256 lines
8.6 KiB
C
256 lines
8.6 KiB
C
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/*
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* Copyright (c) 2003-2006, 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 _EXT4_EXTENTS
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#define _EXT4_EXTENTS
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#include "ext4.h"
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/*
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* With AGGRESSIVE_TEST defined, the capacity of index/leaf blocks
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* becomes very small, so index split, in-depth growing and
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* other hard changes happen much more often.
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* This is for debug purposes only.
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*/
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#define AGGRESSIVE_TEST_
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/*
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* With EXTENTS_STATS defined, the number of blocks and extents
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* are collected in the truncate path. They'll be shown at
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* umount time.
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*/
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#define EXTENTS_STATS__
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/*
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* If CHECK_BINSEARCH is defined, then the results of the binary search
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* will also be checked by linear search.
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*/
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#define CHECK_BINSEARCH__
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/*
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* Turn on EXT_DEBUG to get lots of info about extents operations.
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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(a...) printk(a)
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#else
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#define ext_debug(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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/*
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* ext4_inode has i_block array (60 bytes total).
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* The first 12 bytes store ext4_extent_header;
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* the remainder stores an array of ext4_extent.
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*/
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/*
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* This is the 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 ext4_extent {
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__le32 ee_block; /* first logical block extent covers */
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__le16 ee_len; /* number of blocks covered by extent */
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__le16 ee_start_hi; /* high 16 bits of physical block */
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__le32 ee_start_lo; /* low 32 bits 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 except the bottom.
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*/
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struct ext4_extent_idx {
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__le32 ei_block; /* index covers logical blocks from 'block' */
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__le32 ei_leaf_lo; /* pointer to the physical block of the next *
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* level. leaf or next index could be there */
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__le16 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 ext4_extent_header {
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__le16 eh_magic; /* probably will support different formats */
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__le16 eh_entries; /* number of valid entries */
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__le16 eh_max; /* capacity of store in entries */
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__le16 eh_depth; /* has tree real underlying blocks? */
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__le32 eh_generation; /* generation of the tree */
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};
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#define EXT4_EXT_MAGIC cpu_to_le16(0xf30a)
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/*
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* Array of ext4_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 ext4_ext_path {
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ext4_fsblk_t p_block;
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__u16 p_depth;
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struct ext4_extent *p_ext;
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struct ext4_extent_idx *p_idx;
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struct ext4_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 EXT4_EXT_CACHE_NO 0
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#define EXT4_EXT_CACHE_GAP 1
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#define EXT4_EXT_CACHE_EXTENT 2
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/*
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* to be called by ext4_ext_walk_space()
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* negative retcode - error
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* positive retcode - signal for ext4_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 inode *, struct ext4_ext_path *,
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struct ext4_ext_cache *,
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struct ext4_extent *, void *);
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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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/* Maximum logical block in a file; ext4_extent's ee_block is __le32 */
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#define EXT_MAX_BLOCK 0xffffffff
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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 ext4_extent *) (((char *) (__hdr__)) + \
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sizeof(struct ext4_extent_header)))
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#define EXT_FIRST_INDEX(__hdr__) \
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((struct ext4_extent_idx *) (((char *) (__hdr__)) + \
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sizeof(struct ext4_extent_header)))
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#define EXT_HAS_FREE_INDEX(__path__) \
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(le16_to_cpu((__path__)->p_hdr->eh_entries) \
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< le16_to_cpu((__path__)->p_hdr->eh_max))
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#define EXT_LAST_EXTENT(__hdr__) \
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(EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
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#define EXT_LAST_INDEX(__hdr__) \
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(EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
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#define EXT_MAX_EXTENT(__hdr__) \
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(EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
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#define EXT_MAX_INDEX(__hdr__) \
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(EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
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static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode)
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{
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return (struct ext4_extent_header *) EXT4_I(inode)->i_data;
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}
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static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh)
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{
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return (struct ext4_extent_header *) bh->b_data;
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}
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static inline unsigned short ext_depth(struct inode *inode)
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{
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return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);
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}
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static inline void
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ext4_ext_invalidate_cache(struct inode *inode)
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{
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EXT4_I(inode)->i_cached_extent.ec_type = EXT4_EXT_CACHE_NO;
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}
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static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext)
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{
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/* We can not have an uninitialized extent of zero length! */
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BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0);
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ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN);
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}
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static inline int ext4_ext_is_uninitialized(struct ext4_extent *ext)
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{
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/* Extent with ee_len of 0x8000 is treated as an initialized extent */
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return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN);
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}
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static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
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{
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return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ?
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le16_to_cpu(ext->ee_len) :
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(le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN));
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}
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static inline void ext4_ext_mark_initialized(struct ext4_extent *ext)
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{
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ext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ext));
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}
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extern int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks);
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extern ext4_fsblk_t ext_pblock(struct ext4_extent *ex);
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extern ext4_fsblk_t idx_pblock(struct ext4_extent_idx *);
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extern void ext4_ext_store_pblock(struct ext4_extent *, ext4_fsblk_t);
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extern int ext4_extent_tree_init(handle_t *, struct inode *);
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extern int ext4_ext_calc_credits_for_single_extent(struct inode *inode,
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int num,
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struct ext4_ext_path *path);
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extern int ext4_can_extents_be_merged(struct inode *inode,
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struct ext4_extent *ex1,
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struct ext4_extent *ex2);
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extern int ext4_ext_try_to_merge(struct inode *inode,
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struct ext4_ext_path *path,
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struct ext4_extent *);
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extern unsigned int ext4_ext_check_overlap(struct inode *, struct ext4_extent *, struct ext4_ext_path *);
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extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *, int);
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extern int ext4_ext_walk_space(struct inode *, ext4_lblk_t, ext4_lblk_t,
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ext_prepare_callback, void *);
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extern struct ext4_ext_path *ext4_ext_find_extent(struct inode *, ext4_lblk_t,
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struct ext4_ext_path *);
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extern int ext4_ext_search_left(struct inode *, struct ext4_ext_path *,
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ext4_lblk_t *, ext4_fsblk_t *);
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extern int ext4_ext_search_right(struct inode *, struct ext4_ext_path *,
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ext4_lblk_t *, ext4_fsblk_t *);
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extern void ext4_ext_drop_refs(struct ext4_ext_path *);
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extern int ext4_ext_check_inode(struct inode *inode);
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#endif /* _EXT4_EXTENTS */
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