mirror of https://github.com/vitalif/e2fsprogs
259 lines
8.1 KiB
C
259 lines
8.1 KiB
C
/*
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* Copyright (c) 2003,2004 Cluster File Systems, Inc, info@clusterfs.com
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* Written by Alex Tomas <alex@clusterfs.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public Licens
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
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*/
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#ifndef _LINUX_EXT3_EXTENTS
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#define _LINUX_EXT3_EXTENTS
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/*
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* with AGRESSIVE_TEST defined capacity of index/leaf blocks
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* become very little, so index split, in-depth growing and
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* other hard changes happens much more often
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* this is for debug purposes only
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*/
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#define AGRESSIVE_TEST_
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/*
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* if CHECK_BINSEARCH defined, then results of binary search
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* will be checked by linear search
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*/
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#define CHECK_BINSEARCH_
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/*
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* if EXT_DEBUG is defined you can use 'extdebug' mount option
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* to get lots of info what's going on
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*/
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//#define EXT_DEBUG
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#ifdef EXT_DEBUG
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#define ext_debug(tree,fmt,a...) \
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do { \
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if (test_opt((tree)->inode->i_sb, EXTDEBUG)) \
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printk(fmt, ##a); \
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} while (0);
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#else
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#define ext_debug(tree,fmt,a...)
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#endif
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/*
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* if EXT_STATS is defined then stats numbers are collected
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* these number will be displayed at umount time
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*/
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#define EXT_STATS_
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#define EXT3_ALLOC_NEEDED 3 /* block bitmap + group desc. + sb */
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/*
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* ext3_inode has i_block array (total 60 bytes)
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* first 4 bytes are used to store:
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* - tree depth (0 mean there is no tree yet. all extents in the inode)
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* - number of alive extents in the inode
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*/
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/*
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* this is extent on-disk structure
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* it's used at the bottom of the tree
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*/
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struct ext3_extent {
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__u32 ee_block; /* first logical block extent covers */
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__u16 ee_len; /* number of blocks covered by extent */
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__u16 ee_start_hi; /* high 16 bits of physical block */
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__u32 ee_start; /* low 32 bigs of physical block */
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};
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/*
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* this is index on-disk structure
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* it's used at all the levels, but the bottom
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*/
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struct ext3_extent_idx {
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__u32 ei_block; /* index covers logical blocks from 'block' */
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__u32 ei_leaf; /* pointer to the physical block of the next *
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* level. leaf or next index could bet here */
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__u16 ei_leaf_hi; /* high 16 bits of physical block */
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__u16 ei_unused;
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};
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/*
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* each block (leaves and indexes), even inode-stored has header
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*/
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struct ext3_extent_header {
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__u16 eh_magic; /* probably will support different formats */
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__u16 eh_entries; /* number of valid entries */
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__u16 eh_max; /* capacity of store in entries */
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__u16 eh_depth; /* has tree real underlaying blocks? */
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__u32 eh_generation; /* generation of the tree */
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};
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#define EXT3_EXT_MAGIC 0xf30a
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/*
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* array of ext3_ext_path contains path to some extent
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* creation/lookup routines use it for traversal/splitting/etc
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* truncate uses it to simulate recursive walking
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*/
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struct ext3_ext_path {
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__u32 p_block;
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__u16 p_depth;
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struct ext3_extent *p_ext;
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struct ext3_extent_idx *p_idx;
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struct ext3_extent_header *p_hdr;
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struct buffer_head *p_bh;
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};
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/*
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* structure for external API
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*/
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#define EXT_CONTINUE 0
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#define EXT_BREAK 1
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#define EXT_REPEAT 2
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#define EXT_MAX_BLOCK 0xffffffff
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#define EXT_CACHE_MARK 0xffff
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/*
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* EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
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* initialized extent. This is 2^15 and not (2^16 - 1), since we use the
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* MSB of ee_len field in the extent datastructure to signify if this
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* particular extent is an initialized extent or an uninitialized (i.e.
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* preallocated).
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* EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an
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* uninitialized extent.
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* If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
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* uninitialized one. In other words, if MSB of ee_len is set, it is an
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* uninitialized extent with only one special scenario when ee_len = 0x8000.
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* In this case we can not have an uninitialized extent of zero length and
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* thus we make it as a special case of initialized extent with 0x8000 length.
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* This way we get better extent-to-group alignment for initialized extents.
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* Hence, the maximum number of blocks we can have in an *initialized*
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* extent is 2^15 (32768) and in an *uninitialized* extent is 2^15-1 (32767).
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*/
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#define EXT_INIT_MAX_LEN (1UL << 15)
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#define EXT_UNINIT_MAX_LEN (EXT_INIT_MAX_LEN - 1)
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#define EXT_FIRST_EXTENT(__hdr__) \
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((struct ext3_extent *) (((char *) (__hdr__)) + \
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sizeof(struct ext3_extent_header)))
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#define EXT_FIRST_INDEX(__hdr__) \
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((struct ext3_extent_idx *) (((char *) (__hdr__)) + \
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sizeof(struct ext3_extent_header)))
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#define EXT_HAS_FREE_INDEX(__path__) \
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((__path__)->p_hdr->eh_entries < (__path__)->p_hdr->eh_max)
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#define EXT_LAST_EXTENT(__hdr__) \
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(EXT_FIRST_EXTENT((__hdr__)) + (__hdr__)->eh_entries - 1)
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#define EXT_LAST_INDEX(__hdr__) \
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(EXT_FIRST_INDEX((__hdr__)) + (__hdr__)->eh_entries - 1)
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#define EXT_MAX_EXTENT(__hdr__) \
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(EXT_FIRST_EXTENT((__hdr__)) + (__hdr__)->eh_max - 1)
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#define EXT_MAX_INDEX(__hdr__) \
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(EXT_FIRST_INDEX((__hdr__)) + (__hdr__)->eh_max - 1)
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#define EXT_ROOT_HDR(tree) \
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((struct ext3_extent_header *) (tree)->root)
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#define EXT_BLOCK_HDR(bh) \
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((struct ext3_extent_header *) (bh)->b_data)
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#define EXT_DEPTH(_t_) \
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(((struct ext3_extent_header *)((_t_)->root))->eh_depth)
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#define EXT_GENERATION(_t_) \
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(((struct ext3_extent_header *)((_t_)->root))->eh_generation)
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#define EXT_ASSERT(__x__) if (!(__x__)) BUG();
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/*
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* this structure is used to gather extents from the tree via ioctl
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*/
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struct ext3_extent_buf {
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unsigned long start;
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int buflen;
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void *buffer;
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void *cur;
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int err;
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};
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/*
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* this structure is used to collect stats info about the tree
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*/
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struct ext3_extent_tree_stats {
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int depth;
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int extents_num;
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int leaf_num;
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};
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#ifdef __KERNEL__
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/*
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* ext3_extents_tree is used to pass initial information
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* to top-level extents API
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*/
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struct ext3_extents_helpers;
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struct ext3_extents_tree {
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struct inode *inode; /* inode which tree belongs to */
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void *root; /* ptr to data top of tree resides at */
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void *buffer; /* will be passed as arg to ^^ routines */
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int buffer_len;
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void *private;
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struct ext3_extent *cex;/* last found extent */
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struct ext3_extents_helpers *ops;
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};
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struct ext3_extents_helpers {
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int (*get_write_access)(handle_t *h, void *buffer);
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int (*mark_buffer_dirty)(handle_t *h, void *buffer);
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int (*mergable)(struct ext3_extent *ex1, struct ext3_extent *ex2);
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int (*remove_extent_credits)(struct ext3_extents_tree *,
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struct ext3_extent *, unsigned long,
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unsigned long);
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int (*remove_extent)(struct ext3_extents_tree *,
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struct ext3_extent *, unsigned long,
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unsigned long);
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int (*new_block)(handle_t *, struct ext3_extents_tree *,
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struct ext3_ext_path *, struct ext3_extent *,
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int *);
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};
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/*
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* to be called by ext3_ext_walk_space()
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* negative retcode - error
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* positive retcode - signal for ext3_ext_walk_space(), see below
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* callback must return valid extent (passed or newly created)
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*/
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typedef int (*ext_prepare_callback)(struct ext3_extents_tree *,
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struct ext3_ext_path *,
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struct ext3_extent *, int);
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void ext3_init_tree_desc(struct ext3_extents_tree *, struct inode *);
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extern int ext3_extent_tree_init(handle_t *, struct ext3_extents_tree *);
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extern int ext3_ext_calc_credits_for_insert(struct ext3_extents_tree *, struct ext3_ext_path *);
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extern int ext3_ext_insert_extent(handle_t *, struct ext3_extents_tree *, struct ext3_ext_path *, struct ext3_extent *);
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extern int ext3_ext_walk_space(struct ext3_extents_tree *, unsigned long, unsigned long, ext_prepare_callback);
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extern int ext3_ext_remove_space(struct ext3_extents_tree *, unsigned long, unsigned long);
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extern struct ext3_ext_path * ext3_ext_find_extent(struct ext3_extents_tree *, int, struct ext3_ext_path *);
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static inline void
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ext3_ext_invalidate_cache(struct ext3_extents_tree *tree)
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{
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if (tree->cex)
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tree->cex->ee_len = 0;
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}
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#endif /* __KERNEL__ */
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#endif /* _LINUX_EXT3_EXTENTS */
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