[PATCH 2/3] ext3: release block-device-mapping buffer_heads which have the filesystem
private data for avoiding oom-killer
Implement releasepage() of a client of a block device to release its private
data (journal_heads) and the page. The client is an ext3 filesystem.
This function is called from releasepage() of the block-device mapping,
blkdev_releasepage().
Signed-off-by: Toshiyuki Okajima <toshi.okajima@xxxxxxxxxxxxxx>
---
fs/ext3/inode.c | 16 ++++++++++++++++
fs/ext3/super.c | 2 ++
include/linux/ext3_fs.h | 2 ++
3 files changed, 20 insertions(+)
diff -Nurp linux-2.6.28-rc4.orig/fs/ext3/inode.c linux-2.6.28-rc4/fs/ext3/inode.c
--- linux-2.6.28-rc4.orig/fs/ext3/inode.c 2008-11-10 09:36:15.000000000 +0900
+++ linux-2.6.28-rc4/fs/ext3/inode.c 2008-11-11 09:31:13.000000000 +0900
@@ -1680,6 +1680,28 @@ static int ext3_releasepage(struct page
}
/*
+ * ext3_release_metadata: try to release own page.
+ * The mapping of this page is block device's. Therefore try_to_free_buffers()
+ * cannot release it. As a result, a function which releases own page is
+ * required.
+ */
+int ext3_release_metadata(void *client, struct page *page, gfp_t wait)
+{
+ struct super_block *sb = (struct super_block*)client;
+ journal_t *journal;
+
+ WARN_ON(PageChecked(page));
+ if (!page_has_buffers(page))
+ return 0;
+ BUG_ON(EXT3_SB(sb) == NULL);
+ journal = EXT3_SB(sb)->s_journal;
+ if (journal != NULL)
+ return journal_try_to_free_buffers(journal, page, wait);
+ else
+ return try_to_free_buffers(page);
+}
+
+/*
* If the O_DIRECT write will extend the file then add this inode to the
* orphan list. So recovery will truncate it back to the original size
* if the machine crashes during the write.
diff -Nurp linux-2.6.28-rc4.orig/fs/ext3/super.c linux-2.6.28-rc4/fs/ext3/super.c
--- linux-2.6.28-rc4.orig/fs/ext3/super.c 2008-11-10 09:36:15.000000000 +0900
+++ linux-2.6.28-rc4/fs/ext3/super.c 2008-11-11 09:01:53.000000000 +0900
@@ -2972,6 +2972,8 @@ static struct file_system_type ext3_fs_t
.name = "ext3",
.get_sb = ext3_get_sb,
.kill_sb = kill_block_super,
+ .release_metadata
+ = ext3_release_metadata,
.fs_flags = FS_REQUIRES_DEV,
};
diff -Nurp linux-2.6.28-rc4.orig/include/linux/ext3_fs.h linux-2.6.28-rc4/include/linux/ext3_fs.h
--- linux-2.6.28-rc4.orig/include/linux/ext3_fs.h 2008-11-10 09:36:15.000000000 +0900
+++ linux-2.6.28-rc4/include/linux/ext3_fs.h 2008-11-10 18:33:52.000000000 +0900
@@ -841,6 +841,8 @@ extern void ext3_get_inode_flags(struct
extern void ext3_set_aops(struct inode *inode);
extern int ext3_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
u64 start, u64 len);
+extern int ext3_release_metadata(void *client, struct page *page,
+ gfp_t wait);
/* ioctl.c */
extern int ext3_ioctl (struct inode *, struct file *, unsigned int,
--
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