BKL-removal: remove incorrect BKL comment in ext2
[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 "ext2.h"
35 #include "acl.h"
36 #include "xip.h"
37
38 MODULE_AUTHOR("Remy Card and others");
39 MODULE_DESCRIPTION("Second Extended Filesystem");
40 MODULE_LICENSE("GPL");
41
42 static int ext2_update_inode(struct inode * inode, int do_sync);
43
44 /*
45  * Test whether an inode is a fast symlink.
46  */
47 static inline int ext2_inode_is_fast_symlink(struct inode *inode)
48 {
49         int ea_blocks = EXT2_I(inode)->i_file_acl ?
50                 (inode->i_sb->s_blocksize >> 9) : 0;
51
52         return (S_ISLNK(inode->i_mode) &&
53                 inode->i_blocks - ea_blocks == 0);
54 }
55
56 /*
57  * Called at the last iput() if i_nlink is zero.
58  */
59 void ext2_delete_inode (struct inode * inode)
60 {
61         truncate_inode_pages(&inode->i_data, 0);
62
63         if (is_bad_inode(inode))
64                 goto no_delete;
65         EXT2_I(inode)->i_dtime  = get_seconds();
66         mark_inode_dirty(inode);
67         ext2_update_inode(inode, inode_needs_sync(inode));
68
69         inode->i_size = 0;
70         if (inode->i_blocks)
71                 ext2_truncate (inode);
72         ext2_free_inode (inode);
73
74         return;
75 no_delete:
76         clear_inode(inode);     /* We must guarantee clearing of inode... */
77 }
78
79 typedef struct {
80         __le32  *p;
81         __le32  key;
82         struct buffer_head *bh;
83 } Indirect;
84
85 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
86 {
87         p->key = *(p->p = v);
88         p->bh = bh;
89 }
90
91 static inline int verify_chain(Indirect *from, Indirect *to)
92 {
93         while (from <= to && from->key == *from->p)
94                 from++;
95         return (from > to);
96 }
97
98 /**
99  *      ext2_block_to_path - parse the block number into array of offsets
100  *      @inode: inode in question (we are only interested in its superblock)
101  *      @i_block: block number to be parsed
102  *      @offsets: array to store the offsets in
103  *      @boundary: set this non-zero if the referred-to block is likely to be
104  *             followed (on disk) by an indirect block.
105  *      To store the locations of file's data ext2 uses a data structure common
106  *      for UNIX filesystems - tree of pointers anchored in the inode, with
107  *      data blocks at leaves and indirect blocks in intermediate nodes.
108  *      This function translates the block number into path in that tree -
109  *      return value is the path length and @offsets[n] is the offset of
110  *      pointer to (n+1)th node in the nth one. If @block is out of range
111  *      (negative or too large) warning is printed and zero returned.
112  *
113  *      Note: function doesn't find node addresses, so no IO is needed. All
114  *      we need to know is the capacity of indirect blocks (taken from the
115  *      inode->i_sb).
116  */
117
118 /*
119  * Portability note: the last comparison (check that we fit into triple
120  * indirect block) is spelled differently, because otherwise on an
121  * architecture with 32-bit longs and 8Kb pages we might get into trouble
122  * if our filesystem had 8Kb blocks. We might use long long, but that would
123  * kill us on x86. Oh, well, at least the sign propagation does not matter -
124  * i_block would have to be negative in the very beginning, so we would not
125  * get there at all.
126  */
127
128 static int ext2_block_to_path(struct inode *inode,
129                         long i_block, int offsets[4], int *boundary)
130 {
131         int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
132         int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
133         const long direct_blocks = EXT2_NDIR_BLOCKS,
134                 indirect_blocks = ptrs,
135                 double_blocks = (1 << (ptrs_bits * 2));
136         int n = 0;
137         int final = 0;
138
139         if (i_block < 0) {
140                 ext2_warning (inode->i_sb, "ext2_block_to_path", "block < 0");
141         } else if (i_block < direct_blocks) {
142                 offsets[n++] = i_block;
143                 final = direct_blocks;
144         } else if ( (i_block -= direct_blocks) < indirect_blocks) {
145                 offsets[n++] = EXT2_IND_BLOCK;
146                 offsets[n++] = i_block;
147                 final = ptrs;
148         } else if ((i_block -= indirect_blocks) < double_blocks) {
149                 offsets[n++] = EXT2_DIND_BLOCK;
150                 offsets[n++] = i_block >> ptrs_bits;
151                 offsets[n++] = i_block & (ptrs - 1);
152                 final = ptrs;
153         } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
154                 offsets[n++] = EXT2_TIND_BLOCK;
155                 offsets[n++] = i_block >> (ptrs_bits * 2);
156                 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
157                 offsets[n++] = i_block & (ptrs - 1);
158                 final = ptrs;
159         } else {
160                 ext2_warning (inode->i_sb, "ext2_block_to_path", "block > big");
161         }
162         if (boundary)
163                 *boundary = final - 1 - (i_block & (ptrs - 1));
164
165         return n;
166 }
167
168 /**
169  *      ext2_get_branch - read the chain of indirect blocks leading to data
170  *      @inode: inode in question
171  *      @depth: depth of the chain (1 - direct pointer, etc.)
172  *      @offsets: offsets of pointers in inode/indirect blocks
173  *      @chain: place to store the result
174  *      @err: here we store the error value
175  *
176  *      Function fills the array of triples <key, p, bh> and returns %NULL
177  *      if everything went OK or the pointer to the last filled triple
178  *      (incomplete one) otherwise. Upon the return chain[i].key contains
179  *      the number of (i+1)-th block in the chain (as it is stored in memory,
180  *      i.e. little-endian 32-bit), chain[i].p contains the address of that
181  *      number (it points into struct inode for i==0 and into the bh->b_data
182  *      for i>0) and chain[i].bh points to the buffer_head of i-th indirect
183  *      block for i>0 and NULL for i==0. In other words, it holds the block
184  *      numbers of the chain, addresses they were taken from (and where we can
185  *      verify that chain did not change) and buffer_heads hosting these
186  *      numbers.
187  *
188  *      Function stops when it stumbles upon zero pointer (absent block)
189  *              (pointer to last triple returned, *@err == 0)
190  *      or when it gets an IO error reading an indirect block
191  *              (ditto, *@err == -EIO)
192  *      or when it notices that chain had been changed while it was reading
193  *              (ditto, *@err == -EAGAIN)
194  *      or when it reads all @depth-1 indirect blocks successfully and finds
195  *      the whole chain, all way to the data (returns %NULL, *err == 0).
196  */
197 static Indirect *ext2_get_branch(struct inode *inode,
198                                  int depth,
199                                  int *offsets,
200                                  Indirect chain[4],
201                                  int *err)
202 {
203         struct super_block *sb = inode->i_sb;
204         Indirect *p = chain;
205         struct buffer_head *bh;
206
207         *err = 0;
208         /* i_data is not going away, no lock needed */
209         add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
210         if (!p->key)
211                 goto no_block;
212         while (--depth) {
213                 bh = sb_bread(sb, le32_to_cpu(p->key));
214                 if (!bh)
215                         goto failure;
216                 read_lock(&EXT2_I(inode)->i_meta_lock);
217                 if (!verify_chain(chain, p))
218                         goto changed;
219                 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
220                 read_unlock(&EXT2_I(inode)->i_meta_lock);
221                 if (!p->key)
222                         goto no_block;
223         }
224         return NULL;
225
226 changed:
227         read_unlock(&EXT2_I(inode)->i_meta_lock);
228         brelse(bh);
229         *err = -EAGAIN;
230         goto no_block;
231 failure:
232         *err = -EIO;
233 no_block:
234         return p;
235 }
236
237 /**
238  *      ext2_find_near - find a place for allocation with sufficient locality
239  *      @inode: owner
240  *      @ind: descriptor of indirect block.
241  *
242  *      This function returns the prefered place for block allocation.
243  *      It is used when heuristic for sequential allocation fails.
244  *      Rules are:
245  *        + if there is a block to the left of our position - allocate near it.
246  *        + if pointer will live in indirect block - allocate near that block.
247  *        + if pointer will live in inode - allocate in the same cylinder group.
248  *
249  * In the latter case we colour the starting block by the callers PID to
250  * prevent it from clashing with concurrent allocations for a different inode
251  * in the same block group.   The PID is used here so that functionally related
252  * files will be close-by on-disk.
253  *
254  *      Caller must make sure that @ind is valid and will stay that way.
255  */
256
257 static unsigned long ext2_find_near(struct inode *inode, Indirect *ind)
258 {
259         struct ext2_inode_info *ei = EXT2_I(inode);
260         __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
261         __le32 *p;
262         unsigned long bg_start;
263         unsigned long colour;
264
265         /* Try to find previous block */
266         for (p = ind->p - 1; p >= start; p--)
267                 if (*p)
268                         return le32_to_cpu(*p);
269
270         /* No such thing, so let's try location of indirect block */
271         if (ind->bh)
272                 return ind->bh->b_blocknr;
273
274         /*
275          * It is going to be refered from inode itself? OK, just put it into
276          * the same cylinder group then.
277          */
278         bg_start = (ei->i_block_group * EXT2_BLOCKS_PER_GROUP(inode->i_sb)) +
279                 le32_to_cpu(EXT2_SB(inode->i_sb)->s_es->s_first_data_block);
280         colour = (current->pid % 16) *
281                         (EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
282         return bg_start + colour;
283 }
284
285 /**
286  *      ext2_find_goal - find a prefered place for allocation.
287  *      @inode: owner
288  *      @block:  block we want
289  *      @chain:  chain of indirect blocks
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 int ext2_find_goal(struct inode *inode,
296                                  long block,
297                                  Indirect chain[4],
298                                  Indirect *partial)
299 {
300         struct ext2_block_alloc_info *block_i;
301
302         block_i = EXT2_I(inode)->i_block_alloc_info;
303
304         /*
305          * try the heuristic for sequential allocation,
306          * failing that at least try to get decent locality.
307          */
308         if (block_i && (block == block_i->last_alloc_logical_block + 1)
309                 && (block_i->last_alloc_physical_block != 0)) {
310                 return block_i->last_alloc_physical_block + 1;
311         }
312
313         return ext2_find_near(inode, partial);
314 }
315
316 /**
317  *      ext2_blks_to_allocate: Look up the block map and count the number
318  *      of direct blocks need to be allocated for the given branch.
319  *
320  *      @branch: chain of indirect blocks
321  *      @k: number of blocks need for indirect blocks
322  *      @blks: number of data blocks to be mapped.
323  *      @blocks_to_boundary:  the offset in the indirect block
324  *
325  *      return the total number of blocks to be allocate, including the
326  *      direct and indirect blocks.
327  */
328 static int
329 ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
330                 int blocks_to_boundary)
331 {
332         unsigned long count = 0;
333
334         /*
335          * Simple case, [t,d]Indirect block(s) has not allocated yet
336          * then it's clear blocks on that path have not allocated
337          */
338         if (k > 0) {
339                 /* right now don't hanel cross boundary allocation */
340                 if (blks < blocks_to_boundary + 1)
341                         count += blks;
342                 else
343                         count += blocks_to_boundary + 1;
344                 return count;
345         }
346
347         count++;
348         while (count < blks && count <= blocks_to_boundary
349                 && le32_to_cpu(*(branch[0].p + count)) == 0) {
350                 count++;
351         }
352         return count;
353 }
354
355 /**
356  *      ext2_alloc_blocks: multiple allocate blocks needed for a branch
357  *      @indirect_blks: the number of blocks need to allocate for indirect
358  *                      blocks
359  *
360  *      @new_blocks: on return it will store the new block numbers for
361  *      the indirect blocks(if needed) and the first direct block,
362  *      @blks:  on return it will store the total number of allocated
363  *              direct blocks
364  */
365 static int ext2_alloc_blocks(struct inode *inode,
366                         ext2_fsblk_t goal, int indirect_blks, int blks,
367                         ext2_fsblk_t new_blocks[4], int *err)
368 {
369         int target, i;
370         unsigned long count = 0;
371         int index = 0;
372         ext2_fsblk_t current_block = 0;
373         int ret = 0;
374
375         /*
376          * Here we try to allocate the requested multiple blocks at once,
377          * on a best-effort basis.
378          * To build a branch, we should allocate blocks for
379          * the indirect blocks(if not allocated yet), and at least
380          * the first direct block of this branch.  That's the
381          * minimum number of blocks need to allocate(required)
382          */
383         target = blks + indirect_blks;
384
385         while (1) {
386                 count = target;
387                 /* allocating blocks for indirect blocks and direct blocks */
388                 current_block = ext2_new_blocks(inode,goal,&count,err);
389                 if (*err)
390                         goto failed_out;
391
392                 target -= count;
393                 /* allocate blocks for indirect blocks */
394                 while (index < indirect_blks && count) {
395                         new_blocks[index++] = current_block++;
396                         count--;
397                 }
398
399                 if (count > 0)
400                         break;
401         }
402
403         /* save the new block number for the first direct block */
404         new_blocks[index] = current_block;
405
406         /* total number of blocks allocated for direct blocks */
407         ret = count;
408         *err = 0;
409         return ret;
410 failed_out:
411         for (i = 0; i <index; i++)
412                 ext2_free_blocks(inode, new_blocks[i], 1);
413         return ret;
414 }
415
416 /**
417  *      ext2_alloc_branch - allocate and set up a chain of blocks.
418  *      @inode: owner
419  *      @num: depth of the chain (number of blocks to allocate)
420  *      @offsets: offsets (in the blocks) to store the pointers to next.
421  *      @branch: place to store the chain in.
422  *
423  *      This function allocates @num blocks, zeroes out all but the last one,
424  *      links them into chain and (if we are synchronous) writes them to disk.
425  *      In other words, it prepares a branch that can be spliced onto the
426  *      inode. It stores the information about that chain in the branch[], in
427  *      the same format as ext2_get_branch() would do. We are calling it after
428  *      we had read the existing part of chain and partial points to the last
429  *      triple of that (one with zero ->key). Upon the exit we have the same
430  *      picture as after the successful ext2_get_block(), excpet that in one
431  *      place chain is disconnected - *branch->p is still zero (we did not
432  *      set the last link), but branch->key contains the number that should
433  *      be placed into *branch->p to fill that gap.
434  *
435  *      If allocation fails we free all blocks we've allocated (and forget
436  *      their buffer_heads) and return the error value the from failed
437  *      ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
438  *      as described above and return 0.
439  */
440
441 static int ext2_alloc_branch(struct inode *inode,
442                         int indirect_blks, int *blks, ext2_fsblk_t goal,
443                         int *offsets, Indirect *branch)
444 {
445         int blocksize = inode->i_sb->s_blocksize;
446         int i, n = 0;
447         int err = 0;
448         struct buffer_head *bh;
449         int num;
450         ext2_fsblk_t new_blocks[4];
451         ext2_fsblk_t current_block;
452
453         num = ext2_alloc_blocks(inode, goal, indirect_blks,
454                                 *blks, new_blocks, &err);
455         if (err)
456                 return err;
457
458         branch[0].key = cpu_to_le32(new_blocks[0]);
459         /*
460          * metadata blocks and data blocks are allocated.
461          */
462         for (n = 1; n <= indirect_blks;  n++) {
463                 /*
464                  * Get buffer_head for parent block, zero it out
465                  * and set the pointer to new one, then send
466                  * parent to disk.
467                  */
468                 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
469                 branch[n].bh = bh;
470                 lock_buffer(bh);
471                 memset(bh->b_data, 0, blocksize);
472                 branch[n].p = (__le32 *) bh->b_data + offsets[n];
473                 branch[n].key = cpu_to_le32(new_blocks[n]);
474                 *branch[n].p = branch[n].key;
475                 if ( n == indirect_blks) {
476                         current_block = new_blocks[n];
477                         /*
478                          * End of chain, update the last new metablock of
479                          * the chain to point to the new allocated
480                          * data blocks numbers
481                          */
482                         for (i=1; i < num; i++)
483                                 *(branch[n].p + i) = cpu_to_le32(++current_block);
484                 }
485                 set_buffer_uptodate(bh);
486                 unlock_buffer(bh);
487                 mark_buffer_dirty_inode(bh, inode);
488                 /* We used to sync bh here if IS_SYNC(inode).
489                  * But we now rely upon generic_osync_inode()
490                  * and b_inode_buffers.  But not for directories.
491                  */
492                 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
493                         sync_dirty_buffer(bh);
494         }
495         *blks = num;
496         return err;
497 }
498
499 /**
500  * ext2_splice_branch - splice the allocated branch onto inode.
501  * @inode: owner
502  * @block: (logical) number of block we are adding
503  * @chain: chain of indirect blocks (with a missing link - see
504  *      ext2_alloc_branch)
505  * @where: location of missing link
506  * @num:   number of indirect blocks we are adding
507  * @blks:  number of direct blocks we are adding
508  *
509  * This function fills the missing link and does all housekeeping needed in
510  * inode (->i_blocks, etc.). In case of success we end up with the full
511  * chain to new block and return 0.
512  */
513 static void ext2_splice_branch(struct inode *inode,
514                         long block, Indirect *where, int num, int blks)
515 {
516         int i;
517         struct ext2_block_alloc_info *block_i;
518         ext2_fsblk_t current_block;
519
520         block_i = EXT2_I(inode)->i_block_alloc_info;
521
522         /* XXX LOCKING probably should have i_meta_lock ?*/
523         /* That's it */
524
525         *where->p = where->key;
526
527         /*
528          * Update the host buffer_head or inode to point to more just allocated
529          * direct blocks blocks
530          */
531         if (num == 0 && blks > 1) {
532                 current_block = le32_to_cpu(where->key) + 1;
533                 for (i = 1; i < blks; i++)
534                         *(where->p + i ) = cpu_to_le32(current_block++);
535         }
536
537         /*
538          * update the most recently allocated logical & physical block
539          * in i_block_alloc_info, to assist find the proper goal block for next
540          * allocation
541          */
542         if (block_i) {
543                 block_i->last_alloc_logical_block = block + blks - 1;
544                 block_i->last_alloc_physical_block =
545                                 le32_to_cpu(where[num].key) + blks - 1;
546         }
547
548         /* We are done with atomic stuff, now do the rest of housekeeping */
549
550         /* had we spliced it onto indirect block? */
551         if (where->bh)
552                 mark_buffer_dirty_inode(where->bh, inode);
553
554         inode->i_ctime = CURRENT_TIME_SEC;
555         mark_inode_dirty(inode);
556 }
557
558 /*
559  * Allocation strategy is simple: if we have to allocate something, we will
560  * have to go the whole way to leaf. So let's do it before attaching anything
561  * to tree, set linkage between the newborn blocks, write them if sync is
562  * required, recheck the path, free and repeat if check fails, otherwise
563  * set the last missing link (that will protect us from any truncate-generated
564  * removals - all blocks on the path are immune now) and possibly force the
565  * write on the parent block.
566  * That has a nice additional property: no special recovery from the failed
567  * allocations is needed - we simply release blocks and do not touch anything
568  * reachable from inode.
569  *
570  * `handle' can be NULL if create == 0.
571  *
572  * return > 0, # of blocks mapped or allocated.
573  * return = 0, if plain lookup failed.
574  * return < 0, error case.
575  */
576 static int ext2_get_blocks(struct inode *inode,
577                            sector_t iblock, unsigned long maxblocks,
578                            struct buffer_head *bh_result,
579                            int create)
580 {
581         int err = -EIO;
582         int offsets[4];
583         Indirect chain[4];
584         Indirect *partial;
585         ext2_fsblk_t goal;
586         int indirect_blks;
587         int blocks_to_boundary = 0;
588         int depth;
589         struct ext2_inode_info *ei = EXT2_I(inode);
590         int count = 0;
591         ext2_fsblk_t first_block = 0;
592
593         depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
594
595         if (depth == 0)
596                 return (err);
597 reread:
598         partial = ext2_get_branch(inode, depth, offsets, chain, &err);
599
600         /* Simplest case - block found, no allocation needed */
601         if (!partial) {
602                 first_block = le32_to_cpu(chain[depth - 1].key);
603                 clear_buffer_new(bh_result); /* What's this do? */
604                 count++;
605                 /*map more blocks*/
606                 while (count < maxblocks && count <= blocks_to_boundary) {
607                         ext2_fsblk_t blk;
608
609                         if (!verify_chain(chain, partial)) {
610                                 /*
611                                  * Indirect block might be removed by
612                                  * truncate while we were reading it.
613                                  * Handling of that case: forget what we've
614                                  * got now, go to reread.
615                                  */
616                                 count = 0;
617                                 goto changed;
618                         }
619                         blk = le32_to_cpu(*(chain[depth-1].p + count));
620                         if (blk == first_block + count)
621                                 count++;
622                         else
623                                 break;
624                 }
625                 goto got_it;
626         }
627
628         /* Next simple case - plain lookup or failed read of indirect block */
629         if (!create || err == -EIO)
630                 goto cleanup;
631
632         mutex_lock(&ei->truncate_mutex);
633
634         /*
635          * Okay, we need to do block allocation.  Lazily initialize the block
636          * allocation info here if necessary
637         */
638         if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
639                 ext2_init_block_alloc_info(inode);
640
641         goal = ext2_find_goal(inode, iblock, chain, partial);
642
643         /* the number of blocks need to allocate for [d,t]indirect blocks */
644         indirect_blks = (chain + depth) - partial - 1;
645         /*
646          * Next look up the indirect map to count the totoal number of
647          * direct blocks to allocate for this branch.
648          */
649         count = ext2_blks_to_allocate(partial, indirect_blks,
650                                         maxblocks, blocks_to_boundary);
651         /*
652          * XXX ???? Block out ext2_truncate while we alter the tree
653          */
654         err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
655                                 offsets + (partial - chain), partial);
656
657         if (err) {
658                 mutex_unlock(&ei->truncate_mutex);
659                 goto cleanup;
660         }
661
662         if (ext2_use_xip(inode->i_sb)) {
663                 /*
664                  * we need to clear the block
665                  */
666                 err = ext2_clear_xip_target (inode,
667                         le32_to_cpu(chain[depth-1].key));
668                 if (err) {
669                         mutex_unlock(&ei->truncate_mutex);
670                         goto cleanup;
671                 }
672         }
673
674         ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
675         mutex_unlock(&ei->truncate_mutex);
676         set_buffer_new(bh_result);
677 got_it:
678         map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
679         if (count > blocks_to_boundary)
680                 set_buffer_boundary(bh_result);
681         err = count;
682         /* Clean up and exit */
683         partial = chain + depth - 1;    /* the whole chain */
684 cleanup:
685         while (partial > chain) {
686                 brelse(partial->bh);
687                 partial--;
688         }
689         return err;
690 changed:
691         while (partial > chain) {
692                 brelse(partial->bh);
693                 partial--;
694         }
695         goto reread;
696 }
697
698 int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
699 {
700         unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
701         int ret = ext2_get_blocks(inode, iblock, max_blocks,
702                               bh_result, create);
703         if (ret > 0) {
704                 bh_result->b_size = (ret << inode->i_blkbits);
705                 ret = 0;
706         }
707         return ret;
708
709 }
710
711 static int ext2_writepage(struct page *page, struct writeback_control *wbc)
712 {
713         return block_write_full_page(page, ext2_get_block, wbc);
714 }
715
716 static int ext2_readpage(struct file *file, struct page *page)
717 {
718         return mpage_readpage(page, ext2_get_block);
719 }
720
721 static int
722 ext2_readpages(struct file *file, struct address_space *mapping,
723                 struct list_head *pages, unsigned nr_pages)
724 {
725         return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
726 }
727
728 int __ext2_write_begin(struct file *file, struct address_space *mapping,
729                 loff_t pos, unsigned len, unsigned flags,
730                 struct page **pagep, void **fsdata)
731 {
732         return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
733                                                         ext2_get_block);
734 }
735
736 static int
737 ext2_write_begin(struct file *file, struct address_space *mapping,
738                 loff_t pos, unsigned len, unsigned flags,
739                 struct page **pagep, void **fsdata)
740 {
741         *pagep = NULL;
742         return __ext2_write_begin(file, mapping, pos, len, flags, pagep,fsdata);
743 }
744
745 static int
746 ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
747                 loff_t pos, unsigned len, unsigned flags,
748                 struct page **pagep, void **fsdata)
749 {
750         /*
751          * Dir-in-pagecache still uses ext2_write_begin. Would have to rework
752          * directory handling code to pass around offsets rather than struct
753          * pages in order to make this work easily.
754          */
755         return nobh_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
756                                                         ext2_get_block);
757 }
758
759 static int ext2_nobh_writepage(struct page *page,
760                         struct writeback_control *wbc)
761 {
762         return nobh_writepage(page, ext2_get_block, wbc);
763 }
764
765 static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
766 {
767         return generic_block_bmap(mapping,block,ext2_get_block);
768 }
769
770 static ssize_t
771 ext2_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
772                         loff_t offset, unsigned long nr_segs)
773 {
774         struct file *file = iocb->ki_filp;
775         struct inode *inode = file->f_mapping->host;
776
777         return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
778                                 offset, nr_segs, ext2_get_block, NULL);
779 }
780
781 static int
782 ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
783 {
784         return mpage_writepages(mapping, wbc, ext2_get_block);
785 }
786
787 const struct address_space_operations ext2_aops = {
788         .readpage               = ext2_readpage,
789         .readpages              = ext2_readpages,
790         .writepage              = ext2_writepage,
791         .sync_page              = block_sync_page,
792         .write_begin            = ext2_write_begin,
793         .write_end              = generic_write_end,
794         .bmap                   = ext2_bmap,
795         .direct_IO              = ext2_direct_IO,
796         .writepages             = ext2_writepages,
797         .migratepage            = buffer_migrate_page,
798 };
799
800 const struct address_space_operations ext2_aops_xip = {
801         .bmap                   = ext2_bmap,
802         .get_xip_page           = ext2_get_xip_page,
803 };
804
805 const struct address_space_operations ext2_nobh_aops = {
806         .readpage               = ext2_readpage,
807         .readpages              = ext2_readpages,
808         .writepage              = ext2_nobh_writepage,
809         .sync_page              = block_sync_page,
810         .write_begin            = ext2_nobh_write_begin,
811         .write_end              = nobh_write_end,
812         .bmap                   = ext2_bmap,
813         .direct_IO              = ext2_direct_IO,
814         .writepages             = ext2_writepages,
815         .migratepage            = buffer_migrate_page,
816 };
817
818 /*
819  * Probably it should be a library function... search for first non-zero word
820  * or memcmp with zero_page, whatever is better for particular architecture.
821  * Linus?
822  */
823 static inline int all_zeroes(__le32 *p, __le32 *q)
824 {
825         while (p < q)
826                 if (*p++)
827                         return 0;
828         return 1;
829 }
830
831 /**
832  *      ext2_find_shared - find the indirect blocks for partial truncation.
833  *      @inode:   inode in question
834  *      @depth:   depth of the affected branch
835  *      @offsets: offsets of pointers in that branch (see ext2_block_to_path)
836  *      @chain:   place to store the pointers to partial indirect blocks
837  *      @top:     place to the (detached) top of branch
838  *
839  *      This is a helper function used by ext2_truncate().
840  *
841  *      When we do truncate() we may have to clean the ends of several indirect
842  *      blocks but leave the blocks themselves alive. Block is partially
843  *      truncated if some data below the new i_size is refered from it (and
844  *      it is on the path to the first completely truncated data block, indeed).
845  *      We have to free the top of that path along with everything to the right
846  *      of the path. Since no allocation past the truncation point is possible
847  *      until ext2_truncate() finishes, we may safely do the latter, but top
848  *      of branch may require special attention - pageout below the truncation
849  *      point might try to populate it.
850  *
851  *      We atomically detach the top of branch from the tree, store the block
852  *      number of its root in *@top, pointers to buffer_heads of partially
853  *      truncated blocks - in @chain[].bh and pointers to their last elements
854  *      that should not be removed - in @chain[].p. Return value is the pointer
855  *      to last filled element of @chain.
856  *
857  *      The work left to caller to do the actual freeing of subtrees:
858  *              a) free the subtree starting from *@top
859  *              b) free the subtrees whose roots are stored in
860  *                      (@chain[i].p+1 .. end of @chain[i].bh->b_data)
861  *              c) free the subtrees growing from the inode past the @chain[0].p
862  *                      (no partially truncated stuff there).
863  */
864
865 static Indirect *ext2_find_shared(struct inode *inode,
866                                 int depth,
867                                 int offsets[4],
868                                 Indirect chain[4],
869                                 __le32 *top)
870 {
871         Indirect *partial, *p;
872         int k, err;
873
874         *top = 0;
875         for (k = depth; k > 1 && !offsets[k-1]; k--)
876                 ;
877         partial = ext2_get_branch(inode, k, offsets, chain, &err);
878         if (!partial)
879                 partial = chain + k-1;
880         /*
881          * If the branch acquired continuation since we've looked at it -
882          * fine, it should all survive and (new) top doesn't belong to us.
883          */
884         write_lock(&EXT2_I(inode)->i_meta_lock);
885         if (!partial->key && *partial->p) {
886                 write_unlock(&EXT2_I(inode)->i_meta_lock);
887                 goto no_top;
888         }
889         for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
890                 ;
891         /*
892          * OK, we've found the last block that must survive. The rest of our
893          * branch should be detached before unlocking. However, if that rest
894          * of branch is all ours and does not grow immediately from the inode
895          * it's easier to cheat and just decrement partial->p.
896          */
897         if (p == chain + k - 1 && p > chain) {
898                 p->p--;
899         } else {
900                 *top = *p->p;
901                 *p->p = 0;
902         }
903         write_unlock(&EXT2_I(inode)->i_meta_lock);
904
905         while(partial > p)
906         {
907                 brelse(partial->bh);
908                 partial--;
909         }
910 no_top:
911         return partial;
912 }
913
914 /**
915  *      ext2_free_data - free a list of data blocks
916  *      @inode: inode we are dealing with
917  *      @p:     array of block numbers
918  *      @q:     points immediately past the end of array
919  *
920  *      We are freeing all blocks refered from that array (numbers are
921  *      stored as little-endian 32-bit) and updating @inode->i_blocks
922  *      appropriately.
923  */
924 static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
925 {
926         unsigned long block_to_free = 0, count = 0;
927         unsigned long nr;
928
929         for ( ; p < q ; p++) {
930                 nr = le32_to_cpu(*p);
931                 if (nr) {
932                         *p = 0;
933                         /* accumulate blocks to free if they're contiguous */
934                         if (count == 0)
935                                 goto free_this;
936                         else if (block_to_free == nr - count)
937                                 count++;
938                         else {
939                                 mark_inode_dirty(inode);
940                                 ext2_free_blocks (inode, block_to_free, count);
941                         free_this:
942                                 block_to_free = nr;
943                                 count = 1;
944                         }
945                 }
946         }
947         if (count > 0) {
948                 mark_inode_dirty(inode);
949                 ext2_free_blocks (inode, block_to_free, count);
950         }
951 }
952
953 /**
954  *      ext2_free_branches - free an array of branches
955  *      @inode: inode we are dealing with
956  *      @p:     array of block numbers
957  *      @q:     pointer immediately past the end of array
958  *      @depth: depth of the branches to free
959  *
960  *      We are freeing all blocks refered from these branches (numbers are
961  *      stored as little-endian 32-bit) and updating @inode->i_blocks
962  *      appropriately.
963  */
964 static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
965 {
966         struct buffer_head * bh;
967         unsigned long nr;
968
969         if (depth--) {
970                 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
971                 for ( ; p < q ; p++) {
972                         nr = le32_to_cpu(*p);
973                         if (!nr)
974                                 continue;
975                         *p = 0;
976                         bh = sb_bread(inode->i_sb, nr);
977                         /*
978                          * A read failure? Report error and clear slot
979                          * (should be rare).
980                          */ 
981                         if (!bh) {
982                                 ext2_error(inode->i_sb, "ext2_free_branches",
983                                         "Read failure, inode=%ld, block=%ld",
984                                         inode->i_ino, nr);
985                                 continue;
986                         }
987                         ext2_free_branches(inode,
988                                            (__le32*)bh->b_data,
989                                            (__le32*)bh->b_data + addr_per_block,
990                                            depth);
991                         bforget(bh);
992                         ext2_free_blocks(inode, nr, 1);
993                         mark_inode_dirty(inode);
994                 }
995         } else
996                 ext2_free_data(inode, p, q);
997 }
998
999 void ext2_truncate(struct inode *inode)
1000 {
1001         __le32 *i_data = EXT2_I(inode)->i_data;
1002         struct ext2_inode_info *ei = EXT2_I(inode);
1003         int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1004         int offsets[4];
1005         Indirect chain[4];
1006         Indirect *partial;
1007         __le32 nr = 0;
1008         int n;
1009         long iblock;
1010         unsigned blocksize;
1011
1012         if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1013             S_ISLNK(inode->i_mode)))
1014                 return;
1015         if (ext2_inode_is_fast_symlink(inode))
1016                 return;
1017         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1018                 return;
1019
1020         blocksize = inode->i_sb->s_blocksize;
1021         iblock = (inode->i_size + blocksize-1)
1022                                         >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1023
1024         if (mapping_is_xip(inode->i_mapping))
1025                 xip_truncate_page(inode->i_mapping, inode->i_size);
1026         else if (test_opt(inode->i_sb, NOBH))
1027                 nobh_truncate_page(inode->i_mapping,
1028                                 inode->i_size, ext2_get_block);
1029         else
1030                 block_truncate_page(inode->i_mapping,
1031                                 inode->i_size, ext2_get_block);
1032
1033         n = ext2_block_to_path(inode, iblock, offsets, NULL);
1034         if (n == 0)
1035                 return;
1036
1037         /*
1038          * From here we block out all ext2_get_block() callers who want to
1039          * modify the block allocation tree.
1040          */
1041         mutex_lock(&ei->truncate_mutex);
1042
1043         if (n == 1) {
1044                 ext2_free_data(inode, i_data+offsets[0],
1045                                         i_data + EXT2_NDIR_BLOCKS);
1046                 goto do_indirects;
1047         }
1048
1049         partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1050         /* Kill the top of shared branch (already detached) */
1051         if (nr) {
1052                 if (partial == chain)
1053                         mark_inode_dirty(inode);
1054                 else
1055                         mark_buffer_dirty_inode(partial->bh, inode);
1056                 ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1057         }
1058         /* Clear the ends of indirect blocks on the shared branch */
1059         while (partial > chain) {
1060                 ext2_free_branches(inode,
1061                                    partial->p + 1,
1062                                    (__le32*)partial->bh->b_data+addr_per_block,
1063                                    (chain+n-1) - partial);
1064                 mark_buffer_dirty_inode(partial->bh, inode);
1065                 brelse (partial->bh);
1066                 partial--;
1067         }
1068 do_indirects:
1069         /* Kill the remaining (whole) subtrees */
1070         switch (offsets[0]) {
1071                 default:
1072                         nr = i_data[EXT2_IND_BLOCK];
1073                         if (nr) {
1074                                 i_data[EXT2_IND_BLOCK] = 0;
1075                                 mark_inode_dirty(inode);
1076                                 ext2_free_branches(inode, &nr, &nr+1, 1);
1077                         }
1078                 case EXT2_IND_BLOCK:
1079                         nr = i_data[EXT2_DIND_BLOCK];
1080                         if (nr) {
1081                                 i_data[EXT2_DIND_BLOCK] = 0;
1082                                 mark_inode_dirty(inode);
1083                                 ext2_free_branches(inode, &nr, &nr+1, 2);
1084                         }
1085                 case EXT2_DIND_BLOCK:
1086                         nr = i_data[EXT2_TIND_BLOCK];
1087                         if (nr) {
1088                                 i_data[EXT2_TIND_BLOCK] = 0;
1089                                 mark_inode_dirty(inode);
1090                                 ext2_free_branches(inode, &nr, &nr+1, 3);
1091                         }
1092                 case EXT2_TIND_BLOCK:
1093                         ;
1094         }
1095
1096         ext2_discard_reservation(inode);
1097
1098         mutex_unlock(&ei->truncate_mutex);
1099         inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
1100         if (inode_needs_sync(inode)) {
1101                 sync_mapping_buffers(inode->i_mapping);
1102                 ext2_sync_inode (inode);
1103         } else {
1104                 mark_inode_dirty(inode);
1105         }
1106 }
1107
1108 static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1109                                         struct buffer_head **p)
1110 {
1111         struct buffer_head * bh;
1112         unsigned long block_group;
1113         unsigned long block;
1114         unsigned long offset;
1115         struct ext2_group_desc * gdp;
1116
1117         *p = NULL;
1118         if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1119             ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1120                 goto Einval;
1121
1122         block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
1123         gdp = ext2_get_group_desc(sb, block_group, NULL);
1124         if (!gdp)
1125                 goto Egdp;
1126         /*
1127          * Figure out the offset within the block group inode table
1128          */
1129         offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1130         block = le32_to_cpu(gdp->bg_inode_table) +
1131                 (offset >> EXT2_BLOCK_SIZE_BITS(sb));
1132         if (!(bh = sb_bread(sb, block)))
1133                 goto Eio;
1134
1135         *p = bh;
1136         offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1137         return (struct ext2_inode *) (bh->b_data + offset);
1138
1139 Einval:
1140         ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1141                    (unsigned long) ino);
1142         return ERR_PTR(-EINVAL);
1143 Eio:
1144         ext2_error(sb, "ext2_get_inode",
1145                    "unable to read inode block - inode=%lu, block=%lu",
1146                    (unsigned long) ino, block);
1147 Egdp:
1148         return ERR_PTR(-EIO);
1149 }
1150
1151 void ext2_set_inode_flags(struct inode *inode)
1152 {
1153         unsigned int flags = EXT2_I(inode)->i_flags;
1154
1155         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
1156         if (flags & EXT2_SYNC_FL)
1157                 inode->i_flags |= S_SYNC;
1158         if (flags & EXT2_APPEND_FL)
1159                 inode->i_flags |= S_APPEND;
1160         if (flags & EXT2_IMMUTABLE_FL)
1161                 inode->i_flags |= S_IMMUTABLE;
1162         if (flags & EXT2_NOATIME_FL)
1163                 inode->i_flags |= S_NOATIME;
1164         if (flags & EXT2_DIRSYNC_FL)
1165                 inode->i_flags |= S_DIRSYNC;
1166 }
1167
1168 /* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
1169 void ext2_get_inode_flags(struct ext2_inode_info *ei)
1170 {
1171         unsigned int flags = ei->vfs_inode.i_flags;
1172
1173         ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|
1174                         EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL);
1175         if (flags & S_SYNC)
1176                 ei->i_flags |= EXT2_SYNC_FL;
1177         if (flags & S_APPEND)
1178                 ei->i_flags |= EXT2_APPEND_FL;
1179         if (flags & S_IMMUTABLE)
1180                 ei->i_flags |= EXT2_IMMUTABLE_FL;
1181         if (flags & S_NOATIME)
1182                 ei->i_flags |= EXT2_NOATIME_FL;
1183         if (flags & S_DIRSYNC)
1184                 ei->i_flags |= EXT2_DIRSYNC_FL;
1185 }
1186
1187 void ext2_read_inode (struct inode * inode)
1188 {
1189         struct ext2_inode_info *ei = EXT2_I(inode);
1190         ino_t ino = inode->i_ino;
1191         struct buffer_head * bh;
1192         struct ext2_inode * raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1193         int n;
1194
1195 #ifdef CONFIG_EXT2_FS_POSIX_ACL
1196         ei->i_acl = EXT2_ACL_NOT_CACHED;
1197         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
1198 #endif
1199         ei->i_block_alloc_info = NULL;
1200
1201         if (IS_ERR(raw_inode))
1202                 goto bad_inode;
1203
1204         inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1205         inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1206         inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1207         if (!(test_opt (inode->i_sb, NO_UID32))) {
1208                 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1209                 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1210         }
1211         inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
1212         inode->i_size = le32_to_cpu(raw_inode->i_size);
1213         inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
1214         inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
1215         inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
1216         inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1217         ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1218         /* We now have enough fields to check if the inode was active or not.
1219          * This is needed because nfsd might try to access dead inodes
1220          * the test is that same one that e2fsck uses
1221          * NeilBrown 1999oct15
1222          */
1223         if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1224                 /* this inode is deleted */
1225                 brelse (bh);
1226                 goto bad_inode;
1227         }
1228         inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1229         ei->i_flags = le32_to_cpu(raw_inode->i_flags);
1230         ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1231         ei->i_frag_no = raw_inode->i_frag;
1232         ei->i_frag_size = raw_inode->i_fsize;
1233         ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1234         ei->i_dir_acl = 0;
1235         if (S_ISREG(inode->i_mode))
1236                 inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1237         else
1238                 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1239         ei->i_dtime = 0;
1240         inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1241         ei->i_state = 0;
1242         ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1243         ei->i_dir_start_lookup = 0;
1244
1245         /*
1246          * NOTE! The in-memory inode i_data array is in little-endian order
1247          * even on big-endian machines: we do NOT byteswap the block numbers!
1248          */
1249         for (n = 0; n < EXT2_N_BLOCKS; n++)
1250                 ei->i_data[n] = raw_inode->i_block[n];
1251
1252         if (S_ISREG(inode->i_mode)) {
1253                 inode->i_op = &ext2_file_inode_operations;
1254                 if (ext2_use_xip(inode->i_sb)) {
1255                         inode->i_mapping->a_ops = &ext2_aops_xip;
1256                         inode->i_fop = &ext2_xip_file_operations;
1257                 } else if (test_opt(inode->i_sb, NOBH)) {
1258                         inode->i_mapping->a_ops = &ext2_nobh_aops;
1259                         inode->i_fop = &ext2_file_operations;
1260                 } else {
1261                         inode->i_mapping->a_ops = &ext2_aops;
1262                         inode->i_fop = &ext2_file_operations;
1263                 }
1264         } else if (S_ISDIR(inode->i_mode)) {
1265                 inode->i_op = &ext2_dir_inode_operations;
1266                 inode->i_fop = &ext2_dir_operations;
1267                 if (test_opt(inode->i_sb, NOBH))
1268                         inode->i_mapping->a_ops = &ext2_nobh_aops;
1269                 else
1270                         inode->i_mapping->a_ops = &ext2_aops;
1271         } else if (S_ISLNK(inode->i_mode)) {
1272                 if (ext2_inode_is_fast_symlink(inode))
1273                         inode->i_op = &ext2_fast_symlink_inode_operations;
1274                 else {
1275                         inode->i_op = &ext2_symlink_inode_operations;
1276                         if (test_opt(inode->i_sb, NOBH))
1277                                 inode->i_mapping->a_ops = &ext2_nobh_aops;
1278                         else
1279                                 inode->i_mapping->a_ops = &ext2_aops;
1280                 }
1281         } else {
1282                 inode->i_op = &ext2_special_inode_operations;
1283                 if (raw_inode->i_block[0])
1284                         init_special_inode(inode, inode->i_mode,
1285                            old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1286                 else 
1287                         init_special_inode(inode, inode->i_mode,
1288                            new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1289         }
1290         brelse (bh);
1291         ext2_set_inode_flags(inode);
1292         return;
1293         
1294 bad_inode:
1295         make_bad_inode(inode);
1296         return;
1297 }
1298
1299 static int ext2_update_inode(struct inode * inode, int do_sync)
1300 {
1301         struct ext2_inode_info *ei = EXT2_I(inode);
1302         struct super_block *sb = inode->i_sb;
1303         ino_t ino = inode->i_ino;
1304         uid_t uid = inode->i_uid;
1305         gid_t gid = inode->i_gid;
1306         struct buffer_head * bh;
1307         struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1308         int n;
1309         int err = 0;
1310
1311         if (IS_ERR(raw_inode))
1312                 return -EIO;
1313
1314         /* For fields not not tracking in the in-memory inode,
1315          * initialise them to zero for new inodes. */
1316         if (ei->i_state & EXT2_STATE_NEW)
1317                 memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1318
1319         ext2_get_inode_flags(ei);
1320         raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1321         if (!(test_opt(sb, NO_UID32))) {
1322                 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1323                 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1324 /*
1325  * Fix up interoperability with old kernels. Otherwise, old inodes get
1326  * re-used with the upper 16 bits of the uid/gid intact
1327  */
1328                 if (!ei->i_dtime) {
1329                         raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1330                         raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1331                 } else {
1332                         raw_inode->i_uid_high = 0;
1333                         raw_inode->i_gid_high = 0;
1334                 }
1335         } else {
1336                 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1337                 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1338                 raw_inode->i_uid_high = 0;
1339                 raw_inode->i_gid_high = 0;
1340         }
1341         raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1342         raw_inode->i_size = cpu_to_le32(inode->i_size);
1343         raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
1344         raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
1345         raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
1346
1347         raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1348         raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1349         raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1350         raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1351         raw_inode->i_frag = ei->i_frag_no;
1352         raw_inode->i_fsize = ei->i_frag_size;
1353         raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1354         if (!S_ISREG(inode->i_mode))
1355                 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1356         else {
1357                 raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1358                 if (inode->i_size > 0x7fffffffULL) {
1359                         if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1360                                         EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1361                             EXT2_SB(sb)->s_es->s_rev_level ==
1362                                         cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1363                                /* If this is the first large file
1364                                 * created, add a flag to the superblock.
1365                                 */
1366                                 lock_kernel();
1367                                 ext2_update_dynamic_rev(sb);
1368                                 EXT2_SET_RO_COMPAT_FEATURE(sb,
1369                                         EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1370                                 unlock_kernel();
1371                                 ext2_write_super(sb);
1372                         }
1373                 }
1374         }
1375         
1376         raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1377         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1378                 if (old_valid_dev(inode->i_rdev)) {
1379                         raw_inode->i_block[0] =
1380                                 cpu_to_le32(old_encode_dev(inode->i_rdev));
1381                         raw_inode->i_block[1] = 0;
1382                 } else {
1383                         raw_inode->i_block[0] = 0;
1384                         raw_inode->i_block[1] =
1385                                 cpu_to_le32(new_encode_dev(inode->i_rdev));
1386                         raw_inode->i_block[2] = 0;
1387                 }
1388         } else for (n = 0; n < EXT2_N_BLOCKS; n++)
1389                 raw_inode->i_block[n] = ei->i_data[n];
1390         mark_buffer_dirty(bh);
1391         if (do_sync) {
1392                 sync_dirty_buffer(bh);
1393                 if (buffer_req(bh) && !buffer_uptodate(bh)) {
1394                         printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1395                                 sb->s_id, (unsigned long) ino);
1396                         err = -EIO;
1397                 }
1398         }
1399         ei->i_state &= ~EXT2_STATE_NEW;
1400         brelse (bh);
1401         return err;
1402 }
1403
1404 int ext2_write_inode(struct inode *inode, int wait)
1405 {
1406         return ext2_update_inode(inode, wait);
1407 }
1408
1409 int ext2_sync_inode(struct inode *inode)
1410 {
1411         struct writeback_control wbc = {
1412                 .sync_mode = WB_SYNC_ALL,
1413                 .nr_to_write = 0,       /* sys_fsync did this */
1414         };
1415         return sync_inode(inode, &wbc);
1416 }
1417
1418 int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
1419 {
1420         struct inode *inode = dentry->d_inode;
1421         int error;
1422
1423         error = inode_change_ok(inode, iattr);
1424         if (error)
1425                 return error;
1426         if ((iattr->ia_valid & ATTR_UID && iattr->ia_uid != inode->i_uid) ||
1427             (iattr->ia_valid & ATTR_GID && iattr->ia_gid != inode->i_gid)) {
1428                 error = DQUOT_TRANSFER(inode, iattr) ? -EDQUOT : 0;
1429                 if (error)
1430                         return error;
1431         }
1432         error = inode_setattr(inode, iattr);
1433         if (!error && (iattr->ia_valid & ATTR_MODE))
1434                 error = ext2_acl_chmod(inode);
1435         return error;
1436 }