diff options
| -rw-r--r-- | fs/xfs/xfs_iomap.c | 62 |
1 files changed, 60 insertions, 2 deletions
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 166fba2ff1ef..ff05e6b1b0bb 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -798,6 +798,38 @@ imap_spans_range( return true; } +static bool +xfs_bmap_hw_atomic_write_possible( + struct xfs_inode *ip, + struct xfs_bmbt_irec *imap, + xfs_fileoff_t offset_fsb, + xfs_fileoff_t end_fsb) +{ + struct xfs_mount *mp = ip->i_mount; + xfs_fsize_t len = XFS_FSB_TO_B(mp, end_fsb - offset_fsb); + + /* + * atomic writes are required to be naturally aligned for disk blocks, + * which ensures that we adhere to block layer rules that we won't + * straddle any boundary or violate write alignment requirement. + */ + if (!IS_ALIGNED(imap->br_startblock, imap->br_blockcount)) + return false; + + /* + * Spanning multiple extents would mean that multiple BIOs would be + * issued, and so would lose atomicity required for REQ_ATOMIC-based + * atomics. + */ + if (!imap_spans_range(imap, offset_fsb, end_fsb)) + return false; + + /* + * The ->iomap_begin caller should ensure this, but check anyway. + */ + return len <= xfs_inode_buftarg(ip)->bt_bdev_awu_max; +} + static int xfs_direct_write_iomap_begin( struct inode *inode, @@ -812,9 +844,11 @@ xfs_direct_write_iomap_begin( struct xfs_bmbt_irec imap, cmap; xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset); xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length); + xfs_fileoff_t orig_end_fsb = end_fsb; int nimaps = 1, error = 0; bool shared = false; u16 iomap_flags = 0; + bool needs_alloc; unsigned int lockmode; u64 seq; @@ -875,13 +909,37 @@ relock: (flags & IOMAP_DIRECT) || IS_DAX(inode)); if (error) goto out_unlock; - if (shared) + if (shared) { + if ((flags & IOMAP_ATOMIC) && + !xfs_bmap_hw_atomic_write_possible(ip, &cmap, + offset_fsb, end_fsb)) { + error = -ENOPROTOOPT; + goto out_unlock; + } goto out_found_cow; + } end_fsb = imap.br_startoff + imap.br_blockcount; length = XFS_FSB_TO_B(mp, end_fsb) - offset; } - if (imap_needs_alloc(inode, flags, &imap, nimaps)) + needs_alloc = imap_needs_alloc(inode, flags, &imap, nimaps); + + if (flags & IOMAP_ATOMIC) { + error = -ENOPROTOOPT; + /* + * If we allocate less than what is required for the write + * then we may end up with multiple extents, which means that + * REQ_ATOMIC-based cannot be used, so avoid this possibility. + */ + if (needs_alloc && orig_end_fsb - offset_fsb > 1) + goto out_unlock; + + if (!xfs_bmap_hw_atomic_write_possible(ip, &imap, offset_fsb, + orig_end_fsb)) + goto out_unlock; + } + + if (needs_alloc) goto allocate_blocks; /* |