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SubjectRe: [PATCH 2/2] UBIFS: Implement ->migratepage()
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On 03/31/2016 11:58 PM, Richard Weinberger wrote:
> From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
>
> During page migrations UBIFS might get confused
> and the following assert triggers:
> UBIFS assert failed in ubifs_set_page_dirty at 1451 (pid 436)

It would be useful to have the full trace in changelog.

> 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().
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> [rw: Massaged changelog]
> Signed-off-by: Richard Weinberger <richard@nod.at>

Stable?

> Signed-off-by: Richard Weinberger <richard@nod.at>
> ---
> fs/ubifs/file.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
> index 065c88f..5eea5f5 100644
> --- a/fs/ubifs/file.c
> +++ b/fs/ubifs/file.c
> @@ -52,6 +52,7 @@
> #include "ubifs.h"
> #include <linux/mount.h>
> #include <linux/slab.h>
> +#include <linux/migrate.h>
>
> static int read_block(struct inode *inode, void *addr, unsigned int block,
> struct ubifs_data_node *dn)
> @@ -1452,6 +1453,24 @@ static int ubifs_set_page_dirty(struct page *page)
> return ret;
> }
>
> +static int ubifs_migrate_page(struct address_space *mapping,
> + struct page *newpage, struct page *page, enum migrate_mode mode)
> +{
> + int rc;
> +
> + rc = migrate_page_move_mapping(mapping, newpage, page, NULL, mode, 0);
> + if (rc != MIGRATEPAGE_SUCCESS)
> + return rc;
> +
> + if (PagePrivate(page)) {
> + ClearPagePrivate(page);
> + SetPagePrivate(newpage);
> + }
> +
> + migrate_page_copy(newpage, page);
> + return MIGRATEPAGE_SUCCESS;
> +}
> +
> static int ubifs_releasepage(struct page *page, gfp_t unused_gfp_flags)
> {
> /*
> @@ -1591,6 +1610,7 @@ const struct address_space_operations ubifs_file_address_operations = {
> .write_end = ubifs_write_end,
> .invalidatepage = ubifs_invalidatepage,
> .set_page_dirty = ubifs_set_page_dirty,
> + .migratepage = ubifs_migrate_page,
> .releasepage = ubifs_releasepage,
> };
>
>

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