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Commit 905685f6 authored by Anton Altaparmakov's avatar Anton Altaparmakov
Browse files

NTFS: - Modify ->readpage and ->writepage (fs/ntfs/aops.c) so they detect 


        and handle the case where an attribute is converted from resident
        to non-resident by a concurrent file write.
      - Reorder some operations when converting an attribute from resident
        to non-resident (fs/ntfs/attrib.c) so it is safe wrt concurrent
        ->readpage and ->writepage.

Signed-off-by: default avatarAnton Altaparmakov <aia21@cantab.net>
parent 43b01fda

fs/ntfs/ChangeLog

+3 −0
Original line number Diff line number Diff line
@@ -100,6 +100,9 @@ ToDo/Notes: 
	- Add fs/ntfs/attrib.[hc]::ntfs_attr_make_non_resident().

	- Fix sign of various error return values to be negative in

	  fs/ntfs/lcnalloc.c.

	- Modify ->readpage and ->writepage (fs/ntfs/aops.c) so they detect and

	  handle the case where an attribute is converted from resident to

	  non-resident by a concurrent file write.



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

fs/ntfs/aops.c

+18 −0
Original line number Diff line number Diff line
@@ -355,6 +355,7 @@ static int ntfs_readpage(struct file *file, struct page *page) 
	u32 attr_len;

	int err = 0;



retry_readpage:

	BUG_ON(!PageLocked(page));

	/*

	 * This can potentially happen because we clear PageUptodate() during
@@ -408,6 +409,14 @@ static int ntfs_readpage(struct file *file, struct page *page) 
		err = PTR_ERR(mrec);

		goto err_out;

	}

	/*

	 * If a parallel write made the attribute non-resident, drop the mft

	 * record and retry the readpage.

	 */

	if (unlikely(NInoNonResident(ni))) {

		unmap_mft_record(base_ni);

		goto retry_readpage;

	}

	ctx = ntfs_attr_get_search_ctx(base_ni, mrec);

	if (unlikely(!ctx)) {

		err = -ENOMEM;
@@ -1248,6 +1257,7 @@ static int ntfs_writepage(struct page *page, struct writeback_control *wbc) 
	u32 attr_len;

	int err;



retry_writepage:

	BUG_ON(!PageLocked(page));

	i_size = i_size_read(vi);

	/* Is the page fully outside i_size? (truncate in progress) */
@@ -1338,6 +1348,14 @@ static int ntfs_writepage(struct page *page, struct writeback_control *wbc) 
		ctx = NULL;

		goto err_out;

	}

	/*

	 * If a parallel write made the attribute non-resident, drop the mft

	 * record and retry the writepage.

	 */

	if (unlikely(NInoNonResident(ni))) {

		unmap_mft_record(base_ni);

		goto retry_writepage;

	}

	ctx = ntfs_attr_get_search_ctx(base_ni, m);

	if (unlikely(!ctx)) {

		err = -ENOMEM;

fs/ntfs/attrib.c

+25 −16
Original line number Diff line number Diff line
@@ -1376,19 +1376,6 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni) 
	err = ntfs_attr_record_resize(m, a, arec_size);

	if (unlikely(err))

		goto err_out;

	/* Setup the in-memory attribute structure to be non-resident. */

	NInoSetNonResident(ni);

	ni->runlist.rl = rl;

	write_lock_irqsave(&ni->size_lock, flags);

	ni->allocated_size = new_size;

	write_unlock_irqrestore(&ni->size_lock, flags);

	/*

	 * FIXME: For now just clear all of these as we do not support them

	 * when writing.

	 */

	NInoClearCompressed(ni);

	NInoClearSparse(ni);

	NInoClearEncrypted(ni);

	/*

	 * Convert the resident part of the attribute record to describe a

	 * non-resident attribute.
@@ -1399,7 +1386,10 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni) 
		memmove((u8*)a + name_ofs, (u8*)a + le16_to_cpu(a->name_offset),

				a->name_length * sizeof(ntfschar));

	a->name_offset = cpu_to_le16(name_ofs);

	/* Update the flags to match the in-memory ones. */

	/*

	 * FIXME: For now just clear all of these as we do not support them

	 * when writing.

	 */

	a->flags &= cpu_to_le16(0xffff & ~le16_to_cpu(ATTR_IS_SPARSE |

			ATTR_IS_ENCRYPTED | ATTR_COMPRESSION_MASK));

	/* Setup the fields specific to non-resident attributes. */
@@ -1422,6 +1412,25 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni) 
				err);

		goto undo_err_out;

	}

	/* Setup the in-memory attribute structure to be non-resident. */

	/*

	 * FIXME: For now just clear all of these as we do not support them

	 * when writing.

	 */

	NInoClearSparse(ni);

	NInoClearEncrypted(ni);

	NInoClearCompressed(ni);

	ni->runlist.rl = rl;

	write_lock_irqsave(&ni->size_lock, flags);

	ni->allocated_size = new_size;

	write_unlock_irqrestore(&ni->size_lock, flags);

	/*

	 * This needs to be last since the address space operations ->readpage

	 * and ->writepage can run concurrently with us as they are not

	 * serialized on i_sem.  Note, we are not allowed to fail once we flip

	 * this switch, which is another reason to do this last.

	 */

	NInoSetNonResident(ni);

	/* Mark the mft record dirty, so it gets written back. */

	flush_dcache_mft_record_page(ctx->ntfs_ino);

	mark_mft_record_dirty(ctx->ntfs_ino);
@@ -1431,6 +1440,7 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni) 
	if (page) {

		set_page_dirty(page);

		unlock_page(page);

		mark_page_accessed(page);

		page_cache_release(page);

	}

	ntfs_debug("Done.");
@@ -1492,11 +1502,10 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni) 
		memcpy((u8*)a + mp_ofs, kaddr, attr_size);

		kunmap_atomic(kaddr, KM_USER0);

	}

	/* Finally setup the ntfs inode appropriately. */

	/* Setup the allocated size in the ntfs inode in case it changed. */

	write_lock_irqsave(&ni->size_lock, flags);

	ni->allocated_size = arec_size - mp_ofs;

	write_unlock_irqrestore(&ni->size_lock, flags);

	NInoClearNonResident(ni);

	/* Mark the mft record dirty, so it gets written back. */

	flush_dcache_mft_record_page(ctx->ntfs_ino);

	mark_mft_record_dirty(ctx->ntfs_ino);