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1/*
2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
3 * Written by Alex Tomas <alex@clusterfs.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public Licens
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
17 */
18
19#ifndef _EXT4_EXTENTS
20#define _EXT4_EXTENTS
21
22#include "ext4.h"
23
24/*
25 * With AGGRESSIVE_TEST defined, the capacity of index/leaf blocks
26 * becomes very small, so index split, in-depth growing and
27 * other hard changes happen much more often.
28 * This is for debug purposes only.
29 */
30#define AGGRESSIVE_TEST_
31
32/*
33 * With EXTENTS_STATS defined, the number of blocks and extents
34 * are collected in the truncate path. They'll be shown at
35 * umount time.
36 */
37#define EXTENTS_STATS__
38
39/*
40 * If CHECK_BINSEARCH is defined, then the results of the binary search
41 * will also be checked by linear search.
42 */
43#define CHECK_BINSEARCH__
44
45/*
46 * Turn on EXT_DEBUG to get lots of info about extents operations.
47 */
48#define EXT_DEBUG__
49#ifdef EXT_DEBUG
50#define ext_debug(a...) printk(a)
51#else
52#define ext_debug(a...)
53#endif
54
55/*
56 * If EXT_STATS is defined then stats numbers are collected.
57 * These number will be displayed at umount time.
58 */
59#define EXT_STATS_
60
61
62/*
63 * ext4_inode has i_block array (60 bytes total).
64 * The first 12 bytes store ext4_extent_header;
65 * the remainder stores an array of ext4_extent.
66 */
67
68/*
69 * This is the extent on-disk structure.
70 * It's used at the bottom of the tree.
71 */
72struct ext4_extent {
73 __le32 ee_block; /* first logical block extent covers */
74 __le16 ee_len; /* number of blocks covered by extent */
75 __le16 ee_start_hi; /* high 16 bits of physical block */
76 __le32 ee_start_lo; /* low 32 bits of physical block */
77};
78
79/*
80 * This is index on-disk structure.
81 * It's used at all the levels except the bottom.
82 */
83struct ext4_extent_idx {
84 __le32 ei_block; /* index covers logical blocks from 'block' */
85 __le32 ei_leaf_lo; /* pointer to the physical block of the next *
86 * level. leaf or next index could be there */
87 __le16 ei_leaf_hi; /* high 16 bits of physical block */
88 __u16 ei_unused;
89};
90
91/*
92 * Each block (leaves and indexes), even inode-stored has header.
93 */
94struct ext4_extent_header {
95 __le16 eh_magic; /* probably will support different formats */
96 __le16 eh_entries; /* number of valid entries */
97 __le16 eh_max; /* capacity of store in entries */
98 __le16 eh_depth; /* has tree real underlying blocks? */
99 __le32 eh_generation; /* generation of the tree */
100};
101
102#define EXT4_EXT_MAGIC cpu_to_le16(0xf30a)
103
104/*
105 * Array of ext4_ext_path contains path to some extent.
106 * Creation/lookup routines use it for traversal/splitting/etc.
107 * Truncate uses it to simulate recursive walking.
108 */
109struct ext4_ext_path {
110 ext4_fsblk_t p_block;
111 __u16 p_depth;
112 struct ext4_extent *p_ext;
113 struct ext4_extent_idx *p_idx;
114 struct ext4_extent_header *p_hdr;
115 struct buffer_head *p_bh;
116};
117
118/*
119 * structure for external API
120 */
121
122/*
123 * to be called by ext4_ext_walk_space()
124 * negative retcode - error
125 * positive retcode - signal for ext4_ext_walk_space(), see below
126 * callback must return valid extent (passed or newly created)
127 */
128typedef int (*ext_prepare_callback)(struct inode *, ext4_lblk_t,
129 struct ext4_ext_cache *,
130 struct ext4_extent *, void *);
131
132#define EXT_CONTINUE 0
133#define EXT_BREAK 1
134#define EXT_REPEAT 2
135
136/*
137 * Maximum number of logical blocks in a file; ext4_extent's ee_block is
138 * __le32.
139 */
140#define EXT_MAX_BLOCKS 0xffffffff
141
142/*
143 * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
144 * initialized extent. This is 2^15 and not (2^16 - 1), since we use the
145 * MSB of ee_len field in the extent datastructure to signify if this
146 * particular extent is an initialized extent or an uninitialized (i.e.
147 * preallocated).
148 * EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an
149 * uninitialized extent.
150 * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
151 * uninitialized one. In other words, if MSB of ee_len is set, it is an
152 * uninitialized extent with only one special scenario when ee_len = 0x8000.
153 * In this case we can not have an uninitialized extent of zero length and
154 * thus we make it as a special case of initialized extent with 0x8000 length.
155 * This way we get better extent-to-group alignment for initialized extents.
156 * Hence, the maximum number of blocks we can have in an *initialized*
157 * extent is 2^15 (32768) and in an *uninitialized* extent is 2^15-1 (32767).
158 */
159#define EXT_INIT_MAX_LEN (1UL << 15)
160#define EXT_UNINIT_MAX_LEN (EXT_INIT_MAX_LEN - 1)
161
162
163#define EXT_FIRST_EXTENT(__hdr__) \
164 ((struct ext4_extent *) (((char *) (__hdr__)) + \
165 sizeof(struct ext4_extent_header)))
166#define EXT_FIRST_INDEX(__hdr__) \
167 ((struct ext4_extent_idx *) (((char *) (__hdr__)) + \
168 sizeof(struct ext4_extent_header)))
169#define EXT_HAS_FREE_INDEX(__path__) \
170 (le16_to_cpu((__path__)->p_hdr->eh_entries) \
171 < le16_to_cpu((__path__)->p_hdr->eh_max))
172#define EXT_LAST_EXTENT(__hdr__) \
173 (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
174#define EXT_LAST_INDEX(__hdr__) \
175 (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
176#define EXT_MAX_EXTENT(__hdr__) \
177 (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
178#define EXT_MAX_INDEX(__hdr__) \
179 (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
180
181static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode)
182{
183 return (struct ext4_extent_header *) EXT4_I(inode)->i_data;
184}
185
186static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh)
187{
188 return (struct ext4_extent_header *) bh->b_data;
189}
190
191static inline unsigned short ext_depth(struct inode *inode)
192{
193 return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);
194}
195
196static inline void
197ext4_ext_invalidate_cache(struct inode *inode)
198{
199 EXT4_I(inode)->i_cached_extent.ec_len = 0;
200}
201
202static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext)
203{
204 /* We can not have an uninitialized extent of zero length! */
205 BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0);
206 ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN);
207}
208
209static inline int ext4_ext_is_uninitialized(struct ext4_extent *ext)
210{
211 /* Extent with ee_len of 0x8000 is treated as an initialized extent */
212 return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN);
213}
214
215static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
216{
217 return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ?
218 le16_to_cpu(ext->ee_len) :
219 (le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN));
220}
221
222static inline void ext4_ext_mark_initialized(struct ext4_extent *ext)
223{
224 ext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ext));
225}
226
227/*
228 * ext4_ext_pblock:
229 * combine low and high parts of physical block number into ext4_fsblk_t
230 */
231static inline ext4_fsblk_t ext4_ext_pblock(struct ext4_extent *ex)
232{
233 ext4_fsblk_t block;
234
235 block = le32_to_cpu(ex->ee_start_lo);
236 block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
237 return block;
238}
239
240/*
241 * ext4_idx_pblock:
242 * combine low and high parts of a leaf physical block number into ext4_fsblk_t
243 */
244static inline ext4_fsblk_t ext4_idx_pblock(struct ext4_extent_idx *ix)
245{
246 ext4_fsblk_t block;
247
248 block = le32_to_cpu(ix->ei_leaf_lo);
249 block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
250 return block;
251}
252
253/*
254 * ext4_ext_store_pblock:
255 * stores a large physical block number into an extent struct,
256 * breaking it into parts
257 */
258static inline void ext4_ext_store_pblock(struct ext4_extent *ex,
259 ext4_fsblk_t pb)
260{
261 ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
262 ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) &
263 0xffff);
264}
265
266/*
267 * ext4_idx_store_pblock:
268 * stores a large physical block number into an index struct,
269 * breaking it into parts
270 */
271static inline void ext4_idx_store_pblock(struct ext4_extent_idx *ix,
272 ext4_fsblk_t pb)
273{
274 ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
275 ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) &
276 0xffff);
277}
278
279extern int ext4_ext_calc_metadata_amount(struct inode *inode,
280 ext4_lblk_t lblocks);
281extern int ext4_extent_tree_init(handle_t *, struct inode *);
282extern int ext4_ext_calc_credits_for_single_extent(struct inode *inode,
283 int num,
284 struct ext4_ext_path *path);
285extern int ext4_can_extents_be_merged(struct inode *inode,
286 struct ext4_extent *ex1,
287 struct ext4_extent *ex2);
288extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *, int);
289extern struct ext4_ext_path *ext4_ext_find_extent(struct inode *, ext4_lblk_t,
290 struct ext4_ext_path *);
291extern void ext4_ext_drop_refs(struct ext4_ext_path *);
292extern int ext4_ext_check_inode(struct inode *inode);
293#endif /* _EXT4_EXTENTS */
294
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
4 * Written by Alex Tomas <alex@clusterfs.com>
5 */
6
7#ifndef _EXT4_EXTENTS
8#define _EXT4_EXTENTS
9
10#include "ext4.h"
11
12/*
13 * With AGGRESSIVE_TEST defined, the capacity of index/leaf blocks
14 * becomes very small, so index split, in-depth growing and
15 * other hard changes happen much more often.
16 * This is for debug purposes only.
17 */
18#define AGGRESSIVE_TEST_
19
20/*
21 * With EXTENTS_STATS defined, the number of blocks and extents
22 * are collected in the truncate path. They'll be shown at
23 * umount time.
24 */
25#define EXTENTS_STATS__
26
27/*
28 * If CHECK_BINSEARCH is defined, then the results of the binary search
29 * will also be checked by linear search.
30 */
31#define CHECK_BINSEARCH__
32
33/*
34 * If EXT_STATS is defined then stats numbers are collected.
35 * These number will be displayed at umount time.
36 */
37#define EXT_STATS_
38
39
40/*
41 * ext4_inode has i_block array (60 bytes total).
42 * The first 12 bytes store ext4_extent_header;
43 * the remainder stores an array of ext4_extent.
44 * For non-inode extent blocks, ext4_extent_tail
45 * follows the array.
46 */
47
48/*
49 * This is the extent tail on-disk structure.
50 * All other extent structures are 12 bytes long. It turns out that
51 * block_size % 12 >= 4 for at least all powers of 2 greater than 512, which
52 * covers all valid ext4 block sizes. Therefore, this tail structure can be
53 * crammed into the end of the block without having to rebalance the tree.
54 */
55struct ext4_extent_tail {
56 __le32 et_checksum; /* crc32c(uuid+inum+extent_block) */
57};
58
59/*
60 * This is the extent on-disk structure.
61 * It's used at the bottom of the tree.
62 */
63struct ext4_extent {
64 __le32 ee_block; /* first logical block extent covers */
65 __le16 ee_len; /* number of blocks covered by extent */
66 __le16 ee_start_hi; /* high 16 bits of physical block */
67 __le32 ee_start_lo; /* low 32 bits of physical block */
68};
69
70/*
71 * This is index on-disk structure.
72 * It's used at all the levels except the bottom.
73 */
74struct ext4_extent_idx {
75 __le32 ei_block; /* index covers logical blocks from 'block' */
76 __le32 ei_leaf_lo; /* pointer to the physical block of the next *
77 * level. leaf or next index could be there */
78 __le16 ei_leaf_hi; /* high 16 bits of physical block */
79 __u16 ei_unused;
80};
81
82/*
83 * Each block (leaves and indexes), even inode-stored has header.
84 */
85struct ext4_extent_header {
86 __le16 eh_magic; /* probably will support different formats */
87 __le16 eh_entries; /* number of valid entries */
88 __le16 eh_max; /* capacity of store in entries */
89 __le16 eh_depth; /* has tree real underlying blocks? */
90 __le32 eh_generation; /* generation of the tree */
91};
92
93#define EXT4_EXT_MAGIC cpu_to_le16(0xf30a)
94#define EXT4_MAX_EXTENT_DEPTH 5
95
96#define EXT4_EXTENT_TAIL_OFFSET(hdr) \
97 (sizeof(struct ext4_extent_header) + \
98 (sizeof(struct ext4_extent) * le16_to_cpu((hdr)->eh_max)))
99
100static inline struct ext4_extent_tail *
101find_ext4_extent_tail(struct ext4_extent_header *eh)
102{
103 return (struct ext4_extent_tail *)(((void *)eh) +
104 EXT4_EXTENT_TAIL_OFFSET(eh));
105}
106
107/*
108 * Array of ext4_ext_path contains path to some extent.
109 * Creation/lookup routines use it for traversal/splitting/etc.
110 * Truncate uses it to simulate recursive walking.
111 */
112struct ext4_ext_path {
113 ext4_fsblk_t p_block;
114 __u16 p_depth;
115 __u16 p_maxdepth;
116 struct ext4_extent *p_ext;
117 struct ext4_extent_idx *p_idx;
118 struct ext4_extent_header *p_hdr;
119 struct buffer_head *p_bh;
120};
121
122/*
123 * Used to record a portion of a cluster found at the beginning or end
124 * of an extent while traversing the extent tree during space removal.
125 * A partial cluster may be removed if it does not contain blocks shared
126 * with extents that aren't being deleted (tofree state). Otherwise,
127 * it cannot be removed (nofree state).
128 */
129struct partial_cluster {
130 ext4_fsblk_t pclu; /* physical cluster number */
131 ext4_lblk_t lblk; /* logical block number within logical cluster */
132 enum {initial, tofree, nofree} state;
133};
134
135/*
136 * structure for external API
137 */
138
139/*
140 * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
141 * initialized extent. This is 2^15 and not (2^16 - 1), since we use the
142 * MSB of ee_len field in the extent datastructure to signify if this
143 * particular extent is an initialized extent or an unwritten (i.e.
144 * preallocated).
145 * EXT_UNWRITTEN_MAX_LEN is the maximum number of blocks we can have in an
146 * unwritten extent.
147 * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
148 * unwritten one. In other words, if MSB of ee_len is set, it is an
149 * unwritten extent with only one special scenario when ee_len = 0x8000.
150 * In this case we can not have an unwritten extent of zero length and
151 * thus we make it as a special case of initialized extent with 0x8000 length.
152 * This way we get better extent-to-group alignment for initialized extents.
153 * Hence, the maximum number of blocks we can have in an *initialized*
154 * extent is 2^15 (32768) and in an *unwritten* extent is 2^15-1 (32767).
155 */
156#define EXT_INIT_MAX_LEN (1UL << 15)
157#define EXT_UNWRITTEN_MAX_LEN (EXT_INIT_MAX_LEN - 1)
158
159
160#define EXT_FIRST_EXTENT(__hdr__) \
161 ((struct ext4_extent *) (((char *) (__hdr__)) + \
162 sizeof(struct ext4_extent_header)))
163#define EXT_FIRST_INDEX(__hdr__) \
164 ((struct ext4_extent_idx *) (((char *) (__hdr__)) + \
165 sizeof(struct ext4_extent_header)))
166#define EXT_HAS_FREE_INDEX(__path__) \
167 (le16_to_cpu((__path__)->p_hdr->eh_entries) \
168 < le16_to_cpu((__path__)->p_hdr->eh_max))
169#define EXT_LAST_EXTENT(__hdr__) \
170 (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
171#define EXT_LAST_INDEX(__hdr__) \
172 (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
173#define EXT_MAX_EXTENT(__hdr__) \
174 ((le16_to_cpu((__hdr__)->eh_max)) ? \
175 ((EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)) \
176 : 0)
177#define EXT_MAX_INDEX(__hdr__) \
178 ((le16_to_cpu((__hdr__)->eh_max)) ? \
179 ((EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)) : 0)
180
181static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode)
182{
183 return (struct ext4_extent_header *) EXT4_I(inode)->i_data;
184}
185
186static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh)
187{
188 return (struct ext4_extent_header *) bh->b_data;
189}
190
191static inline unsigned short ext_depth(struct inode *inode)
192{
193 return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);
194}
195
196static inline void ext4_ext_mark_unwritten(struct ext4_extent *ext)
197{
198 /* We can not have an unwritten extent of zero length! */
199 BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0);
200 ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN);
201}
202
203static inline int ext4_ext_is_unwritten(struct ext4_extent *ext)
204{
205 /* Extent with ee_len of 0x8000 is treated as an initialized extent */
206 return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN);
207}
208
209static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
210{
211 return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ?
212 le16_to_cpu(ext->ee_len) :
213 (le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN));
214}
215
216static inline void ext4_ext_mark_initialized(struct ext4_extent *ext)
217{
218 ext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ext));
219}
220
221/*
222 * ext4_ext_pblock:
223 * combine low and high parts of physical block number into ext4_fsblk_t
224 */
225static inline ext4_fsblk_t ext4_ext_pblock(struct ext4_extent *ex)
226{
227 ext4_fsblk_t block;
228
229 block = le32_to_cpu(ex->ee_start_lo);
230 block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
231 return block;
232}
233
234/*
235 * ext4_idx_pblock:
236 * combine low and high parts of a leaf physical block number into ext4_fsblk_t
237 */
238static inline ext4_fsblk_t ext4_idx_pblock(struct ext4_extent_idx *ix)
239{
240 ext4_fsblk_t block;
241
242 block = le32_to_cpu(ix->ei_leaf_lo);
243 block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
244 return block;
245}
246
247/*
248 * ext4_ext_store_pblock:
249 * stores a large physical block number into an extent struct,
250 * breaking it into parts
251 */
252static inline void ext4_ext_store_pblock(struct ext4_extent *ex,
253 ext4_fsblk_t pb)
254{
255 ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
256 ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) &
257 0xffff);
258}
259
260/*
261 * ext4_idx_store_pblock:
262 * stores a large physical block number into an index struct,
263 * breaking it into parts
264 */
265static inline void ext4_idx_store_pblock(struct ext4_extent_idx *ix,
266 ext4_fsblk_t pb)
267{
268 ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
269 ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) &
270 0xffff);
271}
272
273#endif /* _EXT4_EXTENTS */
274