linux-stable.git/fs/ext4, branch v6.7.8

ext4: correct the hole length returned by ext4_map_blocks()

2024-03-01T12:41:39+00:00

[ Upstream commit 6430dea07e85958fa87d0276c0c4388dd51e630b ]

In ext4_map_blocks(), if we can't find a range of mapping in the
extents cache, we are calling ext4_ext_map_blocks() to search the real
path and ext4_ext_determine_hole() to determine the hole range. But if
the querying range was partially or completely overlaped by a delalloc
extent, we can't find it in the real extent path, so the returned hole
length could be incorrect.

Fortunately, ext4_ext_put_gap_in_cache() have already handle delalloc
extent, but it searches start from the expanded hole_start, doesn't
start from the querying range, so the delalloc extent found could not be
the one that overlaped the querying range, plus, it also didn't adjust
the hole length. Let's just remove ext4_ext_put_gap_in_cache(), handle
delalloc and insert adjusted hole extent in ext4_ext_determine_hole().

Signed-off-by: Zhang Yi 
Suggested-by: Jan Kara 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20240127015825.1608160-4-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: avoid allocating blocks from corrupted group in ext4_mb_find_by_goal()

2024-03-01T12:41:36+00:00

[ Upstream commit 832698373a25950942c04a512daa652c18a9b513 ]

Places the logic for checking if the group's block bitmap is corrupt under
the protection of the group lock to avoid allocating blocks from the group
with a corrupted block bitmap.

Signed-off-by: Baokun Li 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20240104142040.2835097-8-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: avoid allocating blocks from corrupted group in ext4_mb_try_best_found()

2024-03-01T12:41:36+00:00

[ Upstream commit 4530b3660d396a646aad91a787b6ab37cf604b53 ]

Determine if the group block bitmap is corrupted before using ac_b_ex in
ext4_mb_try_best_found() to avoid allocating blocks from a group with a
corrupted block bitmap in the following concurrency and making the
situation worse.

ext4_mb_regular_allocator
  ext4_lock_group(sb, group)
  ext4_mb_good_group
   // check if the group bbitmap is corrupted
  ext4_mb_complex_scan_group
   // Scan group gets ac_b_ex but doesn't use it
  ext4_unlock_group(sb, group)
                           ext4_mark_group_bitmap_corrupted(group)
                           // The block bitmap was corrupted during
                           // the group unlock gap.
  ext4_mb_try_best_found
    ext4_lock_group(ac->ac_sb, group)
    ext4_mb_use_best_found
      mb_mark_used
      // Allocating blocks in block bitmap corrupted group

Signed-off-by: Baokun Li 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20240104142040.2835097-7-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: avoid dividing by 0 in mb_update_avg_fragment_size() when block bitmap corrupt

2024-03-01T12:41:36+00:00

[ Upstream commit 993bf0f4c393b3667830918f9247438a8f6fdb5b ]

Determine if bb_fragments is 0 instead of determining bb_free to eliminate
the risk of dividing by zero when the block bitmap is corrupted.

Signed-off-by: Baokun Li 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20240104142040.2835097-6-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: avoid bb_free and bb_fragments inconsistency in mb_free_blocks()

2024-02-23T08:51:40+00:00

commit 2331fd4a49864e1571b4f50aa3aa1536ed6220d0 upstream.

After updating bb_free in mb_free_blocks, it is possible to return without
updating bb_fragments because the block being freed is found to have
already been freed, which leads to inconsistency between bb_free and
bb_fragments.

Since the group may be unlocked in ext4_grp_locked_error(), this can lead
to problems such as dividing by zero when calculating the average fragment
length. Hence move the update of bb_free to after the block double-free
check guarantees that the corresponding statistics are updated only after
the core block bitmap is modified.

Fixes: eabe0444df90 ("ext4: speed-up releasing blocks on commit")
CC:   # 3.10
Suggested-by: Jan Kara 
Signed-off-by: Baokun Li 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20240104142040.2835097-5-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: fix double-free of blocks due to wrong extents moved_len

2024-02-23T08:51:40+00:00

commit 55583e899a5357308274601364741a83e78d6ac4 upstream.

In ext4_move_extents(), moved_len is only updated when all moves are
successfully executed, and only discards orig_inode and donor_inode
preallocations when moved_len is not zero. When the loop fails to exit
after successfully moving some extents, moved_len is not updated and
remains at 0, so it does not discard the preallocations.

If the moved extents overlap with the preallocated extents, the
overlapped extents are freed twice in ext4_mb_release_inode_pa() and
ext4_process_freed_data() (as described in commit 94d7c16cbbbd ("ext4:
Fix double-free of blocks with EXT4_IOC_MOVE_EXT")), and bb_free is
incremented twice. Hence when trim is executed, a zero-division bug is
triggered in mb_update_avg_fragment_size() because bb_free is not zero
and bb_fragments is zero.

Therefore, update move_len after each extent move to avoid the issue.

Reported-by: Wei Chen 
Reported-by: xingwei lee 
Closes: https://lore.kernel.org/r/CAO4mrferzqBUnCag8R3m2zf897ts9UEuhjFQGPtODT92rYyR2Q@mail.gmail.com
Fixes: fcf6b1b729bc ("ext4: refactor ext4_move_extents code base")
CC:   # 3.18
Signed-off-by: Baokun Li 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20240104142040.2835097-2-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: regenerate buddy after block freeing failed if under fc replay

2024-02-16T18:14:16+00:00

[ Upstream commit c9b528c35795b711331ed36dc3dbee90d5812d4e ]

This mostly reverts commit 6bd97bf273bd ("ext4: remove redundant
mb_regenerate_buddy()") and reintroduces mb_regenerate_buddy(). Based on
code in mb_free_blocks(), fast commit replay can end up marking as free
blocks that are already marked as such. This causes corruption of the
buddy bitmap so we need to regenerate it in that case.

Reported-by: Jan Kara 
Fixes: 6bd97bf273bd ("ext4: remove redundant mb_regenerate_buddy()")
Signed-off-by: Baokun Li 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20240104142040.2835097-4-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: avoid online resizing failures due to oversized flex bg

2024-02-05T20:16:49+00:00

[ Upstream commit 5d1935ac02ca5aee364a449a35e2977ea84509b0 ]

When we online resize an ext4 filesystem with a oversized flexbg_size,

     mkfs.ext4 -F -G 67108864 $dev -b 4096 100M
     mount $dev $dir
     resize2fs $dev 16G

the following WARN_ON is triggered:
==================================================================
WARNING: CPU: 0 PID: 427 at mm/page_alloc.c:4402 __alloc_pages+0x411/0x550
Modules linked in: sg(E)
CPU: 0 PID: 427 Comm: resize2fs Tainted: G  E  6.6.0-rc5+ #314
RIP: 0010:__alloc_pages+0x411/0x550
Call Trace:
 
 __kmalloc_large_node+0xa2/0x200
 __kmalloc+0x16e/0x290
 ext4_resize_fs+0x481/0xd80
 __ext4_ioctl+0x1616/0x1d90
 ext4_ioctl+0x12/0x20
 __x64_sys_ioctl+0xf0/0x150
 do_syscall_64+0x3b/0x90
==================================================================

This is because flexbg_size is too large and the size of the new_group_data
array to be allocated exceeds MAX_ORDER. Currently, the minimum value of
MAX_ORDER is 8, the minimum value of PAGE_SIZE is 4096, the corresponding
maximum number of groups that can be allocated is:

 (PAGE_SIZE << MAX_ORDER) / sizeof(struct ext4_new_group_data) ≈ 21845

And the value that is down-aligned to the power of 2 is 16384. Therefore,
this value is defined as MAX_RESIZE_BG, and the number of groups added
each time does not exceed this value during resizing, and is added multiple
times to complete the online resizing. The difference is that the metadata
in a flex_bg may be more dispersed.

Signed-off-by: Baokun Li 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20231023013057.2117948-4-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: remove unnecessary check from alloc_flex_gd()

2024-02-05T20:16:48+00:00

[ Upstream commit b099eb87de105cf07cad731ded6fb40b2675108b ]

In commit 967ac8af4475 ("ext4: fix potential integer overflow in
alloc_flex_gd()"), an overflow check is added to alloc_flex_gd() to
prevent the allocated memory from being smaller than expected due to
the overflow. However, after kmalloc() is replaced with kmalloc_array()
in commit 6da2ec56059c ("treewide: kmalloc() -> kmalloc_array()"), the
kmalloc_array() function has an overflow check, so the above problem
will not occur. Therefore, the extra check is removed.

Signed-off-by: Baokun Li 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20231023013057.2117948-3-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o 
Stable-dep-of: 5d1935ac02ca ("ext4: avoid online resizing failures due to oversized flex bg")
Signed-off-by: Sasha Levin

ext4: unify the type of flexbg_size to unsigned int

2024-02-05T20:16:48+00:00

[ Upstream commit 658a52344fb139f9531e7543a6e0015b630feb38 ]

The maximum value of flexbg_size is 2^31, but the maximum value of int
is (2^31 - 1), so overflow may occur when the type of flexbg_size is
declared as int.

For example, when uninit_mask is initialized in ext4_alloc_group_tables(),
if flexbg_size == 2^31, the initialized uninit_mask is incorrect, and this
may causes set_flexbg_block_bitmap() to trigger a BUG_ON().

Therefore, the flexbg_size type is declared as unsigned int to avoid
overflow and memory waste.

Signed-off-by: Baokun Li 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20231023013057.2117948-2-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o 
Stable-dep-of: 5d1935ac02ca ("ext4: avoid online resizing failures due to oversized flex bg")
Signed-off-by: Sasha Levin