The initial sb read is always for a device logical block size buffer. The device logical block size is provided in the bt_logical_sectorsize in struct buftarg, so use that instead of the confusingly named xfs_getsize_buftarg buffer that reads it from the bdev. Update the comments surrounding the code to better describe what is going on. Signed-off-by: Christoph Hellwig <hch@xxxxxx> --- fs/xfs/xfs_buf.h | 1 - fs/xfs/xfs_mount.c | 21 +++++++++++---------- 2 files changed, 11 insertions(+), 11 deletions(-) diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h index 9d2ab567cf81..294dd9d61dbb 100644 --- a/fs/xfs/xfs_buf.h +++ b/fs/xfs/xfs_buf.h @@ -376,7 +376,6 @@ extern void xfs_buftarg_wait(struct xfs_buftarg *); extern void xfs_buftarg_drain(struct xfs_buftarg *); int xfs_configure_buftarg(struct xfs_buftarg *btp, unsigned int sectorsize); -#define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev) #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) int xfs_buf_reverify(struct xfs_buf *bp, const struct xfs_buf_ops *ops); diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c index 29276fe60df9..047100b080aa 100644 --- a/fs/xfs/xfs_mount.c +++ b/fs/xfs/xfs_mount.c @@ -171,19 +171,16 @@ xfs_readsb( ASSERT(mp->m_ddev_targp != NULL); /* - * For the initial read, we must guess at the sector - * size based on the block device. It's enough to - * get the sb_sectsize out of the superblock and - * then reread with the proper length. - * We don't verify it yet, because it may not be complete. + * In the first pass, use the device sector size to just read enough + * of the superblock to extract the XFS sector size. + * + * The device sector size must be smaller than or equal to the XFS + * sector size and thus we can always read the superblock. Once we know + * the XFS sector size, re-read it and run the buffer verifier. */ - sector_size = xfs_getsize_buftarg(mp->m_ddev_targp); + sector_size = mp->m_ddev_targp->bt_logical_sectorsize; buf_ops = NULL; - /* - * Allocate a (locked) buffer to hold the superblock. This will be kept - * around at all times to optimize access to the superblock. - */ reread: error = xfs_buf_read_uncached(mp->m_ddev_targp, XFS_SB_DADDR, BTOBB(sector_size), &bp, buf_ops); @@ -247,6 +244,10 @@ xfs_readsb( /* no need to be quiet anymore, so reset the buf ops */ bp->b_ops = &xfs_sb_buf_ops; + /* + * Keep a pointer of the sb buffer around instead of caching it in the + * buffer cache because we access it frequently. + */ mp->m_sb_bp = bp; xfs_buf_unlock(bp); return 0; -- 2.47.2
