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Commit 946929d8 authored by Anton Altaparmakov's avatar Anton Altaparmakov
Browse files

NTFS: Fixup the resident attribute resizing code in 


      fs/ntfs/aops.c::ntfs_{prepare,commit}_write()() and re-enable it.
      It should be safe now.  (Famous last words...)

Signed-off-by: default avatarAnton Altaparmakov <aia21@cantab.net>
parent 3834c3f2

fs/ntfs/ChangeLog

+5 −0
Original line number Diff line number Diff line
@@ -51,6 +51,11 @@ ToDo/Notes: 
	  value afterwards when reading the size of the bitmap inode.

	- Use i_size_{read,write}() in fs/ntfs/{aops.c,mft.c} and protect

	  access to the i_size and other size fields using the size_lock.

	- Implement extension of resident files in the regular file write code

	  paths (fs/ntfs/aops.c::ntfs_{prepare,commit}_write()).  At present

	  this only works until the data attribute becomes too big for the mft

	  record after which we abort the write returning -EOPNOTSUPP from

	  ntfs_prepare_write().



2.1.22 - Many bug and race fixes and error handling improvements.

fs/ntfs/aops.c

+14 −7
Original line number Diff line number Diff line
@@ -872,6 +872,7 @@ static int ntfs_write_mst_block(struct page *page, 
		if (likely(block < rec_block)) {

			if (unlikely(block >= dblock)) {

				clear_buffer_dirty(bh);

				set_buffer_uptodate(bh);

				continue;

			}

			/*
@@ -1830,6 +1831,7 @@ static int ntfs_prepare_write(struct file *file, struct page *page, 
		unsigned from, unsigned to)

{

	s64 new_size;

	unsigned long flags;

	struct inode *vi = page->mapping->host;

	ntfs_inode *base_ni = NULL, *ni = NTFS_I(vi);

	ntfs_volume *vol = ni->vol;
@@ -1903,12 +1905,6 @@ static int ntfs_prepare_write(struct file *file, struct page *page, 
	/* If we do not need to resize the attribute allocation we are done. */

	if (new_size <= i_size_read(vi))

		goto done;



	// FIXME: We abort for now as this code is not safe.

	ntfs_error(vi->i_sb, "Changing the file size is not supported yet.  "

			"Sorry.");

	return -EOPNOTSUPP;



	/* Map, pin, and lock the (base) mft record. */

	if (!NInoAttr(ni))

		base_ni = ni;
@@ -1937,7 +1933,17 @@ static int ntfs_prepare_write(struct file *file, struct page *page, 
	a = ctx->attr;

	/* The total length of the attribute value. */

	attr_len = le32_to_cpu(a->data.resident.value_length);

	BUG_ON(i_size_read(vi) != attr_len);

	/* Fix an eventual previous failure of ntfs_commit_write(). */

	read_lock_irqsave(&ni->size_lock, flags);

	if (unlikely(ni->initialized_size < attr_len)) {

		attr_len = ni->initialized_size;

		a->data.resident.value_length = cpu_to_le32(attr_len);

		BUG_ON(attr_len < i_size_read(vi));

	}

	read_unlock_irqrestore(&ni->size_lock, flags);

	/* If we do not need to resize the attribute allocation we are done. */

	if (new_size <= attr_len)

		goto done_unm;

	/* Check if new size is allowed in $AttrDef. */

	err = ntfs_attr_size_bounds_check(vol, ni->type, new_size);

	if (unlikely(err)) {
@@ -1995,6 +2001,7 @@ static int ntfs_prepare_write(struct file *file, struct page *page, 
	}

	flush_dcache_mft_record_page(ctx->ntfs_ino);

	mark_mft_record_dirty(ctx->ntfs_ino);

done_unm:

	ntfs_attr_put_search_ctx(ctx);

	unmap_mft_record(base_ni);

	/*