lwn.git/fs/ext4/balloc.c, branch docs-6.9

ext4: add some kunit stub for mballoc kunit test

2023-10-06T02:32:16+00:00

Multiblocks allocation will read and write block bitmap and group descriptor which reside on disk. Add kunit stub to function ext4_get_group_desc, ext4_read_block_bitmap_nowait, ext4_wait_block_bitmap and ext4_mb_mark_context to avoid real IO to disk. Signed-off-by: Kemeng Shi Reviewed-by: "Ritesh Harjani (IBM)" Link: https://lore.kernel.org/r/20230928160407.142069-11-shikemeng@huaweicloud.com Signed-off-by: Theodore Ts'o

ext4: fix traditional comparison using max/min method

2023-10-06T01:48:02+00:00

It would be better to replace the traditional ternary conditional operator with max()/min() Signed-off-by: Lu Hongfei Reviewed-by: Kemeng Shi Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20230529070930.37949-1-luhongfei@vivo.com Signed-off-by: Theodore Ts'o

ext4: add correct group descriptors and reserved GDT blocks to system zone

2023-08-27T15:27:12+00:00

When setup_system_zone, flex_bg is not initialized so it is always 1. Use a new helper function, ext4_num_base_meta_blocks() which does not depend on sbi->s_log_groups_per_flex being initialized. [ Squashed two patches in the Link URL's below together into a single commit, which is simpler to review/understand. Also fix checkpatch warnings. --TYT ] Cc: stable@kernel.org Signed-off-by: Wang Jianjian Link: https://lore.kernel.org/r/tencent_21AF0D446A9916ED5C51492CC6C9A0A77B05@qq.com Link: https://lore.kernel.org/r/tencent_D744D1450CC169AEA77FCF0A64719909ED05@qq.com Signed-off-by: Theodore Ts'o

ext4: drop the call to ext4_error() from ext4_get_group_info()

2023-06-15T02:24:05+00:00

A recent patch added a call to ext4_error() which is problematic since some callers of the ext4_get_group_info() function may be holding a spinlock, whereas ext4_error() must never be called in atomic context. This triggered a report from Syzbot: "BUG: sleeping function called from invalid context in ext4_update_super" (see the link below). Therefore, drop the call to ext4_error() from ext4_get_group_info(). In the meantime use eight characters tabs instead of nine characters ones. Reported-by: syzbot+4acc7d910e617b360859@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/00000000000070575805fdc6cdb2@google.com/ Fixes: 5354b2af3406 ("ext4: allow ext4_get_group_info() to fail") Suggested-by: Theodore Ts'o Signed-off-by: Fabio M. De Francesco Link: https://lore.kernel.org/r/20230614100446.14337-1-fmdefrancesco@gmail.com

Revert "ext4: remove unnecessary check in ext4_bg_num_gdb_nometa"

2023-06-15T02:22:27+00:00

This reverts commit ad3f09be6cfe332be8ff46c78e6ec0f8839107aa. The reverted commit was intended to simpfy the code to get group descriptor block number in non-meta block group by assuming s_gdb_count is block number used for all non-meta block group descriptors. However s_gdb_count is block number used for all meta *and* non-meta group descriptors. So s_gdb_group will be > actual group descriptor block number used for all non-meta block group which should be "total non-meta block group" / "group descriptors per block", e.g. s_first_meta_bg. Signed-off-by: Kemeng Shi Link: https://lore.kernel.org/r/20230613225025.3859522-1-shikemeng@huaweicloud.com Fixes: ad3f09be6cfe ("ext4: remove unnecessary check in ext4_bg_num_gdb_nometa") Cc: stable@kernel.org Signed-off-by: Theodore Ts'o

ext4: allow ext4_get_group_info() to fail

2023-05-13T22:02:46+00:00

Previously, ext4_get_group_info() would treat an invalid group number as BUG(), since in theory it should never happen. However, if a malicious attaker (or fuzzer) modifies the superblock via the block device while it is the file system is mounted, it is possible for s_first_data_block to get set to a very large number. In that case, when calculating the block group of some block number (such as the starting block of a preallocation region), could result in an underflow and very large block group number. Then the BUG_ON check in ext4_get_group_info() would fire, resutling in a denial of service attack that can be triggered by root or someone with write access to the block device. For a quality of implementation perspective, it's best that even if the system administrator does something that they shouldn't, that it will not trigger a BUG. So instead of BUG'ing, ext4_get_group_info() will call ext4_error and return NULL. We also add fallback code in all of the callers of ext4_get_group_info() that it might NULL. Also, since ext4_get_group_info() was already borderline to be an inline function, un-inline it. The results in a next reduction of the compiled text size of ext4 by roughly 2k. Cc: stable@kernel.org Link: https://lore.kernel.org/r/20230430154311.579720-2-tytso@mit.edu Reported-by: syzbot+e2efa3efc15a1c9e95c3@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=69b28112e098b070f639efb356393af3ffec4220 Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara

ext4: fix WARNING in mb_find_extent

2023-05-08T01:03:24+00:00

Syzbot found the following issue: EXT4-fs: Warning: mounting with data=journal disables delayed allocation, dioread_nolock, O_DIRECT and fast_commit support! EXT4-fs (loop0): orphan cleanup on readonly fs ------------[ cut here ]------------ WARNING: CPU: 1 PID: 5067 at fs/ext4/mballoc.c:1869 mb_find_extent+0x8a1/0xe30 Modules linked in: CPU: 1 PID: 5067 Comm: syz-executor307 Not tainted 6.2.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 RIP: 0010:mb_find_extent+0x8a1/0xe30 fs/ext4/mballoc.c:1869 RSP: 0018:ffffc90003c9e098 EFLAGS: 00010293 RAX: ffffffff82405731 RBX: 0000000000000041 RCX: ffff8880783457c0 RDX: 0000000000000000 RSI: 0000000000000041 RDI: 0000000000000040 RBP: 0000000000000040 R08: ffffffff82405723 R09: ffffed10053c9402 R10: ffffed10053c9402 R11: 1ffff110053c9401 R12: 0000000000000000 R13: ffffc90003c9e538 R14: dffffc0000000000 R15: ffffc90003c9e2cc FS: 0000555556665300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000056312f6796f8 CR3: 0000000022437000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ext4_mb_complex_scan_group+0x353/0x1100 fs/ext4/mballoc.c:2307 ext4_mb_regular_allocator+0x1533/0x3860 fs/ext4/mballoc.c:2735 ext4_mb_new_blocks+0xddf/0x3db0 fs/ext4/mballoc.c:5605 ext4_ext_map_blocks+0x1868/0x6880 fs/ext4/extents.c:4286 ext4_map_blocks+0xa49/0x1cc0 fs/ext4/inode.c:651 ext4_getblk+0x1b9/0x770 fs/ext4/inode.c:864 ext4_bread+0x2a/0x170 fs/ext4/inode.c:920 ext4_quota_write+0x225/0x570 fs/ext4/super.c:7105 write_blk fs/quota/quota_tree.c:64 [inline] get_free_dqblk+0x34a/0x6d0 fs/quota/quota_tree.c:130 do_insert_tree+0x26b/0x1aa0 fs/quota/quota_tree.c:340 do_insert_tree+0x722/0x1aa0 fs/quota/quota_tree.c:375 do_insert_tree+0x722/0x1aa0 fs/quota/quota_tree.c:375 do_insert_tree+0x722/0x1aa0 fs/quota/quota_tree.c:375 dq_insert_tree fs/quota/quota_tree.c:401 [inline] qtree_write_dquot+0x3b6/0x530 fs/quota/quota_tree.c:420 v2_write_dquot+0x11b/0x190 fs/quota/quota_v2.c:358 dquot_acquire+0x348/0x670 fs/quota/dquot.c:444 ext4_acquire_dquot+0x2dc/0x400 fs/ext4/super.c:6740 dqget+0x999/0xdc0 fs/quota/dquot.c:914 __dquot_initialize+0x3d0/0xcf0 fs/quota/dquot.c:1492 ext4_process_orphan+0x57/0x2d0 fs/ext4/orphan.c:329 ext4_orphan_cleanup+0xb60/0x1340 fs/ext4/orphan.c:474 __ext4_fill_super fs/ext4/super.c:5516 [inline] ext4_fill_super+0x81cd/0x8700 fs/ext4/super.c:5644 get_tree_bdev+0x400/0x620 fs/super.c:1282 vfs_get_tree+0x88/0x270 fs/super.c:1489 do_new_mount+0x289/0xad0 fs/namespace.c:3145 do_mount fs/namespace.c:3488 [inline] __do_sys_mount fs/namespace.c:3697 [inline] __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3674 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Add some debug information: mb_find_extent: mb_find_extent block=41, order=0 needed=64 next=0 ex=0/41/1@3735929054 64 64 7 block_bitmap: ff 3f 0c 00 fc 01 00 00 d2 3d 00 00 00 00 00 00 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff Acctually, blocks per group is 64, but block bitmap indicate at least has 128 blocks. Now, ext4_validate_block_bitmap() didn't check invalid block's bitmap if set. To resolve above issue, add check like fsck "Padding at end of block bitmap is not set". Cc: stable@kernel.org Reported-by: syzbot+68223fe9f6c95ad43bed@syzkaller.appspotmail.com Signed-off-by: Ye Bin Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20230116020015.1506120-1-yebin@huaweicloud.com Signed-off-by: Theodore Ts'o

ext4: remove unused group parameter in ext4_block_bitmap_csum_verify

2023-03-24T03:00:08+00:00

Remove unused group parameter in ext4_block_bitmap_csum_verify. Signed-off-by: Kemeng Shi Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20230221203027.2359920-4-shikemeng@huaweicloud.com Signed-off-by: Theodore Ts'o

ext4: improve inode table blocks counting in ext4_num_overhead_clusters

2023-03-24T03:00:08+00:00

As inode table blocks are contiguous, inode table blocks inside the block_group can be represented as range [itbl_cluster_start, itbl_cluster_last]. Then we can simply account inode table cluters and check cluster overlap with [itbl_cluster_start, itbl_cluster_last] instead of traverse each block of inode table. By the way, this patch fixes code style problem of comment for ext4_num_overhead_clusters. [ Merged fix-up patch which fixed potentially access to an uninitialzied stack variable. --TYT ] Signed-off-by: Kemeng Shi Link: https://lore.kernel.org/r/20230221115919.1918161-8-shikemeng@huaweicloud.com Link: https://lore.kernel.org/r/202303171446.eLEhZzAu-lkp@intel.com/ Reported-by: kernel test robot Reported-by: Dan Carpenter Signed-off-by: Theodore Ts'o

ext4: stop trying to verify just initialized bitmap in ext4_read_block_bitmap_nowait

2023-03-24T03:00:08+00:00

For case we initialize a bitmap bh, we will set bitmap bh verified. We can return immediately instead of goto verify to remove unnecessary work for trying to verify bitmap bh. Signed-off-by: Kemeng Shi Link: https://lore.kernel.org/r/20230221115919.1918161-7-shikemeng@huaweicloud.com Signed-off-by: Theodore Ts'o