| Message ID | 1543376991-5764-7-git-send-email-allison.henderson@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Block/XFS: Support alternative mirror device retry | expand |
On Tue, Nov 27, 2018 at 08:49:50PM -0700, Allison Henderson wrote: > If we had to try more than one mirror to get a successful > read, then write that buffer back to correct the bad mirro > > Signed-off-by: Allison Henderson <allison.henderson@oracle.com> > --- > fs/xfs/xfs_buf.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c > index f102d01..81f6491 100644 > --- a/fs/xfs/xfs_buf.c > +++ b/fs/xfs/xfs_buf.c > @@ -847,6 +847,14 @@ xfs_buf_read_map( > > } > retry_done: > + > + /* > + * if we had to try more than one mirror to sucessfully read > + * the buffer, write the buffer back > + */ > + if (!bp->b_error && i > 0) > + xfs_bwrite(bp); > + This can go in the case statement on retry and then you don't need to check for i > 0 or, well, bp->b_error. i.e. swtich (bp->b_error) { case -EBADCRC: case -EIO: case -EFSCORRUPTED: /* try again from different copy */ continue; 0: /* good copy, rewrite it to repair bad copy */ xfs_bwrite(bp); /* fallthrough */ default: return bp; } Cheers, Dave.
On Wed, Nov 28, 2018 at 04:17:19PM +1100, Dave Chinner wrote: > On Tue, Nov 27, 2018 at 08:49:50PM -0700, Allison Henderson wrote: > > If we had to try more than one mirror to get a successful > > read, then write that buffer back to correct the bad mirro > > > > Signed-off-by: Allison Henderson <allison.henderson@oracle.com> > > --- > > fs/xfs/xfs_buf.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c > > index f102d01..81f6491 100644 > > --- a/fs/xfs/xfs_buf.c > > +++ b/fs/xfs/xfs_buf.c > > @@ -847,6 +847,14 @@ xfs_buf_read_map( > > > > } > > retry_done: > > + > > + /* > > + * if we had to try more than one mirror to sucessfully read > > + * the buffer, write the buffer back > > + */ > > + if (!bp->b_error && i > 0) > > + xfs_bwrite(bp); > > + > > This can go in the case statement on retry and then you don't need > to check for i > 0 or, well, bp->b_error. i.e. > > swtich (bp->b_error) { > case -EBADCRC: > case -EIO: > case -EFSCORRUPTED: > /* try again from different copy */ > continue; > 0: > /* good copy, rewrite it to repair bad copy */ > xfs_bwrite(bp); Some day we might want to provide some controls for how long we'll retry these reads and whether or not we automatically rewrite buffers, since some administrators might prefer fast fail to get failover started. (Not now though) --D > /* fallthrough */ > default: > return bp; > } > > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com
On Tue, Nov 27, 2018 at 09:26:04PM -0800, Darrick J. Wong wrote: > On Wed, Nov 28, 2018 at 04:17:19PM +1100, Dave Chinner wrote: > > On Tue, Nov 27, 2018 at 08:49:50PM -0700, Allison Henderson wrote: > > > If we had to try more than one mirror to get a successful > > > read, then write that buffer back to correct the bad mirro > > > > > > Signed-off-by: Allison Henderson <allison.henderson@oracle.com> > > > --- > > > fs/xfs/xfs_buf.c | 8 ++++++++ > > > 1 file changed, 8 insertions(+) > > > > > > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c > > > index f102d01..81f6491 100644 > > > --- a/fs/xfs/xfs_buf.c > > > +++ b/fs/xfs/xfs_buf.c > > > @@ -847,6 +847,14 @@ xfs_buf_read_map( > > > > > > } > > > retry_done: > > > + > > > + /* > > > + * if we had to try more than one mirror to sucessfully read > > > + * the buffer, write the buffer back > > > + */ > > > + if (!bp->b_error && i > 0) > > > + xfs_bwrite(bp); > > > + > > > > This can go in the case statement on retry and then you don't need > > to check for i > 0 or, well, bp->b_error. i.e. > > > > swtich (bp->b_error) { > > case -EBADCRC: > > case -EIO: > > case -EFSCORRUPTED: > > /* try again from different copy */ > > continue; > > 0: > > /* good copy, rewrite it to repair bad copy */ > > xfs_bwrite(bp); > > Some day we might want to provide some controls for how long we'll retry > these reads and whether or not we automatically rewrite buffers, since > some administrators might prefer fast fail to get failover started. Sure, but if the recovery code is trewn all through the read code, it becomes a mess to untangle. isolate the recovery code as much as possible, that way we can factor it out as it becomes more complex. > (Not now though) Which is exactly my point about future recovery complexity.... :P Cheers, Dave.
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index f102d01..81f6491 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -847,6 +847,14 @@ xfs_buf_read_map( } retry_done: + + /* + * if we had to try more than one mirror to sucessfully read + * the buffer, write the buffer back + */ + if (!bp->b_error && i > 0) + xfs_bwrite(bp); + return bp; }
If we had to try more than one mirror to get a successful read, then write that buffer back to correct the bad mirro Signed-off-by: Allison Henderson <allison.henderson@oracle.com> --- fs/xfs/xfs_buf.c | 8 ++++++++ 1 file changed, 8 insertions(+)