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96c36eaa77
[BUG] Test case btrfs/124 failed if larger metadata folio is enabled, the dying message looks like this: BTRFS error (device dm-2): bad tree block start, mirror 2 want 31686656 have 0 BTRFS info (device dm-2): read error corrected: ino 0 off 31686656 (dev /dev/mapper/test-scratch2 sector 20928) BUG: kernel NULL pointer dereference, address: 0000000000000020 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page CPU: 6 PID: 350881 Comm: btrfs Tainted: G OE 6.7.0-rc3-custom+ #128 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 2/2/2022 RIP: 0010:btrfs_read_extent_buffer+0x106/0x180 [btrfs] PKRU: 55555554 Call Trace: <TASK> read_tree_block+0x33/0xb0 [btrfs] read_block_for_search+0x23e/0x340 [btrfs] btrfs_search_slot+0x2f9/0xe60 [btrfs] btrfs_lookup_csum+0x75/0x160 [btrfs] btrfs_lookup_bio_sums+0x21a/0x560 [btrfs] btrfs_submit_chunk+0x152/0x680 [btrfs] btrfs_submit_bio+0x1c/0x50 [btrfs] submit_one_bio+0x40/0x80 [btrfs] submit_extent_page+0x158/0x390 [btrfs] btrfs_do_readpage+0x330/0x740 [btrfs] extent_readahead+0x38d/0x6c0 [btrfs] read_pages+0x94/0x2c0 page_cache_ra_unbounded+0x12d/0x190 relocate_file_extent_cluster+0x7c1/0x9d0 [btrfs] relocate_block_group+0x2d3/0x560 [btrfs] btrfs_relocate_block_group+0x2c7/0x4b0 [btrfs] btrfs_relocate_chunk+0x4c/0x1a0 [btrfs] btrfs_balance+0x925/0x13c0 [btrfs] btrfs_ioctl+0x19f1/0x25d0 [btrfs] __x64_sys_ioctl+0x90/0xd0 do_syscall_64+0x3f/0xf0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 [CAUSE] The dying line is at btrfs_repair_io_failure() call inside btrfs_repair_eb_io_failure(). The function is still relying on the extent buffer using page sized folios. When the extent buffer is using larger folio, we go into the 2nd slot of folios[], and triggered the NULL pointer dereference. [FIX] Migrate btrfs_repair_io_failure() to folio interfaces. So that when we hit a larger folio, we just submit the whole folio in one go. This also affects data repair path through btrfs_end_repair_bio(), thankfully data is still fully page based, we can just add an ASSERT(), and use page_folio() to convert the page to folio. Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.