diff options
Diffstat (limited to 'fs/xfs/xfs_buf.c')
-rw-r--r-- | fs/xfs/xfs_buf.c | 63 |
1 files changed, 47 insertions, 16 deletions
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index 5c07b4a70026..871abaabff3d 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -796,47 +796,76 @@ xfs_buf_reverify( return bp->b_error; } -xfs_buf_t * +int xfs_buf_read_map( struct xfs_buftarg *target, struct xfs_buf_map *map, int nmaps, xfs_buf_flags_t flags, + struct xfs_buf **bpp, const struct xfs_buf_ops *ops) { struct xfs_buf *bp; int error; flags |= XBF_READ; + *bpp = NULL; error = xfs_buf_get_map(target, map, nmaps, flags, &bp); if (error) - return NULL; + return error; trace_xfs_buf_read(bp, flags, _RET_IP_); if (!(bp->b_flags & XBF_DONE)) { + /* Initiate the buffer read and wait. */ XFS_STATS_INC(target->bt_mount, xb_get_read); bp->b_ops = ops; - _xfs_buf_read(bp, flags); - return bp; + error = _xfs_buf_read(bp, flags); + + /* Readahead iodone already dropped the buffer, so exit. */ + if (flags & XBF_ASYNC) + return 0; + } else { + /* Buffer already read; all we need to do is check it. */ + error = xfs_buf_reverify(bp, ops); + + /* Readahead already finished; drop the buffer and exit. */ + if (flags & XBF_ASYNC) { + xfs_buf_relse(bp); + return 0; + } + + /* We do not want read in the flags */ + bp->b_flags &= ~XBF_READ; + ASSERT(bp->b_ops != NULL || ops == NULL); } - xfs_buf_reverify(bp, ops); + /* + * If we've had a read error, then the contents of the buffer are + * invalid and should not be used. To ensure that a followup read tries + * to pull the buffer from disk again, we clear the XBF_DONE flag and + * mark the buffer stale. This ensures that anyone who has a current + * reference to the buffer will interpret it's contents correctly and + * future cache lookups will also treat it as an empty, uninitialised + * buffer. + */ + if (error) { + if (!XFS_FORCED_SHUTDOWN(target->bt_mount)) + xfs_buf_ioerror_alert(bp, __func__); - if (flags & XBF_ASYNC) { - /* - * Read ahead call which is already satisfied, - * drop the buffer - */ + bp->b_flags &= ~XBF_DONE; + xfs_buf_stale(bp); xfs_buf_relse(bp); - return NULL; + + /* bad CRC means corrupted metadata */ + if (error == -EFSBADCRC) + error = -EFSCORRUPTED; + return error; } - /* We do not want read in the flags */ - bp->b_flags &= ~XBF_READ; - ASSERT(bp->b_ops != NULL || ops == NULL); - return bp; + *bpp = bp; + return 0; } /* @@ -850,11 +879,13 @@ xfs_buf_readahead_map( int nmaps, const struct xfs_buf_ops *ops) { + struct xfs_buf *bp; + if (bdi_read_congested(target->bt_bdev->bd_bdi)) return; xfs_buf_read_map(target, map, nmaps, - XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD, ops); + XBF_TRYLOCK | XBF_ASYNC | XBF_READ_AHEAD, &bp, ops); } /* |