From 8867bc9bf0aed7181aa72c7c938c6ce830b75166 Mon Sep 17 00:00:00 2001 From: Mandy Kirkconnell Date: Fri, 17 Mar 2006 17:25:04 +1100 Subject: [XFS] There are a few problems with the new xfs_bmap_search_multi_extents() wrapper function that I introduced in mod xfs-linux:xfs-kern:207393a. The function was added as a wrapper around xfs_bmap_do_search_extents() to avoid breaking the top-of-tree CXFS interface. The idea of the function was basically to extract the target extent buffer (if muli- level extent allocation mode), then call xfs_bmap_do_search_extents() with either a pointer to the first extent in the target buffer or a pointer to the first extent in the file, depending on which extent mode was being used. However, in addition to locating the target extent record for block bno, xfs_bmap_do_search_extents() also sets four parameters needed by the caller: *lastx, *eofp, *gotp, *prevp. Passing only the target extent buffer to xfs_bmap_do_search_extents() causes *eofp to be set incorrectly if the extent is at the end of the target list but there are actually more extents in the next er_extbuf. Likewise, if the extent is the first one in the buffer but NOT the first in the file, *prevp is incorrectly set to NULL. Adding the needed functionality to xfs_bmap_search_multi_extents() to re-set any incorrectly set fields is redundant and makes the call to xfs_bmap_do_search_extents() not make much sense when multi-level extent allocation mode is being used. This mod basically extracts the two functional components from xfs_bmap_do_search_extents(), with the intent of obsoleting/removing xfs_bmap_do_search_extents() after the CXFS mult-level in-core extent changes are checked in. The two components are: 1) The binary search to locate the target extent record, and 2) Setting the four parameters needed by the caller (*lastx, *eofp, *gotp, *prevp). Component 1: I created a new function in xfs_inode.c called xfs_iext_bno_to_ext(), which executes the binary search to find the target extent record. xfs_bmap_search_multi_extents() has been modified to call xfs_iext_bno_to_ext() rather than xfs_bmap_do_search_extents(). Component 2: The parameter setting functionality has been added to xfs_bmap_search_multi_extents(), eliminating the need for xfs_bmap_do_search_extents(). These changes make the removal of xfs_bmap_do_search_extents() trival once the CXFS changes are in place. They also allow us to maintain the current XFS interface, using the new search function introduced in mod xfs-linux:xfs-kern:207393a. SGI-PV: 928864 SGI-Modid: xfs-linux-melb:xfs-kern:207866a Signed-off-by: Mandy Kirkconnell Signed-off-by: Nathan Scott --- fs/xfs/xfs_bmap.c | 57 +++++++++++++++++++++++++++++-------------------------- 1 file changed, 30 insertions(+), 27 deletions(-) (limited to 'fs/xfs/xfs_bmap.c') diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c index 64a02ea..2d702e4 100644 --- a/fs/xfs/xfs_bmap.c +++ b/fs/xfs/xfs_bmap.c @@ -3575,10 +3575,11 @@ xfs_bmap_do_search_extents( } /* - * Call xfs_bmap_do_search_extents() to search for the extent - * record containing block bno. If in multi-level in-core extent - * allocation mode, find and extract the target extent buffer, - * otherwise just use the direct extent list. + * Search the extent records for the entry containing block bno. + * If bno lies in a hole, point to the next entry. If bno lies + * past eof, *eofp will be set, and *prevp will contain the last + * entry (null if none). Else, *lastxp will be set to the index + * of the found entry; *gotp will contain the entry. */ xfs_bmbt_rec_t * /* pointer to found extent entry */ xfs_bmap_search_multi_extents( @@ -3589,36 +3590,38 @@ xfs_bmap_search_multi_extents( xfs_bmbt_irec_t *gotp, /* out: extent entry found */ xfs_bmbt_irec_t *prevp) /* out: previous extent entry found */ { - xfs_bmbt_rec_t *base; /* base of extent records */ xfs_bmbt_rec_t *ep; /* extent record pointer */ - xfs_ext_irec_t *erp = NULL; /* indirection array pointer */ xfs_extnum_t lastx; /* last extent index */ - xfs_extnum_t nextents; /* number of file extents */ /* - * For multi-level extent allocation mode, find the - * target extent list and pass only the contiguous - * list to xfs_bmap_do_search_extents. Convert lastx - * from a file extent index to an index within the - * target extent list. + * Initialize the extent entry structure to catch access to + * uninitialized br_startblock field. */ - if (ifp->if_flags & XFS_IFEXTIREC) { - int erp_idx = 0; - erp = xfs_iext_bno_to_irec(ifp, bno, &erp_idx); - base = erp->er_extbuf; - nextents = erp->er_extcount; - lastx = ifp->if_lastex - erp->er_extoff; - } else { - base = &ifp->if_u1.if_extents[0]; - nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t); - lastx = ifp->if_lastex; + gotp->br_startoff = 0xffa5a5a5a5a5a5a5LL; + gotp->br_blockcount = 0xa55a5a5a5a5a5a5aLL; + gotp->br_state = XFS_EXT_INVALID; +#if XFS_BIG_BLKNOS + gotp->br_startblock = 0xffffa5a5a5a5a5a5LL; +#else + gotp->br_startblock = 0xffffa5a5; +#endif + prevp->br_startoff = NULLFILEOFF; + + ep = xfs_iext_bno_to_ext(ifp, bno, &lastx); + if (lastx > 0) { + xfs_bmbt_get_all(xfs_iext_get_ext(ifp, lastx - 1), prevp); } - ep = xfs_bmap_do_search_extents(base, lastx, nextents, bno, - eofp, lastxp, gotp, prevp); - /* Convert lastx back to file-based index */ - if (ifp->if_flags & XFS_IFEXTIREC) { - *lastxp += erp->er_extoff; + if (lastx < (ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t))) { + xfs_bmbt_get_all(ep, gotp); + *eofp = 0; + } else { + if (lastx > 0) { + *gotp = *prevp; + } + *eofp = 1; + ep = NULL; } + *lastxp = lastx; return ep; } -- cgit v1.1