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? > #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, and verity data can't be straddling the EOF folio, no matter how large it is. Right? --D > + > /* Nothing to do if we've written the entire delalloc extent */ > start_byte = iomap_last_written_block(inode, offset, written); > end_byte = round_up(offset + length, i_blocksize(inode)); > > -- > 2.50.0 > >
