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This is a tidy up of the GFS2 bmap code. The main change is that the bh is passed to gfs2_block_map allowing the flags to be set directly rather than having to repeat that code several times in ops_address.c. At the same time, the extent mapping code from gfs2_extent_map has been moved into gfs2_block_map. This allows all calls to gfs2_block_map to map extents in the case that no allocation is taking place. As a result reads and non-allocating writes should be faster. A quick test with postmark appears to support this. There is a limit on the number of blocks mapped in a single bmap call in that it will only ever map blocks which are pointed to from a single pointer block. So in other words, it will never try to do additional i/o in order to satisfy read-ahead. The maximum number of blocks is thus somewhat less than 512 (the GFS2 4k block size minus the header divided by sizeof(u64)). I've further limited the mapping of "normal" blocks to 32 blocks (to avoid extra work) since readpages() will currently read a maximum of 32 blocks ahead (128k). Some further work will probably be needed to set a suitable value for DIO as well, but for now thats left at the maximum 512 (see ops_address.c:gfs2_get_block_direct). There is probably a lot more that can be done to improve bmap for GFS2, but this is a good first step. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
32 lines
1.1 KiB
C
32 lines
1.1 KiB
C
/*
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* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU General Public License version 2.
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*/
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#ifndef __BMAP_DOT_H__
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#define __BMAP_DOT_H__
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struct inode;
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struct gfs2_inode;
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struct page;
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int gfs2_unstuff_dinode(struct gfs2_inode *ip, struct page *page);
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int gfs2_block_map(struct inode *inode, u64 lblock, int create, struct buffer_head *bh, unsigned int maxlen);
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int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsigned *extlen);
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int gfs2_truncatei(struct gfs2_inode *ip, u64 size);
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int gfs2_truncatei_resume(struct gfs2_inode *ip);
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int gfs2_file_dealloc(struct gfs2_inode *ip);
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void gfs2_write_calc_reserv(struct gfs2_inode *ip, unsigned int len,
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unsigned int *data_blocks,
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unsigned int *ind_blocks);
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int gfs2_write_alloc_required(struct gfs2_inode *ip, u64 offset,
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unsigned int len, int *alloc_required);
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#endif /* __BMAP_DOT_H__ */
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