Hey Linus,
/* Summary */
This contains fixes for iomap to prevent data corruption bugs in the
fallocate unshare range implementation of fsdax and a small cleanup to
turn iomap_want_unshare_iter() into an inline function.
/* Testing */
gcc version 14.2.0 (Debian 14.2.0-3)
Debian clang version 16.0.6 (27+b1)
All patches are based on v6.11-rc2 and have been sitting in linux-next.
No build failures or warnings were observed.
/* Conflicts */
There will be a minor merge conflict with mainline due to some xfs
changes that came in. After conflict resolution mainline should looke like this:
diff --cc include/linux/iomap.h
index d0420e962ffd,0198f36e521e..000000000000
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@@ -256,20 -256,25 +256,39 @@@ static inline const struct iomap *iomap
return &i->iomap;
}
+/*
+ * Return the file offset for the first unchanged block after a short write.
+ *
+ * If nothing was written, round @pos down to point at the first block in
+ * the range, else round up to include the partially written block.
+ */
+static inline loff_t iomap_last_written_block(struct inode *inode, loff_t pos,
+ ssize_t written)
+{
+ if (unlikely(!written))
+ return round_down(pos, i_blocksize(inode));
+ return round_up(pos + written, i_blocksize(inode));
+}
+
+ /*
+ * Check if the range needs to be unshared for a FALLOC_FL_UNSHARE_RANGE
+ * operation.
+ *
+ * Don't bother with blocks that are not shared to start with; or mappings that
+ * cannot be shared, such as inline data, delalloc reservations, holes or
+ * unwritten extents.
+ *
+ * Note that we use srcmap directly instead of iomap_iter_srcmap as unsharing
+ * requires providing a separate source map, and the presence of one is a good
+ * indicator that unsharing is needed, unlike IOMAP_F_SHARED which can be set
+ * for any data that goes into the COW fork for XFS.
+ */
+ static inline bool iomap_want_unshare_iter(const struct iomap_iter *iter)
+ {
+ return (iter->iomap.flags & IOMAP_F_SHARED) &&
+ iter->srcmap.type == IOMAP_MAPPED;
+ }
+
ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
const struct iomap_ops *ops, void *private);
int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops);
The following changes since commit 8cf0b93919e13d1e8d4466eb4080a4c4d9d66d7b:
Linux 6.12-rc2 (2024-10-06 15:32:27 -0700)
are available in the Git repository at:
git@xxxxxxxxxxxxxxxxxxx:pub/scm/linux/kernel/git/vfs/vfs tags/vfs-6.12-rc6.iomap
for you to fetch changes up to 6db388585e486c0261aeef55f8bc63a9b45756c0:
iomap: turn iomap_want_unshare_iter into an inline function (2024-10-21 17:01:01 +0200)
(Note, I'm still not fully recovered so currently with a little reduced
activity.)
Please consider pulling these changes from the signed vfs-6.12-rc6.iomap tag.
Thanks!
Christian
----------------------------------------------------------------
vfs-6.12-rc6.iomap
----------------------------------------------------------------
Christian Brauner (1):
Merge patch series "fsdax/xfs: unshare range fixes for 6.12"
Christoph Hellwig (1):
iomap: turn iomap_want_unshare_iter into an inline function
Darrick J. Wong (4):
xfs: don't allocate COW extents when unsharing a hole
iomap: share iomap_unshare_iter predicate code with fsdax
fsdax: remove zeroing code from dax_unshare_iter
fsdax: dax_unshare_iter needs to copy entire blocks
fs/dax.c | 45 ++++++++++++++++++++++++++++-----------------
fs/iomap/buffered-io.c | 17 +----------------
fs/xfs/xfs_iomap.c | 2 +-
include/linux/iomap.h | 19 +++++++++++++++++++
4 files changed, 49 insertions(+), 34 deletions(-)
