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authorToshiyuki Okajima <toshi.okajima@jp.fujitsu.com>2009-01-05 22:38:14 -0500
committerTheodore Ts'o <tytso@mit.edu>2009-01-05 22:38:14 -0500
commit6b082b531228c43d454c082fc0f969da1695b060 (patch)
treedbd2f64945064e31383a24729fcdb672a23f65e9 /fs/ext3/super.c
parent87d8fe1ee6b8d2f95076142d58c440dba4e7bdc2 (diff)
downloadop-kernel-dev-6b082b531228c43d454c082fc0f969da1695b060.zip
op-kernel-dev-6b082b531228c43d454c082fc0f969da1695b060.tar.gz
ext3: provide function to release metadata pages under memory pressure
Pages in the page cache belonging to ext3 data files are released via the ext3_releasepage() function specified in the ext3 inode's address_space_ops. However, metadata blocks (such as indirect blocks, directory blocks, etc) are managed via the block device address_space_ops, and they can not be released by try_to_free_buffers() if they have a journal head attached to them. To address this, we supply a try_to_free_pages() function which calls journal_try_to_free_buffers() function to free the metadata, and which is called by the block device's blkdev_releasepage() function. Signed-off-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: linux-fsdevel@vger.kernel.org
Diffstat (limited to 'fs/ext3/super.c')
-rw-r--r--fs/ext3/super.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index 541d5e4..6900ff0 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -682,6 +682,26 @@ static struct dentry *ext3_fh_to_parent(struct super_block *sb, struct fid *fid,
ext3_nfs_get_inode);
}
+/*
+ * Try to release metadata pages (indirect blocks, directories) which are
+ * mapped via the block device. Since these pages could have journal heads
+ * which would prevent try_to_free_buffers() from freeing them, we must use
+ * jbd layer's try_to_free_buffers() function to release them.
+ */
+static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
+ gfp_t wait)
+{
+ journal_t *journal = EXT3_SB(sb)->s_journal;
+
+ WARN_ON(PageChecked(page));
+ if (!page_has_buffers(page))
+ return 0;
+ if (journal)
+ return journal_try_to_free_buffers(journal, page,
+ wait & ~__GFP_WAIT);
+ return try_to_free_buffers(page);
+}
+
#ifdef CONFIG_QUOTA
#define QTYPE2NAME(t) ((t)==USRQUOTA?"user":"group")
#define QTYPE2MOPT(on, t) ((t)==USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
@@ -746,6 +766,7 @@ static const struct super_operations ext3_sops = {
.quota_read = ext3_quota_read,
.quota_write = ext3_quota_write,
#endif
+ .bdev_try_to_free_page = bdev_try_to_free_page,
};
static const struct export_operations ext3_export_ops = {
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