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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
95#define EXT4_EXTENT_TAIL_OFFSET(hdr) \
96 (sizeof(struct ext4_extent_header) + \
97 (sizeof(struct ext4_extent) * le16_to_cpu((hdr)->eh_max)))
98
99static inline struct ext4_extent_tail *
100find_ext4_extent_tail(struct ext4_extent_header *eh)
101{
102 return (struct ext4_extent_tail *)(((void *)eh) +
103 EXT4_EXTENT_TAIL_OFFSET(eh));
104}
105
106/*
107 * Array of ext4_ext_path contains path to some extent.
108 * Creation/lookup routines use it for traversal/splitting/etc.
109 * Truncate uses it to simulate recursive walking.
110 */
111struct ext4_ext_path {
112 ext4_fsblk_t p_block;
113 __u16 p_depth;
114 __u16 p_maxdepth;
115 struct ext4_extent *p_ext;
116 struct ext4_extent_idx *p_idx;
117 struct ext4_extent_header *p_hdr;
118 struct buffer_head *p_bh;
119};
120
121/*
122 * structure for external API
123 */
124
125/*
126 * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
127 * initialized extent. This is 2^15 and not (2^16 - 1), since we use the
128 * MSB of ee_len field in the extent datastructure to signify if this
129 * particular extent is an initialized extent or an unwritten (i.e.
130 * preallocated).
131 * EXT_UNWRITTEN_MAX_LEN is the maximum number of blocks we can have in an
132 * unwritten extent.
133 * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
134 * unwritten one. In other words, if MSB of ee_len is set, it is an
135 * unwritten extent with only one special scenario when ee_len = 0x8000.
136 * In this case we can not have an unwritten extent of zero length and
137 * thus we make it as a special case of initialized extent with 0x8000 length.
138 * This way we get better extent-to-group alignment for initialized extents.
139 * Hence, the maximum number of blocks we can have in an *initialized*
140 * extent is 2^15 (32768) and in an *unwritten* extent is 2^15-1 (32767).
141 */
142#define EXT_INIT_MAX_LEN (1UL << 15)
143#define EXT_UNWRITTEN_MAX_LEN (EXT_INIT_MAX_LEN - 1)
144
145
146#define EXT_FIRST_EXTENT(__hdr__) \
147 ((struct ext4_extent *) (((char *) (__hdr__)) + \
148 sizeof(struct ext4_extent_header)))
149#define EXT_FIRST_INDEX(__hdr__) \
150 ((struct ext4_extent_idx *) (((char *) (__hdr__)) + \
151 sizeof(struct ext4_extent_header)))
152#define EXT_HAS_FREE_INDEX(__path__) \
153 (le16_to_cpu((__path__)->p_hdr->eh_entries) \
154 < le16_to_cpu((__path__)->p_hdr->eh_max))
155#define EXT_LAST_EXTENT(__hdr__) \
156 (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
157#define EXT_LAST_INDEX(__hdr__) \
158 (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
159#define EXT_MAX_EXTENT(__hdr__) \
160 (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
161#define EXT_MAX_INDEX(__hdr__) \
162 (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
163
164static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode)
165{
166 return (struct ext4_extent_header *) EXT4_I(inode)->i_data;
167}
168
169static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh)
170{
171 return (struct ext4_extent_header *) bh->b_data;
172}
173
174static inline unsigned short ext_depth(struct inode *inode)
175{
176 return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);
177}
178
179static inline void ext4_ext_mark_unwritten(struct ext4_extent *ext)
180{
181 /* We can not have an unwritten extent of zero length! */
182 BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0);
183 ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN);
184}
185
186static inline int ext4_ext_is_unwritten(struct ext4_extent *ext)
187{
188 /* Extent with ee_len of 0x8000 is treated as an initialized extent */
189 return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN);
190}
191
192static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
193{
194 return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ?
195 le16_to_cpu(ext->ee_len) :
196 (le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN));
197}
198
199static inline void ext4_ext_mark_initialized(struct ext4_extent *ext)
200{
201 ext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ext));
202}
203
204/*
205 * ext4_ext_pblock:
206 * combine low and high parts of physical block number into ext4_fsblk_t
207 */
208static inline ext4_fsblk_t ext4_ext_pblock(struct ext4_extent *ex)
209{
210 ext4_fsblk_t block;
211
212 block = le32_to_cpu(ex->ee_start_lo);
213 block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
214 return block;
215}
216
217/*
218 * ext4_idx_pblock:
219 * combine low and high parts of a leaf physical block number into ext4_fsblk_t
220 */
221static inline ext4_fsblk_t ext4_idx_pblock(struct ext4_extent_idx *ix)
222{
223 ext4_fsblk_t block;
224
225 block = le32_to_cpu(ix->ei_leaf_lo);
226 block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
227 return block;
228}
229
230/*
231 * ext4_ext_store_pblock:
232 * stores a large physical block number into an extent struct,
233 * breaking it into parts
234 */
235static inline void ext4_ext_store_pblock(struct ext4_extent *ex,
236 ext4_fsblk_t pb)
237{
238 ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
239 ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) &
240 0xffff);
241}
242
243/*
244 * ext4_idx_store_pblock:
245 * stores a large physical block number into an index struct,
246 * breaking it into parts
247 */
248static inline void ext4_idx_store_pblock(struct ext4_extent_idx *ix,
249 ext4_fsblk_t pb)
250{
251 ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
252 ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) &
253 0xffff);
254}
255
256#define ext4_ext_dirty(handle, inode, path) \
257 __ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))
258int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
259 struct inode *inode, struct ext4_ext_path *path);
260
261#endif /* _EXT4_EXTENTS */
262
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 * If EXT_STATS is defined then stats numbers are collected.
47 * These number will be displayed at umount time.
48 */
49#define EXT_STATS_
50
51
52/*
53 * ext4_inode has i_block array (60 bytes total).
54 * The first 12 bytes store ext4_extent_header;
55 * the remainder stores an array of ext4_extent.
56 * For non-inode extent blocks, ext4_extent_tail
57 * follows the array.
58 */
59
60/*
61 * This is the extent tail on-disk structure.
62 * All other extent structures are 12 bytes long. It turns out that
63 * block_size % 12 >= 4 for at least all powers of 2 greater than 512, which
64 * covers all valid ext4 block sizes. Therefore, this tail structure can be
65 * crammed into the end of the block without having to rebalance the tree.
66 */
67struct ext4_extent_tail {
68 __le32 et_checksum; /* crc32c(uuid+inum+extent_block) */
69};
70
71/*
72 * This is the extent on-disk structure.
73 * It's used at the bottom of the tree.
74 */
75struct ext4_extent {
76 __le32 ee_block; /* first logical block extent covers */
77 __le16 ee_len; /* number of blocks covered by extent */
78 __le16 ee_start_hi; /* high 16 bits of physical block */
79 __le32 ee_start_lo; /* low 32 bits of physical block */
80};
81
82/*
83 * This is index on-disk structure.
84 * It's used at all the levels except the bottom.
85 */
86struct ext4_extent_idx {
87 __le32 ei_block; /* index covers logical blocks from 'block' */
88 __le32 ei_leaf_lo; /* pointer to the physical block of the next *
89 * level. leaf or next index could be there */
90 __le16 ei_leaf_hi; /* high 16 bits of physical block */
91 __u16 ei_unused;
92};
93
94/*
95 * Each block (leaves and indexes), even inode-stored has header.
96 */
97struct ext4_extent_header {
98 __le16 eh_magic; /* probably will support different formats */
99 __le16 eh_entries; /* number of valid entries */
100 __le16 eh_max; /* capacity of store in entries */
101 __le16 eh_depth; /* has tree real underlying blocks? */
102 __le32 eh_generation; /* generation of the tree */
103};
104
105#define EXT4_EXT_MAGIC cpu_to_le16(0xf30a)
106
107#define EXT4_EXTENT_TAIL_OFFSET(hdr) \
108 (sizeof(struct ext4_extent_header) + \
109 (sizeof(struct ext4_extent) * le16_to_cpu((hdr)->eh_max)))
110
111static inline struct ext4_extent_tail *
112find_ext4_extent_tail(struct ext4_extent_header *eh)
113{
114 return (struct ext4_extent_tail *)(((void *)eh) +
115 EXT4_EXTENT_TAIL_OFFSET(eh));
116}
117
118/*
119 * Array of ext4_ext_path contains path to some extent.
120 * Creation/lookup routines use it for traversal/splitting/etc.
121 * Truncate uses it to simulate recursive walking.
122 */
123struct ext4_ext_path {
124 ext4_fsblk_t p_block;
125 __u16 p_depth;
126 struct ext4_extent *p_ext;
127 struct ext4_extent_idx *p_idx;
128 struct ext4_extent_header *p_hdr;
129 struct buffer_head *p_bh;
130};
131
132/*
133 * structure for external API
134 */
135
136/*
137 * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
138 * initialized extent. This is 2^15 and not (2^16 - 1), since we use the
139 * MSB of ee_len field in the extent datastructure to signify if this
140 * particular extent is an initialized extent or an uninitialized (i.e.
141 * preallocated).
142 * EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an
143 * uninitialized extent.
144 * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
145 * uninitialized one. In other words, if MSB of ee_len is set, it is an
146 * uninitialized extent with only one special scenario when ee_len = 0x8000.
147 * In this case we can not have an uninitialized extent of zero length and
148 * thus we make it as a special case of initialized extent with 0x8000 length.
149 * This way we get better extent-to-group alignment for initialized extents.
150 * Hence, the maximum number of blocks we can have in an *initialized*
151 * extent is 2^15 (32768) and in an *uninitialized* extent is 2^15-1 (32767).
152 */
153#define EXT_INIT_MAX_LEN (1UL << 15)
154#define EXT_UNINIT_MAX_LEN (EXT_INIT_MAX_LEN - 1)
155
156
157#define EXT_FIRST_EXTENT(__hdr__) \
158 ((struct ext4_extent *) (((char *) (__hdr__)) + \
159 sizeof(struct ext4_extent_header)))
160#define EXT_FIRST_INDEX(__hdr__) \
161 ((struct ext4_extent_idx *) (((char *) (__hdr__)) + \
162 sizeof(struct ext4_extent_header)))
163#define EXT_HAS_FREE_INDEX(__path__) \
164 (le16_to_cpu((__path__)->p_hdr->eh_entries) \
165 < le16_to_cpu((__path__)->p_hdr->eh_max))
166#define EXT_LAST_EXTENT(__hdr__) \
167 (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
168#define EXT_LAST_INDEX(__hdr__) \
169 (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
170#define EXT_MAX_EXTENT(__hdr__) \
171 (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
172#define EXT_MAX_INDEX(__hdr__) \
173 (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
174
175static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode)
176{
177 return (struct ext4_extent_header *) EXT4_I(inode)->i_data;
178}
179
180static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh)
181{
182 return (struct ext4_extent_header *) bh->b_data;
183}
184
185static inline unsigned short ext_depth(struct inode *inode)
186{
187 return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);
188}
189
190static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext)
191{
192 /* We can not have an uninitialized extent of zero length! */
193 BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0);
194 ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN);
195}
196
197static inline int ext4_ext_is_uninitialized(struct ext4_extent *ext)
198{
199 /* Extent with ee_len of 0x8000 is treated as an initialized extent */
200 return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN);
201}
202
203static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
204{
205 return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ?
206 le16_to_cpu(ext->ee_len) :
207 (le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN));
208}
209
210static inline void ext4_ext_mark_initialized(struct ext4_extent *ext)
211{
212 ext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ext));
213}
214
215/*
216 * ext4_ext_pblock:
217 * combine low and high parts of physical block number into ext4_fsblk_t
218 */
219static inline ext4_fsblk_t ext4_ext_pblock(struct ext4_extent *ex)
220{
221 ext4_fsblk_t block;
222
223 block = le32_to_cpu(ex->ee_start_lo);
224 block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
225 return block;
226}
227
228/*
229 * ext4_idx_pblock:
230 * combine low and high parts of a leaf physical block number into ext4_fsblk_t
231 */
232static inline ext4_fsblk_t ext4_idx_pblock(struct ext4_extent_idx *ix)
233{
234 ext4_fsblk_t block;
235
236 block = le32_to_cpu(ix->ei_leaf_lo);
237 block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
238 return block;
239}
240
241/*
242 * ext4_ext_store_pblock:
243 * stores a large physical block number into an extent struct,
244 * breaking it into parts
245 */
246static inline void ext4_ext_store_pblock(struct ext4_extent *ex,
247 ext4_fsblk_t pb)
248{
249 ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
250 ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) &
251 0xffff);
252}
253
254/*
255 * ext4_idx_store_pblock:
256 * stores a large physical block number into an index struct,
257 * breaking it into parts
258 */
259static inline void ext4_idx_store_pblock(struct ext4_extent_idx *ix,
260 ext4_fsblk_t pb)
261{
262 ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
263 ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) &
264 0xffff);
265}
266
267#define ext4_ext_dirty(handle, inode, path) \
268 __ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))
269int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
270 struct inode *inode, struct ext4_ext_path *path);
271
272#endif /* _EXT4_EXTENTS */
273