• Kirill A. Shutemov's avatar
    UBIFS: Implement ->migratepage() · 4ac1c17b
    Kirill A. Shutemov authored
    During page migrations UBIFS might get confused
    and the following assert triggers:
    [  213.480000] UBIFS assert failed in ubifs_set_page_dirty at 1451 (pid 436)
    [  213.490000] CPU: 0 PID: 436 Comm: drm-stress-test Not tainted 4.4.4-00176-geaa802524636-dirty #1008
    [  213.490000] Hardware name: Allwinner sun4i/sun5i Families
    [  213.490000] [<c0015e70>] (unwind_backtrace) from [<c0012cdc>] (show_stack+0x10/0x14)
    [  213.490000] [<c0012cdc>] (show_stack) from [<c02ad834>] (dump_stack+0x8c/0xa0)
    [  213.490000] [<c02ad834>] (dump_stack) from [<c0236ee8>] (ubifs_set_page_dirty+0x44/0x50)
    [  213.490000] [<c0236ee8>] (ubifs_set_page_dirty) from [<c00fa0bc>] (try_to_unmap_one+0x10c/0x3a8)
    [  213.490000] [<c00fa0bc>] (try_to_unmap_one) from [<c00fadb4>] (rmap_walk+0xb4/0x290)
    [  213.490000] [<c00fadb4>] (rmap_walk) from [<c00fb1bc>] (try_to_unmap+0x64/0x80)
    [  213.490000] [<c00fb1bc>] (try_to_unmap) from [<c010dc28>] (migrate_pages+0x328/0x7a0)
    [  213.490000] [<c010dc28>] (migrate_pages) from [<c00d0cb0>] (alloc_contig_range+0x168/0x2f4)
    [  213.490000] [<c00d0cb0>] (alloc_contig_range) from [<c010ec00>] (cma_alloc+0x170/0x2c0)
    [  213.490000] [<c010ec00>] (cma_alloc) from [<c001a958>] (__alloc_from_contiguous+0x38/0xd8)
    [  213.490000] [<c001a958>] (__alloc_from_contiguous) from [<c001ad44>] (__dma_alloc+0x23c/0x274)
    [  213.490000] [<c001ad44>] (__dma_alloc) from [<c001ae08>] (arm_dma_alloc+0x54/0x5c)
    [  213.490000] [<c001ae08>] (arm_dma_alloc) from [<c035cecc>] (drm_gem_cma_create+0xb8/0xf0)
    [  213.490000] [<c035cecc>] (drm_gem_cma_create) from [<c035cf20>] (drm_gem_cma_create_with_handle+0x1c/0xe8)
    [  213.490000] [<c035cf20>] (drm_gem_cma_create_with_handle) from [<c035d088>] (drm_gem_cma_dumb_create+0x3c/0x48)
    [  213.490000] [<c035d088>] (drm_gem_cma_dumb_create) from [<c0341ed8>] (drm_ioctl+0x12c/0x444)
    [  213.490000] [<c0341ed8>] (drm_ioctl) from [<c0121adc>] (do_vfs_ioctl+0x3f4/0x614)
    [  213.490000] [<c0121adc>] (do_vfs_ioctl) from [<c0121d30>] (SyS_ioctl+0x34/0x5c)
    [  213.490000] [<c0121d30>] (SyS_ioctl) from [<c000f2c0>] (ret_fast_syscall+0x0/0x34)
    
    UBIFS is using PagePrivate() which can have different meanings across
    filesystems. Therefore the generic page migration code cannot handle this
    case correctly.
    We have to implement our own migration function which basically does a
    plain copy but also duplicates the page private flag.
    UBIFS is not a block device filesystem and cannot use buffer_migrate_page().
    
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
    [rw: Massaged changelog, build fixes, etc...]
    Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
    Acked-by: default avatarChristoph Hellwig <hch@lst.de>
    4ac1c17b
file.c 46.4 KB