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authorChristoph Hellwig <hch@lst.de>2010-06-07 09:29:20 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2010-08-09 16:47:40 -0400
commit1e2317350971c8b01e6adddc798a00e9bcc1a440 (patch)
tree651dd728ac563504c510356bddcc8ae879c2d3fe /Documentation/filesystems/porting
parent2c27c65ed0696f0b5df2dad2cf6462d72164d547 (diff)
update documentation for the new truncate sequence
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'Documentation/filesystems/porting')
-rw-r--r--Documentation/filesystems/porting18
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index a7e9746ee7e..f9547a5c187 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -273,3 +273,21 @@ it's safe to remove it. If you don't need it, remove it.
deliberate; as soon as struct block_device * is propagated in a reasonable
way by that code fixing will become trivial; until then nothing can be
done.
+
+[mandatory]
+
+ block truncatation on error exit from ->write_begin, and ->direct_IO
+moved from generic methods (block_write_begin, cont_write_begin,
+nobh_write_begin, blockdev_direct_IO*) to callers. Take a look at
+ext2_write_failed and callers for an example.
+
+[mandatory]
+
+ ->truncate is going away. The whole truncate sequence needs to be
+implemented in ->setattr, which is now mandatory for filesystems
+implementing on-disk size changes. Start with a copy of the old inode_setattr
+and vmtruncate, and the reorder the vmtruncate + foofs_vmtruncate sequence to
+be in order of zeroing blocks using block_truncate_page or similar helpers,
+size update and on finally on-disk truncation which should not fail.
+inode_change_ok now includes the size checks for ATTR_SIZE and must be called
+in the beginning of ->setattr unconditionally.