4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Brian Foster <[email protected]> commit 974ae922efd93b07b6cdf989ae959883f6f05fd8 upstream. Speculative preallocation is currently processed entirely by the callers of xfs_bmapi_reserve_delalloc(). The caller determines how much preallocation to include, adjusts the extent length and passes down the resulting request. While this works fine for post-eof speculative preallocation, it is not as reliable for COW fork preallocation. COW fork preallocation is implemented via the cowextszhint, which aligns the start offset as well as the length of the extent. Further, it is difficult for the caller to accurately identify when preallocation occurs because the returned extent could have been merged with neighboring extents in the fork. To simplify this situation and facilitate further COW fork preallocation enhancements, update xfs_bmapi_reserve_delalloc() to take a separate preallocation parameter to incorporate into the allocation request. The preallocation blocks value is tacked onto the end of the request and adjusted to accommodate neighboring extents and extent size limits. Since xfs_bmapi_reserve_delalloc() now knows precisely how much preallocation was included in the allocation, it can also tag the inodes appropriately to support preallocation reclaim. Note that xfs_bmapi_reserve_delalloc() callers are not yet updated to use the preallocation mechanism. This patch should not change behavior outside of correctly tagging reflink inodes when start offset preallocation occurs (which the caller does not handle correctly). Signed-off-by: Brian Foster <[email protected]> Reviewed-by: Dave Chinner <[email protected]> Signed-off-by: Dave Chinner <[email protected]> Cc: Christoph Hellwig <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/xfs/libxfs/xfs_bmap.c | 23 +++++++++++++++++++++-- fs/xfs/libxfs/xfs_bmap.h | 2 +- fs/xfs/xfs_iomap.c | 2 +- fs/xfs/xfs_reflink.c | 2 +- 4 files changed, 24 insertions(+), 5 deletions(-) --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -50,6 +50,7 @@ #include "xfs_ag_resv.h" #include "xfs_refcount.h" #include "xfs_rmap_btree.h" +#include "xfs_icache.h" kmem_zone_t *xfs_bmap_free_item_zone; @@ -4247,8 +4248,9 @@ int xfs_bmapi_reserve_delalloc( struct xfs_inode *ip, int whichfork, - xfs_fileoff_t aoff, + xfs_fileoff_t off, xfs_filblks_t len, + xfs_filblks_t prealloc, struct xfs_bmbt_irec *got, xfs_extnum_t *lastx, int eof) @@ -4260,10 +4262,17 @@ xfs_bmapi_reserve_delalloc( char rt = XFS_IS_REALTIME_INODE(ip); xfs_extlen_t extsz; int error; + xfs_fileoff_t aoff = off; - alen = XFS_FILBLKS_MIN(len, MAXEXTLEN); + /* + * Cap the alloc length. Keep track of prealloc so we know whether to + * tag the inode before we return. + */ + alen = XFS_FILBLKS_MIN(len + prealloc, MAXEXTLEN); if (!eof) alen = XFS_FILBLKS_MIN(alen, got->br_startoff - aoff); + if (prealloc && alen >= len) + prealloc = alen - len; /* Figure out the extent size, adjust alen */ if (whichfork == XFS_COW_FORK) @@ -4329,6 +4338,16 @@ xfs_bmapi_reserve_delalloc( */ xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *lastx), got); + /* + * Tag the inode if blocks were preallocated. Note that COW fork + * preallocation can occur at the start or end of the extent, even when + * prealloc == 0, so we must also check the aligned offset and length. + */ + if (whichfork == XFS_DATA_FORK && prealloc) + xfs_inode_set_eofblocks_tag(ip); + if (whichfork == XFS_COW_FORK && (prealloc || aoff < off || alen > len)) + xfs_inode_set_cowblocks_tag(ip); + ASSERT(got->br_startoff <= aoff); ASSERT(got->br_startoff + got->br_blockcount >= aoff + alen); ASSERT(isnullstartblock(got->br_startblock)); --- a/fs/xfs/libxfs/xfs_bmap.h +++ b/fs/xfs/libxfs/xfs_bmap.h @@ -242,7 +242,7 @@ struct xfs_bmbt_rec_host * int fork, int *eofp, xfs_extnum_t *lastxp, struct xfs_bmbt_irec *gotp, struct xfs_bmbt_irec *prevp); int xfs_bmapi_reserve_delalloc(struct xfs_inode *ip, int whichfork, - xfs_fileoff_t aoff, xfs_filblks_t len, + xfs_fileoff_t off, xfs_filblks_t len, xfs_filblks_t prealloc, struct xfs_bmbt_irec *got, xfs_extnum_t *lastx, int eof); enum xfs_bmap_intent_type { --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -622,7 +622,7 @@ xfs_file_iomap_begin_delay( retry: error = xfs_bmapi_reserve_delalloc(ip, XFS_DATA_FORK, offset_fsb, - end_fsb - offset_fsb, &got, &idx, eof); + end_fsb - offset_fsb, 0, &got, &idx, eof); switch (error) { case 0: break; --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -293,7 +293,7 @@ xfs_reflink_reserve_cow( retry: error = xfs_bmapi_reserve_delalloc(ip, XFS_COW_FORK, imap->br_startoff, - end_fsb - imap->br_startoff, &got, &idx, eof); + end_fsb - imap->br_startoff, 0, &got, &idx, eof); switch (error) { case 0: break;
