Merge commit 'v2.6.30-rc5' into sched/core
[linux-2.6] / fs / ext2 / inode.c
1 /*
2  *  linux/fs/ext2/inode.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  from
10  *
11  *  linux/fs/minix/inode.c
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  *
15  *  Goal-directed block allocation by Stephen Tweedie
16  *      (sct@dcs.ed.ac.uk), 1993, 1998
17  *  Big-endian to little-endian byte-swapping/bitmaps by
18  *        David S. Miller (davem@caip.rutgers.edu), 1995
19  *  64-bit file support on 64-bit platforms by Jakub Jelinek
20  *      (jj@sunsite.ms.mff.cuni.cz)
21  *
22  *  Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
23  */
24
25 #include <linux/smp_lock.h>
26 #include <linux/time.h>
27 #include <linux/highuid.h>
28 #include <linux/pagemap.h>
29 #include <linux/quotaops.h>
30 #include <linux/module.h>
31 #include <linux/writeback.h>
32 #include <linux/buffer_head.h>
33 #include <linux/mpage.h>
34 #include <linux/fiemap.h>
35 #include <linux/namei.h>
36 #include "ext2.h"
37 #include "acl.h"
38 #include "xip.h"
39
40 MODULE_AUTHOR("Remy Card and others");
41 MODULE_DESCRIPTION("Second Extended Filesystem");
42 MODULE_LICENSE("GPL");
43
44 static int ext2_update_inode(struct inode * inode, int do_sync);
45
46 /*
47  * Test whether an inode is a fast symlink.
48  */
49 static inline int ext2_inode_is_fast_symlink(struct inode *inode)
50 {
51         int ea_blocks = EXT2_I(inode)->i_file_acl ?
52                 (inode->i_sb->s_blocksize >> 9) : 0;
53
54         return (S_ISLNK(inode->i_mode) &&
55                 inode->i_blocks - ea_blocks == 0);
56 }
57
58 /*
59  * Called at the last iput() if i_nlink is zero.
60  */
61 void ext2_delete_inode (struct inode * inode)
62 {
63         truncate_inode_pages(&inode->i_data, 0);
64
65         if (is_bad_inode(inode))
66                 goto no_delete;
67         EXT2_I(inode)->i_dtime  = get_seconds();
68         mark_inode_dirty(inode);
69         ext2_update_inode(inode, inode_needs_sync(inode));
70
71         inode->i_size = 0;
72         if (inode->i_blocks)
73                 ext2_truncate (inode);
74         ext2_free_inode (inode);
75
76         return;
77 no_delete:
78         clear_inode(inode);     /* We must guarantee clearing of inode... */
79 }
80
81 typedef struct {
82         __le32  *p;
83         __le32  key;
84         struct buffer_head *bh;
85 } Indirect;
86
87 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
88 {
89         p->key = *(p->p = v);
90         p->bh = bh;
91 }
92
93 static inline int verify_chain(Indirect *from, Indirect *to)
94 {
95         while (from <= to && from->key == *from->p)
96                 from++;
97         return (from > to);
98 }
99
100 /**
101  *      ext2_block_to_path - parse the block number into array of offsets
102  *      @inode: inode in question (we are only interested in its superblock)
103  *      @i_block: block number to be parsed
104  *      @offsets: array to store the offsets in
105  *      @boundary: set this non-zero if the referred-to block is likely to be
106  *             followed (on disk) by an indirect block.
107  *      To store the locations of file's data ext2 uses a data structure common
108  *      for UNIX filesystems - tree of pointers anchored in the inode, with
109  *      data blocks at leaves and indirect blocks in intermediate nodes.
110  *      This function translates the block number into path in that tree -
111  *      return value is the path length and @offsets[n] is the offset of
112  *      pointer to (n+1)th node in the nth one. If @block is out of range
113  *      (negative or too large) warning is printed and zero returned.
114  *
115  *      Note: function doesn't find node addresses, so no IO is needed. All
116  *      we need to know is the capacity of indirect blocks (taken from the
117  *      inode->i_sb).
118  */
119
120 /*
121  * Portability note: the last comparison (check that we fit into triple
122  * indirect block) is spelled differently, because otherwise on an
123  * architecture with 32-bit longs and 8Kb pages we might get into trouble
124  * if our filesystem had 8Kb blocks. We might use long long, but that would
125  * kill us on x86. Oh, well, at least the sign propagation does not matter -
126  * i_block would have to be negative in the very beginning, so we would not
127  * get there at all.
128  */
129
130 static int ext2_block_to_path(struct inode *inode,
131                         long i_block, int offsets[4], int *boundary)
132 {
133         int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
134         int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
135         const long direct_blocks = EXT2_NDIR_BLOCKS,
136                 indirect_blocks = ptrs,
137                 double_blocks = (1 << (ptrs_bits * 2));
138         int n = 0;
139         int final = 0;
140
141         if (i_block < 0) {
142                 ext2_warning (inode->i_sb, "ext2_block_to_path", "block < 0");
143         } else if (i_block < direct_blocks) {
144                 offsets[n++] = i_block;
145                 final = direct_blocks;
146         } else if ( (i_block -= direct_blocks) < indirect_blocks) {
147                 offsets[n++] = EXT2_IND_BLOCK;
148                 offsets[n++] = i_block;
149                 final = ptrs;
150         } else if ((i_block -= indirect_blocks) < double_blocks) {
151                 offsets[n++] = EXT2_DIND_BLOCK;
152                 offsets[n++] = i_block >> ptrs_bits;
153                 offsets[n++] = i_block & (ptrs - 1);
154                 final = ptrs;
155         } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
156                 offsets[n++] = EXT2_TIND_BLOCK;
157                 offsets[n++] = i_block >> (ptrs_bits * 2);
158                 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
159                 offsets[n++] = i_block & (ptrs - 1);
160                 final = ptrs;
161         } else {
162                 ext2_warning (inode->i_sb, "ext2_block_to_path", "block > big");
163         }
164         if (boundary)
165                 *boundary = final - 1 - (i_block & (ptrs - 1));
166
167         return n;
168 }
169
170 /**
171  *      ext2_get_branch - read the chain of indirect blocks leading to data
172  *      @inode: inode in question
173  *      @depth: depth of the chain (1 - direct pointer, etc.)
174  *      @offsets: offsets of pointers in inode/indirect blocks
175  *      @chain: place to store the result
176  *      @err: here we store the error value
177  *
178  *      Function fills the array of triples <key, p, bh> and returns %NULL
179  *      if everything went OK or the pointer to the last filled triple
180  *      (incomplete one) otherwise. Upon the return chain[i].key contains
181  *      the number of (i+1)-th block in the chain (as it is stored in memory,
182  *      i.e. little-endian 32-bit), chain[i].p contains the address of that
183  *      number (it points into struct inode for i==0 and into the bh->b_data
184  *      for i>0) and chain[i].bh points to the buffer_head of i-th indirect
185  *      block for i>0 and NULL for i==0. In other words, it holds the block
186  *      numbers of the chain, addresses they were taken from (and where we can
187  *      verify that chain did not change) and buffer_heads hosting these
188  *      numbers.
189  *
190  *      Function stops when it stumbles upon zero pointer (absent block)
191  *              (pointer to last triple returned, *@err == 0)
192  *      or when it gets an IO error reading an indirect block
193  *              (ditto, *@err == -EIO)
194  *      or when it notices that chain had been changed while it was reading
195  *              (ditto, *@err == -EAGAIN)
196  *      or when it reads all @depth-1 indirect blocks successfully and finds
197  *      the whole chain, all way to the data (returns %NULL, *err == 0).
198  */
199 static Indirect *ext2_get_branch(struct inode *inode,
200                                  int depth,
201                                  int *offsets,
202                                  Indirect chain[4],
203                                  int *err)
204 {
205         struct super_block *sb = inode->i_sb;
206         Indirect *p = chain;
207         struct buffer_head *bh;
208
209         *err = 0;
210         /* i_data is not going away, no lock needed */
211         add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
212         if (!p->key)
213                 goto no_block;
214         while (--depth) {
215                 bh = sb_bread(sb, le32_to_cpu(p->key));
216                 if (!bh)
217                         goto failure;
218                 read_lock(&EXT2_I(inode)->i_meta_lock);
219                 if (!verify_chain(chain, p))
220                         goto changed;
221                 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
222                 read_unlock(&EXT2_I(inode)->i_meta_lock);
223                 if (!p->key)
224                         goto no_block;
225         }
226         return NULL;
227
228 changed:
229         read_unlock(&EXT2_I(inode)->i_meta_lock);
230         brelse(bh);
231         *err = -EAGAIN;
232         goto no_block;
233 failure:
234         *err = -EIO;
235 no_block:
236         return p;
237 }
238
239 /**
240  *      ext2_find_near - find a place for allocation with sufficient locality
241  *      @inode: owner
242  *      @ind: descriptor of indirect block.
243  *
244  *      This function returns the preferred place for block allocation.
245  *      It is used when heuristic for sequential allocation fails.
246  *      Rules are:
247  *        + if there is a block to the left of our position - allocate near it.
248  *        + if pointer will live in indirect block - allocate near that block.
249  *        + if pointer will live in inode - allocate in the same cylinder group.
250  *
251  * In the latter case we colour the starting block by the callers PID to
252  * prevent it from clashing with concurrent allocations for a different inode
253  * in the same block group.   The PID is used here so that functionally related
254  * files will be close-by on-disk.
255  *
256  *      Caller must make sure that @ind is valid and will stay that way.
257  */
258
259 static ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind)
260 {
261         struct ext2_inode_info *ei = EXT2_I(inode);
262         __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
263         __le32 *p;
264         ext2_fsblk_t bg_start;
265         ext2_fsblk_t colour;
266
267         /* Try to find previous block */
268         for (p = ind->p - 1; p >= start; p--)
269                 if (*p)
270                         return le32_to_cpu(*p);
271
272         /* No such thing, so let's try location of indirect block */
273         if (ind->bh)
274                 return ind->bh->b_blocknr;
275
276         /*
277          * It is going to be refered from inode itself? OK, just put it into
278          * the same cylinder group then.
279          */
280         bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group);
281         colour = (current->pid % 16) *
282                         (EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
283         return bg_start + colour;
284 }
285
286 /**
287  *      ext2_find_goal - find a preferred place for allocation.
288  *      @inode: owner
289  *      @block:  block we want
290  *      @partial: pointer to the last triple within a chain
291  *
292  *      Returns preferred place for a block (the goal).
293  */
294
295 static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block,
296                                           Indirect *partial)
297 {
298         struct ext2_block_alloc_info *block_i;
299
300         block_i = EXT2_I(inode)->i_block_alloc_info;
301
302         /*
303          * try the heuristic for sequential allocation,
304          * failing that at least try to get decent locality.
305          */
306         if (block_i && (block == block_i->last_alloc_logical_block + 1)
307                 && (block_i->last_alloc_physical_block != 0)) {
308                 return block_i->last_alloc_physical_block + 1;
309         }
310
311         return ext2_find_near(inode, partial);
312 }
313
314 /**
315  *      ext2_blks_to_allocate: Look up the block map and count the number
316  *      of direct blocks need to be allocated for the given branch.
317  *
318  *      @branch: chain of indirect blocks
319  *      @k: number of blocks need for indirect blocks
320  *      @blks: number of data blocks to be mapped.
321  *      @blocks_to_boundary:  the offset in the indirect block
322  *
323  *      return the total number of blocks to be allocate, including the
324  *      direct and indirect blocks.
325  */
326 static int
327 ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
328                 int blocks_to_boundary)
329 {
330         unsigned long count = 0;
331
332         /*
333          * Simple case, [t,d]Indirect block(s) has not allocated yet
334          * then it's clear blocks on that path have not allocated
335          */
336         if (k > 0) {
337                 /* right now don't hanel cross boundary allocation */
338                 if (blks < blocks_to_boundary + 1)
339                         count += blks;
340                 else
341                         count += blocks_to_boundary + 1;
342                 return count;
343         }
344
345         count++;
346         while (count < blks && count <= blocks_to_boundary
347                 && le32_to_cpu(*(branch[0].p + count)) == 0) {
348                 count++;
349         }
350         return count;
351 }
352
353 /**
354  *      ext2_alloc_blocks: multiple allocate blocks needed for a branch
355  *      @indirect_blks: the number of blocks need to allocate for indirect
356  *                      blocks
357  *
358  *      @new_blocks: on return it will store the new block numbers for
359  *      the indirect blocks(if needed) and the first direct block,
360  *      @blks:  on return it will store the total number of allocated
361  *              direct blocks
362  */
363 static int ext2_alloc_blocks(struct inode *inode,
364                         ext2_fsblk_t goal, int indirect_blks, int blks,
365                         ext2_fsblk_t new_blocks[4], int *err)
366 {
367         int target, i;
368         unsigned long count = 0;
369         int index = 0;
370         ext2_fsblk_t current_block = 0;
371         int ret = 0;
372
373         /*
374          * Here we try to allocate the requested multiple blocks at once,
375          * on a best-effort basis.
376          * To build a branch, we should allocate blocks for
377          * the indirect blocks(if not allocated yet), and at least
378          * the first direct block of this branch.  That's the
379          * minimum number of blocks need to allocate(required)
380          */
381         target = blks + indirect_blks;
382
383         while (1) {
384                 count = target;
385                 /* allocating blocks for indirect blocks and direct blocks */
386                 current_block = ext2_new_blocks(inode,goal,&count,err);
387                 if (*err)
388                         goto failed_out;
389
390                 target -= count;
391                 /* allocate blocks for indirect blocks */
392                 while (index < indirect_blks && count) {
393                         new_blocks[index++] = current_block++;
394                         count--;
395                 }
396
397                 if (count > 0)
398                         break;
399         }
400
401         /* save the new block number for the first direct block */
402         new_blocks[index] = current_block;
403
404         /* total number of blocks allocated for direct blocks */
405         ret = count;
406         *err = 0;
407         return ret;
408 failed_out:
409         for (i = 0; i <index; i++)
410                 ext2_free_blocks(inode, new_blocks[i], 1);
411         return ret;
412 }
413
414 /**
415  *      ext2_alloc_branch - allocate and set up a chain of blocks.
416  *      @inode: owner
417  *      @num: depth of the chain (number of blocks to allocate)
418  *      @offsets: offsets (in the blocks) to store the pointers to next.
419  *      @branch: place to store the chain in.
420  *
421  *      This function allocates @num blocks, zeroes out all but the last one,
422  *      links them into chain and (if we are synchronous) writes them to disk.
423  *      In other words, it prepares a branch that can be spliced onto the
424  *      inode. It stores the information about that chain in the branch[], in
425  *      the same format as ext2_get_branch() would do. We are calling it after
426  *      we had read the existing part of chain and partial points to the last
427  *      triple of that (one with zero ->key). Upon the exit we have the same
428  *      picture as after the successful ext2_get_block(), excpet that in one
429  *      place chain is disconnected - *branch->p is still zero (we did not
430  *      set the last link), but branch->key contains the number that should
431  *      be placed into *branch->p to fill that gap.
432  *
433  *      If allocation fails we free all blocks we've allocated (and forget
434  *      their buffer_heads) and return the error value the from failed
435  *      ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
436  *      as described above and return 0.
437  */
438
439 static int ext2_alloc_branch(struct inode *inode,
440                         int indirect_blks, int *blks, ext2_fsblk_t goal,
441                         int *offsets, Indirect *branch)
442 {
443         int blocksize = inode->i_sb->s_blocksize;
444         int i, n = 0;
445         int err = 0;
446         struct buffer_head *bh;
447         int num;
448         ext2_fsblk_t new_blocks[4];
449         ext2_fsblk_t current_block;
450
451         num = ext2_alloc_blocks(inode, goal, indirect_blks,
452                                 *blks, new_blocks, &err);
453         if (err)
454                 return err;
455
456         branch[0].key = cpu_to_le32(new_blocks[0]);
457         /*
458          * metadata blocks and data blocks are allocated.
459          */
460         for (n = 1; n <= indirect_blks;  n++) {
461                 /*
462                  * Get buffer_head for parent block, zero it out
463                  * and set the pointer to new one, then send
464                  * parent to disk.
465                  */
466                 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
467                 branch[n].bh = bh;
468                 lock_buffer(bh);
469                 memset(bh->b_data, 0, blocksize);
470                 branch[n].p = (__le32 *) bh->b_data + offsets[n];
471                 branch[n].key = cpu_to_le32(new_blocks[n]);
472                 *branch[n].p = branch[n].key;
473                 if ( n == indirect_blks) {
474                         current_block = new_blocks[n];
475                         /*
476                          * End of chain, update the last new metablock of
477                          * the chain to point to the new allocated
478                          * data blocks numbers
479                          */
480                         for (i=1; i < num; i++)
481                                 *(branch[n].p + i) = cpu_to_le32(++current_block);
482                 }
483                 set_buffer_uptodate(bh);
484                 unlock_buffer(bh);
485                 mark_buffer_dirty_inode(bh, inode);
486                 /* We used to sync bh here if IS_SYNC(inode).
487                  * But we now rely upon generic_osync_inode()
488                  * and b_inode_buffers.  But not for directories.
489                  */
490                 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
491                         sync_dirty_buffer(bh);
492         }
493         *blks = num;
494         return err;
495 }
496
497 /**
498  * ext2_splice_branch - splice the allocated branch onto inode.
499  * @inode: owner
500  * @block: (logical) number of block we are adding
501  * @where: location of missing link
502  * @num:   number of indirect blocks we are adding
503  * @blks:  number of direct blocks we are adding
504  *
505  * This function fills the missing link and does all housekeeping needed in
506  * inode (->i_blocks, etc.). In case of success we end up with the full
507  * chain to new block and return 0.
508  */
509 static void ext2_splice_branch(struct inode *inode,
510                         long block, Indirect *where, int num, int blks)
511 {
512         int i;
513         struct ext2_block_alloc_info *block_i;
514         ext2_fsblk_t current_block;
515
516         block_i = EXT2_I(inode)->i_block_alloc_info;
517
518         /* XXX LOCKING probably should have i_meta_lock ?*/
519         /* That's it */
520
521         *where->p = where->key;
522
523         /*
524          * Update the host buffer_head or inode to point to more just allocated
525          * direct blocks blocks
526          */
527         if (num == 0 && blks > 1) {
528                 current_block = le32_to_cpu(where->key) + 1;
529                 for (i = 1; i < blks; i++)
530                         *(where->p + i ) = cpu_to_le32(current_block++);
531         }
532
533         /*
534          * update the most recently allocated logical & physical block
535          * in i_block_alloc_info, to assist find the proper goal block for next
536          * allocation
537          */
538         if (block_i) {
539                 block_i->last_alloc_logical_block = block + blks - 1;
540                 block_i->last_alloc_physical_block =
541                                 le32_to_cpu(where[num].key) + blks - 1;
542         }
543
544         /* We are done with atomic stuff, now do the rest of housekeeping */
545
546         /* had we spliced it onto indirect block? */
547         if (where->bh)
548                 mark_buffer_dirty_inode(where->bh, inode);
549
550         inode->i_ctime = CURRENT_TIME_SEC;
551         mark_inode_dirty(inode);
552 }
553
554 /*
555  * Allocation strategy is simple: if we have to allocate something, we will
556  * have to go the whole way to leaf. So let's do it before attaching anything
557  * to tree, set linkage between the newborn blocks, write them if sync is
558  * required, recheck the path, free and repeat if check fails, otherwise
559  * set the last missing link (that will protect us from any truncate-generated
560  * removals - all blocks on the path are immune now) and possibly force the
561  * write on the parent block.
562  * That has a nice additional property: no special recovery from the failed
563  * allocations is needed - we simply release blocks and do not touch anything
564  * reachable from inode.
565  *
566  * `handle' can be NULL if create == 0.
567  *
568  * return > 0, # of blocks mapped or allocated.
569  * return = 0, if plain lookup failed.
570  * return < 0, error case.
571  */
572 static int ext2_get_blocks(struct inode *inode,
573                            sector_t iblock, unsigned long maxblocks,
574                            struct buffer_head *bh_result,
575                            int create)
576 {
577         int err = -EIO;
578         int offsets[4];
579         Indirect chain[4];
580         Indirect *partial;
581         ext2_fsblk_t goal;
582         int indirect_blks;
583         int blocks_to_boundary = 0;
584         int depth;
585         struct ext2_inode_info *ei = EXT2_I(inode);
586         int count = 0;
587         ext2_fsblk_t first_block = 0;
588
589         depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
590
591         if (depth == 0)
592                 return (err);
593
594         partial = ext2_get_branch(inode, depth, offsets, chain, &err);
595         /* Simplest case - block found, no allocation needed */
596         if (!partial) {
597                 first_block = le32_to_cpu(chain[depth - 1].key);
598                 clear_buffer_new(bh_result); /* What's this do? */
599                 count++;
600                 /*map more blocks*/
601                 while (count < maxblocks && count <= blocks_to_boundary) {
602                         ext2_fsblk_t blk;
603
604                         if (!verify_chain(chain, chain + depth - 1)) {
605                                 /*
606                                  * Indirect block might be removed by
607                                  * truncate while we were reading it.
608                                  * Handling of that case: forget what we've
609                                  * got now, go to reread.
610                                  */
611                                 err = -EAGAIN;
612                                 count = 0;
613                                 break;
614                         }
615                         blk = le32_to_cpu(*(chain[depth-1].p + count));
616                         if (blk == first_block + count)
617                                 count++;
618                         else
619                                 break;
620                 }
621                 if (err != -EAGAIN)
622                         goto got_it;
623         }
624
625         /* Next simple case - plain lookup or failed read of indirect block */
626         if (!create || err == -EIO)
627                 goto cleanup;
628
629         mutex_lock(&ei->truncate_mutex);
630         /*
631          * If the indirect block is missing while we are reading
632          * the chain(ext3_get_branch() returns -EAGAIN err), or
633          * if the chain has been changed after we grab the semaphore,
634          * (either because another process truncated this branch, or
635          * another get_block allocated this branch) re-grab the chain to see if
636          * the request block has been allocated or not.
637          *
638          * Since we already block the truncate/other get_block
639          * at this point, we will have the current copy of the chain when we
640          * splice the branch into the tree.
641          */
642         if (err == -EAGAIN || !verify_chain(chain, partial)) {
643                 while (partial > chain) {
644                         brelse(partial->bh);
645                         partial--;
646                 }
647                 partial = ext2_get_branch(inode, depth, offsets, chain, &err);
648                 if (!partial) {
649                         count++;
650                         mutex_unlock(&ei->truncate_mutex);
651                         if (err)
652                                 goto cleanup;
653                         clear_buffer_new(bh_result);
654                         goto got_it;
655                 }
656         }
657
658         /*
659          * Okay, we need to do block allocation.  Lazily initialize the block
660          * allocation info here if necessary
661         */
662         if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
663                 ext2_init_block_alloc_info(inode);
664
665         goal = ext2_find_goal(inode, iblock, partial);
666
667         /* the number of blocks need to allocate for [d,t]indirect blocks */
668         indirect_blks = (chain + depth) - partial - 1;
669         /*
670          * Next look up the indirect map to count the totoal number of
671          * direct blocks to allocate for this branch.
672          */
673         count = ext2_blks_to_allocate(partial, indirect_blks,
674                                         maxblocks, blocks_to_boundary);
675         /*
676          * XXX ???? Block out ext2_truncate while we alter the tree
677          */
678         err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
679                                 offsets + (partial - chain), partial);
680
681         if (err) {
682                 mutex_unlock(&ei->truncate_mutex);
683                 goto cleanup;
684         }
685
686         if (ext2_use_xip(inode->i_sb)) {
687                 /*
688                  * we need to clear the block
689                  */
690                 err = ext2_clear_xip_target (inode,
691                         le32_to_cpu(chain[depth-1].key));
692                 if (err) {
693                         mutex_unlock(&ei->truncate_mutex);
694                         goto cleanup;
695                 }
696         }
697
698         ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
699         mutex_unlock(&ei->truncate_mutex);
700         set_buffer_new(bh_result);
701 got_it:
702         map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
703         if (count > blocks_to_boundary)
704                 set_buffer_boundary(bh_result);
705         err = count;
706         /* Clean up and exit */
707         partial = chain + depth - 1;    /* the whole chain */
708 cleanup:
709         while (partial > chain) {
710                 brelse(partial->bh);
711                 partial--;
712         }
713         return err;
714 }
715
716 int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
717 {
718         unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
719         int ret = ext2_get_blocks(inode, iblock, max_blocks,
720                               bh_result, create);
721         if (ret > 0) {
722                 bh_result->b_size = (ret << inode->i_blkbits);
723                 ret = 0;
724         }
725         return ret;
726
727 }
728
729 int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
730                 u64 start, u64 len)
731 {
732         return generic_block_fiemap(inode, fieinfo, start, len,
733                                     ext2_get_block);
734 }
735
736 static int ext2_writepage(struct page *page, struct writeback_control *wbc)
737 {
738         return block_write_full_page(page, ext2_get_block, wbc);
739 }
740
741 static int ext2_readpage(struct file *file, struct page *page)
742 {
743         return mpage_readpage(page, ext2_get_block);
744 }
745
746 static int
747 ext2_readpages(struct file *file, struct address_space *mapping,
748                 struct list_head *pages, unsigned nr_pages)
749 {
750         return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
751 }
752
753 int __ext2_write_begin(struct file *file, struct address_space *mapping,
754                 loff_t pos, unsigned len, unsigned flags,
755                 struct page **pagep, void **fsdata)
756 {
757         return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
758                                                         ext2_get_block);
759 }
760
761 static int
762 ext2_write_begin(struct file *file, struct address_space *mapping,
763                 loff_t pos, unsigned len, unsigned flags,
764                 struct page **pagep, void **fsdata)
765 {
766         *pagep = NULL;
767         return __ext2_write_begin(file, mapping, pos, len, flags, pagep,fsdata);
768 }
769
770 static int
771 ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
772                 loff_t pos, unsigned len, unsigned flags,
773                 struct page **pagep, void **fsdata)
774 {
775         /*
776          * Dir-in-pagecache still uses ext2_write_begin. Would have to rework
777          * directory handling code to pass around offsets rather than struct
778          * pages in order to make this work easily.
779          */
780         return nobh_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
781                                                         ext2_get_block);
782 }
783
784 static int ext2_nobh_writepage(struct page *page,
785                         struct writeback_control *wbc)
786 {
787         return nobh_writepage(page, ext2_get_block, wbc);
788 }
789
790 static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
791 {
792         return generic_block_bmap(mapping,block,ext2_get_block);
793 }
794
795 static ssize_t
796 ext2_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
797                         loff_t offset, unsigned long nr_segs)
798 {
799         struct file *file = iocb->ki_filp;
800         struct inode *inode = file->f_mapping->host;
801
802         return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
803                                 offset, nr_segs, ext2_get_block, NULL);
804 }
805
806 static int
807 ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
808 {
809         return mpage_writepages(mapping, wbc, ext2_get_block);
810 }
811
812 const struct address_space_operations ext2_aops = {
813         .readpage               = ext2_readpage,
814         .readpages              = ext2_readpages,
815         .writepage              = ext2_writepage,
816         .sync_page              = block_sync_page,
817         .write_begin            = ext2_write_begin,
818         .write_end              = generic_write_end,
819         .bmap                   = ext2_bmap,
820         .direct_IO              = ext2_direct_IO,
821         .writepages             = ext2_writepages,
822         .migratepage            = buffer_migrate_page,
823         .is_partially_uptodate  = block_is_partially_uptodate,
824 };
825
826 const struct address_space_operations ext2_aops_xip = {
827         .bmap                   = ext2_bmap,
828         .get_xip_mem            = ext2_get_xip_mem,
829 };
830
831 const struct address_space_operations ext2_nobh_aops = {
832         .readpage               = ext2_readpage,
833         .readpages              = ext2_readpages,
834         .writepage              = ext2_nobh_writepage,
835         .sync_page              = block_sync_page,
836         .write_begin            = ext2_nobh_write_begin,
837         .write_end              = nobh_write_end,
838         .bmap                   = ext2_bmap,
839         .direct_IO              = ext2_direct_IO,
840         .writepages             = ext2_writepages,
841         .migratepage            = buffer_migrate_page,
842 };
843
844 /*
845  * Probably it should be a library function... search for first non-zero word
846  * or memcmp with zero_page, whatever is better for particular architecture.
847  * Linus?
848  */
849 static inline int all_zeroes(__le32 *p, __le32 *q)
850 {
851         while (p < q)
852                 if (*p++)
853                         return 0;
854         return 1;
855 }
856
857 /**
858  *      ext2_find_shared - find the indirect blocks for partial truncation.
859  *      @inode:   inode in question
860  *      @depth:   depth of the affected branch
861  *      @offsets: offsets of pointers in that branch (see ext2_block_to_path)
862  *      @chain:   place to store the pointers to partial indirect blocks
863  *      @top:     place to the (detached) top of branch
864  *
865  *      This is a helper function used by ext2_truncate().
866  *
867  *      When we do truncate() we may have to clean the ends of several indirect
868  *      blocks but leave the blocks themselves alive. Block is partially
869  *      truncated if some data below the new i_size is refered from it (and
870  *      it is on the path to the first completely truncated data block, indeed).
871  *      We have to free the top of that path along with everything to the right
872  *      of the path. Since no allocation past the truncation point is possible
873  *      until ext2_truncate() finishes, we may safely do the latter, but top
874  *      of branch may require special attention - pageout below the truncation
875  *      point might try to populate it.
876  *
877  *      We atomically detach the top of branch from the tree, store the block
878  *      number of its root in *@top, pointers to buffer_heads of partially
879  *      truncated blocks - in @chain[].bh and pointers to their last elements
880  *      that should not be removed - in @chain[].p. Return value is the pointer
881  *      to last filled element of @chain.
882  *
883  *      The work left to caller to do the actual freeing of subtrees:
884  *              a) free the subtree starting from *@top
885  *              b) free the subtrees whose roots are stored in
886  *                      (@chain[i].p+1 .. end of @chain[i].bh->b_data)
887  *              c) free the subtrees growing from the inode past the @chain[0].p
888  *                      (no partially truncated stuff there).
889  */
890
891 static Indirect *ext2_find_shared(struct inode *inode,
892                                 int depth,
893                                 int offsets[4],
894                                 Indirect chain[4],
895                                 __le32 *top)
896 {
897         Indirect *partial, *p;
898         int k, err;
899
900         *top = 0;
901         for (k = depth; k > 1 && !offsets[k-1]; k--)
902                 ;
903         partial = ext2_get_branch(inode, k, offsets, chain, &err);
904         if (!partial)
905                 partial = chain + k-1;
906         /*
907          * If the branch acquired continuation since we've looked at it -
908          * fine, it should all survive and (new) top doesn't belong to us.
909          */
910         write_lock(&EXT2_I(inode)->i_meta_lock);
911         if (!partial->key && *partial->p) {
912                 write_unlock(&EXT2_I(inode)->i_meta_lock);
913                 goto no_top;
914         }
915         for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
916                 ;
917         /*
918          * OK, we've found the last block that must survive. The rest of our
919          * branch should be detached before unlocking. However, if that rest
920          * of branch is all ours and does not grow immediately from the inode
921          * it's easier to cheat and just decrement partial->p.
922          */
923         if (p == chain + k - 1 && p > chain) {
924                 p->p--;
925         } else {
926                 *top = *p->p;
927                 *p->p = 0;
928         }
929         write_unlock(&EXT2_I(inode)->i_meta_lock);
930
931         while(partial > p)
932         {
933                 brelse(partial->bh);
934                 partial--;
935         }
936 no_top:
937         return partial;
938 }
939
940 /**
941  *      ext2_free_data - free a list of data blocks
942  *      @inode: inode we are dealing with
943  *      @p:     array of block numbers
944  *      @q:     points immediately past the end of array
945  *
946  *      We are freeing all blocks refered from that array (numbers are
947  *      stored as little-endian 32-bit) and updating @inode->i_blocks
948  *      appropriately.
949  */
950 static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
951 {
952         unsigned long block_to_free = 0, count = 0;
953         unsigned long nr;
954
955         for ( ; p < q ; p++) {
956                 nr = le32_to_cpu(*p);
957                 if (nr) {
958                         *p = 0;
959                         /* accumulate blocks to free if they're contiguous */
960                         if (count == 0)
961                                 goto free_this;
962                         else if (block_to_free == nr - count)
963                                 count++;
964                         else {
965                                 mark_inode_dirty(inode);
966                                 ext2_free_blocks (inode, block_to_free, count);
967                         free_this:
968                                 block_to_free = nr;
969                                 count = 1;
970                         }
971                 }
972         }
973         if (count > 0) {
974                 mark_inode_dirty(inode);
975                 ext2_free_blocks (inode, block_to_free, count);
976         }
977 }
978
979 /**
980  *      ext2_free_branches - free an array of branches
981  *      @inode: inode we are dealing with
982  *      @p:     array of block numbers
983  *      @q:     pointer immediately past the end of array
984  *      @depth: depth of the branches to free
985  *
986  *      We are freeing all blocks refered from these branches (numbers are
987  *      stored as little-endian 32-bit) and updating @inode->i_blocks
988  *      appropriately.
989  */
990 static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
991 {
992         struct buffer_head * bh;
993         unsigned long nr;
994
995         if (depth--) {
996                 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
997                 for ( ; p < q ; p++) {
998                         nr = le32_to_cpu(*p);
999                         if (!nr)
1000                                 continue;
1001                         *p = 0;
1002                         bh = sb_bread(inode->i_sb, nr);
1003                         /*
1004                          * A read failure? Report error and clear slot
1005                          * (should be rare).
1006                          */ 
1007                         if (!bh) {
1008                                 ext2_error(inode->i_sb, "ext2_free_branches",
1009                                         "Read failure, inode=%ld, block=%ld",
1010                                         inode->i_ino, nr);
1011                                 continue;
1012                         }
1013                         ext2_free_branches(inode,
1014                                            (__le32*)bh->b_data,
1015                                            (__le32*)bh->b_data + addr_per_block,
1016                                            depth);
1017                         bforget(bh);
1018                         ext2_free_blocks(inode, nr, 1);
1019                         mark_inode_dirty(inode);
1020                 }
1021         } else
1022                 ext2_free_data(inode, p, q);
1023 }
1024
1025 void ext2_truncate(struct inode *inode)
1026 {
1027         __le32 *i_data = EXT2_I(inode)->i_data;
1028         struct ext2_inode_info *ei = EXT2_I(inode);
1029         int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1030         int offsets[4];
1031         Indirect chain[4];
1032         Indirect *partial;
1033         __le32 nr = 0;
1034         int n;
1035         long iblock;
1036         unsigned blocksize;
1037
1038         if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1039             S_ISLNK(inode->i_mode)))
1040                 return;
1041         if (ext2_inode_is_fast_symlink(inode))
1042                 return;
1043         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1044                 return;
1045
1046         blocksize = inode->i_sb->s_blocksize;
1047         iblock = (inode->i_size + blocksize-1)
1048                                         >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1049
1050         if (mapping_is_xip(inode->i_mapping))
1051                 xip_truncate_page(inode->i_mapping, inode->i_size);
1052         else if (test_opt(inode->i_sb, NOBH))
1053                 nobh_truncate_page(inode->i_mapping,
1054                                 inode->i_size, ext2_get_block);
1055         else
1056                 block_truncate_page(inode->i_mapping,
1057                                 inode->i_size, ext2_get_block);
1058
1059         n = ext2_block_to_path(inode, iblock, offsets, NULL);
1060         if (n == 0)
1061                 return;
1062
1063         /*
1064          * From here we block out all ext2_get_block() callers who want to
1065          * modify the block allocation tree.
1066          */
1067         mutex_lock(&ei->truncate_mutex);
1068
1069         if (n == 1) {
1070                 ext2_free_data(inode, i_data+offsets[0],
1071                                         i_data + EXT2_NDIR_BLOCKS);
1072                 goto do_indirects;
1073         }
1074
1075         partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1076         /* Kill the top of shared branch (already detached) */
1077         if (nr) {
1078                 if (partial == chain)
1079                         mark_inode_dirty(inode);
1080                 else
1081                         mark_buffer_dirty_inode(partial->bh, inode);
1082                 ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1083         }
1084         /* Clear the ends of indirect blocks on the shared branch */
1085         while (partial > chain) {
1086                 ext2_free_branches(inode,
1087                                    partial->p + 1,
1088                                    (__le32*)partial->bh->b_data+addr_per_block,
1089                                    (chain+n-1) - partial);
1090                 mark_buffer_dirty_inode(partial->bh, inode);
1091                 brelse (partial->bh);
1092                 partial--;
1093         }
1094 do_indirects:
1095         /* Kill the remaining (whole) subtrees */
1096         switch (offsets[0]) {
1097                 default:
1098                         nr = i_data[EXT2_IND_BLOCK];
1099                         if (nr) {
1100                                 i_data[EXT2_IND_BLOCK] = 0;
1101                                 mark_inode_dirty(inode);
1102                                 ext2_free_branches(inode, &nr, &nr+1, 1);
1103                         }
1104                 case EXT2_IND_BLOCK:
1105                         nr = i_data[EXT2_DIND_BLOCK];
1106                         if (nr) {
1107                                 i_data[EXT2_DIND_BLOCK] = 0;
1108                                 mark_inode_dirty(inode);
1109                                 ext2_free_branches(inode, &nr, &nr+1, 2);
1110                         }
1111                 case EXT2_DIND_BLOCK:
1112                         nr = i_data[EXT2_TIND_BLOCK];
1113                         if (nr) {
1114                                 i_data[EXT2_TIND_BLOCK] = 0;
1115                                 mark_inode_dirty(inode);
1116                                 ext2_free_branches(inode, &nr, &nr+1, 3);
1117                         }
1118                 case EXT2_TIND_BLOCK:
1119                         ;
1120         }
1121
1122         ext2_discard_reservation(inode);
1123
1124         mutex_unlock(&ei->truncate_mutex);
1125         inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
1126         if (inode_needs_sync(inode)) {
1127                 sync_mapping_buffers(inode->i_mapping);
1128                 ext2_sync_inode (inode);
1129         } else {
1130                 mark_inode_dirty(inode);
1131         }
1132 }
1133
1134 static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1135                                         struct buffer_head **p)
1136 {
1137         struct buffer_head * bh;
1138         unsigned long block_group;
1139         unsigned long block;
1140         unsigned long offset;
1141         struct ext2_group_desc * gdp;
1142
1143         *p = NULL;
1144         if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1145             ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1146                 goto Einval;
1147
1148         block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
1149         gdp = ext2_get_group_desc(sb, block_group, NULL);
1150         if (!gdp)
1151                 goto Egdp;
1152         /*
1153          * Figure out the offset within the block group inode table
1154          */
1155         offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1156         block = le32_to_cpu(gdp->bg_inode_table) +
1157                 (offset >> EXT2_BLOCK_SIZE_BITS(sb));
1158         if (!(bh = sb_bread(sb, block)))
1159                 goto Eio;
1160
1161         *p = bh;
1162         offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1163         return (struct ext2_inode *) (bh->b_data + offset);
1164
1165 Einval:
1166         ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1167                    (unsigned long) ino);
1168         return ERR_PTR(-EINVAL);
1169 Eio:
1170         ext2_error(sb, "ext2_get_inode",
1171                    "unable to read inode block - inode=%lu, block=%lu",
1172                    (unsigned long) ino, block);
1173 Egdp:
1174         return ERR_PTR(-EIO);
1175 }
1176
1177 void ext2_set_inode_flags(struct inode *inode)
1178 {
1179         unsigned int flags = EXT2_I(inode)->i_flags;
1180
1181         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
1182         if (flags & EXT2_SYNC_FL)
1183                 inode->i_flags |= S_SYNC;
1184         if (flags & EXT2_APPEND_FL)
1185                 inode->i_flags |= S_APPEND;
1186         if (flags & EXT2_IMMUTABLE_FL)
1187                 inode->i_flags |= S_IMMUTABLE;
1188         if (flags & EXT2_NOATIME_FL)
1189                 inode->i_flags |= S_NOATIME;
1190         if (flags & EXT2_DIRSYNC_FL)
1191                 inode->i_flags |= S_DIRSYNC;
1192 }
1193
1194 /* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
1195 void ext2_get_inode_flags(struct ext2_inode_info *ei)
1196 {
1197         unsigned int flags = ei->vfs_inode.i_flags;
1198
1199         ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|
1200                         EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL);
1201         if (flags & S_SYNC)
1202                 ei->i_flags |= EXT2_SYNC_FL;
1203         if (flags & S_APPEND)
1204                 ei->i_flags |= EXT2_APPEND_FL;
1205         if (flags & S_IMMUTABLE)
1206                 ei->i_flags |= EXT2_IMMUTABLE_FL;
1207         if (flags & S_NOATIME)
1208                 ei->i_flags |= EXT2_NOATIME_FL;
1209         if (flags & S_DIRSYNC)
1210                 ei->i_flags |= EXT2_DIRSYNC_FL;
1211 }
1212
1213 struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
1214 {
1215         struct ext2_inode_info *ei;
1216         struct buffer_head * bh;
1217         struct ext2_inode *raw_inode;
1218         struct inode *inode;
1219         long ret = -EIO;
1220         int n;
1221
1222         inode = iget_locked(sb, ino);
1223         if (!inode)
1224                 return ERR_PTR(-ENOMEM);
1225         if (!(inode->i_state & I_NEW))
1226                 return inode;
1227
1228         ei = EXT2_I(inode);
1229 #ifdef CONFIG_EXT2_FS_POSIX_ACL
1230         ei->i_acl = EXT2_ACL_NOT_CACHED;
1231         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
1232 #endif
1233         ei->i_block_alloc_info = NULL;
1234
1235         raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1236         if (IS_ERR(raw_inode)) {
1237                 ret = PTR_ERR(raw_inode);
1238                 goto bad_inode;
1239         }
1240
1241         inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1242         inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1243         inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1244         if (!(test_opt (inode->i_sb, NO_UID32))) {
1245                 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1246                 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1247         }
1248         inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
1249         inode->i_size = le32_to_cpu(raw_inode->i_size);
1250         inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
1251         inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
1252         inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
1253         inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1254         ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1255         /* We now have enough fields to check if the inode was active or not.
1256          * This is needed because nfsd might try to access dead inodes
1257          * the test is that same one that e2fsck uses
1258          * NeilBrown 1999oct15
1259          */
1260         if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1261                 /* this inode is deleted */
1262                 brelse (bh);
1263                 ret = -ESTALE;
1264                 goto bad_inode;
1265         }
1266         inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1267         ei->i_flags = le32_to_cpu(raw_inode->i_flags);
1268         ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1269         ei->i_frag_no = raw_inode->i_frag;
1270         ei->i_frag_size = raw_inode->i_fsize;
1271         ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1272         ei->i_dir_acl = 0;
1273         if (S_ISREG(inode->i_mode))
1274                 inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1275         else
1276                 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1277         ei->i_dtime = 0;
1278         inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1279         ei->i_state = 0;
1280         ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1281         ei->i_dir_start_lookup = 0;
1282
1283         /*
1284          * NOTE! The in-memory inode i_data array is in little-endian order
1285          * even on big-endian machines: we do NOT byteswap the block numbers!
1286          */
1287         for (n = 0; n < EXT2_N_BLOCKS; n++)
1288                 ei->i_data[n] = raw_inode->i_block[n];
1289
1290         if (S_ISREG(inode->i_mode)) {
1291                 inode->i_op = &ext2_file_inode_operations;
1292                 if (ext2_use_xip(inode->i_sb)) {
1293                         inode->i_mapping->a_ops = &ext2_aops_xip;
1294                         inode->i_fop = &ext2_xip_file_operations;
1295                 } else if (test_opt(inode->i_sb, NOBH)) {
1296                         inode->i_mapping->a_ops = &ext2_nobh_aops;
1297                         inode->i_fop = &ext2_file_operations;
1298                 } else {
1299                         inode->i_mapping->a_ops = &ext2_aops;
1300                         inode->i_fop = &ext2_file_operations;
1301                 }
1302         } else if (S_ISDIR(inode->i_mode)) {
1303                 inode->i_op = &ext2_dir_inode_operations;
1304                 inode->i_fop = &ext2_dir_operations;
1305                 if (test_opt(inode->i_sb, NOBH))
1306                         inode->i_mapping->a_ops = &ext2_nobh_aops;
1307                 else
1308                         inode->i_mapping->a_ops = &ext2_aops;
1309         } else if (S_ISLNK(inode->i_mode)) {
1310                 if (ext2_inode_is_fast_symlink(inode)) {
1311                         inode->i_op = &ext2_fast_symlink_inode_operations;
1312                         nd_terminate_link(ei->i_data, inode->i_size,
1313                                 sizeof(ei->i_data) - 1);
1314                 } else {
1315                         inode->i_op = &ext2_symlink_inode_operations;
1316                         if (test_opt(inode->i_sb, NOBH))
1317                                 inode->i_mapping->a_ops = &ext2_nobh_aops;
1318                         else
1319                                 inode->i_mapping->a_ops = &ext2_aops;
1320                 }
1321         } else {
1322                 inode->i_op = &ext2_special_inode_operations;
1323                 if (raw_inode->i_block[0])
1324                         init_special_inode(inode, inode->i_mode,
1325                            old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1326                 else 
1327                         init_special_inode(inode, inode->i_mode,
1328                            new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1329         }
1330         brelse (bh);
1331         ext2_set_inode_flags(inode);
1332         unlock_new_inode(inode);
1333         return inode;
1334         
1335 bad_inode:
1336         iget_failed(inode);
1337         return ERR_PTR(ret);
1338 }
1339
1340 static int ext2_update_inode(struct inode * inode, int do_sync)
1341 {
1342         struct ext2_inode_info *ei = EXT2_I(inode);
1343         struct super_block *sb = inode->i_sb;
1344         ino_t ino = inode->i_ino;
1345         uid_t uid = inode->i_uid;
1346         gid_t gid = inode->i_gid;
1347         struct buffer_head * bh;
1348         struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1349         int n;
1350         int err = 0;
1351
1352         if (IS_ERR(raw_inode))
1353                 return -EIO;
1354
1355         /* For fields not not tracking in the in-memory inode,
1356          * initialise them to zero for new inodes. */
1357         if (ei->i_state & EXT2_STATE_NEW)
1358                 memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1359
1360         ext2_get_inode_flags(ei);
1361         raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1362         if (!(test_opt(sb, NO_UID32))) {
1363                 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1364                 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1365 /*
1366  * Fix up interoperability with old kernels. Otherwise, old inodes get
1367  * re-used with the upper 16 bits of the uid/gid intact
1368  */
1369                 if (!ei->i_dtime) {
1370                         raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1371                         raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1372                 } else {
1373                         raw_inode->i_uid_high = 0;
1374                         raw_inode->i_gid_high = 0;
1375                 }
1376         } else {
1377                 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1378                 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1379                 raw_inode->i_uid_high = 0;
1380                 raw_inode->i_gid_high = 0;
1381         }
1382         raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1383         raw_inode->i_size = cpu_to_le32(inode->i_size);
1384         raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
1385         raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
1386         raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
1387
1388         raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1389         raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1390         raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1391         raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1392         raw_inode->i_frag = ei->i_frag_no;
1393         raw_inode->i_fsize = ei->i_frag_size;
1394         raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1395         if (!S_ISREG(inode->i_mode))
1396                 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1397         else {
1398                 raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1399                 if (inode->i_size > 0x7fffffffULL) {
1400                         if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1401                                         EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1402                             EXT2_SB(sb)->s_es->s_rev_level ==
1403                                         cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1404                                /* If this is the first large file
1405                                 * created, add a flag to the superblock.
1406                                 */
1407                                 lock_kernel();
1408                                 ext2_update_dynamic_rev(sb);
1409                                 EXT2_SET_RO_COMPAT_FEATURE(sb,
1410                                         EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1411                                 unlock_kernel();
1412                                 ext2_write_super(sb);
1413                         }
1414                 }
1415         }
1416         
1417         raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1418         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1419                 if (old_valid_dev(inode->i_rdev)) {
1420                         raw_inode->i_block[0] =
1421                                 cpu_to_le32(old_encode_dev(inode->i_rdev));
1422                         raw_inode->i_block[1] = 0;
1423                 } else {
1424                         raw_inode->i_block[0] = 0;
1425                         raw_inode->i_block[1] =
1426                                 cpu_to_le32(new_encode_dev(inode->i_rdev));
1427                         raw_inode->i_block[2] = 0;
1428                 }
1429         } else for (n = 0; n < EXT2_N_BLOCKS; n++)
1430                 raw_inode->i_block[n] = ei->i_data[n];
1431         mark_buffer_dirty(bh);
1432         if (do_sync) {
1433                 sync_dirty_buffer(bh);
1434                 if (buffer_req(bh) && !buffer_uptodate(bh)) {
1435                         printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1436                                 sb->s_id, (unsigned long) ino);
1437                         err = -EIO;
1438                 }
1439         }
1440         ei->i_state &= ~EXT2_STATE_NEW;
1441         brelse (bh);
1442         return err;
1443 }
1444
1445 int ext2_write_inode(struct inode *inode, int wait)
1446 {
1447         return ext2_update_inode(inode, wait);
1448 }
1449
1450 int ext2_sync_inode(struct inode *inode)
1451 {
1452         struct writeback_control wbc = {
1453                 .sync_mode = WB_SYNC_ALL,
1454                 .nr_to_write = 0,       /* sys_fsync did this */
1455         };
1456         return sync_inode(inode, &wbc);
1457 }
1458
1459 int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
1460 {
1461         struct inode *inode = dentry->d_inode;
1462         int error;
1463
1464         error = inode_change_ok(inode, iattr);
1465         if (error)
1466                 return error;
1467         if ((iattr->ia_valid & ATTR_UID && iattr->ia_uid != inode->i_uid) ||
1468             (iattr->ia_valid & ATTR_GID && iattr->ia_gid != inode->i_gid)) {
1469                 error = vfs_dq_transfer(inode, iattr) ? -EDQUOT : 0;
1470                 if (error)
1471                         return error;
1472         }
1473         error = inode_setattr(inode, iattr);
1474         if (!error && (iattr->ia_valid & ATTR_MODE))
1475                 error = ext2_acl_chmod(inode);
1476         return error;
1477 }