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authorYongqiang Yang <xiaoqiangnk@gmail.com>2011-12-13 21:51:55 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2011-12-21 12:57:44 -0800
commit8fe5e8ff93473129957c6d4a7df80046186b9c7b (patch)
tree9561105270aeec6e9c28fc3cbb430040a5be6ca7
parentdda54df863232231ce851045834f475f02a7e565 (diff)
ext4: avoid potential hang in mpage_submit_io() when blocksize < pagesize
commit 13a79a4741d37fda2fbafb953f0f301dc007928f upstream. If there is an unwritten but clean buffer in a page and there is a dirty buffer after the buffer, then mpage_submit_io does not write the dirty buffer out. As a result, da_writepages loops forever. This patch fixes the problem by checking dirty flag. Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--fs/ext4/inode.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ea9076b8d917..af0906080fd8 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2126,8 +2126,11 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd,
clear_buffer_unwritten(bh);
}
- /* skip page if block allocation undone */
- if (buffer_delay(bh) || buffer_unwritten(bh))
+ /*
+ * skip page if block allocation undone and
+ * block is dirty
+ */
+ if (ext4_bh_delay_or_unwritten(NULL, bh))
skip_page = 1;
bh = bh->b_this_page;
block_start += bh->b_size;