In a situation like:
truncate(f, 1024);
a = mmap(f, 0, 4096);
a[0] = 'a';
truncate(f, 4096);
we end up with a dirty page which does not have all blocks allocated /
reserved. Fix the problem by using new VFS infrastructure.
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/ext4/inode.c | 10 ++++++++++
1 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c6bd6ce..8f51219 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3363,6 +3363,7 @@ static const struct address_space_operations ext4_ordered_aops = {
.sync_page = block_sync_page,
.write_begin = ext4_write_begin,
.write_end = ext4_ordered_write_end,
+ .extend_i_size = block_extend_i_size,
.bmap = ext4_bmap,
.invalidatepage = ext4_invalidatepage,
.releasepage = ext4_releasepage,
@@ -3378,6 +3379,7 @@ static const struct address_space_operations ext4_writeback_aops = {
.sync_page = block_sync_page,
.write_begin = ext4_write_begin,
.write_end = ext4_writeback_write_end,
+ .extend_i_size = block_extend_i_size,
.bmap = ext4_bmap,
.invalidatepage = ext4_invalidatepage,
.releasepage = ext4_releasepage,
@@ -3393,6 +3395,7 @@ static const struct address_space_operations ext4_journalled_aops = {
.sync_page = block_sync_page,
.write_begin = ext4_write_begin,
.write_end = ext4_journalled_write_end,
+ .extend_i_size = block_extend_i_size,
.set_page_dirty = ext4_journalled_set_page_dirty,
.bmap = ext4_bmap,
.invalidatepage = ext4_invalidatepage,
@@ -3408,6 +3411,7 @@ static const struct address_space_operations ext4_da_aops = {
.sync_page = block_sync_page,
.write_begin = ext4_da_write_begin,
.write_end = ext4_da_write_end,
+ .extend_i_size = block_extend_i_size,
.bmap = ext4_bmap,
.invalidatepage = ext4_da_invalidatepage,
.releasepage = ext4_releasepage,
@@ -5260,6 +5264,12 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
struct address_space *mapping = inode->i_mapping;
/*
+ * Wait for extending of i_size, after this moment, next truncate /
+ * write can create holes under us but they writeprotect our page so
+ * we'll be called again to fill the hole.
+ */
+ block_wait_on_hole_extend(inode, page_offset(page));
+ /*
* Get i_alloc_sem to stop truncates messing with the inode. We cannot
* get i_mutex because we are already holding mmap_sem.
*/
--
1.6.0.2
--
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