diff options
| -rw-r--r-- | fs/xfs/xfs_aops.c | 60 | ||||
| -rw-r--r-- | fs/xfs/xfs_iomap.c | 5 |
2 files changed, 49 insertions, 16 deletions
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index d9048bcea49c..5b0256a8a420 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -29,6 +29,7 @@ struct xfs_writepage_ctx { struct xfs_bmbt_irec imap; unsigned int io_type; + unsigned int data_seq; unsigned int cow_seq; struct xfs_ioend *ioend; }; @@ -301,6 +302,42 @@ xfs_end_bio( xfs_destroy_ioend(ioend, blk_status_to_errno(bio->bi_status)); } +/* + * Fast revalidation of the cached writeback mapping. Return true if the current + * mapping is valid, false otherwise. + */ +static bool +xfs_imap_valid( + struct xfs_writepage_ctx *wpc, + struct xfs_inode *ip, + xfs_fileoff_t offset_fsb) +{ + if (offset_fsb < wpc->imap.br_startoff || + offset_fsb >= wpc->imap.br_startoff + wpc->imap.br_blockcount) + return false; + /* + * If this is a COW mapping, it is sufficient to check that the mapping + * covers the offset. Be careful to check this first because the caller + * can revalidate a COW mapping without updating the data seqno. + */ + if (wpc->io_type == XFS_IO_COW) + return true; + + /* + * This is not a COW mapping. Check the sequence number of the data fork + * because concurrent changes could have invalidated the extent. Check + * the COW fork because concurrent changes since the last time we + * checked (and found nothing at this offset) could have added + * overlapping blocks. + */ + if (wpc->data_seq != READ_ONCE(ip->i_df.if_seq)) + return false; + if (xfs_inode_has_cow_data(ip) && + wpc->cow_seq != READ_ONCE(ip->i_cowfp->if_seq)) + return false; + return true; +} + STATIC int xfs_map_blocks( struct xfs_writepage_ctx *wpc, @@ -315,9 +352,11 @@ xfs_map_blocks( struct xfs_bmbt_irec imap; int whichfork = XFS_DATA_FORK; struct xfs_iext_cursor icur; - bool imap_valid; int error = 0; + if (XFS_FORCED_SHUTDOWN(mp)) + return -EIO; + /* * We have to make sure the cached mapping is within EOF to protect * against eofblocks trimming on file release leaving us with a stale @@ -346,17 +385,9 @@ xfs_map_blocks( * against concurrent updates and provides a memory barrier on the way * out that ensures that we always see the current value. */ - imap_valid = offset_fsb >= wpc->imap.br_startoff && - offset_fsb < wpc->imap.br_startoff + wpc->imap.br_blockcount; - if (imap_valid && - (!xfs_inode_has_cow_data(ip) || - wpc->io_type == XFS_IO_COW || - wpc->cow_seq == READ_ONCE(ip->i_cowfp->if_seq))) + if (xfs_imap_valid(wpc, ip, offset_fsb)) return 0; - if (XFS_FORCED_SHUTDOWN(mp)) - return -EIO; - /* * If we don't have a valid map, now it's time to get a new one for this * offset. This will convert delayed allocations (including COW ones) @@ -403,9 +434,10 @@ xfs_map_blocks( } /* - * Map valid and no COW extent in the way? We're done. + * No COW extent overlap. Revalidate now that we may have updated + * ->cow_seq. If the data mapping is still valid, we're done. */ - if (imap_valid) { + if (xfs_imap_valid(wpc, ip, offset_fsb)) { xfs_iunlock(ip, XFS_ILOCK_SHARED); return 0; } @@ -417,6 +449,7 @@ xfs_map_blocks( */ if (!xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap)) imap.br_startoff = end_fsb; /* fake a hole past EOF */ + wpc->data_seq = READ_ONCE(ip->i_df.if_seq); xfs_iunlock(ip, XFS_ILOCK_SHARED); if (imap.br_startoff > offset_fsb) { @@ -454,7 +487,8 @@ xfs_map_blocks( return 0; allocate_blocks: error = xfs_iomap_write_allocate(ip, whichfork, offset, &imap, - &wpc->cow_seq); + whichfork == XFS_COW_FORK ? + &wpc->cow_seq : &wpc->data_seq); if (error) return error; ASSERT(whichfork == XFS_COW_FORK || cow_fsb == NULLFILEOFF || diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 27c93b5f029d..ab69caa685b4 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -681,7 +681,7 @@ xfs_iomap_write_allocate( int whichfork, xfs_off_t offset, xfs_bmbt_irec_t *imap, - unsigned int *cow_seq) + unsigned int *seq) { xfs_mount_t *mp = ip->i_mount; struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, whichfork); @@ -797,8 +797,7 @@ xfs_iomap_write_allocate( if (error) goto error0; - if (whichfork == XFS_COW_FORK) - *cow_seq = READ_ONCE(ifp->if_seq); + *seq = READ_ONCE(ifp->if_seq); xfs_iunlock(ip, XFS_ILOCK_EXCL); } |