xref: /openbmc/linux/fs/ext2/inode.c (revision 78700c0a)
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/time.h>
26 #include <linux/highuid.h>
27 #include <linux/pagemap.h>
28 #include <linux/dax.h>
29 #include <linux/blkdev.h>
30 #include <linux/quotaops.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 <linux/uio.h>
37 #include "ext2.h"
38 #include "acl.h"
39 #include "xattr.h"
40 
41 static int __ext2_write_inode(struct inode *inode, int do_sync);
42 
43 /*
44  * Test whether an inode is a fast symlink.
45  */
46 static inline int ext2_inode_is_fast_symlink(struct inode *inode)
47 {
48 	int ea_blocks = EXT2_I(inode)->i_file_acl ?
49 		(inode->i_sb->s_blocksize >> 9) : 0;
50 
51 	return (S_ISLNK(inode->i_mode) &&
52 		inode->i_blocks - ea_blocks == 0);
53 }
54 
55 static void ext2_truncate_blocks(struct inode *inode, loff_t offset);
56 
57 static void ext2_write_failed(struct address_space *mapping, loff_t to)
58 {
59 	struct inode *inode = mapping->host;
60 
61 	if (to > inode->i_size) {
62 		truncate_pagecache(inode, inode->i_size);
63 		ext2_truncate_blocks(inode, inode->i_size);
64 	}
65 }
66 
67 /*
68  * Called at the last iput() if i_nlink is zero.
69  */
70 void ext2_evict_inode(struct inode * inode)
71 {
72 	struct ext2_block_alloc_info *rsv;
73 	int want_delete = 0;
74 
75 	if (!inode->i_nlink && !is_bad_inode(inode)) {
76 		want_delete = 1;
77 		dquot_initialize(inode);
78 	} else {
79 		dquot_drop(inode);
80 	}
81 
82 	truncate_inode_pages_final(&inode->i_data);
83 
84 	if (want_delete) {
85 		sb_start_intwrite(inode->i_sb);
86 		/* set dtime */
87 		EXT2_I(inode)->i_dtime	= get_seconds();
88 		mark_inode_dirty(inode);
89 		__ext2_write_inode(inode, inode_needs_sync(inode));
90 		/* truncate to 0 */
91 		inode->i_size = 0;
92 		if (inode->i_blocks)
93 			ext2_truncate_blocks(inode, 0);
94 		ext2_xattr_delete_inode(inode);
95 	}
96 
97 	invalidate_inode_buffers(inode);
98 	clear_inode(inode);
99 
100 	ext2_discard_reservation(inode);
101 	rsv = EXT2_I(inode)->i_block_alloc_info;
102 	EXT2_I(inode)->i_block_alloc_info = NULL;
103 	if (unlikely(rsv))
104 		kfree(rsv);
105 
106 	if (want_delete) {
107 		ext2_free_inode(inode);
108 		sb_end_intwrite(inode->i_sb);
109 	}
110 }
111 
112 typedef struct {
113 	__le32	*p;
114 	__le32	key;
115 	struct buffer_head *bh;
116 } Indirect;
117 
118 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
119 {
120 	p->key = *(p->p = v);
121 	p->bh = bh;
122 }
123 
124 static inline int verify_chain(Indirect *from, Indirect *to)
125 {
126 	while (from <= to && from->key == *from->p)
127 		from++;
128 	return (from > to);
129 }
130 
131 /**
132  *	ext2_block_to_path - parse the block number into array of offsets
133  *	@inode: inode in question (we are only interested in its superblock)
134  *	@i_block: block number to be parsed
135  *	@offsets: array to store the offsets in
136  *      @boundary: set this non-zero if the referred-to block is likely to be
137  *             followed (on disk) by an indirect block.
138  *	To store the locations of file's data ext2 uses a data structure common
139  *	for UNIX filesystems - tree of pointers anchored in the inode, with
140  *	data blocks at leaves and indirect blocks in intermediate nodes.
141  *	This function translates the block number into path in that tree -
142  *	return value is the path length and @offsets[n] is the offset of
143  *	pointer to (n+1)th node in the nth one. If @block is out of range
144  *	(negative or too large) warning is printed and zero returned.
145  *
146  *	Note: function doesn't find node addresses, so no IO is needed. All
147  *	we need to know is the capacity of indirect blocks (taken from the
148  *	inode->i_sb).
149  */
150 
151 /*
152  * Portability note: the last comparison (check that we fit into triple
153  * indirect block) is spelled differently, because otherwise on an
154  * architecture with 32-bit longs and 8Kb pages we might get into trouble
155  * if our filesystem had 8Kb blocks. We might use long long, but that would
156  * kill us on x86. Oh, well, at least the sign propagation does not matter -
157  * i_block would have to be negative in the very beginning, so we would not
158  * get there at all.
159  */
160 
161 static int ext2_block_to_path(struct inode *inode,
162 			long i_block, int offsets[4], int *boundary)
163 {
164 	int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
165 	int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
166 	const long direct_blocks = EXT2_NDIR_BLOCKS,
167 		indirect_blocks = ptrs,
168 		double_blocks = (1 << (ptrs_bits * 2));
169 	int n = 0;
170 	int final = 0;
171 
172 	if (i_block < 0) {
173 		ext2_msg(inode->i_sb, KERN_WARNING,
174 			"warning: %s: block < 0", __func__);
175 	} else if (i_block < direct_blocks) {
176 		offsets[n++] = i_block;
177 		final = direct_blocks;
178 	} else if ( (i_block -= direct_blocks) < indirect_blocks) {
179 		offsets[n++] = EXT2_IND_BLOCK;
180 		offsets[n++] = i_block;
181 		final = ptrs;
182 	} else if ((i_block -= indirect_blocks) < double_blocks) {
183 		offsets[n++] = EXT2_DIND_BLOCK;
184 		offsets[n++] = i_block >> ptrs_bits;
185 		offsets[n++] = i_block & (ptrs - 1);
186 		final = ptrs;
187 	} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
188 		offsets[n++] = EXT2_TIND_BLOCK;
189 		offsets[n++] = i_block >> (ptrs_bits * 2);
190 		offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
191 		offsets[n++] = i_block & (ptrs - 1);
192 		final = ptrs;
193 	} else {
194 		ext2_msg(inode->i_sb, KERN_WARNING,
195 			"warning: %s: block is too big", __func__);
196 	}
197 	if (boundary)
198 		*boundary = final - 1 - (i_block & (ptrs - 1));
199 
200 	return n;
201 }
202 
203 /**
204  *	ext2_get_branch - read the chain of indirect blocks leading to data
205  *	@inode: inode in question
206  *	@depth: depth of the chain (1 - direct pointer, etc.)
207  *	@offsets: offsets of pointers in inode/indirect blocks
208  *	@chain: place to store the result
209  *	@err: here we store the error value
210  *
211  *	Function fills the array of triples <key, p, bh> and returns %NULL
212  *	if everything went OK or the pointer to the last filled triple
213  *	(incomplete one) otherwise. Upon the return chain[i].key contains
214  *	the number of (i+1)-th block in the chain (as it is stored in memory,
215  *	i.e. little-endian 32-bit), chain[i].p contains the address of that
216  *	number (it points into struct inode for i==0 and into the bh->b_data
217  *	for i>0) and chain[i].bh points to the buffer_head of i-th indirect
218  *	block for i>0 and NULL for i==0. In other words, it holds the block
219  *	numbers of the chain, addresses they were taken from (and where we can
220  *	verify that chain did not change) and buffer_heads hosting these
221  *	numbers.
222  *
223  *	Function stops when it stumbles upon zero pointer (absent block)
224  *		(pointer to last triple returned, *@err == 0)
225  *	or when it gets an IO error reading an indirect block
226  *		(ditto, *@err == -EIO)
227  *	or when it notices that chain had been changed while it was reading
228  *		(ditto, *@err == -EAGAIN)
229  *	or when it reads all @depth-1 indirect blocks successfully and finds
230  *	the whole chain, all way to the data (returns %NULL, *err == 0).
231  */
232 static Indirect *ext2_get_branch(struct inode *inode,
233 				 int depth,
234 				 int *offsets,
235 				 Indirect chain[4],
236 				 int *err)
237 {
238 	struct super_block *sb = inode->i_sb;
239 	Indirect *p = chain;
240 	struct buffer_head *bh;
241 
242 	*err = 0;
243 	/* i_data is not going away, no lock needed */
244 	add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
245 	if (!p->key)
246 		goto no_block;
247 	while (--depth) {
248 		bh = sb_bread(sb, le32_to_cpu(p->key));
249 		if (!bh)
250 			goto failure;
251 		read_lock(&EXT2_I(inode)->i_meta_lock);
252 		if (!verify_chain(chain, p))
253 			goto changed;
254 		add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
255 		read_unlock(&EXT2_I(inode)->i_meta_lock);
256 		if (!p->key)
257 			goto no_block;
258 	}
259 	return NULL;
260 
261 changed:
262 	read_unlock(&EXT2_I(inode)->i_meta_lock);
263 	brelse(bh);
264 	*err = -EAGAIN;
265 	goto no_block;
266 failure:
267 	*err = -EIO;
268 no_block:
269 	return p;
270 }
271 
272 /**
273  *	ext2_find_near - find a place for allocation with sufficient locality
274  *	@inode: owner
275  *	@ind: descriptor of indirect block.
276  *
277  *	This function returns the preferred place for block allocation.
278  *	It is used when heuristic for sequential allocation fails.
279  *	Rules are:
280  *	  + if there is a block to the left of our position - allocate near it.
281  *	  + if pointer will live in indirect block - allocate near that block.
282  *	  + if pointer will live in inode - allocate in the same cylinder group.
283  *
284  * In the latter case we colour the starting block by the callers PID to
285  * prevent it from clashing with concurrent allocations for a different inode
286  * in the same block group.   The PID is used here so that functionally related
287  * files will be close-by on-disk.
288  *
289  *	Caller must make sure that @ind is valid and will stay that way.
290  */
291 
292 static ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind)
293 {
294 	struct ext2_inode_info *ei = EXT2_I(inode);
295 	__le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
296 	__le32 *p;
297 	ext2_fsblk_t bg_start;
298 	ext2_fsblk_t colour;
299 
300 	/* Try to find previous block */
301 	for (p = ind->p - 1; p >= start; p--)
302 		if (*p)
303 			return le32_to_cpu(*p);
304 
305 	/* No such thing, so let's try location of indirect block */
306 	if (ind->bh)
307 		return ind->bh->b_blocknr;
308 
309 	/*
310 	 * It is going to be referred from inode itself? OK, just put it into
311 	 * the same cylinder group then.
312 	 */
313 	bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group);
314 	colour = (current->pid % 16) *
315 			(EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
316 	return bg_start + colour;
317 }
318 
319 /**
320  *	ext2_find_goal - find a preferred place for allocation.
321  *	@inode: owner
322  *	@block:  block we want
323  *	@partial: pointer to the last triple within a chain
324  *
325  *	Returns preferred place for a block (the goal).
326  */
327 
328 static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block,
329 					  Indirect *partial)
330 {
331 	struct ext2_block_alloc_info *block_i;
332 
333 	block_i = EXT2_I(inode)->i_block_alloc_info;
334 
335 	/*
336 	 * try the heuristic for sequential allocation,
337 	 * failing that at least try to get decent locality.
338 	 */
339 	if (block_i && (block == block_i->last_alloc_logical_block + 1)
340 		&& (block_i->last_alloc_physical_block != 0)) {
341 		return block_i->last_alloc_physical_block + 1;
342 	}
343 
344 	return ext2_find_near(inode, partial);
345 }
346 
347 /**
348  *	ext2_blks_to_allocate: Look up the block map and count the number
349  *	of direct blocks need to be allocated for the given branch.
350  *
351  * 	@branch: chain of indirect blocks
352  *	@k: number of blocks need for indirect blocks
353  *	@blks: number of data blocks to be mapped.
354  *	@blocks_to_boundary:  the offset in the indirect block
355  *
356  *	return the total number of blocks to be allocate, including the
357  *	direct and indirect blocks.
358  */
359 static int
360 ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
361 		int blocks_to_boundary)
362 {
363 	unsigned long count = 0;
364 
365 	/*
366 	 * Simple case, [t,d]Indirect block(s) has not allocated yet
367 	 * then it's clear blocks on that path have not allocated
368 	 */
369 	if (k > 0) {
370 		/* right now don't hanel cross boundary allocation */
371 		if (blks < blocks_to_boundary + 1)
372 			count += blks;
373 		else
374 			count += blocks_to_boundary + 1;
375 		return count;
376 	}
377 
378 	count++;
379 	while (count < blks && count <= blocks_to_boundary
380 		&& le32_to_cpu(*(branch[0].p + count)) == 0) {
381 		count++;
382 	}
383 	return count;
384 }
385 
386 /**
387  *	ext2_alloc_blocks: multiple allocate blocks needed for a branch
388  *	@indirect_blks: the number of blocks need to allocate for indirect
389  *			blocks
390  *
391  *	@new_blocks: on return it will store the new block numbers for
392  *	the indirect blocks(if needed) and the first direct block,
393  *	@blks:	on return it will store the total number of allocated
394  *		direct blocks
395  */
396 static int ext2_alloc_blocks(struct inode *inode,
397 			ext2_fsblk_t goal, int indirect_blks, int blks,
398 			ext2_fsblk_t new_blocks[4], int *err)
399 {
400 	int target, i;
401 	unsigned long count = 0;
402 	int index = 0;
403 	ext2_fsblk_t current_block = 0;
404 	int ret = 0;
405 
406 	/*
407 	 * Here we try to allocate the requested multiple blocks at once,
408 	 * on a best-effort basis.
409 	 * To build a branch, we should allocate blocks for
410 	 * the indirect blocks(if not allocated yet), and at least
411 	 * the first direct block of this branch.  That's the
412 	 * minimum number of blocks need to allocate(required)
413 	 */
414 	target = blks + indirect_blks;
415 
416 	while (1) {
417 		count = target;
418 		/* allocating blocks for indirect blocks and direct blocks */
419 		current_block = ext2_new_blocks(inode,goal,&count,err);
420 		if (*err)
421 			goto failed_out;
422 
423 		target -= count;
424 		/* allocate blocks for indirect blocks */
425 		while (index < indirect_blks && count) {
426 			new_blocks[index++] = current_block++;
427 			count--;
428 		}
429 
430 		if (count > 0)
431 			break;
432 	}
433 
434 	/* save the new block number for the first direct block */
435 	new_blocks[index] = current_block;
436 
437 	/* total number of blocks allocated for direct blocks */
438 	ret = count;
439 	*err = 0;
440 	return ret;
441 failed_out:
442 	for (i = 0; i <index; i++)
443 		ext2_free_blocks(inode, new_blocks[i], 1);
444 	if (index)
445 		mark_inode_dirty(inode);
446 	return ret;
447 }
448 
449 /**
450  *	ext2_alloc_branch - allocate and set up a chain of blocks.
451  *	@inode: owner
452  *	@num: depth of the chain (number of blocks to allocate)
453  *	@offsets: offsets (in the blocks) to store the pointers to next.
454  *	@branch: place to store the chain in.
455  *
456  *	This function allocates @num blocks, zeroes out all but the last one,
457  *	links them into chain and (if we are synchronous) writes them to disk.
458  *	In other words, it prepares a branch that can be spliced onto the
459  *	inode. It stores the information about that chain in the branch[], in
460  *	the same format as ext2_get_branch() would do. We are calling it after
461  *	we had read the existing part of chain and partial points to the last
462  *	triple of that (one with zero ->key). Upon the exit we have the same
463  *	picture as after the successful ext2_get_block(), except that in one
464  *	place chain is disconnected - *branch->p is still zero (we did not
465  *	set the last link), but branch->key contains the number that should
466  *	be placed into *branch->p to fill that gap.
467  *
468  *	If allocation fails we free all blocks we've allocated (and forget
469  *	their buffer_heads) and return the error value the from failed
470  *	ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
471  *	as described above and return 0.
472  */
473 
474 static int ext2_alloc_branch(struct inode *inode,
475 			int indirect_blks, int *blks, ext2_fsblk_t goal,
476 			int *offsets, Indirect *branch)
477 {
478 	int blocksize = inode->i_sb->s_blocksize;
479 	int i, n = 0;
480 	int err = 0;
481 	struct buffer_head *bh;
482 	int num;
483 	ext2_fsblk_t new_blocks[4];
484 	ext2_fsblk_t current_block;
485 
486 	num = ext2_alloc_blocks(inode, goal, indirect_blks,
487 				*blks, new_blocks, &err);
488 	if (err)
489 		return err;
490 
491 	branch[0].key = cpu_to_le32(new_blocks[0]);
492 	/*
493 	 * metadata blocks and data blocks are allocated.
494 	 */
495 	for (n = 1; n <= indirect_blks;  n++) {
496 		/*
497 		 * Get buffer_head for parent block, zero it out
498 		 * and set the pointer to new one, then send
499 		 * parent to disk.
500 		 */
501 		bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
502 		if (unlikely(!bh)) {
503 			err = -ENOMEM;
504 			goto failed;
505 		}
506 		branch[n].bh = bh;
507 		lock_buffer(bh);
508 		memset(bh->b_data, 0, blocksize);
509 		branch[n].p = (__le32 *) bh->b_data + offsets[n];
510 		branch[n].key = cpu_to_le32(new_blocks[n]);
511 		*branch[n].p = branch[n].key;
512 		if ( n == indirect_blks) {
513 			current_block = new_blocks[n];
514 			/*
515 			 * End of chain, update the last new metablock of
516 			 * the chain to point to the new allocated
517 			 * data blocks numbers
518 			 */
519 			for (i=1; i < num; i++)
520 				*(branch[n].p + i) = cpu_to_le32(++current_block);
521 		}
522 		set_buffer_uptodate(bh);
523 		unlock_buffer(bh);
524 		mark_buffer_dirty_inode(bh, inode);
525 		/* We used to sync bh here if IS_SYNC(inode).
526 		 * But we now rely upon generic_write_sync()
527 		 * and b_inode_buffers.  But not for directories.
528 		 */
529 		if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
530 			sync_dirty_buffer(bh);
531 	}
532 	*blks = num;
533 	return err;
534 
535 failed:
536 	for (i = 1; i < n; i++)
537 		bforget(branch[i].bh);
538 	for (i = 0; i < indirect_blks; i++)
539 		ext2_free_blocks(inode, new_blocks[i], 1);
540 	ext2_free_blocks(inode, new_blocks[i], num);
541 	return err;
542 }
543 
544 /**
545  * ext2_splice_branch - splice the allocated branch onto inode.
546  * @inode: owner
547  * @block: (logical) number of block we are adding
548  * @where: location of missing link
549  * @num:   number of indirect blocks we are adding
550  * @blks:  number of direct blocks we are adding
551  *
552  * This function fills the missing link and does all housekeeping needed in
553  * inode (->i_blocks, etc.). In case of success we end up with the full
554  * chain to new block and return 0.
555  */
556 static void ext2_splice_branch(struct inode *inode,
557 			long block, Indirect *where, int num, int blks)
558 {
559 	int i;
560 	struct ext2_block_alloc_info *block_i;
561 	ext2_fsblk_t current_block;
562 
563 	block_i = EXT2_I(inode)->i_block_alloc_info;
564 
565 	/* XXX LOCKING probably should have i_meta_lock ?*/
566 	/* That's it */
567 
568 	*where->p = where->key;
569 
570 	/*
571 	 * Update the host buffer_head or inode to point to more just allocated
572 	 * direct blocks blocks
573 	 */
574 	if (num == 0 && blks > 1) {
575 		current_block = le32_to_cpu(where->key) + 1;
576 		for (i = 1; i < blks; i++)
577 			*(where->p + i ) = cpu_to_le32(current_block++);
578 	}
579 
580 	/*
581 	 * update the most recently allocated logical & physical block
582 	 * in i_block_alloc_info, to assist find the proper goal block for next
583 	 * allocation
584 	 */
585 	if (block_i) {
586 		block_i->last_alloc_logical_block = block + blks - 1;
587 		block_i->last_alloc_physical_block =
588 				le32_to_cpu(where[num].key) + blks - 1;
589 	}
590 
591 	/* We are done with atomic stuff, now do the rest of housekeeping */
592 
593 	/* had we spliced it onto indirect block? */
594 	if (where->bh)
595 		mark_buffer_dirty_inode(where->bh, inode);
596 
597 	inode->i_ctime = CURRENT_TIME_SEC;
598 	mark_inode_dirty(inode);
599 }
600 
601 /*
602  * Allocation strategy is simple: if we have to allocate something, we will
603  * have to go the whole way to leaf. So let's do it before attaching anything
604  * to tree, set linkage between the newborn blocks, write them if sync is
605  * required, recheck the path, free and repeat if check fails, otherwise
606  * set the last missing link (that will protect us from any truncate-generated
607  * removals - all blocks on the path are immune now) and possibly force the
608  * write on the parent block.
609  * That has a nice additional property: no special recovery from the failed
610  * allocations is needed - we simply release blocks and do not touch anything
611  * reachable from inode.
612  *
613  * `handle' can be NULL if create == 0.
614  *
615  * return > 0, # of blocks mapped or allocated.
616  * return = 0, if plain lookup failed.
617  * return < 0, error case.
618  */
619 static int ext2_get_blocks(struct inode *inode,
620 			   sector_t iblock, unsigned long maxblocks,
621 			   struct buffer_head *bh_result,
622 			   int create)
623 {
624 	int err = -EIO;
625 	int offsets[4];
626 	Indirect chain[4];
627 	Indirect *partial;
628 	ext2_fsblk_t goal;
629 	int indirect_blks;
630 	int blocks_to_boundary = 0;
631 	int depth;
632 	struct ext2_inode_info *ei = EXT2_I(inode);
633 	int count = 0;
634 	ext2_fsblk_t first_block = 0;
635 
636 	BUG_ON(maxblocks == 0);
637 
638 	depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
639 
640 	if (depth == 0)
641 		return (err);
642 
643 	partial = ext2_get_branch(inode, depth, offsets, chain, &err);
644 	/* Simplest case - block found, no allocation needed */
645 	if (!partial) {
646 		first_block = le32_to_cpu(chain[depth - 1].key);
647 		clear_buffer_new(bh_result); /* What's this do? */
648 		count++;
649 		/*map more blocks*/
650 		while (count < maxblocks && count <= blocks_to_boundary) {
651 			ext2_fsblk_t blk;
652 
653 			if (!verify_chain(chain, chain + depth - 1)) {
654 				/*
655 				 * Indirect block might be removed by
656 				 * truncate while we were reading it.
657 				 * Handling of that case: forget what we've
658 				 * got now, go to reread.
659 				 */
660 				err = -EAGAIN;
661 				count = 0;
662 				break;
663 			}
664 			blk = le32_to_cpu(*(chain[depth-1].p + count));
665 			if (blk == first_block + count)
666 				count++;
667 			else
668 				break;
669 		}
670 		if (err != -EAGAIN)
671 			goto got_it;
672 	}
673 
674 	/* Next simple case - plain lookup or failed read of indirect block */
675 	if (!create || err == -EIO)
676 		goto cleanup;
677 
678 	mutex_lock(&ei->truncate_mutex);
679 	/*
680 	 * If the indirect block is missing while we are reading
681 	 * the chain(ext2_get_branch() returns -EAGAIN err), or
682 	 * if the chain has been changed after we grab the semaphore,
683 	 * (either because another process truncated this branch, or
684 	 * another get_block allocated this branch) re-grab the chain to see if
685 	 * the request block has been allocated or not.
686 	 *
687 	 * Since we already block the truncate/other get_block
688 	 * at this point, we will have the current copy of the chain when we
689 	 * splice the branch into the tree.
690 	 */
691 	if (err == -EAGAIN || !verify_chain(chain, partial)) {
692 		while (partial > chain) {
693 			brelse(partial->bh);
694 			partial--;
695 		}
696 		partial = ext2_get_branch(inode, depth, offsets, chain, &err);
697 		if (!partial) {
698 			count++;
699 			mutex_unlock(&ei->truncate_mutex);
700 			if (err)
701 				goto cleanup;
702 			clear_buffer_new(bh_result);
703 			goto got_it;
704 		}
705 	}
706 
707 	/*
708 	 * Okay, we need to do block allocation.  Lazily initialize the block
709 	 * allocation info here if necessary
710 	*/
711 	if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
712 		ext2_init_block_alloc_info(inode);
713 
714 	goal = ext2_find_goal(inode, iblock, partial);
715 
716 	/* the number of blocks need to allocate for [d,t]indirect blocks */
717 	indirect_blks = (chain + depth) - partial - 1;
718 	/*
719 	 * Next look up the indirect map to count the totoal number of
720 	 * direct blocks to allocate for this branch.
721 	 */
722 	count = ext2_blks_to_allocate(partial, indirect_blks,
723 					maxblocks, blocks_to_boundary);
724 	/*
725 	 * XXX ???? Block out ext2_truncate while we alter the tree
726 	 */
727 	err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
728 				offsets + (partial - chain), partial);
729 
730 	if (err) {
731 		mutex_unlock(&ei->truncate_mutex);
732 		goto cleanup;
733 	}
734 
735 	if (IS_DAX(inode)) {
736 		/*
737 		 * block must be initialised before we put it in the tree
738 		 * so that it's not found by another thread before it's
739 		 * initialised
740 		 */
741 		err = sb_issue_zeroout(inode->i_sb,
742 				le32_to_cpu(chain[depth-1].key), count,
743 				GFP_NOFS);
744 		if (err) {
745 			mutex_unlock(&ei->truncate_mutex);
746 			goto cleanup;
747 		}
748 	} else
749 		set_buffer_new(bh_result);
750 
751 	ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
752 	mutex_unlock(&ei->truncate_mutex);
753 got_it:
754 	map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
755 	if (count > blocks_to_boundary)
756 		set_buffer_boundary(bh_result);
757 	err = count;
758 	/* Clean up and exit */
759 	partial = chain + depth - 1;	/* the whole chain */
760 cleanup:
761 	while (partial > chain) {
762 		brelse(partial->bh);
763 		partial--;
764 	}
765 	return err;
766 }
767 
768 int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
769 {
770 	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
771 	int ret = ext2_get_blocks(inode, iblock, max_blocks,
772 			      bh_result, create);
773 	if (ret > 0) {
774 		bh_result->b_size = (ret << inode->i_blkbits);
775 		ret = 0;
776 	}
777 	return ret;
778 
779 }
780 
781 int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
782 		u64 start, u64 len)
783 {
784 	return generic_block_fiemap(inode, fieinfo, start, len,
785 				    ext2_get_block);
786 }
787 
788 static int ext2_writepage(struct page *page, struct writeback_control *wbc)
789 {
790 	return block_write_full_page(page, ext2_get_block, wbc);
791 }
792 
793 static int ext2_readpage(struct file *file, struct page *page)
794 {
795 	return mpage_readpage(page, ext2_get_block);
796 }
797 
798 static int
799 ext2_readpages(struct file *file, struct address_space *mapping,
800 		struct list_head *pages, unsigned nr_pages)
801 {
802 	return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
803 }
804 
805 static int
806 ext2_write_begin(struct file *file, struct address_space *mapping,
807 		loff_t pos, unsigned len, unsigned flags,
808 		struct page **pagep, void **fsdata)
809 {
810 	int ret;
811 
812 	ret = block_write_begin(mapping, pos, len, flags, pagep,
813 				ext2_get_block);
814 	if (ret < 0)
815 		ext2_write_failed(mapping, pos + len);
816 	return ret;
817 }
818 
819 static int ext2_write_end(struct file *file, struct address_space *mapping,
820 			loff_t pos, unsigned len, unsigned copied,
821 			struct page *page, void *fsdata)
822 {
823 	int ret;
824 
825 	ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
826 	if (ret < len)
827 		ext2_write_failed(mapping, pos + len);
828 	return ret;
829 }
830 
831 static int
832 ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
833 		loff_t pos, unsigned len, unsigned flags,
834 		struct page **pagep, void **fsdata)
835 {
836 	int ret;
837 
838 	ret = nobh_write_begin(mapping, pos, len, flags, pagep, fsdata,
839 			       ext2_get_block);
840 	if (ret < 0)
841 		ext2_write_failed(mapping, pos + len);
842 	return ret;
843 }
844 
845 static int ext2_nobh_writepage(struct page *page,
846 			struct writeback_control *wbc)
847 {
848 	return nobh_writepage(page, ext2_get_block, wbc);
849 }
850 
851 static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
852 {
853 	return generic_block_bmap(mapping,block,ext2_get_block);
854 }
855 
856 static ssize_t
857 ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
858 {
859 	struct file *file = iocb->ki_filp;
860 	struct address_space *mapping = file->f_mapping;
861 	struct inode *inode = mapping->host;
862 	size_t count = iov_iter_count(iter);
863 	loff_t offset = iocb->ki_pos;
864 	ssize_t ret;
865 
866 	if (IS_DAX(inode))
867 		ret = dax_do_io(iocb, inode, iter, ext2_get_block, NULL,
868 				DIO_LOCKING);
869 	else
870 		ret = blockdev_direct_IO(iocb, inode, iter, ext2_get_block);
871 	if (ret < 0 && iov_iter_rw(iter) == WRITE)
872 		ext2_write_failed(mapping, offset + count);
873 	return ret;
874 }
875 
876 static int
877 ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
878 {
879 #ifdef CONFIG_FS_DAX
880 	if (dax_mapping(mapping)) {
881 		return dax_writeback_mapping_range(mapping,
882 						   mapping->host->i_sb->s_bdev,
883 						   wbc);
884 	}
885 #endif
886 
887 	return mpage_writepages(mapping, wbc, ext2_get_block);
888 }
889 
890 const struct address_space_operations ext2_aops = {
891 	.readpage		= ext2_readpage,
892 	.readpages		= ext2_readpages,
893 	.writepage		= ext2_writepage,
894 	.write_begin		= ext2_write_begin,
895 	.write_end		= ext2_write_end,
896 	.bmap			= ext2_bmap,
897 	.direct_IO		= ext2_direct_IO,
898 	.writepages		= ext2_writepages,
899 	.migratepage		= buffer_migrate_page,
900 	.is_partially_uptodate	= block_is_partially_uptodate,
901 	.error_remove_page	= generic_error_remove_page,
902 };
903 
904 const struct address_space_operations ext2_nobh_aops = {
905 	.readpage		= ext2_readpage,
906 	.readpages		= ext2_readpages,
907 	.writepage		= ext2_nobh_writepage,
908 	.write_begin		= ext2_nobh_write_begin,
909 	.write_end		= nobh_write_end,
910 	.bmap			= ext2_bmap,
911 	.direct_IO		= ext2_direct_IO,
912 	.writepages		= ext2_writepages,
913 	.migratepage		= buffer_migrate_page,
914 	.error_remove_page	= generic_error_remove_page,
915 };
916 
917 /*
918  * Probably it should be a library function... search for first non-zero word
919  * or memcmp with zero_page, whatever is better for particular architecture.
920  * Linus?
921  */
922 static inline int all_zeroes(__le32 *p, __le32 *q)
923 {
924 	while (p < q)
925 		if (*p++)
926 			return 0;
927 	return 1;
928 }
929 
930 /**
931  *	ext2_find_shared - find the indirect blocks for partial truncation.
932  *	@inode:	  inode in question
933  *	@depth:	  depth of the affected branch
934  *	@offsets: offsets of pointers in that branch (see ext2_block_to_path)
935  *	@chain:	  place to store the pointers to partial indirect blocks
936  *	@top:	  place to the (detached) top of branch
937  *
938  *	This is a helper function used by ext2_truncate().
939  *
940  *	When we do truncate() we may have to clean the ends of several indirect
941  *	blocks but leave the blocks themselves alive. Block is partially
942  *	truncated if some data below the new i_size is referred from it (and
943  *	it is on the path to the first completely truncated data block, indeed).
944  *	We have to free the top of that path along with everything to the right
945  *	of the path. Since no allocation past the truncation point is possible
946  *	until ext2_truncate() finishes, we may safely do the latter, but top
947  *	of branch may require special attention - pageout below the truncation
948  *	point might try to populate it.
949  *
950  *	We atomically detach the top of branch from the tree, store the block
951  *	number of its root in *@top, pointers to buffer_heads of partially
952  *	truncated blocks - in @chain[].bh and pointers to their last elements
953  *	that should not be removed - in @chain[].p. Return value is the pointer
954  *	to last filled element of @chain.
955  *
956  *	The work left to caller to do the actual freeing of subtrees:
957  *		a) free the subtree starting from *@top
958  *		b) free the subtrees whose roots are stored in
959  *			(@chain[i].p+1 .. end of @chain[i].bh->b_data)
960  *		c) free the subtrees growing from the inode past the @chain[0].p
961  *			(no partially truncated stuff there).
962  */
963 
964 static Indirect *ext2_find_shared(struct inode *inode,
965 				int depth,
966 				int offsets[4],
967 				Indirect chain[4],
968 				__le32 *top)
969 {
970 	Indirect *partial, *p;
971 	int k, err;
972 
973 	*top = 0;
974 	for (k = depth; k > 1 && !offsets[k-1]; k--)
975 		;
976 	partial = ext2_get_branch(inode, k, offsets, chain, &err);
977 	if (!partial)
978 		partial = chain + k-1;
979 	/*
980 	 * If the branch acquired continuation since we've looked at it -
981 	 * fine, it should all survive and (new) top doesn't belong to us.
982 	 */
983 	write_lock(&EXT2_I(inode)->i_meta_lock);
984 	if (!partial->key && *partial->p) {
985 		write_unlock(&EXT2_I(inode)->i_meta_lock);
986 		goto no_top;
987 	}
988 	for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
989 		;
990 	/*
991 	 * OK, we've found the last block that must survive. The rest of our
992 	 * branch should be detached before unlocking. However, if that rest
993 	 * of branch is all ours and does not grow immediately from the inode
994 	 * it's easier to cheat and just decrement partial->p.
995 	 */
996 	if (p == chain + k - 1 && p > chain) {
997 		p->p--;
998 	} else {
999 		*top = *p->p;
1000 		*p->p = 0;
1001 	}
1002 	write_unlock(&EXT2_I(inode)->i_meta_lock);
1003 
1004 	while(partial > p)
1005 	{
1006 		brelse(partial->bh);
1007 		partial--;
1008 	}
1009 no_top:
1010 	return partial;
1011 }
1012 
1013 /**
1014  *	ext2_free_data - free a list of data blocks
1015  *	@inode:	inode we are dealing with
1016  *	@p:	array of block numbers
1017  *	@q:	points immediately past the end of array
1018  *
1019  *	We are freeing all blocks referred from that array (numbers are
1020  *	stored as little-endian 32-bit) and updating @inode->i_blocks
1021  *	appropriately.
1022  */
1023 static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
1024 {
1025 	unsigned long block_to_free = 0, count = 0;
1026 	unsigned long nr;
1027 
1028 	for ( ; p < q ; p++) {
1029 		nr = le32_to_cpu(*p);
1030 		if (nr) {
1031 			*p = 0;
1032 			/* accumulate blocks to free if they're contiguous */
1033 			if (count == 0)
1034 				goto free_this;
1035 			else if (block_to_free == nr - count)
1036 				count++;
1037 			else {
1038 				ext2_free_blocks (inode, block_to_free, count);
1039 				mark_inode_dirty(inode);
1040 			free_this:
1041 				block_to_free = nr;
1042 				count = 1;
1043 			}
1044 		}
1045 	}
1046 	if (count > 0) {
1047 		ext2_free_blocks (inode, block_to_free, count);
1048 		mark_inode_dirty(inode);
1049 	}
1050 }
1051 
1052 /**
1053  *	ext2_free_branches - free an array of branches
1054  *	@inode:	inode we are dealing with
1055  *	@p:	array of block numbers
1056  *	@q:	pointer immediately past the end of array
1057  *	@depth:	depth of the branches to free
1058  *
1059  *	We are freeing all blocks referred from these branches (numbers are
1060  *	stored as little-endian 32-bit) and updating @inode->i_blocks
1061  *	appropriately.
1062  */
1063 static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
1064 {
1065 	struct buffer_head * bh;
1066 	unsigned long nr;
1067 
1068 	if (depth--) {
1069 		int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1070 		for ( ; p < q ; p++) {
1071 			nr = le32_to_cpu(*p);
1072 			if (!nr)
1073 				continue;
1074 			*p = 0;
1075 			bh = sb_bread(inode->i_sb, nr);
1076 			/*
1077 			 * A read failure? Report error and clear slot
1078 			 * (should be rare).
1079 			 */
1080 			if (!bh) {
1081 				ext2_error(inode->i_sb, "ext2_free_branches",
1082 					"Read failure, inode=%ld, block=%ld",
1083 					inode->i_ino, nr);
1084 				continue;
1085 			}
1086 			ext2_free_branches(inode,
1087 					   (__le32*)bh->b_data,
1088 					   (__le32*)bh->b_data + addr_per_block,
1089 					   depth);
1090 			bforget(bh);
1091 			ext2_free_blocks(inode, nr, 1);
1092 			mark_inode_dirty(inode);
1093 		}
1094 	} else
1095 		ext2_free_data(inode, p, q);
1096 }
1097 
1098 /* dax_sem must be held when calling this function */
1099 static void __ext2_truncate_blocks(struct inode *inode, loff_t offset)
1100 {
1101 	__le32 *i_data = EXT2_I(inode)->i_data;
1102 	struct ext2_inode_info *ei = EXT2_I(inode);
1103 	int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1104 	int offsets[4];
1105 	Indirect chain[4];
1106 	Indirect *partial;
1107 	__le32 nr = 0;
1108 	int n;
1109 	long iblock;
1110 	unsigned blocksize;
1111 	blocksize = inode->i_sb->s_blocksize;
1112 	iblock = (offset + blocksize-1) >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1113 
1114 #ifdef CONFIG_FS_DAX
1115 	WARN_ON(!rwsem_is_locked(&ei->dax_sem));
1116 #endif
1117 
1118 	n = ext2_block_to_path(inode, iblock, offsets, NULL);
1119 	if (n == 0)
1120 		return;
1121 
1122 	/*
1123 	 * From here we block out all ext2_get_block() callers who want to
1124 	 * modify the block allocation tree.
1125 	 */
1126 	mutex_lock(&ei->truncate_mutex);
1127 
1128 	if (n == 1) {
1129 		ext2_free_data(inode, i_data+offsets[0],
1130 					i_data + EXT2_NDIR_BLOCKS);
1131 		goto do_indirects;
1132 	}
1133 
1134 	partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1135 	/* Kill the top of shared branch (already detached) */
1136 	if (nr) {
1137 		if (partial == chain)
1138 			mark_inode_dirty(inode);
1139 		else
1140 			mark_buffer_dirty_inode(partial->bh, inode);
1141 		ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1142 	}
1143 	/* Clear the ends of indirect blocks on the shared branch */
1144 	while (partial > chain) {
1145 		ext2_free_branches(inode,
1146 				   partial->p + 1,
1147 				   (__le32*)partial->bh->b_data+addr_per_block,
1148 				   (chain+n-1) - partial);
1149 		mark_buffer_dirty_inode(partial->bh, inode);
1150 		brelse (partial->bh);
1151 		partial--;
1152 	}
1153 do_indirects:
1154 	/* Kill the remaining (whole) subtrees */
1155 	switch (offsets[0]) {
1156 		default:
1157 			nr = i_data[EXT2_IND_BLOCK];
1158 			if (nr) {
1159 				i_data[EXT2_IND_BLOCK] = 0;
1160 				mark_inode_dirty(inode);
1161 				ext2_free_branches(inode, &nr, &nr+1, 1);
1162 			}
1163 		case EXT2_IND_BLOCK:
1164 			nr = i_data[EXT2_DIND_BLOCK];
1165 			if (nr) {
1166 				i_data[EXT2_DIND_BLOCK] = 0;
1167 				mark_inode_dirty(inode);
1168 				ext2_free_branches(inode, &nr, &nr+1, 2);
1169 			}
1170 		case EXT2_DIND_BLOCK:
1171 			nr = i_data[EXT2_TIND_BLOCK];
1172 			if (nr) {
1173 				i_data[EXT2_TIND_BLOCK] = 0;
1174 				mark_inode_dirty(inode);
1175 				ext2_free_branches(inode, &nr, &nr+1, 3);
1176 			}
1177 		case EXT2_TIND_BLOCK:
1178 			;
1179 	}
1180 
1181 	ext2_discard_reservation(inode);
1182 
1183 	mutex_unlock(&ei->truncate_mutex);
1184 }
1185 
1186 static void ext2_truncate_blocks(struct inode *inode, loff_t offset)
1187 {
1188 	/*
1189 	 * XXX: it seems like a bug here that we don't allow
1190 	 * IS_APPEND inode to have blocks-past-i_size trimmed off.
1191 	 * review and fix this.
1192 	 *
1193 	 * Also would be nice to be able to handle IO errors and such,
1194 	 * but that's probably too much to ask.
1195 	 */
1196 	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1197 	    S_ISLNK(inode->i_mode)))
1198 		return;
1199 	if (ext2_inode_is_fast_symlink(inode))
1200 		return;
1201 	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1202 		return;
1203 
1204 	dax_sem_down_write(EXT2_I(inode));
1205 	__ext2_truncate_blocks(inode, offset);
1206 	dax_sem_up_write(EXT2_I(inode));
1207 }
1208 
1209 static int ext2_setsize(struct inode *inode, loff_t newsize)
1210 {
1211 	int error;
1212 
1213 	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1214 	    S_ISLNK(inode->i_mode)))
1215 		return -EINVAL;
1216 	if (ext2_inode_is_fast_symlink(inode))
1217 		return -EINVAL;
1218 	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1219 		return -EPERM;
1220 
1221 	inode_dio_wait(inode);
1222 
1223 	if (IS_DAX(inode))
1224 		error = dax_truncate_page(inode, newsize, ext2_get_block);
1225 	else if (test_opt(inode->i_sb, NOBH))
1226 		error = nobh_truncate_page(inode->i_mapping,
1227 				newsize, ext2_get_block);
1228 	else
1229 		error = block_truncate_page(inode->i_mapping,
1230 				newsize, ext2_get_block);
1231 	if (error)
1232 		return error;
1233 
1234 	dax_sem_down_write(EXT2_I(inode));
1235 	truncate_setsize(inode, newsize);
1236 	__ext2_truncate_blocks(inode, newsize);
1237 	dax_sem_up_write(EXT2_I(inode));
1238 
1239 	inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
1240 	if (inode_needs_sync(inode)) {
1241 		sync_mapping_buffers(inode->i_mapping);
1242 		sync_inode_metadata(inode, 1);
1243 	} else {
1244 		mark_inode_dirty(inode);
1245 	}
1246 
1247 	return 0;
1248 }
1249 
1250 static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1251 					struct buffer_head **p)
1252 {
1253 	struct buffer_head * bh;
1254 	unsigned long block_group;
1255 	unsigned long block;
1256 	unsigned long offset;
1257 	struct ext2_group_desc * gdp;
1258 
1259 	*p = NULL;
1260 	if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1261 	    ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1262 		goto Einval;
1263 
1264 	block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
1265 	gdp = ext2_get_group_desc(sb, block_group, NULL);
1266 	if (!gdp)
1267 		goto Egdp;
1268 	/*
1269 	 * Figure out the offset within the block group inode table
1270 	 */
1271 	offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1272 	block = le32_to_cpu(gdp->bg_inode_table) +
1273 		(offset >> EXT2_BLOCK_SIZE_BITS(sb));
1274 	if (!(bh = sb_bread(sb, block)))
1275 		goto Eio;
1276 
1277 	*p = bh;
1278 	offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1279 	return (struct ext2_inode *) (bh->b_data + offset);
1280 
1281 Einval:
1282 	ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1283 		   (unsigned long) ino);
1284 	return ERR_PTR(-EINVAL);
1285 Eio:
1286 	ext2_error(sb, "ext2_get_inode",
1287 		   "unable to read inode block - inode=%lu, block=%lu",
1288 		   (unsigned long) ino, block);
1289 Egdp:
1290 	return ERR_PTR(-EIO);
1291 }
1292 
1293 void ext2_set_inode_flags(struct inode *inode)
1294 {
1295 	unsigned int flags = EXT2_I(inode)->i_flags;
1296 
1297 	inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME |
1298 				S_DIRSYNC | S_DAX);
1299 	if (flags & EXT2_SYNC_FL)
1300 		inode->i_flags |= S_SYNC;
1301 	if (flags & EXT2_APPEND_FL)
1302 		inode->i_flags |= S_APPEND;
1303 	if (flags & EXT2_IMMUTABLE_FL)
1304 		inode->i_flags |= S_IMMUTABLE;
1305 	if (flags & EXT2_NOATIME_FL)
1306 		inode->i_flags |= S_NOATIME;
1307 	if (flags & EXT2_DIRSYNC_FL)
1308 		inode->i_flags |= S_DIRSYNC;
1309 	if (test_opt(inode->i_sb, DAX) && S_ISREG(inode->i_mode))
1310 		inode->i_flags |= S_DAX;
1311 }
1312 
1313 /* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
1314 void ext2_get_inode_flags(struct ext2_inode_info *ei)
1315 {
1316 	unsigned int flags = ei->vfs_inode.i_flags;
1317 
1318 	ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|
1319 			EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL);
1320 	if (flags & S_SYNC)
1321 		ei->i_flags |= EXT2_SYNC_FL;
1322 	if (flags & S_APPEND)
1323 		ei->i_flags |= EXT2_APPEND_FL;
1324 	if (flags & S_IMMUTABLE)
1325 		ei->i_flags |= EXT2_IMMUTABLE_FL;
1326 	if (flags & S_NOATIME)
1327 		ei->i_flags |= EXT2_NOATIME_FL;
1328 	if (flags & S_DIRSYNC)
1329 		ei->i_flags |= EXT2_DIRSYNC_FL;
1330 }
1331 
1332 struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
1333 {
1334 	struct ext2_inode_info *ei;
1335 	struct buffer_head * bh;
1336 	struct ext2_inode *raw_inode;
1337 	struct inode *inode;
1338 	long ret = -EIO;
1339 	int n;
1340 	uid_t i_uid;
1341 	gid_t i_gid;
1342 
1343 	inode = iget_locked(sb, ino);
1344 	if (!inode)
1345 		return ERR_PTR(-ENOMEM);
1346 	if (!(inode->i_state & I_NEW))
1347 		return inode;
1348 
1349 	ei = EXT2_I(inode);
1350 	ei->i_block_alloc_info = NULL;
1351 
1352 	raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1353 	if (IS_ERR(raw_inode)) {
1354 		ret = PTR_ERR(raw_inode);
1355  		goto bad_inode;
1356 	}
1357 
1358 	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1359 	i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1360 	i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1361 	if (!(test_opt (inode->i_sb, NO_UID32))) {
1362 		i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1363 		i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1364 	}
1365 	i_uid_write(inode, i_uid);
1366 	i_gid_write(inode, i_gid);
1367 	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
1368 	inode->i_size = le32_to_cpu(raw_inode->i_size);
1369 	inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
1370 	inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
1371 	inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
1372 	inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1373 	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1374 	/* We now have enough fields to check if the inode was active or not.
1375 	 * This is needed because nfsd might try to access dead inodes
1376 	 * the test is that same one that e2fsck uses
1377 	 * NeilBrown 1999oct15
1378 	 */
1379 	if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1380 		/* this inode is deleted */
1381 		brelse (bh);
1382 		ret = -ESTALE;
1383 		goto bad_inode;
1384 	}
1385 	inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1386 	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
1387 	ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1388 	ei->i_frag_no = raw_inode->i_frag;
1389 	ei->i_frag_size = raw_inode->i_fsize;
1390 	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1391 	ei->i_dir_acl = 0;
1392 	if (S_ISREG(inode->i_mode))
1393 		inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1394 	else
1395 		ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1396 	ei->i_dtime = 0;
1397 	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1398 	ei->i_state = 0;
1399 	ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1400 	ei->i_dir_start_lookup = 0;
1401 
1402 	/*
1403 	 * NOTE! The in-memory inode i_data array is in little-endian order
1404 	 * even on big-endian machines: we do NOT byteswap the block numbers!
1405 	 */
1406 	for (n = 0; n < EXT2_N_BLOCKS; n++)
1407 		ei->i_data[n] = raw_inode->i_block[n];
1408 
1409 	if (S_ISREG(inode->i_mode)) {
1410 		inode->i_op = &ext2_file_inode_operations;
1411 		if (test_opt(inode->i_sb, NOBH)) {
1412 			inode->i_mapping->a_ops = &ext2_nobh_aops;
1413 			inode->i_fop = &ext2_file_operations;
1414 		} else {
1415 			inode->i_mapping->a_ops = &ext2_aops;
1416 			inode->i_fop = &ext2_file_operations;
1417 		}
1418 	} else if (S_ISDIR(inode->i_mode)) {
1419 		inode->i_op = &ext2_dir_inode_operations;
1420 		inode->i_fop = &ext2_dir_operations;
1421 		if (test_opt(inode->i_sb, NOBH))
1422 			inode->i_mapping->a_ops = &ext2_nobh_aops;
1423 		else
1424 			inode->i_mapping->a_ops = &ext2_aops;
1425 	} else if (S_ISLNK(inode->i_mode)) {
1426 		if (ext2_inode_is_fast_symlink(inode)) {
1427 			inode->i_link = (char *)ei->i_data;
1428 			inode->i_op = &ext2_fast_symlink_inode_operations;
1429 			nd_terminate_link(ei->i_data, inode->i_size,
1430 				sizeof(ei->i_data) - 1);
1431 		} else {
1432 			inode->i_op = &ext2_symlink_inode_operations;
1433 			inode_nohighmem(inode);
1434 			if (test_opt(inode->i_sb, NOBH))
1435 				inode->i_mapping->a_ops = &ext2_nobh_aops;
1436 			else
1437 				inode->i_mapping->a_ops = &ext2_aops;
1438 		}
1439 	} else {
1440 		inode->i_op = &ext2_special_inode_operations;
1441 		if (raw_inode->i_block[0])
1442 			init_special_inode(inode, inode->i_mode,
1443 			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1444 		else
1445 			init_special_inode(inode, inode->i_mode,
1446 			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1447 	}
1448 	brelse (bh);
1449 	ext2_set_inode_flags(inode);
1450 	unlock_new_inode(inode);
1451 	return inode;
1452 
1453 bad_inode:
1454 	iget_failed(inode);
1455 	return ERR_PTR(ret);
1456 }
1457 
1458 static int __ext2_write_inode(struct inode *inode, int do_sync)
1459 {
1460 	struct ext2_inode_info *ei = EXT2_I(inode);
1461 	struct super_block *sb = inode->i_sb;
1462 	ino_t ino = inode->i_ino;
1463 	uid_t uid = i_uid_read(inode);
1464 	gid_t gid = i_gid_read(inode);
1465 	struct buffer_head * bh;
1466 	struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1467 	int n;
1468 	int err = 0;
1469 
1470 	if (IS_ERR(raw_inode))
1471  		return -EIO;
1472 
1473 	/* For fields not not tracking in the in-memory inode,
1474 	 * initialise them to zero for new inodes. */
1475 	if (ei->i_state & EXT2_STATE_NEW)
1476 		memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1477 
1478 	ext2_get_inode_flags(ei);
1479 	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1480 	if (!(test_opt(sb, NO_UID32))) {
1481 		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1482 		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1483 /*
1484  * Fix up interoperability with old kernels. Otherwise, old inodes get
1485  * re-used with the upper 16 bits of the uid/gid intact
1486  */
1487 		if (!ei->i_dtime) {
1488 			raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1489 			raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1490 		} else {
1491 			raw_inode->i_uid_high = 0;
1492 			raw_inode->i_gid_high = 0;
1493 		}
1494 	} else {
1495 		raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1496 		raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1497 		raw_inode->i_uid_high = 0;
1498 		raw_inode->i_gid_high = 0;
1499 	}
1500 	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1501 	raw_inode->i_size = cpu_to_le32(inode->i_size);
1502 	raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
1503 	raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
1504 	raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
1505 
1506 	raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1507 	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1508 	raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1509 	raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1510 	raw_inode->i_frag = ei->i_frag_no;
1511 	raw_inode->i_fsize = ei->i_frag_size;
1512 	raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1513 	if (!S_ISREG(inode->i_mode))
1514 		raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1515 	else {
1516 		raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1517 		if (inode->i_size > 0x7fffffffULL) {
1518 			if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1519 					EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1520 			    EXT2_SB(sb)->s_es->s_rev_level ==
1521 					cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1522 			       /* If this is the first large file
1523 				* created, add a flag to the superblock.
1524 				*/
1525 				spin_lock(&EXT2_SB(sb)->s_lock);
1526 				ext2_update_dynamic_rev(sb);
1527 				EXT2_SET_RO_COMPAT_FEATURE(sb,
1528 					EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1529 				spin_unlock(&EXT2_SB(sb)->s_lock);
1530 				ext2_write_super(sb);
1531 			}
1532 		}
1533 	}
1534 
1535 	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1536 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1537 		if (old_valid_dev(inode->i_rdev)) {
1538 			raw_inode->i_block[0] =
1539 				cpu_to_le32(old_encode_dev(inode->i_rdev));
1540 			raw_inode->i_block[1] = 0;
1541 		} else {
1542 			raw_inode->i_block[0] = 0;
1543 			raw_inode->i_block[1] =
1544 				cpu_to_le32(new_encode_dev(inode->i_rdev));
1545 			raw_inode->i_block[2] = 0;
1546 		}
1547 	} else for (n = 0; n < EXT2_N_BLOCKS; n++)
1548 		raw_inode->i_block[n] = ei->i_data[n];
1549 	mark_buffer_dirty(bh);
1550 	if (do_sync) {
1551 		sync_dirty_buffer(bh);
1552 		if (buffer_req(bh) && !buffer_uptodate(bh)) {
1553 			printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1554 				sb->s_id, (unsigned long) ino);
1555 			err = -EIO;
1556 		}
1557 	}
1558 	ei->i_state &= ~EXT2_STATE_NEW;
1559 	brelse (bh);
1560 	return err;
1561 }
1562 
1563 int ext2_write_inode(struct inode *inode, struct writeback_control *wbc)
1564 {
1565 	return __ext2_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
1566 }
1567 
1568 int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
1569 {
1570 	struct inode *inode = d_inode(dentry);
1571 	int error;
1572 
1573 	error = inode_change_ok(inode, iattr);
1574 	if (error)
1575 		return error;
1576 
1577 	if (is_quota_modification(inode, iattr)) {
1578 		error = dquot_initialize(inode);
1579 		if (error)
1580 			return error;
1581 	}
1582 	if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
1583 	    (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
1584 		error = dquot_transfer(inode, iattr);
1585 		if (error)
1586 			return error;
1587 	}
1588 	if (iattr->ia_valid & ATTR_SIZE && iattr->ia_size != inode->i_size) {
1589 		error = ext2_setsize(inode, iattr->ia_size);
1590 		if (error)
1591 			return error;
1592 	}
1593 	setattr_copy(inode, iattr);
1594 	if (iattr->ia_valid & ATTR_MODE)
1595 		error = posix_acl_chmod(inode, inode->i_mode);
1596 	mark_inode_dirty(inode);
1597 
1598 	return error;
1599 }
1600