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: Anton Altaparmakov <aia21@cantab.net>
diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c
index 3b9de40..4185934 100644
--- a/fs/ntfs/attrib.c
+++ b/fs/ntfs/attrib.c
@@ -1376,19 +1376,6 @@
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 @@
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 @@
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 @@
if (page) {
set_page_dirty(page);
unlock_page(page);
+ mark_page_accessed(page);
page_cache_release(page);
}
ntfs_debug("Done.");
@@ -1492,11 +1502,10 @@
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);