The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 51ae846cff568c8c29921b1b28eb2dfbcd4ac12d Mon Sep 17 00:00:00 2001 From: Ye Bin yebin10@huawei.com Date: Fri, 17 Jun 2022 09:39:35 +0800 Subject: [PATCH] ext4: fix warning in ext4_iomap_begin as race between bmap and write

We got issue as follows: ------------[ cut here ]------------ WARNING: CPU: 3 PID: 9310 at fs/ext4/inode.c:3441 ext4_iomap_begin+0x182/0x5d0 RIP: 0010:ext4_iomap_begin+0x182/0x5d0 RSP: 0018:ffff88812460fa08 EFLAGS: 00010293 RAX: ffff88811f168000 RBX: 0000000000000000 RCX: ffffffff97793c12 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: ffff88812c669160 R08: ffff88811f168000 R09: ffffed10258cd20f R10: ffff88812c669077 R11: ffffed10258cd20e R12: 0000000000000001 R13: 00000000000000a4 R14: 000000000000000c R15: ffff88812c6691ee FS: 00007fd0d6ff3740(0000) GS:ffff8883af180000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd0d6dda290 CR3: 0000000104a62000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: iomap_apply+0x119/0x570 iomap_bmap+0x124/0x150 ext4_bmap+0x14f/0x250 bmap+0x55/0x80 do_vfs_ioctl+0x952/0xbd0 __x64_sys_ioctl+0xc6/0x170 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Above issue may happen as follows: bmap write bmap ext4_bmap iomap_bmap ext4_iomap_begin ext4_file_write_iter ext4_buffered_write_iter generic_perform_write ext4_da_write_begin ext4_da_write_inline_data_begin ext4_prepare_inline_data ext4_create_inline_data ext4_set_inode_flag(inode, EXT4_INODE_INLINE_DATA); if (WARN_ON_ONCE(ext4_has_inline_data(inode))) ->trigger bug_on

To solved above issue hold inode lock in ext4_bamp.

Signed-off-by: Ye Bin yebin10@huawei.com Link: https://lore.kernel.org/r/20220617013935.397596-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu Cc: stable@kernel.org

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 641c9af91641..7db52defcb16 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3147,13 +3147,15 @@ static sector_t ext4_bmap(struct address_space *mapping, sector_t block) { struct inode *inode = mapping->host; journal_t *journal; + sector_t ret = 0; int err;

+ inode_lock_shared(inode); /* * We can get here for an inline file via the FIBMAP ioctl */ if (ext4_has_inline_data(inode)) - return 0; + goto out;

if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) && test_opt(inode->i_sb, DELALLOC)) { @@ -3192,10 +3194,14 @@ static sector_t ext4_bmap(struct address_space *mapping, sector_t block) jbd2_journal_unlock_updates(journal);

if (err) - return 0; + goto out; }

- return iomap_bmap(mapping, block, &ext4_iomap_ops); + ret = iomap_bmap(mapping, block, &ext4_iomap_ops); + +out: + inode_unlock_shared(inode); + return ret; }

static int ext4_read_folio(struct file *file, struct folio *folio)