[PATCH 3.16 244/366] ext4: fix inline data updates with checksums enabled

Ben Hutchings
2018-11-12T05:48:13Z

From: Theodore Ts'o <tytso@mit.edu>

commit 362eca70b53389bddf3143fe20f53dcce2cfdf61 upstream.

The inline data code was updating the raw inode directly; this is
problematic since if metadata checksums are enabled,
ext4_mark_inode_dirty() must be called to update the inode's checksum.
In addition, the jbd2 layer requires that get_write_access() be called
before the metadata buffer is modified. Fix both of these problems.

https://bugzilla.kernel.org/show_bug.cgi?id=200443

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/ext4/inline.c | 19 +++++++++++--------
fs/ext4/inode.c | 16 +++++++---------
2 files changed, 18 insertions(+), 17 deletions(-)

--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -681,6 +681,10 @@ int ext4_try_to_write_inline_data(struct
goto convert;
}

+ ret = ext4_journal_get_write_access(handle, iloc.bh);
+ if (ret)
+ goto out;
+
flags |= AOP_FLAG_NOFS;

page = grab_cache_page_write_begin(mapping, 0, flags);
@@ -709,7 +713,7 @@ int ext4_try_to_write_inline_data(struct
out_up_read:
up_read(&EXT4_I(inode)->xattr_sem);
out:
- if (handle)
+ if (handle && (ret != 1))
ext4_journal_stop(handle);
brelse(iloc.bh);
return ret;
@@ -751,6 +755,7 @@ int ext4_write_inline_data_end(struct in

ext4_write_unlock_xattr(inode, &no_expand);
brelse(iloc.bh);
+ mark_inode_dirty(inode);
out:
return copied;
}
@@ -911,6 +916,9 @@ retry_journal:
if (ret < 0)
goto out_release_page;
}
+ ret = ext4_journal_get_write_access(handle, iloc.bh);
+ if (ret)
+ goto out_release_page;

up_read(&EXT4_I(inode)->xattr_sem);
*pagep = page;
@@ -931,7 +939,6 @@ int ext4_da_write_inline_data_end(struct
unsigned len, unsigned copied,
struct page *page)
{
- int i_size_changed = 0;
int ret;

ret = ext4_write_inline_data_end(inode, pos, len, copied, page);
@@ -949,10 +956,8 @@ int ext4_da_write_inline_data_end(struct
* But it's important to update i_size while still holding page lock:
* page writeout could otherwise come in and zero beyond i_size.
*/
- if (pos+copied > inode->i_size) {
+ if (pos+copied > inode->i_size)
i_size_write(inode, pos+copied);
- i_size_changed = 1;
- }
unlock_page(page);
page_cache_release(page);

@@ -962,8 +967,7 @@ int ext4_da_write_inline_data_end(struct
* ordering of page lock and transaction start for journaling
* filesystems.
*/
- if (i_size_changed)
- mark_inode_dirty(inode);
+ mark_inode_dirty(inode);

return copied;
}
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1113,9 +1113,10 @@ static int ext4_write_end(struct file *f
struct inode *inode = mapping->host;
int ret = 0, ret2;
int i_size_changed = 0;
+ int inline_data = ext4_has_inline_data(inode);

trace_ext4_write_end(inode, pos, len, copied);
- if (ext4_has_inline_data(inode)) {
+ if (inline_data) {
ret = ext4_write_inline_data_end(inode, pos, len,
copied, page);
if (ret < 0) {
@@ -1141,7 +1142,7 @@ static int ext4_write_end(struct file *f
* ordering of page lock and transaction start for journaling
* filesystems.
*/
- if (i_size_changed)
+ if (i_size_changed || inline_data)
ext4_mark_inode_dirty(handle, inode);

if (pos + len > inode->i_size && ext4_can_truncate(inode))
@@ -1214,6 +1215,7 @@ static int ext4_journalled_write_end(str
int partial = 0;
unsigned from, to;
int size_changed = 0;
+ int inline_data = ext4_has_inline_data(inode);

trace_ext4_journalled_write_end(inode, pos, len, copied);
from = pos & (PAGE_CACHE_SIZE - 1);
@@ -1221,7 +1223,7 @@ static int ext4_journalled_write_end(str

BUG_ON(!ext4_handle_valid(handle));

- if (ext4_has_inline_data(inode)) {
+ if (inline_data) {
ret = ext4_write_inline_data_end(inode, pos, len,
copied, page);
if (ret < 0) {
@@ -1249,7 +1251,7 @@ static int ext4_journalled_write_end(str
unlock_page(page);
page_cache_release(page);

- if (size_changed) {
+ if (size_changed || inline_data) {
ret2 = ext4_mark_inode_dirty(handle, inode);
if (!ret)
ret = ret2;
@@ -1856,11 +1858,7 @@ static int __ext4_journalled_writepage(s
}

if (inline_data) {
- BUFFER_TRACE(inode_bh, "get write access");
- ret = ext4_journal_get_write_access(handle, inode_bh);
-
- err = ext4_handle_dirty_metadata(handle, inode, inode_bh);
-
+ ret = ext4_mark_inode_dirty(handle, inode);
} else {
ret = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
do_journal_get_write_access);