ext2: ensure fast symlinks are NUL-terminated
[linux-2.6.git] / 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  * @chain: chain of indirect blocks (with a missing link - see
502  *      ext2_alloc_branch)
503  * @where: location of missing link
504  * @num:   number of indirect blocks we are adding
505  * @blks:  number of direct blocks we are adding
506  *
507  * This function fills the missing link and does all housekeeping needed in
508  * inode (->i_blocks, etc.). In case of success we end up with the full
509  * chain to new block and return 0.
510  */
511 static void ext2_splice_branch(struct inode *inode,
512                         long block, Indirect *where, int num, int blks)
513 {
514         int i;
515         struct ext2_block_alloc_info *block_i;
516         ext2_fsblk_t current_block;
517
518         block_i = EXT2_I(inode)->i_block_alloc_info;
519
520         /* XXX LOCKING probably should have i_meta_lock ?*/
521         /* That's it */
522
523         *where->p = where->key;
524
525         /*
526          * Update the host buffer_head or inode to point to more just allocated
527          * direct blocks blocks
528          */
529         if (num == 0 && blks > 1) {
530                 current_block = le32_to_cpu(where->key) + 1;
531                 for (i = 1; i < blks; i++)
532                         *(where->p + i ) = cpu_to_le32(current_block++);
533         }
534
535         /*
536          * update the most recently allocated logical & physical block
537          * in i_block_alloc_info, to assist find the proper goal block for next
538          * allocation
539          */
540         if (block_i) {
541                 block_i->last_alloc_logical_block = block + blks - 1;
542                 block_i->last_alloc_physical_block =
543                                 le32_to_cpu(where[num].key) + blks - 1;
544         }
545
546         /* We are done with atomic stuff, now do the rest of housekeeping */
547
548         /* had we spliced it onto indirect block? */
549         if (where->bh)
550                 mark_buffer_dirty_inode(where->bh, inode);
551
552         inode->i_ctime = CURRENT_TIME_SEC;
553         mark_inode_dirty(inode);
554 }
555
556 /*
557  * Allocation strategy is simple: if we have to allocate something, we will
558  * have to go the whole way to leaf. So let's do it before attaching anything
559  * to tree, set linkage between the newborn blocks, write them if sync is
560  * required, recheck the path, free and repeat if check fails, otherwise
561  * set the last missing link (that will protect us from any truncate-generated
562  * removals - all blocks on the path are immune now) and possibly force the
563  * write on the parent block.
564  * That has a nice additional property: no special recovery from the failed
565  * allocations is needed - we simply release blocks and do not touch anything
566  * reachable from inode.
567  *
568  * `handle' can be NULL if create == 0.
569  *
570  * return > 0, # of blocks mapped or allocated.
571  * return = 0, if plain lookup failed.
572  * return < 0, error case.
573  */
574 static int ext2_get_blocks(struct inode *inode,
575                            sector_t iblock, unsigned long maxblocks,
576                            struct buffer_head *bh_result,
577                            int create)
578 {
579         int err = -EIO;
580         int offsets[4];
581         Indirect chain[4];
582         Indirect *partial;
583         ext2_fsblk_t goal;
584         int indirect_blks;
585         int blocks_to_boundary = 0;
586         int depth;
587         struct ext2_inode_info *ei = EXT2_I(inode);
588         int count = 0;
589         ext2_fsblk_t first_block = 0;
590
591         depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
592
593         if (depth == 0)
594                 return (err);
595 reread:
596         partial = ext2_get_branch(inode, depth, offsets, chain, &err);
597
598         /* Simplest case - block found, no allocation needed */
599         if (!partial) {
600                 first_block = le32_to_cpu(chain[depth - 1].key);
601                 clear_buffer_new(bh_result); /* What's this do? */
602                 count++;
603                 /*map more blocks*/
604                 while (count < maxblocks && count <= blocks_to_boundary) {
605                         ext2_fsblk_t blk;
606
607                         if (!verify_chain(chain, partial)) {
608                                 /*
609                                  * Indirect block might be removed by
610                                  * truncate while we were reading it.
611                                  * Handling of that case: forget what we've
612                                  * got now, go to reread.
613                                  */
614                                 count = 0;
615                                 goto changed;
616                         }
617                         blk = le32_to_cpu(*(chain[depth-1].p + count));
618                         if (blk == first_block + count)
619                                 count++;
620                         else
621                                 break;
622                 }
623                 goto got_it;
624         }
625
626         /* Next simple case - plain lookup or failed read of indirect block */
627         if (!create || err == -EIO)
628                 goto cleanup;
629
630         mutex_lock(&ei->truncate_mutex);
631
632         /*
633          * Okay, we need to do block allocation.  Lazily initialize the block
634          * allocation info here if necessary
635         */
636         if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
637                 ext2_init_block_alloc_info(inode);
638
639         goal = ext2_find_goal(inode, iblock, partial);
640
641         /* the number of blocks need to allocate for [d,t]indirect blocks */
642         indirect_blks = (chain + depth) - partial - 1;
643         /*
644          * Next look up the indirect map to count the totoal number of
645          * direct blocks to allocate for this branch.
646          */
647         count = ext2_blks_to_allocate(partial, indirect_blks,
648                                         maxblocks, blocks_to_boundary);
649         /*
650          * XXX ???? Block out ext2_truncate while we alter the tree
651          */
652         err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
653                                 offsets + (partial - chain), partial);
654
655         if (err) {
656                 mutex_unlock(&ei->truncate_mutex);
657                 goto cleanup;
658         }
659
660         if (ext2_use_xip(inode->i_sb)) {
661                 /*
662                  * we need to clear the block
663                  */
664                 err = ext2_clear_xip_target (inode,
665                         le32_to_cpu(chain[depth-1].key));
666                 if (err) {
667                         mutex_unlock(&ei->truncate_mutex);
668                         goto cleanup;
669                 }
670         }
671
672         ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
673         mutex_unlock(&ei->truncate_mutex);
674         set_buffer_new(bh_result);
675 got_it:
676         map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
677         if (count > blocks_to_boundary)
678                 set_buffer_boundary(bh_result);
679         err = count;
680         /* Clean up and exit */
681         partial = chain + depth - 1;    /* the whole chain */
682 cleanup:
683         while (partial > chain) {
684                 brelse(partial->bh);
685                 partial--;
686         }
687         return err;
688 changed:
689         while (partial > chain) {
690                 brelse(partial->bh);
691                 partial--;
692         }
693         goto reread;
694 }
695
696 int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
697 {
698         unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
699         int ret = ext2_get_blocks(inode, iblock, max_blocks,
700                               bh_result, create);
701         if (ret > 0) {
702                 bh_result->b_size = (ret << inode->i_blkbits);
703                 ret = 0;
704         }
705         return ret;
706
707 }
708
709 int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
710                 u64 start, u64 len)
711 {
712         return generic_block_fiemap(inode, fieinfo, start, len,
713                                     ext2_get_block);
714 }
715
716 static int ext2_writepage(struct page *page, struct writeback_control *wbc)
717 {
718         return block_write_full_page(page, ext2_get_block, wbc);
719 }
720
721 static int ext2_readpage(struct file *file, struct page *page)
722 {
723         return mpage_readpage(page, ext2_get_block);
724 }
725
726 static int
727 ext2_readpages(struct file *file, struct address_space *mapping,
728                 struct list_head *pages, unsigned nr_pages)
729 {
730         return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
731 }
732
733 int __ext2_write_begin(struct file *file, struct address_space *mapping,
734                 loff_t pos, unsigned len, unsigned flags,
735                 struct page **pagep, void **fsdata)
736 {
737         return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
738                                                         ext2_get_block);
739 }
740
741 static int
742 ext2_write_begin(struct file *file, struct address_space *mapping,
743                 loff_t pos, unsigned len, unsigned flags,
744                 struct page **pagep, void **fsdata)
745 {
746         *pagep = NULL;
747         return __ext2_write_begin(file, mapping, pos, len, flags, pagep,fsdata);
748 }
749
750 static int
751 ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
752                 loff_t pos, unsigned len, unsigned flags,
753                 struct page **pagep, void **fsdata)
754 {
755         /*
756          * Dir-in-pagecache still uses ext2_write_begin. Would have to rework
757          * directory handling code to pass around offsets rather than struct
758          * pages in order to make this work easily.
759          */
760         return nobh_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
761                                                         ext2_get_block);
762 }
763
764 static int ext2_nobh_writepage(struct page *page,
765                         struct writeback_control *wbc)
766 {
767         return nobh_writepage(page, ext2_get_block, wbc);
768 }
769
770 static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
771 {
772         return generic_block_bmap(mapping,block,ext2_get_block);
773 }
774
775 static ssize_t
776 ext2_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
777                         loff_t offset, unsigned long nr_segs)
778 {
779         struct file *file = iocb->ki_filp;
780         struct inode *inode = file->f_mapping->host;
781
782         return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
783                                 offset, nr_segs, ext2_get_block, NULL);
784 }
785
786 static int
787 ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
788 {
789         return mpage_writepages(mapping, wbc, ext2_get_block);
790 }
791
792 const struct address_space_operations ext2_aops = {
793         .readpage               = ext2_readpage,
794         .readpages              = ext2_readpages,
795         .writepage              = ext2_writepage,
796         .sync_page              = block_sync_page,
797         .write_begin            = ext2_write_begin,
798         .write_end              = generic_write_end,
799         .bmap                   = ext2_bmap,
800         .direct_IO              = ext2_direct_IO,
801         .writepages             = ext2_writepages,
802         .migratepage            = buffer_migrate_page,
803         .is_partially_uptodate  = block_is_partially_uptodate,
804 };
805
806 const struct address_space_operations ext2_aops_xip = {
807         .bmap                   = ext2_bmap,
808         .get_xip_mem            = ext2_get_xip_mem,
809 };
810
811 const struct address_space_operations ext2_nobh_aops = {
812         .readpage               = ext2_readpage,
813         .readpages              = ext2_readpages,
814         .writepage              = ext2_nobh_writepage,
815         .sync_page              = block_sync_page,
816         .write_begin            = ext2_nobh_write_begin,
817         .write_end              = nobh_write_end,
818         .bmap                   = ext2_bmap,
819         .direct_IO              = ext2_direct_IO,
820         .writepages             = ext2_writepages,
821         .migratepage            = buffer_migrate_page,
822 };
823
824 /*
825  * Probably it should be a library function... search for first non-zero word
826  * or memcmp with zero_page, whatever is better for particular architecture.
827  * Linus?
828  */
829 static inline int all_zeroes(__le32 *p, __le32 *q)
830 {
831         while (p < q)
832                 if (*p++)
833                         return 0;
834         return 1;
835 }
836
837 /**
838  *      ext2_find_shared - find the indirect blocks for partial truncation.
839  *      @inode:   inode in question
840  *      @depth:   depth of the affected branch
841  *      @offsets: offsets of pointers in that branch (see ext2_block_to_path)
842  *      @chain:   place to store the pointers to partial indirect blocks
843  *      @top:     place to the (detached) top of branch
844  *
845  *      This is a helper function used by ext2_truncate().
846  *
847  *      When we do truncate() we may have to clean the ends of several indirect
848  *      blocks but leave the blocks themselves alive. Block is partially
849  *      truncated if some data below the new i_size is refered from it (and
850  *      it is on the path to the first completely truncated data block, indeed).
851  *      We have to free the top of that path along with everything to the right
852  *      of the path. Since no allocation past the truncation point is possible
853  *      until ext2_truncate() finishes, we may safely do the latter, but top
854  *      of branch may require special attention - pageout below the truncation
855  *      point might try to populate it.
856  *
857  *      We atomically detach the top of branch from the tree, store the block
858  *      number of its root in *@top, pointers to buffer_heads of partially
859  *      truncated blocks - in @chain[].bh and pointers to their last elements
860  *      that should not be removed - in @chain[].p. Return value is the pointer
861  *      to last filled element of @chain.
862  *
863  *      The work left to caller to do the actual freeing of subtrees:
864  *              a) free the subtree starting from *@top
865  *              b) free the subtrees whose roots are stored in
866  *                      (@chain[i].p+1 .. end of @chain[i].bh->b_data)
867  *              c) free the subtrees growing from the inode past the @chain[0].p
868  *                      (no partially truncated stuff there).
869  */
870
871 static Indirect *ext2_find_shared(struct inode *inode,
872                                 int depth,
873                                 int offsets[4],
874                                 Indirect chain[4],
875                                 __le32 *top)
876 {
877         Indirect *partial, *p;
878         int k, err;
879
880         *top = 0;
881         for (k = depth; k > 1 && !offsets[k-1]; k--)
882                 ;
883         partial = ext2_get_branch(inode, k, offsets, chain, &err);
884         if (!partial)
885                 partial = chain + k-1;
886         /*
887          * If the branch acquired continuation since we've looked at it -
888          * fine, it should all survive and (new) top doesn't belong to us.
889          */
890         write_lock(&EXT2_I(inode)->i_meta_lock);
891         if (!partial->key && *partial->p) {
892                 write_unlock(&EXT2_I(inode)->i_meta_lock);
893                 goto no_top;
894         }
895         for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
896                 ;
897         /*
898          * OK, we've found the last block that must survive. The rest of our
899          * branch should be detached before unlocking. However, if that rest
900          * of branch is all ours and does not grow immediately from the inode
901          * it's easier to cheat and just decrement partial->p.
902          */
903         if (p == chain + k - 1 && p > chain) {
904                 p->p--;
905         } else {
906                 *top = *p->p;
907                 *p->p = 0;
908         }
909         write_unlock(&EXT2_I(inode)->i_meta_lock);
910
911         while(partial > p)
912         {
913                 brelse(partial->bh);
914                 partial--;
915         }
916 no_top:
917         return partial;
918 }
919
920 /**
921  *      ext2_free_data - free a list of data blocks
922  *      @inode: inode we are dealing with
923  *      @p:     array of block numbers
924  *      @q:     points immediately past the end of array
925  *
926  *      We are freeing all blocks refered from that array (numbers are
927  *      stored as little-endian 32-bit) and updating @inode->i_blocks
928  *      appropriately.
929  */
930 static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
931 {
932         unsigned long block_to_free = 0, count = 0;
933         unsigned long nr;
934
935         for ( ; p < q ; p++) {
936                 nr = le32_to_cpu(*p);
937                 if (nr) {
938                         *p = 0;
939                         /* accumulate blocks to free if they're contiguous */
940                         if (count == 0)
941                                 goto free_this;
942                         else if (block_to_free == nr - count)
943                                 count++;
944                         else {
945                                 mark_inode_dirty(inode);
946                                 ext2_free_blocks (inode, block_to_free, count);
947                         free_this:
948                                 block_to_free = nr;
949                                 count = 1;
950                         }
951                 }
952         }
953         if (count > 0) {
954                 mark_inode_dirty(inode);
955                 ext2_free_blocks (inode, block_to_free, count);
956         }
957 }
958
959 /**
960  *      ext2_free_branches - free an array of branches
961  *      @inode: inode we are dealing with
962  *      @p:     array of block numbers
963  *      @q:     pointer immediately past the end of array
964  *      @depth: depth of the branches to free
965  *
966  *      We are freeing all blocks refered from these branches (numbers are
967  *      stored as little-endian 32-bit) and updating @inode->i_blocks
968  *      appropriately.
969  */
970 static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
971 {
972         struct buffer_head * bh;
973         unsigned long nr;
974
975         if (depth--) {
976                 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
977                 for ( ; p < q ; p++) {
978                         nr = le32_to_cpu(*p);
979                         if (!nr)
980                                 continue;
981                         *p = 0;
982                         bh = sb_bread(inode->i_sb, nr);
983                         /*
984                          * A read failure? Report error and clear slot
985                          * (should be rare).
986                          */ 
987                         if (!bh) {
988                                 ext2_error(inode->i_sb, "ext2_free_branches",
989                                         "Read failure, inode=%ld, block=%ld",
990                                         inode->i_ino, nr);
991                                 continue;
992                         }
993                         ext2_free_branches(inode,
994                                            (__le32*)bh->b_data,
995                                            (__le32*)bh->b_data + addr_per_block,
996                                            depth);
997                         bforget(bh);
998                         ext2_free_blocks(inode, nr, 1);
999                         mark_inode_dirty(inode);
1000                 }
1001         } else
1002                 ext2_free_data(inode, p, q);
1003 }
1004
1005 void ext2_truncate(struct inode *inode)
1006 {
1007         __le32 *i_data = EXT2_I(inode)->i_data;
1008         struct ext2_inode_info *ei = EXT2_I(inode);
1009         int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1010         int offsets[4];
1011         Indirect chain[4];
1012         Indirect *partial;
1013         __le32 nr = 0;
1014         int n;
1015         long iblock;
1016         unsigned blocksize;
1017
1018         if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1019             S_ISLNK(inode->i_mode)))
1020                 return;
1021         if (ext2_inode_is_fast_symlink(inode))
1022                 return;
1023         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1024                 return;
1025
1026         blocksize = inode->i_sb->s_blocksize;
1027         iblock = (inode->i_size + blocksize-1)
1028                                         >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1029
1030         if (mapping_is_xip(inode->i_mapping))
1031                 xip_truncate_page(inode->i_mapping, inode->i_size);
1032         else if (test_opt(inode->i_sb, NOBH))
1033                 nobh_truncate_page(inode->i_mapping,
1034                                 inode->i_size, ext2_get_block);
1035         else
1036                 block_truncate_page(inode->i_mapping,
1037                                 inode->i_size, ext2_get_block);
1038
1039         n = ext2_block_to_path(inode, iblock, offsets, NULL);
1040         if (n == 0)
1041                 return;
1042
1043         /*
1044          * From here we block out all ext2_get_block() callers who want to
1045          * modify the block allocation tree.
1046          */
1047         mutex_lock(&ei->truncate_mutex);
1048
1049         if (n == 1) {
1050                 ext2_free_data(inode, i_data+offsets[0],
1051                                         i_data + EXT2_NDIR_BLOCKS);
1052                 goto do_indirects;
1053         }
1054
1055         partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1056         /* Kill the top of shared branch (already detached) */
1057         if (nr) {
1058                 if (partial == chain)
1059                         mark_inode_dirty(inode);
1060                 else
1061                         mark_buffer_dirty_inode(partial->bh, inode);
1062                 ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1063         }
1064         /* Clear the ends of indirect blocks on the shared branch */
1065         while (partial > chain) {
1066                 ext2_free_branches(inode,
1067                                    partial->p + 1,
1068                                    (__le32*)partial->bh->b_data+addr_per_block,
1069                                    (chain+n-1) - partial);
1070                 mark_buffer_dirty_inode(partial->bh, inode);
1071                 brelse (partial->bh);
1072                 partial--;
1073         }
1074 do_indirects:
1075         /* Kill the remaining (whole) subtrees */
1076         switch (offsets[0]) {
1077                 default:
1078                         nr = i_data[EXT2_IND_BLOCK];
1079                         if (nr) {
1080                                 i_data[EXT2_IND_BLOCK] = 0;
1081                                 mark_inode_dirty(inode);
1082                                 ext2_free_branches(inode, &nr, &nr+1, 1);
1083                         }
1084                 case EXT2_IND_BLOCK:
1085                         nr = i_data[EXT2_DIND_BLOCK];
1086                         if (nr) {
1087                                 i_data[EXT2_DIND_BLOCK] = 0;
1088                                 mark_inode_dirty(inode);
1089                                 ext2_free_branches(inode, &nr, &nr+1, 2);
1090                         }
1091                 case EXT2_DIND_BLOCK:
1092                         nr = i_data[EXT2_TIND_BLOCK];
1093                         if (nr) {
1094                                 i_data[EXT2_TIND_BLOCK] = 0;
1095                                 mark_inode_dirty(inode);
1096                                 ext2_free_branches(inode, &nr, &nr+1, 3);
1097                         }
1098                 case EXT2_TIND_BLOCK:
1099                         ;
1100         }
1101
1102         ext2_discard_reservation(inode);
1103
1104         mutex_unlock(&ei->truncate_mutex);
1105         inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
1106         if (inode_needs_sync(inode)) {
1107                 sync_mapping_buffers(inode->i_mapping);
1108                 ext2_sync_inode (inode);
1109         } else {
1110                 mark_inode_dirty(inode);
1111         }
1112 }
1113
1114 static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1115                                         struct buffer_head **p)
1116 {
1117         struct buffer_head * bh;
1118         unsigned long block_group;
1119         unsigned long block;
1120         unsigned long offset;
1121         struct ext2_group_desc * gdp;
1122
1123         *p = NULL;
1124         if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1125             ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1126                 goto Einval;
1127
1128         block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
1129         gdp = ext2_get_group_desc(sb, block_group, NULL);
1130         if (!gdp)
1131                 goto Egdp;
1132         /*
1133          * Figure out the offset within the block group inode table
1134          */
1135         offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1136         block = le32_to_cpu(gdp->bg_inode_table) +
1137                 (offset >> EXT2_BLOCK_SIZE_BITS(sb));
1138         if (!(bh = sb_bread(sb, block)))
1139                 goto Eio;
1140
1141         *p = bh;
1142         offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1143         return (struct ext2_inode *) (bh->b_data + offset);
1144
1145 Einval:
1146         ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1147                    (unsigned long) ino);
1148         return ERR_PTR(-EINVAL);
1149 Eio:
1150         ext2_error(sb, "ext2_get_inode",
1151                    "unable to read inode block - inode=%lu, block=%lu",
1152                    (unsigned long) ino, block);
1153 Egdp:
1154         return ERR_PTR(-EIO);
1155 }
1156
1157 void ext2_set_inode_flags(struct inode *inode)
1158 {
1159         unsigned int flags = EXT2_I(inode)->i_flags;
1160
1161         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
1162         if (flags & EXT2_SYNC_FL)
1163                 inode->i_flags |= S_SYNC;
1164         if (flags & EXT2_APPEND_FL)
1165                 inode->i_flags |= S_APPEND;
1166         if (flags & EXT2_IMMUTABLE_FL)
1167                 inode->i_flags |= S_IMMUTABLE;
1168         if (flags & EXT2_NOATIME_FL)
1169                 inode->i_flags |= S_NOATIME;
1170         if (flags & EXT2_DIRSYNC_FL)
1171                 inode->i_flags |= S_DIRSYNC;
1172 }
1173
1174 /* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
1175 void ext2_get_inode_flags(struct ext2_inode_info *ei)
1176 {
1177         unsigned int flags = ei->vfs_inode.i_flags;
1178
1179         ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|
1180                         EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL);
1181         if (flags & S_SYNC)
1182                 ei->i_flags |= EXT2_SYNC_FL;
1183         if (flags & S_APPEND)
1184                 ei->i_flags |= EXT2_APPEND_FL;
1185         if (flags & S_IMMUTABLE)
1186                 ei->i_flags |= EXT2_IMMUTABLE_FL;
1187         if (flags & S_NOATIME)
1188                 ei->i_flags |= EXT2_NOATIME_FL;
1189         if (flags & S_DIRSYNC)
1190                 ei->i_flags |= EXT2_DIRSYNC_FL;
1191 }
1192
1193 struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
1194 {
1195         struct ext2_inode_info *ei;
1196         struct buffer_head * bh;
1197         struct ext2_inode *raw_inode;
1198         struct inode *inode;
1199         long ret = -EIO;
1200         int n;
1201
1202         inode = iget_locked(sb, ino);
1203         if (!inode)
1204                 return ERR_PTR(-ENOMEM);
1205         if (!(inode->i_state & I_NEW))
1206                 return inode;
1207
1208         ei = EXT2_I(inode);
1209 #ifdef CONFIG_EXT2_FS_POSIX_ACL
1210         ei->i_acl = EXT2_ACL_NOT_CACHED;
1211         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
1212 #endif
1213         ei->i_block_alloc_info = NULL;
1214
1215         raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1216         if (IS_ERR(raw_inode)) {
1217                 ret = PTR_ERR(raw_inode);
1218                 goto bad_inode;
1219         }
1220
1221         inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1222         inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1223         inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1224         if (!(test_opt (inode->i_sb, NO_UID32))) {
1225                 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1226                 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1227         }
1228         inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
1229         inode->i_size = le32_to_cpu(raw_inode->i_size);
1230         inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
1231         inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
1232         inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
1233         inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1234         ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1235         /* We now have enough fields to check if the inode was active or not.
1236          * This is needed because nfsd might try to access dead inodes
1237          * the test is that same one that e2fsck uses
1238          * NeilBrown 1999oct15
1239          */
1240         if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1241                 /* this inode is deleted */
1242                 brelse (bh);
1243                 ret = -ESTALE;
1244                 goto bad_inode;
1245         }
1246         inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1247         ei->i_flags = le32_to_cpu(raw_inode->i_flags);
1248         ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1249         ei->i_frag_no = raw_inode->i_frag;
1250         ei->i_frag_size = raw_inode->i_fsize;
1251         ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1252         ei->i_dir_acl = 0;
1253         if (S_ISREG(inode->i_mode))
1254                 inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1255         else
1256                 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1257         ei->i_dtime = 0;
1258         inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1259         ei->i_state = 0;
1260         ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1261         ei->i_dir_start_lookup = 0;
1262
1263         /*
1264          * NOTE! The in-memory inode i_data array is in little-endian order
1265          * even on big-endian machines: we do NOT byteswap the block numbers!
1266          */
1267         for (n = 0; n < EXT2_N_BLOCKS; n++)
1268                 ei->i_data[n] = raw_inode->i_block[n];
1269
1270         if (S_ISREG(inode->i_mode)) {
1271                 inode->i_op = &ext2_file_inode_operations;
1272                 if (ext2_use_xip(inode->i_sb)) {
1273                         inode->i_mapping->a_ops = &ext2_aops_xip;
1274                         inode->i_fop = &ext2_xip_file_operations;
1275                 } else if (test_opt(inode->i_sb, NOBH)) {
1276                         inode->i_mapping->a_ops = &ext2_nobh_aops;
1277                         inode->i_fop = &ext2_file_operations;
1278                 } else {
1279                         inode->i_mapping->a_ops = &ext2_aops;
1280                         inode->i_fop = &ext2_file_operations;
1281                 }
1282         } else if (S_ISDIR(inode->i_mode)) {
1283                 inode->i_op = &ext2_dir_inode_operations;
1284                 inode->i_fop = &ext2_dir_operations;
1285                 if (test_opt(inode->i_sb, NOBH))
1286                         inode->i_mapping->a_ops = &ext2_nobh_aops;
1287                 else
1288                         inode->i_mapping->a_ops = &ext2_aops;
1289         } else if (S_ISLNK(inode->i_mode)) {
1290                 if (ext2_inode_is_fast_symlink(inode)) {
1291                         inode->i_op = &ext2_fast_symlink_inode_operations;
1292                         nd_terminate_link(ei->i_data, inode->i_size,
1293                                 sizeof(ei->i_data) - 1);
1294                 } else {
1295                         inode->i_op = &ext2_symlink_inode_operations;
1296                         if (test_opt(inode->i_sb, NOBH))
1297                                 inode->i_mapping->a_ops = &ext2_nobh_aops;
1298                         else
1299                                 inode->i_mapping->a_ops = &ext2_aops;
1300                 }
1301         } else {
1302                 inode->i_op = &ext2_special_inode_operations;
1303                 if (raw_inode->i_block[0])
1304                         init_special_inode(inode, inode->i_mode,
1305                            old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1306                 else 
1307                         init_special_inode(inode, inode->i_mode,
1308                            new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1309         }
1310         brelse (bh);
1311         ext2_set_inode_flags(inode);
1312         unlock_new_inode(inode);
1313         return inode;
1314         
1315 bad_inode:
1316         iget_failed(inode);
1317         return ERR_PTR(ret);
1318 }
1319
1320 static int ext2_update_inode(struct inode * inode, int do_sync)
1321 {
1322         struct ext2_inode_info *ei = EXT2_I(inode);
1323         struct super_block *sb = inode->i_sb;
1324         ino_t ino = inode->i_ino;
1325         uid_t uid = inode->i_uid;
1326         gid_t gid = inode->i_gid;
1327         struct buffer_head * bh;
1328         struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1329         int n;
1330         int err = 0;
1331
1332         if (IS_ERR(raw_inode))
1333                 return -EIO;
1334
1335         /* For fields not not tracking in the in-memory inode,
1336          * initialise them to zero for new inodes. */
1337         if (ei->i_state & EXT2_STATE_NEW)
1338                 memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1339
1340         ext2_get_inode_flags(ei);
1341         raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1342         if (!(test_opt(sb, NO_UID32))) {
1343                 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1344                 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1345 /*
1346  * Fix up interoperability with old kernels. Otherwise, old inodes get
1347  * re-used with the upper 16 bits of the uid/gid intact
1348  */
1349                 if (!ei->i_dtime) {
1350                         raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1351                         raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1352                 } else {
1353                         raw_inode->i_uid_high = 0;
1354                         raw_inode->i_gid_high = 0;
1355                 }
1356         } else {
1357                 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1358                 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1359                 raw_inode->i_uid_high = 0;
1360                 raw_inode->i_gid_high = 0;
1361         }
1362         raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1363         raw_inode->i_size = cpu_to_le32(inode->i_size);
1364         raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
1365         raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
1366         raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
1367
1368         raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1369         raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1370         raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1371         raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1372         raw_inode->i_frag = ei->i_frag_no;
1373         raw_inode->i_fsize = ei->i_frag_size;
1374         raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1375         if (!S_ISREG(inode->i_mode))
1376                 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1377         else {
1378                 raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1379                 if (inode->i_size > 0x7fffffffULL) {
1380                         if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1381                                         EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1382                             EXT2_SB(sb)->s_es->s_rev_level ==
1383                                         cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1384                                /* If this is the first large file
1385                                 * created, add a flag to the superblock.
1386                                 */
1387                                 lock_kernel();
1388                                 ext2_update_dynamic_rev(sb);
1389                                 EXT2_SET_RO_COMPAT_FEATURE(sb,
1390                                         EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1391                                 unlock_kernel();
1392                                 ext2_write_super(sb);
1393                         }
1394                 }
1395         }
1396         
1397         raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1398         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1399                 if (old_valid_dev(inode->i_rdev)) {
1400                         raw_inode->i_block[0] =
1401                                 cpu_to_le32(old_encode_dev(inode->i_rdev));
1402                         raw_inode->i_block[1] = 0;
1403                 } else {
1404                         raw_inode->i_block[0] = 0;
1405                         raw_inode->i_block[1] =
1406                                 cpu_to_le32(new_encode_dev(inode->i_rdev));
1407                         raw_inode->i_block[2] = 0;
1408                 }
1409         } else for (n = 0; n < EXT2_N_BLOCKS; n++)
1410                 raw_inode->i_block[n] = ei->i_data[n];
1411         mark_buffer_dirty(bh);
1412         if (do_sync) {
1413                 sync_dirty_buffer(bh);
1414                 if (buffer_req(bh) && !buffer_uptodate(bh)) {
1415                         printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1416                                 sb->s_id, (unsigned long) ino);
1417                         err = -EIO;
1418                 }
1419         }
1420         ei->i_state &= ~EXT2_STATE_NEW;
1421         brelse (bh);
1422         return err;
1423 }
1424
1425 int ext2_write_inode(struct inode *inode, int wait)
1426 {
1427         return ext2_update_inode(inode, wait);
1428 }
1429
1430 int ext2_sync_inode(struct inode *inode)
1431 {
1432         struct writeback_control wbc = {
1433                 .sync_mode = WB_SYNC_ALL,
1434                 .nr_to_write = 0,       /* sys_fsync did this */
1435         };
1436         return sync_inode(inode, &wbc);
1437 }
1438
1439 int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
1440 {
1441         struct inode *inode = dentry->d_inode;
1442         int error;
1443
1444         error = inode_change_ok(inode, iattr);
1445         if (error)
1446                 return error;
1447         if ((iattr->ia_valid & ATTR_UID && iattr->ia_uid != inode->i_uid) ||
1448             (iattr->ia_valid & ATTR_GID && iattr->ia_gid != inode->i_gid)) {
1449                 error = DQUOT_TRANSFER(inode, iattr) ? -EDQUOT : 0;
1450                 if (error)
1451                         return error;
1452         }
1453         error = inode_setattr(inode, iattr);
1454         if (!error && (iattr->ia_valid & ATTR_MODE))
1455                 error = ext2_acl_chmod(inode);
1456         return error;
1457 }