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TOMOYO Linux Cross Reference
Linux/fs/gfs2/file.c

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  1 /*
  2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
  3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
  4  *
  5  * This copyrighted material is made available to anyone wishing to use,
  6  * modify, copy, or redistribute it subject to the terms and conditions
  7  * of the GNU General Public License version 2.
  8  */
  9 
 10 #include <linux/slab.h>
 11 #include <linux/spinlock.h>
 12 #include <linux/completion.h>
 13 #include <linux/buffer_head.h>
 14 #include <linux/pagemap.h>
 15 #include <linux/uio.h>
 16 #include <linux/blkdev.h>
 17 #include <linux/mm.h>
 18 #include <linux/mount.h>
 19 #include <linux/fs.h>
 20 #include <linux/gfs2_ondisk.h>
 21 #include <linux/falloc.h>
 22 #include <linux/swap.h>
 23 #include <linux/crc32.h>
 24 #include <linux/writeback.h>
 25 #include <asm/uaccess.h>
 26 #include <linux/dlm.h>
 27 #include <linux/dlm_plock.h>
 28 #include <linux/delay.h>
 29 
 30 #include "gfs2.h"
 31 #include "incore.h"
 32 #include "bmap.h"
 33 #include "dir.h"
 34 #include "glock.h"
 35 #include "glops.h"
 36 #include "inode.h"
 37 #include "log.h"
 38 #include "meta_io.h"
 39 #include "quota.h"
 40 #include "rgrp.h"
 41 #include "trans.h"
 42 #include "util.h"
 43 
 44 /**
 45  * gfs2_llseek - seek to a location in a file
 46  * @file: the file
 47  * @offset: the offset
 48  * @whence: Where to seek from (SEEK_SET, SEEK_CUR, or SEEK_END)
 49  *
 50  * SEEK_END requires the glock for the file because it references the
 51  * file's size.
 52  *
 53  * Returns: The new offset, or errno
 54  */
 55 
 56 static loff_t gfs2_llseek(struct file *file, loff_t offset, int whence)
 57 {
 58         struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
 59         struct gfs2_holder i_gh;
 60         loff_t error;
 61 
 62         switch (whence) {
 63         case SEEK_END: /* These reference inode->i_size */
 64         case SEEK_DATA:
 65         case SEEK_HOLE:
 66                 error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY,
 67                                            &i_gh);
 68                 if (!error) {
 69                         error = generic_file_llseek(file, offset, whence);
 70                         gfs2_glock_dq_uninit(&i_gh);
 71                 }
 72                 break;
 73         case SEEK_CUR:
 74         case SEEK_SET:
 75                 error = generic_file_llseek(file, offset, whence);
 76                 break;
 77         default:
 78                 error = -EINVAL;
 79         }
 80 
 81         return error;
 82 }
 83 
 84 /**
 85  * gfs2_readdir - Iterator for a directory
 86  * @file: The directory to read from
 87  * @ctx: What to feed directory entries to
 88  *
 89  * Returns: errno
 90  */
 91 
 92 static int gfs2_readdir(struct file *file, struct dir_context *ctx)
 93 {
 94         struct inode *dir = file->f_mapping->host;
 95         struct gfs2_inode *dip = GFS2_I(dir);
 96         struct gfs2_holder d_gh;
 97         int error;
 98 
 99         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
100         if (error)
101                 return error;
102 
103         error = gfs2_dir_read(dir, ctx, &file->f_ra);
104 
105         gfs2_glock_dq_uninit(&d_gh);
106 
107         return error;
108 }
109 
110 /**
111  * fsflags_cvt
112  * @table: A table of 32 u32 flags
113  * @val: a 32 bit value to convert
114  *
115  * This function can be used to convert between fsflags values and
116  * GFS2's own flags values.
117  *
118  * Returns: the converted flags
119  */
120 static u32 fsflags_cvt(const u32 *table, u32 val)
121 {
122         u32 res = 0;
123         while(val) {
124                 if (val & 1)
125                         res |= *table;
126                 table++;
127                 val >>= 1;
128         }
129         return res;
130 }
131 
132 static const u32 fsflags_to_gfs2[32] = {
133         [3] = GFS2_DIF_SYNC,
134         [4] = GFS2_DIF_IMMUTABLE,
135         [5] = GFS2_DIF_APPENDONLY,
136         [7] = GFS2_DIF_NOATIME,
137         [12] = GFS2_DIF_EXHASH,
138         [14] = GFS2_DIF_INHERIT_JDATA,
139         [17] = GFS2_DIF_TOPDIR,
140 };
141 
142 static const u32 gfs2_to_fsflags[32] = {
143         [gfs2fl_Sync] = FS_SYNC_FL,
144         [gfs2fl_Immutable] = FS_IMMUTABLE_FL,
145         [gfs2fl_AppendOnly] = FS_APPEND_FL,
146         [gfs2fl_NoAtime] = FS_NOATIME_FL,
147         [gfs2fl_ExHash] = FS_INDEX_FL,
148         [gfs2fl_TopLevel] = FS_TOPDIR_FL,
149         [gfs2fl_InheritJdata] = FS_JOURNAL_DATA_FL,
150 };
151 
152 static int gfs2_get_flags(struct file *filp, u32 __user *ptr)
153 {
154         struct inode *inode = file_inode(filp);
155         struct gfs2_inode *ip = GFS2_I(inode);
156         struct gfs2_holder gh;
157         int error;
158         u32 fsflags;
159 
160         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
161         error = gfs2_glock_nq(&gh);
162         if (error)
163                 goto out_uninit;
164 
165         fsflags = fsflags_cvt(gfs2_to_fsflags, ip->i_diskflags);
166         if (!S_ISDIR(inode->i_mode) && ip->i_diskflags & GFS2_DIF_JDATA)
167                 fsflags |= FS_JOURNAL_DATA_FL;
168         if (put_user(fsflags, ptr))
169                 error = -EFAULT;
170 
171         gfs2_glock_dq(&gh);
172 out_uninit:
173         gfs2_holder_uninit(&gh);
174         return error;
175 }
176 
177 void gfs2_set_inode_flags(struct inode *inode)
178 {
179         struct gfs2_inode *ip = GFS2_I(inode);
180         unsigned int flags = inode->i_flags;
181 
182         flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_NOSEC);
183         if ((ip->i_eattr == 0) && !is_sxid(inode->i_mode))
184                 flags |= S_NOSEC;
185         if (ip->i_diskflags & GFS2_DIF_IMMUTABLE)
186                 flags |= S_IMMUTABLE;
187         if (ip->i_diskflags & GFS2_DIF_APPENDONLY)
188                 flags |= S_APPEND;
189         if (ip->i_diskflags & GFS2_DIF_NOATIME)
190                 flags |= S_NOATIME;
191         if (ip->i_diskflags & GFS2_DIF_SYNC)
192                 flags |= S_SYNC;
193         inode->i_flags = flags;
194 }
195 
196 /* Flags that can be set by user space */
197 #define GFS2_FLAGS_USER_SET (GFS2_DIF_JDATA|                    \
198                              GFS2_DIF_IMMUTABLE|                \
199                              GFS2_DIF_APPENDONLY|               \
200                              GFS2_DIF_NOATIME|                  \
201                              GFS2_DIF_SYNC|                     \
202                              GFS2_DIF_SYSTEM|                   \
203                              GFS2_DIF_TOPDIR|                   \
204                              GFS2_DIF_INHERIT_JDATA)
205 
206 /**
207  * do_gfs2_set_flags - set flags on an inode
208  * @filp: file pointer
209  * @reqflags: The flags to set
210  * @mask: Indicates which flags are valid
211  *
212  */
213 static int do_gfs2_set_flags(struct file *filp, u32 reqflags, u32 mask)
214 {
215         struct inode *inode = file_inode(filp);
216         struct gfs2_inode *ip = GFS2_I(inode);
217         struct gfs2_sbd *sdp = GFS2_SB(inode);
218         struct buffer_head *bh;
219         struct gfs2_holder gh;
220         int error;
221         u32 new_flags, flags;
222 
223         error = mnt_want_write_file(filp);
224         if (error)
225                 return error;
226 
227         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
228         if (error)
229                 goto out_drop_write;
230 
231         error = -EACCES;
232         if (!inode_owner_or_capable(inode))
233                 goto out;
234 
235         error = 0;
236         flags = ip->i_diskflags;
237         new_flags = (flags & ~mask) | (reqflags & mask);
238         if ((new_flags ^ flags) == 0)
239                 goto out;
240 
241         error = -EINVAL;
242         if ((new_flags ^ flags) & ~GFS2_FLAGS_USER_SET)
243                 goto out;
244 
245         error = -EPERM;
246         if (IS_IMMUTABLE(inode) && (new_flags & GFS2_DIF_IMMUTABLE))
247                 goto out;
248         if (IS_APPEND(inode) && (new_flags & GFS2_DIF_APPENDONLY))
249                 goto out;
250         if (((new_flags ^ flags) & GFS2_DIF_IMMUTABLE) &&
251             !capable(CAP_LINUX_IMMUTABLE))
252                 goto out;
253         if (!IS_IMMUTABLE(inode)) {
254                 error = gfs2_permission(inode, MAY_WRITE);
255                 if (error)
256                         goto out;
257         }
258         if ((flags ^ new_flags) & GFS2_DIF_JDATA) {
259                 if (flags & GFS2_DIF_JDATA)
260                         gfs2_log_flush(sdp, ip->i_gl, NORMAL_FLUSH);
261                 error = filemap_fdatawrite(inode->i_mapping);
262                 if (error)
263                         goto out;
264                 error = filemap_fdatawait(inode->i_mapping);
265                 if (error)
266                         goto out;
267         }
268         error = gfs2_trans_begin(sdp, RES_DINODE, 0);
269         if (error)
270                 goto out;
271         error = gfs2_meta_inode_buffer(ip, &bh);
272         if (error)
273                 goto out_trans_end;
274         gfs2_trans_add_meta(ip->i_gl, bh);
275         ip->i_diskflags = new_flags;
276         gfs2_dinode_out(ip, bh->b_data);
277         brelse(bh);
278         gfs2_set_inode_flags(inode);
279         gfs2_set_aops(inode);
280 out_trans_end:
281         gfs2_trans_end(sdp);
282 out:
283         gfs2_glock_dq_uninit(&gh);
284 out_drop_write:
285         mnt_drop_write_file(filp);
286         return error;
287 }
288 
289 static int gfs2_set_flags(struct file *filp, u32 __user *ptr)
290 {
291         struct inode *inode = file_inode(filp);
292         u32 fsflags, gfsflags;
293 
294         if (get_user(fsflags, ptr))
295                 return -EFAULT;
296 
297         gfsflags = fsflags_cvt(fsflags_to_gfs2, fsflags);
298         if (!S_ISDIR(inode->i_mode)) {
299                 gfsflags &= ~GFS2_DIF_TOPDIR;
300                 if (gfsflags & GFS2_DIF_INHERIT_JDATA)
301                         gfsflags ^= (GFS2_DIF_JDATA | GFS2_DIF_INHERIT_JDATA);
302                 return do_gfs2_set_flags(filp, gfsflags, ~GFS2_DIF_SYSTEM);
303         }
304         return do_gfs2_set_flags(filp, gfsflags, ~(GFS2_DIF_SYSTEM | GFS2_DIF_JDATA));
305 }
306 
307 static long gfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
308 {
309         switch(cmd) {
310         case FS_IOC_GETFLAGS:
311                 return gfs2_get_flags(filp, (u32 __user *)arg);
312         case FS_IOC_SETFLAGS:
313                 return gfs2_set_flags(filp, (u32 __user *)arg);
314         case FITRIM:
315                 return gfs2_fitrim(filp, (void __user *)arg);
316         }
317         return -ENOTTY;
318 }
319 
320 /**
321  * gfs2_size_hint - Give a hint to the size of a write request
322  * @filep: The struct file
323  * @offset: The file offset of the write
324  * @size: The length of the write
325  *
326  * When we are about to do a write, this function records the total
327  * write size in order to provide a suitable hint to the lower layers
328  * about how many blocks will be required.
329  *
330  */
331 
332 static void gfs2_size_hint(struct file *filep, loff_t offset, size_t size)
333 {
334         struct inode *inode = file_inode(filep);
335         struct gfs2_sbd *sdp = GFS2_SB(inode);
336         struct gfs2_inode *ip = GFS2_I(inode);
337         size_t blks = (size + sdp->sd_sb.sb_bsize - 1) >> sdp->sd_sb.sb_bsize_shift;
338         int hint = min_t(size_t, INT_MAX, blks);
339 
340         if (hint > atomic_read(&ip->i_res.rs_sizehint))
341                 atomic_set(&ip->i_res.rs_sizehint, hint);
342 }
343 
344 /**
345  * gfs2_allocate_page_backing - Use bmap to allocate blocks
346  * @page: The (locked) page to allocate backing for
347  *
348  * We try to allocate all the blocks required for the page in
349  * one go. This might fail for various reasons, so we keep
350  * trying until all the blocks to back this page are allocated.
351  * If some of the blocks are already allocated, thats ok too.
352  */
353 
354 static int gfs2_allocate_page_backing(struct page *page)
355 {
356         struct inode *inode = page->mapping->host;
357         struct buffer_head bh;
358         unsigned long size = PAGE_SIZE;
359         u64 lblock = page->index << (PAGE_SHIFT - inode->i_blkbits);
360 
361         do {
362                 bh.b_state = 0;
363                 bh.b_size = size;
364                 gfs2_block_map(inode, lblock, &bh, 1);
365                 if (!buffer_mapped(&bh))
366                         return -EIO;
367                 size -= bh.b_size;
368                 lblock += (bh.b_size >> inode->i_blkbits);
369         } while(size > 0);
370         return 0;
371 }
372 
373 /**
374  * gfs2_page_mkwrite - Make a shared, mmap()ed, page writable
375  * @vma: The virtual memory area
376  * @vmf: The virtual memory fault containing the page to become writable
377  *
378  * When the page becomes writable, we need to ensure that we have
379  * blocks allocated on disk to back that page.
380  */
381 
382 static int gfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
383 {
384         struct page *page = vmf->page;
385         struct inode *inode = file_inode(vma->vm_file);
386         struct gfs2_inode *ip = GFS2_I(inode);
387         struct gfs2_sbd *sdp = GFS2_SB(inode);
388         struct gfs2_alloc_parms ap = { .aflags = 0, };
389         unsigned long last_index;
390         u64 pos = page->index << PAGE_SHIFT;
391         unsigned int data_blocks, ind_blocks, rblocks;
392         struct gfs2_holder gh;
393         loff_t size;
394         int ret;
395 
396         sb_start_pagefault(inode->i_sb);
397 
398         /* Update file times before taking page lock */
399         file_update_time(vma->vm_file);
400 
401         ret = gfs2_rsqa_alloc(ip);
402         if (ret)
403                 goto out;
404 
405         gfs2_size_hint(vma->vm_file, pos, PAGE_SIZE);
406 
407         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
408         ret = gfs2_glock_nq(&gh);
409         if (ret)
410                 goto out_uninit;
411 
412         set_bit(GLF_DIRTY, &ip->i_gl->gl_flags);
413         set_bit(GIF_SW_PAGED, &ip->i_flags);
414 
415         if (!gfs2_write_alloc_required(ip, pos, PAGE_SIZE)) {
416                 lock_page(page);
417                 if (!PageUptodate(page) || page->mapping != inode->i_mapping) {
418                         ret = -EAGAIN;
419                         unlock_page(page);
420                 }
421                 goto out_unlock;
422         }
423 
424         ret = gfs2_rindex_update(sdp);
425         if (ret)
426                 goto out_unlock;
427 
428         gfs2_write_calc_reserv(ip, PAGE_SIZE, &data_blocks, &ind_blocks);
429         ap.target = data_blocks + ind_blocks;
430         ret = gfs2_quota_lock_check(ip, &ap);
431         if (ret)
432                 goto out_unlock;
433         ret = gfs2_inplace_reserve(ip, &ap);
434         if (ret)
435                 goto out_quota_unlock;
436 
437         rblocks = RES_DINODE + ind_blocks;
438         if (gfs2_is_jdata(ip))
439                 rblocks += data_blocks ? data_blocks : 1;
440         if (ind_blocks || data_blocks) {
441                 rblocks += RES_STATFS + RES_QUOTA;
442                 rblocks += gfs2_rg_blocks(ip, data_blocks + ind_blocks);
443         }
444         ret = gfs2_trans_begin(sdp, rblocks, 0);
445         if (ret)
446                 goto out_trans_fail;
447 
448         lock_page(page);
449         ret = -EINVAL;
450         size = i_size_read(inode);
451         last_index = (size - 1) >> PAGE_SHIFT;
452         /* Check page index against inode size */
453         if (size == 0 || (page->index > last_index))
454                 goto out_trans_end;
455 
456         ret = -EAGAIN;
457         /* If truncated, we must retry the operation, we may have raced
458          * with the glock demotion code.
459          */
460         if (!PageUptodate(page) || page->mapping != inode->i_mapping)
461                 goto out_trans_end;
462 
463         /* Unstuff, if required, and allocate backing blocks for page */
464         ret = 0;
465         if (gfs2_is_stuffed(ip))
466                 ret = gfs2_unstuff_dinode(ip, page);
467         if (ret == 0)
468                 ret = gfs2_allocate_page_backing(page);
469 
470 out_trans_end:
471         if (ret)
472                 unlock_page(page);
473         gfs2_trans_end(sdp);
474 out_trans_fail:
475         gfs2_inplace_release(ip);
476 out_quota_unlock:
477         gfs2_quota_unlock(ip);
478 out_unlock:
479         gfs2_glock_dq(&gh);
480 out_uninit:
481         gfs2_holder_uninit(&gh);
482         if (ret == 0) {
483                 set_page_dirty(page);
484                 wait_for_stable_page(page);
485         }
486 out:
487         sb_end_pagefault(inode->i_sb);
488         return block_page_mkwrite_return(ret);
489 }
490 
491 static const struct vm_operations_struct gfs2_vm_ops = {
492         .fault = filemap_fault,
493         .map_pages = filemap_map_pages,
494         .page_mkwrite = gfs2_page_mkwrite,
495 };
496 
497 /**
498  * gfs2_mmap -
499  * @file: The file to map
500  * @vma: The VMA which described the mapping
501  *
502  * There is no need to get a lock here unless we should be updating
503  * atime. We ignore any locking errors since the only consequence is
504  * a missed atime update (which will just be deferred until later).
505  *
506  * Returns: 0
507  */
508 
509 static int gfs2_mmap(struct file *file, struct vm_area_struct *vma)
510 {
511         struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
512 
513         if (!(file->f_flags & O_NOATIME) &&
514             !IS_NOATIME(&ip->i_inode)) {
515                 struct gfs2_holder i_gh;
516                 int error;
517 
518                 error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY,
519                                            &i_gh);
520                 if (error)
521                         return error;
522                 /* grab lock to update inode */
523                 gfs2_glock_dq_uninit(&i_gh);
524                 file_accessed(file);
525         }
526         vma->vm_ops = &gfs2_vm_ops;
527 
528         return 0;
529 }
530 
531 /**
532  * gfs2_open_common - This is common to open and atomic_open
533  * @inode: The inode being opened
534  * @file: The file being opened
535  *
536  * This maybe called under a glock or not depending upon how it has
537  * been called. We must always be called under a glock for regular
538  * files, however. For other file types, it does not matter whether
539  * we hold the glock or not.
540  *
541  * Returns: Error code or 0 for success
542  */
543 
544 int gfs2_open_common(struct inode *inode, struct file *file)
545 {
546         struct gfs2_file *fp;
547         int ret;
548 
549         if (S_ISREG(inode->i_mode)) {
550                 ret = generic_file_open(inode, file);
551                 if (ret)
552                         return ret;
553         }
554 
555         fp = kzalloc(sizeof(struct gfs2_file), GFP_NOFS);
556         if (!fp)
557                 return -ENOMEM;
558 
559         mutex_init(&fp->f_fl_mutex);
560 
561         gfs2_assert_warn(GFS2_SB(inode), !file->private_data);
562         file->private_data = fp;
563         return 0;
564 }
565 
566 /**
567  * gfs2_open - open a file
568  * @inode: the inode to open
569  * @file: the struct file for this opening
570  *
571  * After atomic_open, this function is only used for opening files
572  * which are already cached. We must still get the glock for regular
573  * files to ensure that we have the file size uptodate for the large
574  * file check which is in the common code. That is only an issue for
575  * regular files though.
576  *
577  * Returns: errno
578  */
579 
580 static int gfs2_open(struct inode *inode, struct file *file)
581 {
582         struct gfs2_inode *ip = GFS2_I(inode);
583         struct gfs2_holder i_gh;
584         int error;
585         bool need_unlock = false;
586 
587         if (S_ISREG(ip->i_inode.i_mode)) {
588                 error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY,
589                                            &i_gh);
590                 if (error)
591                         return error;
592                 need_unlock = true;
593         }
594 
595         error = gfs2_open_common(inode, file);
596 
597         if (need_unlock)
598                 gfs2_glock_dq_uninit(&i_gh);
599 
600         return error;
601 }
602 
603 /**
604  * gfs2_release - called to close a struct file
605  * @inode: the inode the struct file belongs to
606  * @file: the struct file being closed
607  *
608  * Returns: errno
609  */
610 
611 static int gfs2_release(struct inode *inode, struct file *file)
612 {
613         struct gfs2_inode *ip = GFS2_I(inode);
614 
615         kfree(file->private_data);
616         file->private_data = NULL;
617 
618         if (!(file->f_mode & FMODE_WRITE))
619                 return 0;
620 
621         gfs2_rsqa_delete(ip, &inode->i_writecount);
622         return 0;
623 }
624 
625 /**
626  * gfs2_fsync - sync the dirty data for a file (across the cluster)
627  * @file: the file that points to the dentry
628  * @start: the start position in the file to sync
629  * @end: the end position in the file to sync
630  * @datasync: set if we can ignore timestamp changes
631  *
632  * We split the data flushing here so that we don't wait for the data
633  * until after we've also sent the metadata to disk. Note that for
634  * data=ordered, we will write & wait for the data at the log flush
635  * stage anyway, so this is unlikely to make much of a difference
636  * except in the data=writeback case.
637  *
638  * If the fdatawrite fails due to any reason except -EIO, we will
639  * continue the remainder of the fsync, although we'll still report
640  * the error at the end. This is to match filemap_write_and_wait_range()
641  * behaviour.
642  *
643  * Returns: errno
644  */
645 
646 static int gfs2_fsync(struct file *file, loff_t start, loff_t end,
647                       int datasync)
648 {
649         struct address_space *mapping = file->f_mapping;
650         struct inode *inode = mapping->host;
651         int sync_state = inode->i_state & I_DIRTY_ALL;
652         struct gfs2_inode *ip = GFS2_I(inode);
653         int ret = 0, ret1 = 0;
654 
655         if (mapping->nrpages) {
656                 ret1 = filemap_fdatawrite_range(mapping, start, end);
657                 if (ret1 == -EIO)
658                         return ret1;
659         }
660 
661         if (!gfs2_is_jdata(ip))
662                 sync_state &= ~I_DIRTY_PAGES;
663         if (datasync)
664                 sync_state &= ~(I_DIRTY_SYNC | I_DIRTY_TIME);
665 
666         if (sync_state) {
667                 ret = sync_inode_metadata(inode, 1);
668                 if (ret)
669                         return ret;
670                 if (gfs2_is_jdata(ip))
671                         filemap_write_and_wait(mapping);
672                 gfs2_ail_flush(ip->i_gl, 1);
673         }
674 
675         if (mapping->nrpages)
676                 ret = filemap_fdatawait_range(mapping, start, end);
677 
678         return ret ? ret : ret1;
679 }
680 
681 /**
682  * gfs2_file_write_iter - Perform a write to a file
683  * @iocb: The io context
684  * @iov: The data to write
685  * @nr_segs: Number of @iov segments
686  * @pos: The file position
687  *
688  * We have to do a lock/unlock here to refresh the inode size for
689  * O_APPEND writes, otherwise we can land up writing at the wrong
690  * offset. There is still a race, but provided the app is using its
691  * own file locking, this will make O_APPEND work as expected.
692  *
693  */
694 
695 static ssize_t gfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
696 {
697         struct file *file = iocb->ki_filp;
698         struct gfs2_inode *ip = GFS2_I(file_inode(file));
699         int ret;
700 
701         ret = gfs2_rsqa_alloc(ip);
702         if (ret)
703                 return ret;
704 
705         gfs2_size_hint(file, iocb->ki_pos, iov_iter_count(from));
706 
707         if (iocb->ki_flags & IOCB_APPEND) {
708                 struct gfs2_holder gh;
709 
710                 ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
711                 if (ret)
712                         return ret;
713                 gfs2_glock_dq_uninit(&gh);
714         }
715 
716         return generic_file_write_iter(iocb, from);
717 }
718 
719 static int fallocate_chunk(struct inode *inode, loff_t offset, loff_t len,
720                            int mode)
721 {
722         struct gfs2_inode *ip = GFS2_I(inode);
723         struct buffer_head *dibh;
724         int error;
725         unsigned int nr_blks;
726         sector_t lblock = offset >> inode->i_blkbits;
727 
728         error = gfs2_meta_inode_buffer(ip, &dibh);
729         if (unlikely(error))
730                 return error;
731 
732         gfs2_trans_add_meta(ip->i_gl, dibh);
733 
734         if (gfs2_is_stuffed(ip)) {
735                 error = gfs2_unstuff_dinode(ip, NULL);
736                 if (unlikely(error))
737                         goto out;
738         }
739 
740         while (len) {
741                 struct buffer_head bh_map = { .b_state = 0, .b_blocknr = 0 };
742                 bh_map.b_size = len;
743                 set_buffer_zeronew(&bh_map);
744 
745                 error = gfs2_block_map(inode, lblock, &bh_map, 1);
746                 if (unlikely(error))
747                         goto out;
748                 len -= bh_map.b_size;
749                 nr_blks = bh_map.b_size >> inode->i_blkbits;
750                 lblock += nr_blks;
751                 if (!buffer_new(&bh_map))
752                         continue;
753                 if (unlikely(!buffer_zeronew(&bh_map))) {
754                         error = -EIO;
755                         goto out;
756                 }
757         }
758 out:
759         brelse(dibh);
760         return error;
761 }
762 /**
763  * calc_max_reserv() - Reverse of write_calc_reserv. Given a number of
764  *                     blocks, determine how many bytes can be written.
765  * @ip:          The inode in question.
766  * @len:         Max cap of bytes. What we return in *len must be <= this.
767  * @data_blocks: Compute and return the number of data blocks needed
768  * @ind_blocks:  Compute and return the number of indirect blocks needed
769  * @max_blocks:  The total blocks available to work with.
770  *
771  * Returns: void, but @len, @data_blocks and @ind_blocks are filled in.
772  */
773 static void calc_max_reserv(struct gfs2_inode *ip, loff_t *len,
774                             unsigned int *data_blocks, unsigned int *ind_blocks,
775                             unsigned int max_blocks)
776 {
777         loff_t max = *len;
778         const struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
779         unsigned int tmp, max_data = max_blocks - 3 * (sdp->sd_max_height - 1);
780 
781         for (tmp = max_data; tmp > sdp->sd_diptrs;) {
782                 tmp = DIV_ROUND_UP(tmp, sdp->sd_inptrs);
783                 max_data -= tmp;
784         }
785 
786         *data_blocks = max_data;
787         *ind_blocks = max_blocks - max_data;
788         *len = ((loff_t)max_data - 3) << sdp->sd_sb.sb_bsize_shift;
789         if (*len > max) {
790                 *len = max;
791                 gfs2_write_calc_reserv(ip, max, data_blocks, ind_blocks);
792         }
793 }
794 
795 static long __gfs2_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
796 {
797         struct inode *inode = file_inode(file);
798         struct gfs2_sbd *sdp = GFS2_SB(inode);
799         struct gfs2_inode *ip = GFS2_I(inode);
800         struct gfs2_alloc_parms ap = { .aflags = 0, };
801         unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
802         loff_t bytes, max_bytes, max_blks = UINT_MAX;
803         int error;
804         const loff_t pos = offset;
805         const loff_t count = len;
806         loff_t bsize_mask = ~((loff_t)sdp->sd_sb.sb_bsize - 1);
807         loff_t next = (offset + len - 1) >> sdp->sd_sb.sb_bsize_shift;
808         loff_t max_chunk_size = UINT_MAX & bsize_mask;
809 
810         next = (next + 1) << sdp->sd_sb.sb_bsize_shift;
811 
812         offset &= bsize_mask;
813 
814         len = next - offset;
815         bytes = sdp->sd_max_rg_data * sdp->sd_sb.sb_bsize / 2;
816         if (!bytes)
817                 bytes = UINT_MAX;
818         bytes &= bsize_mask;
819         if (bytes == 0)
820                 bytes = sdp->sd_sb.sb_bsize;
821 
822         gfs2_size_hint(file, offset, len);
823 
824         gfs2_write_calc_reserv(ip, PAGE_SIZE, &data_blocks, &ind_blocks);
825         ap.min_target = data_blocks + ind_blocks;
826 
827         while (len > 0) {
828                 if (len < bytes)
829                         bytes = len;
830                 if (!gfs2_write_alloc_required(ip, offset, bytes)) {
831                         len -= bytes;
832                         offset += bytes;
833                         continue;
834                 }
835 
836                 /* We need to determine how many bytes we can actually
837                  * fallocate without exceeding quota or going over the
838                  * end of the fs. We start off optimistically by assuming
839                  * we can write max_bytes */
840                 max_bytes = (len > max_chunk_size) ? max_chunk_size : len;
841 
842                 /* Since max_bytes is most likely a theoretical max, we
843                  * calculate a more realistic 'bytes' to serve as a good
844                  * starting point for the number of bytes we may be able
845                  * to write */
846                 gfs2_write_calc_reserv(ip, bytes, &data_blocks, &ind_blocks);
847                 ap.target = data_blocks + ind_blocks;
848 
849                 error = gfs2_quota_lock_check(ip, &ap);
850                 if (error)
851                         return error;
852                 /* ap.allowed tells us how many blocks quota will allow
853                  * us to write. Check if this reduces max_blks */
854                 if (ap.allowed && ap.allowed < max_blks)
855                         max_blks = ap.allowed;
856 
857                 error = gfs2_inplace_reserve(ip, &ap);
858                 if (error)
859                         goto out_qunlock;
860 
861                 /* check if the selected rgrp limits our max_blks further */
862                 if (ap.allowed && ap.allowed < max_blks)
863                         max_blks = ap.allowed;
864 
865                 /* Almost done. Calculate bytes that can be written using
866                  * max_blks. We also recompute max_bytes, data_blocks and
867                  * ind_blocks */
868                 calc_max_reserv(ip, &max_bytes, &data_blocks,
869                                 &ind_blocks, max_blks);
870 
871                 rblocks = RES_DINODE + ind_blocks + RES_STATFS + RES_QUOTA +
872                           RES_RG_HDR + gfs2_rg_blocks(ip, data_blocks + ind_blocks);
873                 if (gfs2_is_jdata(ip))
874                         rblocks += data_blocks ? data_blocks : 1;
875 
876                 error = gfs2_trans_begin(sdp, rblocks,
877                                          PAGE_SIZE/sdp->sd_sb.sb_bsize);
878                 if (error)
879                         goto out_trans_fail;
880 
881                 error = fallocate_chunk(inode, offset, max_bytes, mode);
882                 gfs2_trans_end(sdp);
883 
884                 if (error)
885                         goto out_trans_fail;
886 
887                 len -= max_bytes;
888                 offset += max_bytes;
889                 gfs2_inplace_release(ip);
890                 gfs2_quota_unlock(ip);
891         }
892 
893         if (!(mode & FALLOC_FL_KEEP_SIZE) && (pos + count) > inode->i_size) {
894                 i_size_write(inode, pos + count);
895                 file_update_time(file);
896                 mark_inode_dirty(inode);
897         }
898 
899         if ((file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host))
900                 return vfs_fsync_range(file, pos, pos + count - 1,
901                                (file->f_flags & __O_SYNC) ? 0 : 1);
902         return 0;
903 
904 out_trans_fail:
905         gfs2_inplace_release(ip);
906 out_qunlock:
907         gfs2_quota_unlock(ip);
908         return error;
909 }
910 
911 static long gfs2_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
912 {
913         struct inode *inode = file_inode(file);
914         struct gfs2_inode *ip = GFS2_I(inode);
915         struct gfs2_holder gh;
916         int ret;
917 
918         if ((mode & ~FALLOC_FL_KEEP_SIZE) || gfs2_is_jdata(ip))
919                 return -EOPNOTSUPP;
920 
921         inode_lock(inode);
922 
923         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
924         ret = gfs2_glock_nq(&gh);
925         if (ret)
926                 goto out_uninit;
927 
928         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
929             (offset + len) > inode->i_size) {
930                 ret = inode_newsize_ok(inode, offset + len);
931                 if (ret)
932                         goto out_unlock;
933         }
934 
935         ret = get_write_access(inode);
936         if (ret)
937                 goto out_unlock;
938 
939         ret = gfs2_rsqa_alloc(ip);
940         if (ret)
941                 goto out_putw;
942 
943         ret = __gfs2_fallocate(file, mode, offset, len);
944         if (ret)
945                 gfs2_rs_deltree(&ip->i_res);
946 
947 out_putw:
948         put_write_access(inode);
949 out_unlock:
950         gfs2_glock_dq(&gh);
951 out_uninit:
952         gfs2_holder_uninit(&gh);
953         inode_unlock(inode);
954         return ret;
955 }
956 
957 static ssize_t gfs2_file_splice_read(struct file *in, loff_t *ppos,
958                                      struct pipe_inode_info *pipe, size_t len,
959                                      unsigned int flags)
960 {
961         struct inode *inode = in->f_mapping->host;
962         struct gfs2_inode *ip = GFS2_I(inode);
963         struct gfs2_holder gh;
964         int ret;
965 
966         inode_lock(inode);
967 
968         ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
969         if (ret) {
970                 inode_unlock(inode);
971                 return ret;
972         }
973 
974         gfs2_glock_dq_uninit(&gh);
975         inode_unlock(inode);
976 
977         return generic_file_splice_read(in, ppos, pipe, len, flags);
978 }
979 
980 
981 static ssize_t gfs2_file_splice_write(struct pipe_inode_info *pipe,
982                                       struct file *out, loff_t *ppos,
983                                       size_t len, unsigned int flags)
984 {
985         int error;
986         struct gfs2_inode *ip = GFS2_I(out->f_mapping->host);
987 
988         error = gfs2_rsqa_alloc(ip);
989         if (error)
990                 return (ssize_t)error;
991 
992         gfs2_size_hint(out, *ppos, len);
993 
994         return iter_file_splice_write(pipe, out, ppos, len, flags);
995 }
996 
997 #ifdef CONFIG_GFS2_FS_LOCKING_DLM
998 
999 /**
1000  * gfs2_lock - acquire/release a posix lock on a file
1001  * @file: the file pointer
1002  * @cmd: either modify or retrieve lock state, possibly wait
1003  * @fl: type and range of lock
1004  *
1005  * Returns: errno
1006  */
1007 
1008 static int gfs2_lock(struct file *file, int cmd, struct file_lock *fl)
1009 {
1010         struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
1011         struct gfs2_sbd *sdp = GFS2_SB(file->f_mapping->host);
1012         struct lm_lockstruct *ls = &sdp->sd_lockstruct;
1013 
1014         if (!(fl->fl_flags & FL_POSIX))
1015                 return -ENOLCK;
1016         if (__mandatory_lock(&ip->i_inode) && fl->fl_type != F_UNLCK)
1017                 return -ENOLCK;
1018 
1019         if (cmd == F_CANCELLK) {
1020                 /* Hack: */
1021                 cmd = F_SETLK;
1022                 fl->fl_type = F_UNLCK;
1023         }
1024         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
1025                 if (fl->fl_type == F_UNLCK)
1026                         locks_lock_file_wait(file, fl);
1027                 return -EIO;
1028         }
1029         if (IS_GETLK(cmd))
1030                 return dlm_posix_get(ls->ls_dlm, ip->i_no_addr, file, fl);
1031         else if (fl->fl_type == F_UNLCK)
1032                 return dlm_posix_unlock(ls->ls_dlm, ip->i_no_addr, file, fl);
1033         else
1034                 return dlm_posix_lock(ls->ls_dlm, ip->i_no_addr, file, cmd, fl);
1035 }
1036 
1037 static int do_flock(struct file *file, int cmd, struct file_lock *fl)
1038 {
1039         struct gfs2_file *fp = file->private_data;
1040         struct gfs2_holder *fl_gh = &fp->f_fl_gh;
1041         struct gfs2_inode *ip = GFS2_I(file_inode(file));
1042         struct gfs2_glock *gl;
1043         unsigned int state;
1044         u16 flags;
1045         int error = 0;
1046         int sleeptime;
1047 
1048         state = (fl->fl_type == F_WRLCK) ? LM_ST_EXCLUSIVE : LM_ST_SHARED;
1049         flags = (IS_SETLKW(cmd) ? 0 : LM_FLAG_TRY_1CB) | GL_EXACT;
1050 
1051         mutex_lock(&fp->f_fl_mutex);
1052 
1053         gl = fl_gh->gh_gl;
1054         if (gl) {
1055                 if (fl_gh->gh_state == state)
1056                         goto out;
1057                 locks_lock_file_wait(file,
1058                                      &(struct file_lock) {
1059                                              .fl_type = F_UNLCK,
1060                                              .fl_flags = FL_FLOCK
1061                                      });
1062                 gfs2_glock_dq(fl_gh);
1063                 gfs2_holder_reinit(state, flags, fl_gh);
1064         } else {
1065                 error = gfs2_glock_get(GFS2_SB(&ip->i_inode), ip->i_no_addr,
1066                                        &gfs2_flock_glops, CREATE, &gl);
1067                 if (error)
1068                         goto out;
1069                 gfs2_holder_init(gl, state, flags, fl_gh);
1070                 gfs2_glock_put(gl);
1071         }
1072         for (sleeptime = 1; sleeptime <= 4; sleeptime <<= 1) {
1073                 error = gfs2_glock_nq(fl_gh);
1074                 if (error != GLR_TRYFAILED)
1075                         break;
1076                 fl_gh->gh_flags = LM_FLAG_TRY | GL_EXACT;
1077                 fl_gh->gh_error = 0;
1078                 msleep(sleeptime);
1079         }
1080         if (error) {
1081                 gfs2_holder_uninit(fl_gh);
1082                 if (error == GLR_TRYFAILED)
1083                         error = -EAGAIN;
1084         } else {
1085                 error = locks_lock_file_wait(file, fl);
1086                 gfs2_assert_warn(GFS2_SB(&ip->i_inode), !error);
1087         }
1088 
1089 out:
1090         mutex_unlock(&fp->f_fl_mutex);
1091         return error;
1092 }
1093 
1094 static void do_unflock(struct file *file, struct file_lock *fl)
1095 {
1096         struct gfs2_file *fp = file->private_data;
1097         struct gfs2_holder *fl_gh = &fp->f_fl_gh;
1098 
1099         mutex_lock(&fp->f_fl_mutex);
1100         locks_lock_file_wait(file, fl);
1101         if (fl_gh->gh_gl) {
1102                 gfs2_glock_dq(fl_gh);
1103                 gfs2_holder_uninit(fl_gh);
1104         }
1105         mutex_unlock(&fp->f_fl_mutex);
1106 }
1107 
1108 /**
1109  * gfs2_flock - acquire/release a flock lock on a file
1110  * @file: the file pointer
1111  * @cmd: either modify or retrieve lock state, possibly wait
1112  * @fl: type and range of lock
1113  *
1114  * Returns: errno
1115  */
1116 
1117 static int gfs2_flock(struct file *file, int cmd, struct file_lock *fl)
1118 {
1119         if (!(fl->fl_flags & FL_FLOCK))
1120                 return -ENOLCK;
1121         if (fl->fl_type & LOCK_MAND)
1122                 return -EOPNOTSUPP;
1123 
1124         if (fl->fl_type == F_UNLCK) {
1125                 do_unflock(file, fl);
1126                 return 0;
1127         } else {
1128                 return do_flock(file, cmd, fl);
1129         }
1130 }
1131 
1132 const struct file_operations gfs2_file_fops = {
1133         .llseek         = gfs2_llseek,
1134         .read_iter      = generic_file_read_iter,
1135         .write_iter     = gfs2_file_write_iter,
1136         .unlocked_ioctl = gfs2_ioctl,
1137         .mmap           = gfs2_mmap,
1138         .open           = gfs2_open,
1139         .release        = gfs2_release,
1140         .fsync          = gfs2_fsync,
1141         .lock           = gfs2_lock,
1142         .flock          = gfs2_flock,
1143         .splice_read    = gfs2_file_splice_read,
1144         .splice_write   = gfs2_file_splice_write,
1145         .setlease       = simple_nosetlease,
1146         .fallocate      = gfs2_fallocate,
1147 };
1148 
1149 const struct file_operations gfs2_dir_fops = {
1150         .iterate_shared = gfs2_readdir,
1151         .unlocked_ioctl = gfs2_ioctl,
1152         .open           = gfs2_open,
1153         .release        = gfs2_release,
1154         .fsync          = gfs2_fsync,
1155         .lock           = gfs2_lock,
1156         .flock          = gfs2_flock,
1157         .llseek         = default_llseek,
1158 };
1159 
1160 #endif /* CONFIG_GFS2_FS_LOCKING_DLM */
1161 
1162 const struct file_operations gfs2_file_fops_nolock = {
1163         .llseek         = gfs2_llseek,
1164         .read_iter      = generic_file_read_iter,
1165         .write_iter     = gfs2_file_write_iter,
1166         .unlocked_ioctl = gfs2_ioctl,
1167         .mmap           = gfs2_mmap,
1168         .open           = gfs2_open,
1169         .release        = gfs2_release,
1170         .fsync          = gfs2_fsync,
1171         .splice_read    = gfs2_file_splice_read,
1172         .splice_write   = gfs2_file_splice_write,
1173         .setlease       = generic_setlease,
1174         .fallocate      = gfs2_fallocate,
1175 };
1176 
1177 const struct file_operations gfs2_dir_fops_nolock = {
1178         .iterate_shared = gfs2_readdir,
1179         .unlocked_ioctl = gfs2_ioctl,
1180         .open           = gfs2_open,
1181         .release        = gfs2_release,
1182         .fsync          = gfs2_fsync,
1183         .llseek         = default_llseek,
1184 };
1185 
1186 

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