From 87d8fe1ee6b8d2f95076142d58c440dba4e7bdc2 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 3 Jan 2009 09:47:09 -0500 Subject: add releasepage hooks to block devices which can be used by file systems Implement blkdev_releasepage() to release the buffer_heads and pages after we release private data belonging to a mounted filesystem. Cc: Toshiyuki Okajima Cc: linux-fsdevel@vger.kernel.org Signed-off-by: "Theodore Ts'o" --- fs/block_dev.c | 15 +++++++++++++++ fs/super.c | 2 ++ 2 files changed, 17 insertions(+) (limited to 'fs') diff --git a/fs/block_dev.c b/fs/block_dev.c index 349a26c1000..1dd07e66e98 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1220,6 +1220,20 @@ static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) return blkdev_ioctl(bdev, mode, cmd, arg); } +/* + * Try to release a page associated with block device when the system + * is under memory pressure. + */ +static int blkdev_releasepage(struct page *page, gfp_t wait) +{ + struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super; + + if (super && super->s_op->bdev_try_to_free_page) + return super->s_op->bdev_try_to_free_page(super, page, wait); + + return try_to_free_buffers(page); +} + static const struct address_space_operations def_blk_aops = { .readpage = blkdev_readpage, .writepage = blkdev_writepage, @@ -1227,6 +1241,7 @@ static const struct address_space_operations def_blk_aops = { .write_begin = blkdev_write_begin, .write_end = blkdev_write_end, .writepages = generic_writepages, + .releasepage = blkdev_releasepage, .direct_IO = blkdev_direct_IO, }; diff --git a/fs/super.c b/fs/super.c index ddba069d7a9..d5fd4498548 100644 --- a/fs/super.c +++ b/fs/super.c @@ -800,6 +800,7 @@ int get_sb_bdev(struct file_system_type *fs_type, } s->s_flags |= MS_ACTIVE; + bdev->bd_super = s; } return simple_set_mnt(mnt, s); @@ -819,6 +820,7 @@ void kill_block_super(struct super_block *sb) struct block_device *bdev = sb->s_bdev; fmode_t mode = sb->s_mode; + bdev->bd_super = 0; generic_shutdown_super(sb); sync_blockdev(bdev); close_bdev_exclusive(bdev, mode); -- cgit v1.2.3