On Wed, Feb 19, 2020 at 05:42:06PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> Add a new function that will ensure that everything we changed has
> landed on stable media, and report the results. Subsequent commits will
> teach the individual programs to report when things go wrong.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> include/xfs_mount.h | 3 +++
> libxfs/init.c | 43 +++++++++++++++++++++++++++++++++++++++++++
> libxfs/libxfs_io.h | 2 ++
> libxfs/rdwr.c | 27 +++++++++++++++++++++++++--
> 4 files changed, 73 insertions(+), 2 deletions(-)
>
>
> diff --git a/include/xfs_mount.h b/include/xfs_mount.h
> index 29b3cc1b..c80aaf69 100644
> --- a/include/xfs_mount.h
> +++ b/include/xfs_mount.h
> @@ -187,4 +187,7 @@ extern xfs_mount_t *libxfs_mount (xfs_mount_t *, xfs_sb_t *,
> extern void libxfs_umount (xfs_mount_t *);
> extern void libxfs_rtmount_destroy (xfs_mount_t *);
>
> +void libxfs_flush_devices(struct xfs_mount *mp, int *datadev, int *logdev,
> + int *rtdev);
> +
> #endif /* __XFS_MOUNT_H__ */
> diff --git a/libxfs/init.c b/libxfs/init.c
> index a0d4b7f4..d1d3f4df 100644
> --- a/libxfs/init.c
> +++ b/libxfs/init.c
> @@ -569,6 +569,8 @@ libxfs_buftarg_alloc(
> }
> btp->bt_mount = mp;
> btp->dev = dev;
> + btp->lost_writes = false;
> +
> return btp;
> }
>
> @@ -791,6 +793,47 @@ libxfs_rtmount_destroy(xfs_mount_t *mp)
> mp->m_rsumip = mp->m_rbmip = NULL;
> }
>
> +static inline int
> +libxfs_flush_buftarg(
> + struct xfs_buftarg *btp)
> +{
> + if (btp->lost_writes)
> + return -ENOTRECOVERABLE;
I'm curious why we'd want to skip the flush just because some writes
happened to fail..? I suppose the fs might be borked, but it seems a
little strange to at least not try the flush, particularly since we
might still flush any of the other two possible devices.
> +
> + return libxfs_blkdev_issue_flush(btp);
> +}
> +
> +/*
> + * Purge the buffer cache to write all dirty buffers to disk and free all
> + * incore buffers. Buffers that cannot be written will cause the lost_writes
> + * flag to be set in the buftarg. If there were no lost writes, flush the
> + * device to make sure the writes made it to stable storage.
> + *
> + * For each device, the return code will be set to -ENOTRECOVERABLE if we
> + * couldn't write something to disk; or the results of the block device flush
> + * operation.
Why not -EIO?
Brian
> + */
> +void
> +libxfs_flush_devices(
> + struct xfs_mount *mp,
> + int *datadev,
> + int *logdev,
> + int *rtdev)
> +{
> + *datadev = *logdev = *rtdev = 0;
> +
> + libxfs_bcache_purge();
> +
> + if (mp->m_ddev_targp)
> + *datadev = libxfs_flush_buftarg(mp->m_ddev_targp);
> +
> + if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp)
> + *logdev = libxfs_flush_buftarg(mp->m_logdev_targp);
> +
> + if (mp->m_rtdev_targp)
> + *rtdev = libxfs_flush_buftarg(mp->m_rtdev_targp);
> +}
> +
> /*
> * Release any resource obtained during a mount.
> */
> diff --git a/libxfs/libxfs_io.h b/libxfs/libxfs_io.h
> index 579df52b..fc0fd060 100644
> --- a/libxfs/libxfs_io.h
> +++ b/libxfs/libxfs_io.h
> @@ -23,10 +23,12 @@ struct xfs_perag;
> struct xfs_buftarg {
> struct xfs_mount *bt_mount;
> dev_t dev;
> + bool lost_writes;
> };
>
> extern void libxfs_buftarg_init(struct xfs_mount *mp, dev_t ddev,
> dev_t logdev, dev_t rtdev);
> +int libxfs_blkdev_issue_flush(struct xfs_buftarg *btp);
>
> #define LIBXFS_BBTOOFF64(bbs) (((xfs_off_t)(bbs)) << BBSHIFT)
>
> diff --git a/libxfs/rdwr.c b/libxfs/rdwr.c
> index 8b47d438..92e497f9 100644
> --- a/libxfs/rdwr.c
> +++ b/libxfs/rdwr.c
> @@ -17,6 +17,7 @@
> #include "xfs_inode_fork.h"
> #include "xfs_inode.h"
> #include "xfs_trans.h"
> +#include "libfrog/platform.h"
>
> #include "libxfs.h" /* for LIBXFS_EXIT_ON_FAILURE */
>
> @@ -1227,9 +1228,11 @@ libxfs_brelse(
>
> if (!bp)
> return;
> - if (bp->b_flags & LIBXFS_B_DIRTY)
> + if (bp->b_flags & LIBXFS_B_DIRTY) {
> fprintf(stderr,
> "releasing dirty buffer to free list!\n");
> + bp->b_target->lost_writes = true;
> + }
>
> pthread_mutex_lock(&xfs_buf_freelist.cm_mutex);
> list_add(&bp->b_node.cn_mru, &xfs_buf_freelist.cm_list);
> @@ -1248,9 +1251,11 @@ libxfs_bulkrelse(
> return 0 ;
>
> list_for_each_entry(bp, list, b_node.cn_mru) {
> - if (bp->b_flags & LIBXFS_B_DIRTY)
> + if (bp->b_flags & LIBXFS_B_DIRTY) {
> fprintf(stderr,
> "releasing dirty buffer (bulk) to free list!\n");
> + bp->b_target->lost_writes = true;
> + }
> count++;
> }
>
> @@ -1479,6 +1484,24 @@ libxfs_irele(
> kmem_cache_free(xfs_inode_zone, ip);
> }
>
> +/*
> + * Flush everything dirty in the kernel and disk write caches to stable media.
> + * Returns 0 for success or a negative error code.
> + */
> +int
> +libxfs_blkdev_issue_flush(
> + struct xfs_buftarg *btp)
> +{
> + int fd, ret;
> +
> + if (btp->dev == 0)
> + return 0;
> +
> + fd = libxfs_device_to_fd(btp->dev);
> + ret = platform_flush_device(fd, btp->dev);
> + return ret ? -errno : 0;
> +}
> +
> /*
> * Write out a buffer list synchronously.
> *
>
