On 2025-07-29 15:27:36, Darrick J. Wong wrote: > On Mon, Jul 28, 2025 at 10:30:24PM +0200, Andrey Albershteyn wrote: > > While writing Merkle tree, file is read-only and there's no further > > writes except Merkle tree building. The file is truncated beforehand to > > remove any preallocated extents. > > > > The Merkle tree is the only data XFS will write. As we don't want XFS to > > truncate file after we done writing, let's also skip truncation on > > fsverity files. Therefore, we also need to disable preallocations while > > writing merkle tree as we don't want any unused extents past the tree. > > > > Signed-off-by: Andrey Albershteyn <aalbersh@xxxxxxxxxx> > > --- > > fs/xfs/xfs_iomap.c | 13 ++++++++++++- > > 1 file changed, 12 insertions(+), 1 deletion(-) > > > > diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c > > index ff05e6b1b0bb..00ec1a738b39 100644 > > --- a/fs/xfs/xfs_iomap.c > > +++ b/fs/xfs/xfs_iomap.c > > @@ -32,6 +32,8 @@ > > #include "xfs_rtbitmap.h" > > #include "xfs_icache.h" > > #include "xfs_zone_alloc.h" > > +#include "xfs_fsverity.h" > > +#include <linux/fsverity.h> > > What do these includes pull in for the iflags tests below? Probably need to be removed, thanks for noting > > > #define XFS_ALLOC_ALIGN(mp, off) \ > > (((off) >> mp->m_allocsize_log) << mp->m_allocsize_log) > > @@ -1849,7 +1851,9 @@ xfs_buffered_write_iomap_begin( > > * Determine the initial size of the preallocation. > > * We clean up any extra preallocation when the file is closed. > > */ > > - if (xfs_has_allocsize(mp)) > > + if (xfs_iflags_test(ip, XFS_VERITY_CONSTRUCTION)) > > + prealloc_blocks = 0; > > + else if (xfs_has_allocsize(mp)) > > prealloc_blocks = mp->m_allocsize_blocks; > > else if (allocfork == XFS_DATA_FORK) > > prealloc_blocks = xfs_iomap_prealloc_size(ip, allocfork, > > @@ -1976,6 +1980,13 @@ xfs_buffered_write_iomap_end( > > if (flags & IOMAP_FAULT) > > return 0; > > > > + /* > > + * While writing Merkle tree to disk we would not have any other > > + * delayed allocations > > + */ > > + if (xfs_iflags_test(XFS_I(inode), XFS_VERITY_CONSTRUCTION)) > > + return 0; > > I assume XFS_VERITY_CONSTRUCTION doesn't get set until after we've > locked the inode, flushed the dirty pagecache, and truncated the file to > EOF? In which case I guess this is ok -- we're never going to have new > delalloc reservations, yes, this is my thinking here > and verity data can't be straddling the EOF > folio, no matter how large it is. Right? Not sure, what you mean here. In page cache merkle tree is stored at (1 << 53) offset, and there's check for file overlapping this in patch 22 xfs_fsverity_begin_enable(). -- - Andrey
