4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
22 * Copyright (c) 2011, Lawrence Livermore National Security, LLC.
26 #include <sys/zfs_vfsops.h>
27 #include <sys/zfs_vnops.h>
28 #include <sys/zfs_znode.h>
33 zpl_open(struct inode *ip, struct file *filp)
39 error = -zfs_open(ip, filp->f_mode, filp->f_flags, cr);
41 ASSERT3S(error, <=, 0);
46 return generic_file_open(ip, filp);
50 zpl_release(struct inode *ip, struct file *filp)
55 if (ITOZ(ip)->z_atime_dirty)
59 error = -zfs_close(ip, filp->f_flags, cr);
61 ASSERT3S(error, <=, 0);
67 zpl_iterate(struct file *filp, struct dir_context *ctx)
69 struct dentry *dentry = filp->f_path.dentry;
74 error = -zfs_readdir(dentry->d_inode, ctx, cr);
76 ASSERT3S(error, <=, 0);
81 #if !defined(HAVE_VFS_ITERATE)
83 zpl_readdir(struct file *filp, void *dirent, filldir_t filldir)
85 struct dir_context ctx = DIR_CONTEXT_INIT(dirent, filldir, filp->f_pos);
88 error = zpl_iterate(filp, &ctx);
89 filp->f_pos = ctx.pos;
93 #endif /* HAVE_VFS_ITERATE */
95 #if defined(HAVE_FSYNC_WITH_DENTRY)
97 * Linux 2.6.x - 2.6.34 API,
98 * Through 2.6.34 the nfsd kernel server would pass a NULL 'file struct *'
99 * to the fops->fsync() hook. For this reason, we must be careful not to
100 * use filp unconditionally.
103 zpl_fsync(struct file *filp, struct dentry *dentry, int datasync)
109 error = -zfs_fsync(dentry->d_inode, datasync, cr);
111 ASSERT3S(error, <=, 0);
116 #elif defined(HAVE_FSYNC_WITHOUT_DENTRY)
118 * Linux 2.6.35 - 3.0 API,
119 * As of 2.6.35 the dentry argument to the fops->fsync() hook was deemed
120 * redundant. The dentry is still accessible via filp->f_path.dentry,
121 * and we are guaranteed that filp will never be NULL.
124 zpl_fsync(struct file *filp, int datasync)
126 struct inode *inode = filp->f_mapping->host;
131 error = -zfs_fsync(inode, datasync, cr);
133 ASSERT3S(error, <=, 0);
138 #elif defined(HAVE_FSYNC_RANGE)
140 * Linux 3.1 - 3.x API,
141 * As of 3.1 the responsibility to call filemap_write_and_wait_range() has
142 * been pushed down in to the .fsync() vfs hook. Additionally, the i_mutex
143 * lock is no longer held by the caller, for zfs we don't require the lock
144 * to be held so we don't acquire it.
147 zpl_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
149 struct inode *inode = filp->f_mapping->host;
153 error = filemap_write_and_wait_range(inode->i_mapping, start, end);
158 error = -zfs_fsync(inode, datasync, cr);
160 ASSERT3S(error, <=, 0);
165 #error "Unsupported fops->fsync() implementation"
169 zpl_read_common(struct inode *ip, const char *buf, size_t len, loff_t pos,
170 uio_seg_t segment, int flags, cred_t *cr)
176 iov.iov_base = (void *)buf;
182 uio.uio_loffset = pos;
183 uio.uio_limit = MAXOFFSET_T;
184 uio.uio_segflg = segment;
186 error = -zfs_read(ip, &uio, flags, cr);
190 return (len - uio.uio_resid);
194 zpl_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
200 read = zpl_read_common(filp->f_mapping->host, buf, len, *ppos,
201 UIO_USERSPACE, filp->f_flags, cr);
212 zpl_write_common(struct inode *ip, const char *buf, size_t len, loff_t pos,
213 uio_seg_t segment, int flags, cred_t *cr)
219 iov.iov_base = (void *)buf;
225 uio.uio_loffset = pos;
226 uio.uio_limit = MAXOFFSET_T;
227 uio.uio_segflg = segment;
229 error = -zfs_write(ip, &uio, flags, cr);
233 return (len - uio.uio_resid);
237 zpl_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
243 wrote = zpl_write_common(filp->f_mapping->host, buf, len, *ppos,
244 UIO_USERSPACE, filp->f_flags, cr);
255 zpl_llseek(struct file *filp, loff_t offset, int whence)
257 #if defined(SEEK_HOLE) && defined(SEEK_DATA)
258 if (whence == SEEK_DATA || whence == SEEK_HOLE) {
259 struct inode *ip = filp->f_mapping->host;
260 loff_t maxbytes = ip->i_sb->s_maxbytes;
264 error = -zfs_holey(ip, whence, &offset);
266 error = lseek_execute(filp, ip, offset, maxbytes);
267 spl_inode_unlock(ip);
271 #endif /* SEEK_HOLE && SEEK_DATA */
273 return generic_file_llseek(filp, offset, whence);
277 * It's worth taking a moment to describe how mmap is implemented
278 * for zfs because it differs considerably from other Linux filesystems.
279 * However, this issue is handled the same way under OpenSolaris.
281 * The issue is that by design zfs bypasses the Linux page cache and
282 * leaves all caching up to the ARC. This has been shown to work
283 * well for the common read(2)/write(2) case. However, mmap(2)
284 * is problem because it relies on being tightly integrated with the
285 * page cache. To handle this we cache mmap'ed files twice, once in
286 * the ARC and a second time in the page cache. The code is careful
287 * to keep both copies synchronized.
289 * When a file with an mmap'ed region is written to using write(2)
290 * both the data in the ARC and existing pages in the page cache
291 * are updated. For a read(2) data will be read first from the page
292 * cache then the ARC if needed. Neither a write(2) or read(2) will
293 * will ever result in new pages being added to the page cache.
295 * New pages are added to the page cache only via .readpage() which
296 * is called when the vfs needs to read a page off disk to back the
297 * virtual memory region. These pages may be modified without
298 * notifying the ARC and will be written out periodically via
299 * .writepage(). This will occur due to either a sync or the usual
300 * page aging behavior. Note because a read(2) of a mmap'ed file
301 * will always check the page cache first even when the ARC is out
302 * of date correct data will still be returned.
304 * While this implementation ensures correct behavior it does have
305 * have some drawbacks. The most obvious of which is that it
306 * increases the required memory footprint when access mmap'ed
307 * files. It also adds additional complexity to the code keeping
308 * both caches synchronized.
310 * Longer term it may be possible to cleanly resolve this wart by
311 * mapping page cache pages directly on to the ARC buffers. The
312 * Linux address space operations are flexible enough to allow
313 * selection of which pages back a particular index. The trick
314 * would be working out the details of which subsystem is in
315 * charge, the ARC, the page cache, or both. It may also prove
316 * helpful to move the ARC buffers to a scatter-gather lists
317 * rather than a vmalloc'ed region.
320 zpl_mmap(struct file *filp, struct vm_area_struct *vma)
322 struct inode *ip = filp->f_mapping->host;
323 znode_t *zp = ITOZ(ip);
326 error = -zfs_map(ip, vma->vm_pgoff, (caddr_t *)vma->vm_start,
327 (size_t)(vma->vm_end - vma->vm_start), vma->vm_flags);
331 error = generic_file_mmap(filp, vma);
335 mutex_enter(&zp->z_lock);
337 mutex_exit(&zp->z_lock);
343 * Populate a page with data for the Linux page cache. This function is
344 * only used to support mmap(2). There will be an identical copy of the
345 * data in the ARC which is kept up to date via .write() and .writepage().
347 * Current this function relies on zpl_read_common() and the O_DIRECT
348 * flag to read in a page. This works but the more correct way is to
349 * update zfs_fillpage() to be Linux friendly and use that interface.
352 zpl_readpage(struct file *filp, struct page *pp)
358 ASSERT(PageLocked(pp));
359 ip = pp->mapping->host;
362 error = -zfs_getpage(ip, pl, 1);
366 ClearPageUptodate(pp);
370 flush_dcache_page(pp);
378 * Populate a set of pages with data for the Linux page cache. This
379 * function will only be called for read ahead and never for demand
380 * paging. For simplicity, the code relies on read_cache_pages() to
381 * correctly lock each page for IO and call zpl_readpage().
384 zpl_readpages(struct file *filp, struct address_space *mapping,
385 struct list_head *pages, unsigned nr_pages)
387 return (read_cache_pages(mapping, pages,
388 (filler_t *)zpl_readpage, filp));
392 zpl_putpage(struct page *pp, struct writeback_control *wbc, void *data)
394 struct address_space *mapping = data;
396 ASSERT(PageLocked(pp));
397 ASSERT(!PageWriteback(pp));
398 ASSERT(!(current->flags & PF_NOFS));
401 * Annotate this call path with a flag that indicates that it is
402 * unsafe to use KM_SLEEP during memory allocations due to the
403 * potential for a deadlock. KM_PUSHPAGE should be used instead.
405 current->flags |= PF_NOFS;
406 (void) zfs_putpage(mapping->host, pp, wbc);
407 current->flags &= ~PF_NOFS;
413 zpl_writepages(struct address_space *mapping, struct writeback_control *wbc)
415 return write_cache_pages(mapping, wbc, zpl_putpage, mapping);
419 * Write out dirty pages to the ARC, this function is only required to
420 * support mmap(2). Mapped pages may be dirtied by memory operations
421 * which never call .write(). These dirty pages are kept in sync with
422 * the ARC buffers via this hook.
425 zpl_writepage(struct page *pp, struct writeback_control *wbc)
427 return zpl_putpage(pp, wbc, pp->mapping);
431 * The only flag combination which matches the behavior of zfs_space()
432 * is FALLOC_FL_PUNCH_HOLE. This flag was introduced in the 2.6.38 kernel.
435 zpl_fallocate_common(struct inode *ip, int mode, loff_t offset, loff_t len)
438 int error = -EOPNOTSUPP;
440 if (mode & FALLOC_FL_KEEP_SIZE)
441 return (-EOPNOTSUPP);
445 #ifdef FALLOC_FL_PUNCH_HOLE
446 if (mode & FALLOC_FL_PUNCH_HOLE) {
455 error = -zfs_space(ip, F_FREESP, &bf, FWRITE, offset, cr);
457 #endif /* FALLOC_FL_PUNCH_HOLE */
461 ASSERT3S(error, <=, 0);
465 #ifdef HAVE_FILE_FALLOCATE
467 zpl_fallocate(struct file *filp, int mode, loff_t offset, loff_t len)
469 return zpl_fallocate_common(filp->f_path.dentry->d_inode,
472 #endif /* HAVE_FILE_FALLOCATE */
475 zpl_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
478 case ZFS_IOC_GETFLAGS:
479 case ZFS_IOC_SETFLAGS:
480 return (-EOPNOTSUPP);
488 zpl_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
490 return zpl_ioctl(filp, cmd, arg);
492 #endif /* CONFIG_COMPAT */
495 const struct address_space_operations zpl_address_space_operations = {
496 .readpages = zpl_readpages,
497 .readpage = zpl_readpage,
498 .writepage = zpl_writepage,
499 .writepages = zpl_writepages,
502 const struct file_operations zpl_file_operations = {
504 .release = zpl_release,
505 .llseek = zpl_llseek,
510 #ifdef HAVE_FILE_FALLOCATE
511 .fallocate = zpl_fallocate,
512 #endif /* HAVE_FILE_FALLOCATE */
513 .unlocked_ioctl = zpl_ioctl,
515 .compat_ioctl = zpl_compat_ioctl,
519 const struct file_operations zpl_dir_file_operations = {
520 .llseek = generic_file_llseek,
521 .read = generic_read_dir,
522 #ifdef HAVE_VFS_ITERATE
523 .iterate = zpl_iterate,
525 .readdir = zpl_readdir,
528 .unlocked_ioctl = zpl_ioctl,
530 .compat_ioctl = zpl_compat_ioctl,