| Message ID | 166473480249.1083697.13081552727850377113.stgit@magnolia (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | xfs: improve rt metadata use for scrub | expand |
On Sun, Oct 02, 2022 at 11:20:02AM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong <djwong@kernel.org> > > It turns out that GETFSMAP and online fsck have had a bug for years due > to their use of ILOCK_SHARED to coordinate their linear scans of the > realtime bitmap. If the bitmap file's data fork happens to be in BTREE > format and the scan occurs immediately after mounting, the incore bmbt > will not be populated, leading to ASSERTs tripping over the incorrect > inode state. Because the bitmap scans always lock bitmap buffers in > increasing order of file offset, it is appropriate for these two callers > to take a shared ILOCK to improve scalability. > > To fix this problem, load both data and attr fork state into memory when > mounting the realtime inodes. Realtime metadata files aren't supposed > to have an attr fork so the second step is likely a nop. > > On most filesystems this is unlikely since the rtbitmap data fork is > usually in extents format, but it's possible to craft a filesystem that > will by fragmenting the free space in the data section and growfsing the > rt section. > > Fixes: 4c934c7dd60c ("xfs: report realtime space information via the rtbitmap") > Also-Fixes: 46d9bfb5e706 ("xfs: cross-reference the realtime bitmap") > Signed-off-by: Darrick J. Wong <djwong@kernel.org> > --- > fs/xfs/xfs_rtalloc.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++---- > 1 file changed, 52 insertions(+), 4 deletions(-) Looks fine. Reviewed-by: Dave Chinner <dchinner@redhat.com>
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c index 292d5e54a92c..b0846204c436 100644 --- a/fs/xfs/xfs_rtalloc.c +++ b/fs/xfs/xfs_rtalloc.c @@ -1325,6 +1325,41 @@ xfs_rtalloc_reinit_frextents( return 0; } +/* + * Read in the bmbt of an rt metadata inode so that we never have to load them + * at runtime. This enables the use of shared ILOCKs for rtbitmap scans. Use + * an empty transaction to avoid deadlocking on loops in the bmbt. + */ +static inline int +xfs_rtmount_iread_extents( + struct xfs_inode *ip, + unsigned int lock_class) +{ + struct xfs_trans *tp; + int error; + + error = xfs_trans_alloc_empty(ip->i_mount, &tp); + if (error) + return error; + + xfs_ilock(ip, XFS_ILOCK_EXCL | lock_class); + + error = xfs_iread_extents(tp, ip, XFS_DATA_FORK); + if (error) + goto out_unlock; + + if (xfs_inode_has_attr_fork(ip)) { + error = xfs_iread_extents(tp, ip, XFS_ATTR_FORK); + if (error) + goto out_unlock; + } + +out_unlock: + xfs_iunlock(ip, XFS_ILOCK_EXCL | lock_class); + xfs_trans_cancel(tp); + return error; +} + /* * Get the bitmap and summary inodes and the summary cache into the mount * structure at mount time. @@ -1342,14 +1377,27 @@ xfs_rtmount_inodes( return error; ASSERT(mp->m_rbmip != NULL); + error = xfs_rtmount_iread_extents(mp->m_rbmip, XFS_ILOCK_RTBITMAP); + if (error) + goto out_rele_bitmap; + error = xfs_iget(mp, NULL, sbp->sb_rsumino, 0, 0, &mp->m_rsumip); - if (error) { - xfs_irele(mp->m_rbmip); - return error; - } + if (error) + goto out_rele_bitmap; ASSERT(mp->m_rsumip != NULL); + + error = xfs_rtmount_iread_extents(mp->m_rsumip, XFS_ILOCK_RTSUM); + if (error) + goto out_rele_summary; + xfs_alloc_rsum_cache(mp, sbp->sb_rbmblocks); return 0; + +out_rele_summary: + xfs_irele(mp->m_rsumip); +out_rele_bitmap: + xfs_irele(mp->m_rbmip); + return error; } void