diff options
Diffstat (limited to 'fs/xfs/xfs_reflink.c')
| -rw-r--r-- | fs/xfs/xfs_reflink.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index a5c188b78138..480136136635 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -440,6 +440,7 @@ xfs_reflink_fill_cow_hole( struct xfs_mount *mp = ip->i_mount; struct xfs_trans *tp; xfs_filblks_t resaligned; + unsigned int seq_before = READ_ONCE(ip->i_df.if_seq); unsigned int dblocks = 0, rblocks = 0; int nimaps; int error; @@ -465,6 +466,22 @@ xfs_reflink_fill_cow_hole( *lockmode = XFS_ILOCK_EXCL; + /* + * The data fork mapping may have changed while we dropped the ILOCK + * (a racing O_DIRECT writer under IOLOCK_SHARED can complete a full + * CoW cycle including xfs_reflink_end_cow(), which remaps this offset + * and drops the refcount of the old shared block). Re-read it so the + * shared-status recheck below and the caller's in-place iomap both + * operate on the current mapping rather than a stale physical block. + */ + if (seq_before != READ_ONCE(ip->i_df.if_seq)) { + nimaps = 1; + error = xfs_bmapi_read(ip, imap->br_startoff, + imap->br_blockcount, imap, &nimaps, 0); + if (error) + goto out_trans_cancel; + } + error = xfs_find_trim_cow_extent(ip, imap, cmap, shared, &found); if (error || !*shared) goto out_trans_cancel; @@ -511,6 +528,8 @@ xfs_reflink_fill_delalloc( bool found; do { + unsigned int seq_before = READ_ONCE(ip->i_df.if_seq); + xfs_iunlock(ip, *lockmode); *lockmode = 0; @@ -521,6 +540,23 @@ xfs_reflink_fill_delalloc( *lockmode = XFS_ILOCK_EXCL; + /* + * The data fork mapping may have changed while we dropped the + * ILOCK (a racing O_DIRECT writer under IOLOCK_SHARED can + * complete a full CoW cycle including xfs_reflink_end_cow(), + * which remaps this offset and drops the refcount of the old + * shared block). Re-read it so the shared-status recheck + * below and the caller's in-place iomap both operate on the + * current mapping rather than a stale physical block. + */ + if (seq_before != READ_ONCE(ip->i_df.if_seq)) { + nimaps = 1; + error = xfs_bmapi_read(ip, imap->br_startoff, + imap->br_blockcount, imap, &nimaps, 0); + if (error) + goto out_trans_cancel; + } + error = xfs_find_trim_cow_extent(ip, imap, cmap, shared, &found); if (error || !*shared) |