ctime' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (107 commits)
  btrfs: convert to multigrain timestamps
  ext4: switch to multigrain timestamps
  xfs: switch to multigrain timestamps
  tmpfs: add support for multigrain timestamps
  fs: add infrastructure for multigrain timestamps
  fs: drop the timespec64 argument from update_time
  xfs: have xfs_vn_update_time gets its own timestamp
  fat: make fat_update_time get its own timestamp
  fat: remove i_version handling from fat_update_time
  ubifs: have ubifs_update_time use inode_update_timestamps
  btrfs: have it use inode_update_timestamps
  fs: drop the timespec64 arg from generic_update_time
  fs: pass the request_mask to generic_fillattr
  fs: remove silly warning from current_time
  gfs2: fix timestamp handling on quota inodes
  fs: rename i_ctime field to __i_ctime
  selinux: convert to ctime accessor functions
  security: convert to ctime accessor functions
  apparmor: convert to ctime accessor functions
  sunrpc: convert to ctime accessor functions
  ...
2023-08-28 09:31:32 -07:00
Lee Trager
94628ad944 btrfs: copy dir permission and time when creating a stub subvolume
btrfs supports creating nested subvolumes however snapshots are not
recursive.  When a snapshot is taken of a volume which contains a
subvolume the subvolume is replaced with a stub subvolume which has the
same name and uses inode number 2[1]. The stub subvolume kept the
directory name but did not set the time or permissions of the stub
subvolume. This resulted in all time information being the current time
and ownership defaulting to root. When subvolumes and snapshots are
created using unshare this results in a snapshot directory the user
created but has no permissions for.

Test case:

  [vmuser@archvm ~]# sudo -i
  [root@archvm ~]# mkdir -p /mnt/btrfs/test
  [root@archvm ~]# chown vmuser:users /mnt/btrfs/test/
  [root@archvm ~]# exit
  logout
  [vmuser@archvm ~]$ cd /mnt/btrfs/test
  [vmuser@archvm test]$ unshare --user --keep-caps --map-auto --map-root-user
  [root@archvm test]# btrfs subvolume create subvolume
  Create subvolume './subvolume'
  [root@archvm test]# btrfs subvolume create subvolume/subsubvolume
  Create subvolume 'subvolume/subsubvolume'
  [root@archvm test]# btrfs subvolume snapshot subvolume snapshot
  Create a snapshot of 'subvolume' in './snapshot'
  [root@archvm test]# exit
  logout
  [vmuser@archvm test]$ tree -ug
  [vmuser   users   ]  .
  ├── [vmuser   users   ]  snapshot
  │   └── [vmuser   users   ]  subsubvolume  <-- Without patch perm is root:root
  └── [vmuser   users   ]  subvolume
      └── [vmuser   users   ]  subsubvolume

  5 directories, 0 files

[1] https://btrfs.readthedocs.io/en/latest/btrfs-subvolume.html#nested-subvolumes

Signed-off-by: Lee Trager <lee@trager.us>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21 14:54:48 +02:00
Christoph Hellwig
76c5126e76 btrfs: move the !zoned assert into run_delalloc_cow
Having the assert in the actual helper documents the pre-conditions
much better than having it in the caller, so move it.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21 14:54:47 +02:00
Christoph Hellwig
38dc88890d btrfs: consolidate the error handling in run_delalloc_nocow
Share the calls to extent_clear_unlock_delalloc for btrfs_path allocation
failure handling and the normal exit path.

This relies on btrfs_free_path ignoring a NULL pointer, and the
initialization of cur_offset to start at the beginning of the function.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21 14:54:47 +02:00
Christoph Hellwig
18f62b86c4 btrfs: cleanup the COW fallback logic in run_delalloc_nocow
Use the block group pointer used to track the outstanding NOCOW writes as
a boolean to remove the duplicate nocow variable, and keep it contained
in the main loop to simplify the logic.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21 14:54:47 +02:00
Christoph Hellwig
953fa5ced5 btrfs: fix error handling when in a COW window in run_delalloc_nocow
When run_delalloc_nocow has cow_start set to a value other than (u64)-1,
it has delayed COW writeback pending behind cur_offset.  When an error
occurs in such a window, the range going back to cow_start and not just
cur_offset needs to be unlocked, but only two error cases handle this
correctly  Move the code to handle unlock the COW range to the common
error handling label and document the logic.

To make things even more complicated, cow_file_range as called by
fallback_to_cow will unlock the range it is operating on when it fails as
well, so we need to reset cow_start right after caling fallback_to_cow
instead of only when it succeeded.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21 14:54:47 +02:00
Ruan Jinjie
84af994b85 btrfs: use LIST_HEAD() to initialize the list_head
Use LIST_HEAD() to initialize the list_head instead of open-coding it.

Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21 14:54:46 +02:00
Filipe Manana
a7f8de500e btrfs: return real error when orphan cleanup fails due to a transaction abort
During mount we will call btrfs_orphan_cleanup() to remove any inodes that
were previously deleted (have a link count of 0) but for which we were not
able before to remove their items from the subvolume tree. The removal of
the items will happen by triggering eviction, when we do the final iput()
on them at btrfs_orphan_cleanup(), which will end in the loop at
btrfs_evict_inode() that truncates inode items.

In a dire situation we may have a transaction abort due to -ENOSPC when
attempting to truncate the inode items, and in that case the orphan item
(key type BTRFS_ORPHAN_ITEM_KEY) will remain in the subvolume tree and
when we hit the next iteration of the while loop at btrfs_orphan_cleanup()
we will find the same orphan item as before, and then we will return
-EINVAL from btrfs_orphan_cleanup() through the following if statement:

    if (found_key.offset == last_objectid) {
       btrfs_err(fs_info,
                 "Error removing orphan entry, stopping orphan cleanup");
       ret = -EINVAL;
       goto out;
    }

This makes the mount operation fail with -EINVAL, when it should have been
-ENOSPC. This is confusing because -EINVAL might lead a user into thinking
it provided invalid mount options for example.

An example where this happens:

   $ mount test.img /mnt
   mount: /mnt: wrong fs type, bad option, bad superblock on /dev/loop0, missing codepage or helper program, or other error.

   $ dmesg
   [ 2542.356934] BTRFS: device fsid 977fff75-1181-4d2b-a739-384fa710d16e devid 1 transid 47409973 /dev/loop0 scanned by mount (4459)
   [ 2542.357451] BTRFS info (device loop0): using crc32c (crc32c-intel) checksum algorithm
   [ 2542.357461] BTRFS info (device loop0): disk space caching is enabled
   [ 2542.742287] BTRFS info (device loop0): auto enabling async discard
   [ 2542.764554] BTRFS info (device loop0): checking UUID tree
   [ 2551.743065] ------------[ cut here ]------------
   [ 2551.743068] BTRFS: Transaction aborted (error -28)
   [ 2551.743149] WARNING: CPU: 7 PID: 215 at fs/btrfs/block-group.c:3494 btrfs_write_dirty_block_groups+0x397/0x3d0 [btrfs]
   [ 2551.743311] Modules linked in: btrfs blake2b_generic (...)
   [ 2551.743353] CPU: 7 PID: 215 Comm: kworker/u24:5 Not tainted 6.4.0-rc6-btrfs-next-134+ #1
   [ 2551.743356] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
   [ 2551.743357] Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs]
   [ 2551.743405] RIP: 0010:btrfs_write_dirty_block_groups+0x397/0x3d0 [btrfs]
   [ 2551.743449] Code: 8b 43 0c (...)
   [ 2551.743451] RSP: 0018:ffff982c005a7c40 EFLAGS: 00010286
   [ 2551.743452] RAX: 0000000000000000 RBX: ffff88fc6e44b400 RCX: 0000000000000000
   [ 2551.743453] RDX: 0000000000000002 RSI: ffffffff8dff0878 RDI: 00000000ffffffff
   [ 2551.743454] RBP: ffff88fc51817208 R08: 0000000000000000 R09: ffff982c005a7ae0
   [ 2551.743455] R10: 0000000000000001 R11: 0000000000000001 R12: ffff88fc43d2e570
   [ 2551.743456] R13: ffff88fc43d2e400 R14: ffff88fc8fb08ee0 R15: ffff88fc6e44b530
   [ 2551.743457] FS:  0000000000000000(0000) GS:ffff89035fbc0000(0000) knlGS:0000000000000000
   [ 2551.743458] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   [ 2551.743459] CR2: 00007fa8cdf2f6f4 CR3: 0000000124850003 CR4: 0000000000370ee0
   [ 2551.743462] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   [ 2551.743463] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
   [ 2551.743464] Call Trace:
   [ 2551.743472]  <TASK>
   [ 2551.743474]  ? __warn+0x80/0x130
   [ 2551.743478]  ? btrfs_write_dirty_block_groups+0x397/0x3d0 [btrfs]
   [ 2551.743520]  ? report_bug+0x1f4/0x200
   [ 2551.743523]  ? handle_bug+0x42/0x70
   [ 2551.743526]  ? exc_invalid_op+0x14/0x70
   [ 2551.743528]  ? asm_exc_invalid_op+0x16/0x20
   [ 2551.743532]  ? btrfs_write_dirty_block_groups+0x397/0x3d0 [btrfs]
   [ 2551.743574]  ? _raw_spin_unlock+0x15/0x30
   [ 2551.743576]  ? btrfs_run_delayed_refs+0x1bd/0x200 [btrfs]
   [ 2551.743609]  commit_cowonly_roots+0x1e9/0x260 [btrfs]
   [ 2551.743652]  btrfs_commit_transaction+0x42e/0xfa0 [btrfs]
   [ 2551.743693]  ? __pfx_autoremove_wake_function+0x10/0x10
   [ 2551.743697]  flush_space+0xf1/0x5d0 [btrfs]
   [ 2551.743743]  ? _raw_spin_unlock+0x15/0x30
   [ 2551.743745]  ? finish_task_switch+0x91/0x2a0
   [ 2551.743748]  ? _raw_spin_unlock+0x15/0x30
   [ 2551.743750]  ? btrfs_get_alloc_profile+0xc9/0x1f0 [btrfs]
   [ 2551.743793]  btrfs_async_reclaim_metadata_space+0xe1/0x230 [btrfs]
   [ 2551.743837]  process_one_work+0x1d9/0x3e0
   [ 2551.743844]  worker_thread+0x4a/0x3b0
   [ 2551.743847]  ? __pfx_worker_thread+0x10/0x10
   [ 2551.743849]  kthread+0xee/0x120
   [ 2551.743852]  ? __pfx_kthread+0x10/0x10
   [ 2551.743854]  ret_from_fork+0x29/0x50
   [ 2551.743860]  </TASK>
   [ 2551.743861] ---[ end trace 0000000000000000 ]---
   [ 2551.743863] BTRFS info (device loop0: state A): dumping space info:
   [ 2551.743866] BTRFS info (device loop0: state A): space_info DATA has 126976 free, is full
   [ 2551.743868] BTRFS info (device loop0: state A): space_info total=13458472960, used=13458137088, pinned=143360, reserved=0, may_use=0, readonly=65536 zone_unusable=0
   [ 2551.743870] BTRFS info (device loop0: state A): space_info METADATA has -51625984 free, is full
   [ 2551.743872] BTRFS info (device loop0: state A): space_info total=771751936, used=770146304, pinned=1605632, reserved=0, may_use=51625984, readonly=0 zone_unusable=0
   [ 2551.743874] BTRFS info (device loop0: state A): space_info SYSTEM has 14663680 free, is not full
   [ 2551.743875] BTRFS info (device loop0: state A): space_info total=14680064, used=16384, pinned=0, reserved=0, may_use=0, readonly=0 zone_unusable=0
   [ 2551.743877] BTRFS info (device loop0: state A): global_block_rsv: size 53231616 reserved 51544064
   [ 2551.743878] BTRFS info (device loop0: state A): trans_block_rsv: size 0 reserved 0
   [ 2551.743879] BTRFS info (device loop0: state A): chunk_block_rsv: size 0 reserved 0
   [ 2551.743880] BTRFS info (device loop0: state A): delayed_block_rsv: size 0 reserved 0
   [ 2551.743881] BTRFS info (device loop0: state A): delayed_refs_rsv: size 786432 reserved 0
   [ 2551.743886] BTRFS: error (device loop0: state A) in btrfs_write_dirty_block_groups:3494: errno=-28 No space left
   [ 2551.743911] BTRFS info (device loop0: state EA): forced readonly
   [ 2551.743951] BTRFS warning (device loop0: state EA): could not allocate space for delete; will truncate on mount
   [ 2551.743962] BTRFS error (device loop0: state EA): Error removing orphan entry, stopping orphan cleanup
   [ 2551.743973] BTRFS warning (device loop0: state EA): Skipping commit of aborted transaction.
   [ 2551.743989] BTRFS error (device loop0: state EA): could not do orphan cleanup -22

So make the btrfs_orphan_cleanup() return the value of BTRFS_FS_ERROR(),
if it's set, and -EINVAL otherwise.

For that same example, after this change, the mount operation fails with
-ENOSPC:

   $ mount test.img /mnt
   mount: /mnt: mount(2) system call failed: No space left on device.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21 14:52:18 +02:00
Christoph Hellwig
256b0cf90d btrfs: fix zoned handling in submit_uncompressed_range
For zoned file systems we need to use run_delalloc_zoned to submit
writeback, as we need to write out partial allocations when running into
zone active limits.

submit_uncompressed_range currently always calls cow_file_range to
allocate blocks and thus misses the active zone limits handling.  Fix
this by passing the pages_dirty argument to run_delalloc_zoned and always
using it from submit_uncompressed_range as it does the right thing for
zoned and non-zoned file systems.

To account for the fact that run_delalloc_zoned is now also used for
non-zoned file systems rename it to run_delalloc_cow, and add comment
describing it.

Fixes: 42c0110009 ("btrfs: zoned: introduce dedicated data write path for zoned filesystems")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21 14:52:16 +02:00
Christoph Hellwig
778b878543 btrfs: don't redirty locked_page in run_delalloc_zoned
extent_write_locked_range currently expects that either all or no
pages are dirty when it is called.  Bur run_delalloc_zoned is called
directly in the writepages path, and has the dirty bit cleared only
for locked_page and which the extent_write_cache_pages currently
operates.  It currently works around this by redirtying locked_page,
but that is a bit inefficient and cumbersome.  Pass a locked_page
argument to run_delalloc_zoned so that clearing the dirty bit can
be skipped on just that page.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21 14:52:16 +02:00
Christoph Hellwig
6e144bf16b btrfs: refactor the zoned device handling in cow_file_range
Handling of the done_offset to cow_file_range is a bit confusing, as
it is not updated at all when the function succeeds, and the -EAGAIN
status is used bother for the case where we need to wait for a zone
finish and the one where the allocation was partially successful.

Change the calling convention so that done_offset is always updated,
and 0 is returned if some allocation was successful (partial allocation
can still only happen for zoned devices), and waiting for a zone
finish is done internally in cow_file_range instead of the caller.

Also write a comment explaining the logic.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21 14:52:16 +02:00
Christoph Hellwig
44962ca37c btrfs: don't redirty pages in compress_file_range
compress_file_range needs to clear the dirty bit before handing off work
to the compression worker threads to prevent processes coming in through
mmap and changing the file contents while the compression is accessing
the data (See commit 4adaa61102 ("Btrfs: fix race between mmap writes
and compression").

But when compress_file_range decides to not compress the data, it falls
back to submit_uncompressed_range which uses extent_write_locked_range
to write the uncompressed data.  extent_write_locked_range currently
expects all pages to be marked dirty so that it can clear the dirty
bit itself, and thus compress_file_range has to redirty the page range.

Redirtying the page range is rather inefficient and also pointless,
so instead pass a pages_dirty parameter to extent_write_locked_range
and skip the redirty game entirely.

Note that compress_file_range was even redirtying the locked_page twice
given that extent_range_clear_dirty_for_io already redirties all pages
in the range, which must include locked_page if there is one.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21 14:52:15 +02:00
Christoph Hellwig
f778b6b8e0 btrfs: share the code to free the page array in compress_file_range
compress_file_range has two code blocks to free the page array for the
compressed data.  Share the code using a goto label.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21 14:52:15 +02:00
Christoph Hellwig
184aa1ffa5 btrfs: use a separate label for the incompressible case in compress_file_range
compress_file_range can fail to compress either because of resource or
alignment constraints or because the data is incompressible.  In the latter
case the inode is marked so that compression isn't tried again.  Currently
that check is based on the condition that the pages array has been allocated
which is rather cryptic.  Use a separate label to clearly distinguish this
case.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21 14:52:15 +02:00