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authorMandy Kirkconnell <alkirkco@sgi.com>2006-03-17 01:25:04 -0500
committerNathan Scott <nathans@sgi.com>2006-03-17 01:25:04 -0500
commit8867bc9bf0aed7181aa72c7c938c6ce830b75166 (patch)
treeae2dcc3a986e4e48fd81605f109be44c29362edd /fs/xfs/linux-2.6/xfs_super.h
parent524fbf5dd1b25acffe6f8a4ed5f3cce1023cfdb8 (diff)
[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 <alkirkco@sgi.com> Signed-off-by: Nathan Scott <nathans@sgi.com>
Diffstat (limited to 'fs/xfs/linux-2.6/xfs_super.h')
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