a2df2a6340
This patch implements ->fallocate() inode operation in ext4. With this patch users of ext4 file systems will be able to use fallocate() system call for persistent preallocation. Current implementation only supports preallocation for regular files (directories not supported as of date) with extent maps. This patch does not support block-mapped files currently. Only FALLOC_ALLOCATE and FALLOC_RESV_SPACE modes are being supported as of now. Signed-off-by: Amit Arora <aarora@in.ibm.com>
215 lines
6.3 KiB
C
215 lines
6.3 KiB
C
/*
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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 _LINUX_EXT4_EXTENTS
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#define _LINUX_EXT4_EXTENTS
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#include <linux/ext4_fs.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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* If EXT_DEBUG is defined you can use the 'extdebug' mount option
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* to get lots of info about 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(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; /* 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; /* 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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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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#define EXT_MAX_BLOCK 0xffffffff
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#define EXT_MAX_LEN ((1UL << 15) - 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 ext4_ext_tree_changed(struct inode *inode)
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{
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EXT4_I(inode)->i_ext_generation++;
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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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ext->ee_len |= cpu_to_le16(0x8000);
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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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return (int)(le16_to_cpu((ext)->ee_len) & 0x8000);
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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 (int)(le16_to_cpu((ext)->ee_len) & 0x7FFF);
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}
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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_insert(struct inode *, struct ext4_ext_path *);
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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 *);
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extern int ext4_ext_walk_space(struct inode *, unsigned long, unsigned long, ext_prepare_callback, void *);
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extern struct ext4_ext_path * ext4_ext_find_extent(struct inode *, int, struct ext4_ext_path *);
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#endif /* _LINUX_EXT4_EXTENTS */
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