From: Eric Sandeen <[email protected]> 3.12-stable review patch. If anyone has any objections, please let me know.
=============== commit 59e5a0e821d838854b3afd030d31f82cee3ecd58 upstream. When xfs_growfs_data_private() is updating backup superblocks, it bails out on the first error encountered, whether reading or writing: * If we get an error writing out the alternate superblocks, * just issue a warning and continue. The real work is * already done and committed. This can cause a problem later during repair, because repair looks at all superblocks, and picks the most prevalent one as correct. If we bail out early in the backup superblock loop, we can end up with more "bad" matching superblocks than good, and a post-growfs repair may revert the filesystem to the old geometry. With the combination of superblock verifiers and old bugs, we're more likely to encounter read errors due to verification. And perhaps even worse, we don't even properly write any of the newly-added superblocks in the new AGs. Even with this change, growfs will still say: xfs_growfs: XFS_IOC_FSGROWFSDATA xfsctl failed: Structure needs cleaning data blocks changed from 319815680 to 335216640 which might be confusing to the user, but it at least communicates that something has gone wrong, and dmesg will probably highlight the need for an xfs_repair. And this is still best-effort; if verifiers fail on more than half the backup supers, they may still "win" - but that's probably best left to repair to more gracefully handle by doing its own strict verification as part of the backup super "voting." Signed-off-by: Eric Sandeen <[email protected]> Acked-by: Dave Chinner <[email protected]> Reviewed-by: Mark Tinguely <[email protected]> Signed-off-by: Ben Myers <[email protected]> Signed-off-by: Jiri Slaby <[email protected]> --- fs/xfs/xfs_fsops.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c index c888040a1e93..20ccca12a11d 100644 --- a/fs/xfs/xfs_fsops.c +++ b/fs/xfs/xfs_fsops.c @@ -153,7 +153,7 @@ xfs_growfs_data_private( xfs_buf_t *bp; int bucket; int dpct; - int error; + int error, saved_error = 0; xfs_agnumber_t nagcount; xfs_agnumber_t nagimax = 0; xfs_rfsblock_t nb, nb_mod; @@ -500,29 +500,33 @@ xfs_growfs_data_private( error = ENOMEM; } + /* + * If we get an error reading or writing alternate superblocks, + * continue. xfs_repair chooses the "best" superblock based + * on most matches; if we break early, we'll leave more + * superblocks un-updated than updated, and xfs_repair may + * pick them over the properly-updated primary. + */ if (error) { xfs_warn(mp, "error %d reading secondary superblock for ag %d", error, agno); - break; + saved_error = error; + continue; } xfs_sb_to_disk(XFS_BUF_TO_SBP(bp), &mp->m_sb, XFS_SB_ALL_BITS); - /* - * If we get an error writing out the alternate superblocks, - * just issue a warning and continue. The real work is - * already done and committed. - */ error = xfs_bwrite(bp); xfs_buf_relse(bp); if (error) { xfs_warn(mp, "write error %d updating secondary superblock for ag %d", error, agno); - break; /* no point in continuing */ + saved_error = error; + continue; } } - return error; + return saved_error ? saved_error : error; error0: xfs_trans_cancel(tp, XFS_TRANS_ABORT); -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
