The patch below does not apply to the 4.9-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 f87c7a4b084afc13190cbb263538e444cb2b392a Mon Sep 17 00:00:00 2001 From: Baokun Li libaokun1@huawei.com Date: Thu, 28 Apr 2022 21:40:31 +0800 Subject: [PATCH] ext4: fix race condition between ext4_write and ext4_convert_inline_data
Hulk Robot reported a BUG_ON: ================================================================== EXT4-fs error (device loop3): ext4_mb_generate_buddy:805: group 0, block bitmap and bg descriptor inconsistent: 25 vs 31513 free clusters kernel BUG at fs/ext4/ext4_jbd2.c:53! invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 0 PID: 25371 Comm: syz-executor.3 Not tainted 5.10.0+ #1 RIP: 0010:ext4_put_nojournal fs/ext4/ext4_jbd2.c:53 [inline] RIP: 0010:__ext4_journal_stop+0x10e/0x110 fs/ext4/ext4_jbd2.c:116 [...] Call Trace: ext4_write_inline_data_end+0x59a/0x730 fs/ext4/inline.c:795 generic_perform_write+0x279/0x3c0 mm/filemap.c:3344 ext4_buffered_write_iter+0x2e3/0x3d0 fs/ext4/file.c:270 ext4_file_write_iter+0x30a/0x11c0 fs/ext4/file.c:520 do_iter_readv_writev+0x339/0x3c0 fs/read_write.c:732 do_iter_write+0x107/0x430 fs/read_write.c:861 vfs_writev fs/read_write.c:934 [inline] do_pwritev+0x1e5/0x380 fs/read_write.c:1031 [...] ==================================================================
Above issue may happen as follows: cpu1 cpu2 __________________________|__________________________ do_pwritev vfs_writev do_iter_write ext4_file_write_iter ext4_buffered_write_iter generic_perform_write ext4_da_write_begin vfs_fallocate ext4_fallocate ext4_convert_inline_data ext4_convert_inline_data_nolock ext4_destroy_inline_data_nolock clear EXT4_STATE_MAY_INLINE_DATA ext4_map_blocks ext4_ext_map_blocks ext4_mb_new_blocks ext4_mb_regular_allocator ext4_mb_good_group_nolock ext4_mb_init_group ext4_mb_init_cache ext4_mb_generate_buddy --> error ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) ext4_restore_inline_data set EXT4_STATE_MAY_INLINE_DATA ext4_block_write_begin ext4_da_write_end ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) ext4_write_inline_data_end handle=NULL ext4_journal_stop(handle) __ext4_journal_stop ext4_put_nojournal(handle) ref_cnt = (unsigned long)handle BUG_ON(ref_cnt == 0) ---> BUG_ON
The lock held by ext4_convert_inline_data is xattr_sem, but the lock held by generic_perform_write is i_rwsem. Therefore, the two locks can be concurrent.
To solve above issue, we add inode_lock() for ext4_convert_inline_data(). At the same time, move ext4_convert_inline_data() in front of ext4_punch_hole(), remove similar handling from ext4_punch_hole().
Fixes: 0c8d414f163f ("ext4: let fallocate handle inline data correctly") Cc: stable@vger.kernel.org Reported-by: Hulk Robot hulkci@huawei.com Signed-off-by: Baokun Li libaokun1@huawei.com Reviewed-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/20220428134031.4153381-1-libaokun1@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index e473fde6b64b..474479ce76e0 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -4693,15 +4693,17 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) FALLOC_FL_INSERT_RANGE)) return -EOPNOTSUPP;
+ inode_lock(inode); + ret = ext4_convert_inline_data(inode); + inode_unlock(inode); + if (ret) + goto exit; + if (mode & FALLOC_FL_PUNCH_HOLE) { ret = ext4_punch_hole(file, offset, len); goto exit; }
- ret = ext4_convert_inline_data(inode); - if (ret) - goto exit; - if (mode & FALLOC_FL_COLLAPSE_RANGE) { ret = ext4_collapse_range(file, offset, len); goto exit; diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 5948bbba28e3..890f769d6e20 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3979,15 +3979,6 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
trace_ext4_punch_hole(inode, offset, length, 0);
- ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA); - if (ext4_has_inline_data(inode)) { - filemap_invalidate_lock(mapping); - ret = ext4_convert_inline_data(inode); - filemap_invalidate_unlock(mapping); - if (ret) - return ret; - } - /* * Write out all dirty pages to avoid race conditions * Then release them.