ext4: fix unwritten counter leakage
ext4_set_io_unwritten_flag() will increment i_unwritten counter, so
once we mark end_io with EXT4_END_IO_UNWRITTEN we have to revert it back
on error path.
- add missed error checks to prevent counter leakage
- ext4_end_io_nolock() will clear EXT4_END_IO_UNWRITTEN flag to signal
that conversion finished.
- add BUG_ON to ext4_free_end_io() to prevent similar leakage in future.
Visible effect of this bug is that unaligned aio_stress may deadlock
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index a1f56c3..54a9442 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3633,6 +3633,8 @@
if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
ret = ext4_split_unwritten_extents(handle, inode, map,
path, flags);
+ if (ret <= 0)
+ goto out;
/*
* Flag the inode(non aio case) or end_io struct (aio case)
* that this IO needs to conversion to written when IO is
@@ -3878,6 +3880,7 @@
struct ext4_allocation_request ar;
ext4_io_end_t *io = ext4_inode_aio(inode);
ext4_lblk_t cluster_offset;
+ int set_unwritten = 0;
ext_debug("blocks %u/%u requested for inode %lu\n",
map->m_lblk, map->m_len, inode->i_ino);
@@ -4100,13 +4103,8 @@
* For non asycn direct IO case, flag the inode state
* that we need to perform conversion when IO is done.
*/
- if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
- if (io)
- ext4_set_io_unwritten_flag(inode, io);
- else
- ext4_set_inode_state(inode,
- EXT4_STATE_DIO_UNWRITTEN);
- }
+ if ((flags & EXT4_GET_BLOCKS_PRE_IO))
+ set_unwritten = 1;
if (ext4_should_dioread_nolock(inode))
map->m_flags |= EXT4_MAP_UNINIT;
}
@@ -4118,6 +4116,15 @@
if (!err)
err = ext4_ext_insert_extent(handle, inode, path,
&newex, flags);
+
+ if (!err && set_unwritten) {
+ if (io)
+ ext4_set_io_unwritten_flag(inode, io);
+ else
+ ext4_set_inode_state(inode,
+ EXT4_STATE_DIO_UNWRITTEN);
+ }
+
if (err && free_on_err) {
int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
