static int
+zpl_open(struct inode *ip, struct file *filp)
+{
+ cred_t *cr = CRED();
+ int error;
+
+ crhold(cr);
+ error = -zfs_open(ip, filp->f_mode, filp->f_flags, cr);
+ crfree(cr);
+ ASSERT3S(error, <=, 0);
+
+ if (error)
+ return (error);
+
+ return generic_file_open(ip, filp);
+}
+
+static int
+zpl_release(struct inode *ip, struct file *filp)
+{
+ cred_t *cr = CRED();
+ int error;
+
+ crhold(cr);
+ error = -zfs_close(ip, filp->f_flags, cr);
+ crfree(cr);
+ ASSERT3S(error, <=, 0);
+
+ return (error);
+}
+
+static int
zpl_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
struct dentry *dentry = filp->f_path.dentry;
- cred_t *cr;
+ cred_t *cr = CRED();
int error;
- cr = (cred_t *)get_current_cred();
+ crhold(cr);
error = -zfs_readdir(dentry->d_inode, dirent, filldir,
&filp->f_pos, cr);
- put_cred(cr);
+ crfree(cr);
ASSERT3S(error, <=, 0);
return (error);
}
+#if defined(HAVE_FSYNC_WITH_DENTRY)
+/*
+ * Linux 2.6.x - 2.6.34 API,
+ * Through 2.6.34 the nfsd kernel server would pass a NULL 'file struct *'
+ * to the fops->fsync() hook. For this reason, we must be careful not to
+ * use filp unconditionally.
+ */
static int
zpl_fsync(struct file *filp, struct dentry *dentry, int datasync)
{
- cred_t *cr;
+ cred_t *cr = CRED();
+ int error;
+
+ crhold(cr);
+ error = -zfs_fsync(dentry->d_inode, datasync, cr);
+ crfree(cr);
+ ASSERT3S(error, <=, 0);
+
+ return (error);
+}
+
+#elif defined(HAVE_FSYNC_WITHOUT_DENTRY)
+/*
+ * Linux 2.6.35 - 3.0 API,
+ * As of 2.6.35 the dentry argument to the fops->fsync() hook was deemed
+ * redundant. The dentry is still accessible via filp->f_path.dentry,
+ * and we are guaranteed that filp will never be NULL.
+ */
+static int
+zpl_fsync(struct file *filp, int datasync)
+{
+ struct inode *inode = filp->f_mapping->host;
+ cred_t *cr = CRED();
int error;
- cr = (cred_t *)get_current_cred();
- error = -zfs_fsync(filp->f_path.dentry->d_inode, datasync, cr);
- put_cred(cr);
+ crhold(cr);
+ error = -zfs_fsync(inode, datasync, cr);
+ crfree(cr);
ASSERT3S(error, <=, 0);
return (error);
}
+#elif defined(HAVE_FSYNC_RANGE)
+/*
+ * Linux 3.1 - 3.x API,
+ * As of 3.1 the responsibility to call filemap_write_and_wait_range() has
+ * been pushed down in to the .fsync() vfs hook. Additionally, the i_mutex
+ * lock is no longer held by the caller, for zfs we don't require the lock
+ * to be held so we don't acquire it.
+ */
+static int
+zpl_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
+{
+ struct inode *inode = filp->f_mapping->host;
+ cred_t *cr = CRED();
+ int error;
+
+ error = filemap_write_and_wait_range(inode->i_mapping, start, end);
+ if (error)
+ return (error);
+
+ crhold(cr);
+ error = -zfs_fsync(inode, datasync, cr);
+ crfree(cr);
+ ASSERT3S(error, <=, 0);
+
+ return (error);
+}
+#else
+#error "Unsupported fops->fsync() implementation"
+#endif
+
ssize_t
zpl_read_common(struct inode *ip, const char *buf, size_t len, loff_t pos,
uio_seg_t segment, int flags, cred_t *cr)
static ssize_t
zpl_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
{
- cred_t *cr;
+ cred_t *cr = CRED();
ssize_t read;
- cr = (cred_t *)get_current_cred();
+ crhold(cr);
read = zpl_read_common(filp->f_mapping->host, buf, len, *ppos,
UIO_USERSPACE, filp->f_flags, cr);
- put_cred(cr);
+ crfree(cr);
if (read < 0)
return (read);
static ssize_t
zpl_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
{
- cred_t *cr;
+ cred_t *cr = CRED();
ssize_t wrote;
- cr = (cred_t *)get_current_cred();
+ crhold(cr);
wrote = zpl_write_common(filp->f_mapping->host, buf, len, *ppos,
UIO_USERSPACE, filp->f_flags, cr);
- put_cred(cr);
+ crfree(cr);
if (wrote < 0)
return (wrote);
return (wrote);
}
+/*
+ * It's worth taking a moment to describe how mmap is implemented
+ * for zfs because it differs considerably from other Linux filesystems.
+ * However, this issue is handled the same way under OpenSolaris.
+ *
+ * The issue is that by design zfs bypasses the Linux page cache and
+ * leaves all caching up to the ARC. This has been shown to work
+ * well for the common read(2)/write(2) case. However, mmap(2)
+ * is problem because it relies on being tightly integrated with the
+ * page cache. To handle this we cache mmap'ed files twice, once in
+ * the ARC and a second time in the page cache. The code is careful
+ * to keep both copies synchronized.
+ *
+ * When a file with an mmap'ed region is written to using write(2)
+ * both the data in the ARC and existing pages in the page cache
+ * are updated. For a read(2) data will be read first from the page
+ * cache then the ARC if needed. Neither a write(2) or read(2) will
+ * will ever result in new pages being added to the page cache.
+ *
+ * New pages are added to the page cache only via .readpage() which
+ * is called when the vfs needs to read a page off disk to back the
+ * virtual memory region. These pages may be modified without
+ * notifying the ARC and will be written out periodically via
+ * .writepage(). This will occur due to either a sync or the usual
+ * page aging behavior. Note because a read(2) of a mmap'ed file
+ * will always check the page cache first even when the ARC is out
+ * of date correct data will still be returned.
+ *
+ * While this implementation ensures correct behavior it does have
+ * have some drawbacks. The most obvious of which is that it
+ * increases the required memory footprint when access mmap'ed
+ * files. It also adds additional complexity to the code keeping
+ * both caches synchronized.
+ *
+ * Longer term it may be possible to cleanly resolve this wart by
+ * mapping page cache pages directly on to the ARC buffers. The
+ * Linux address space operations are flexible enough to allow
+ * selection of which pages back a particular index. The trick
+ * would be working out the details of which subsystem is in
+ * charge, the ARC, the page cache, or both. It may also prove
+ * helpful to move the ARC buffers to a scatter-gather lists
+ * rather than a vmalloc'ed region.
+ */
+static int
+zpl_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+ struct inode *ip = filp->f_mapping->host;
+ znode_t *zp = ITOZ(ip);
+ int error;
+
+ error = -zfs_map(ip, vma->vm_pgoff, (caddr_t *)vma->vm_start,
+ (size_t)(vma->vm_end - vma->vm_start), vma->vm_flags);
+ if (error)
+ return (error);
+
+ error = generic_file_mmap(filp, vma);
+ if (error)
+ return (error);
+
+ mutex_enter(&zp->z_lock);
+ zp->z_is_mapped = 1;
+ mutex_exit(&zp->z_lock);
+
+ return (error);
+}
+
+/*
+ * Populate a page with data for the Linux page cache. This function is
+ * only used to support mmap(2). There will be an identical copy of the
+ * data in the ARC which is kept up to date via .write() and .writepage().
+ *
+ * Current this function relies on zpl_read_common() and the O_DIRECT
+ * flag to read in a page. This works but the more correct way is to
+ * update zfs_fillpage() to be Linux friendly and use that interface.
+ */
+static int
+zpl_readpage(struct file *filp, struct page *pp)
+{
+ struct inode *ip;
+ struct page *pl[1];
+ int error = 0;
+
+ ASSERT(PageLocked(pp));
+ ip = pp->mapping->host;
+ pl[0] = pp;
+
+ error = -zfs_getpage(ip, pl, 1);
+
+ if (error) {
+ SetPageError(pp);
+ ClearPageUptodate(pp);
+ } else {
+ ClearPageError(pp);
+ SetPageUptodate(pp);
+ flush_dcache_page(pp);
+ }
+
+ unlock_page(pp);
+ return error;
+}
+
+/*
+ * Populate a set of pages with data for the Linux page cache. This
+ * function will only be called for read ahead and never for demand
+ * paging. For simplicity, the code relies on read_cache_pages() to
+ * correctly lock each page for IO and call zpl_readpage().
+ */
+static int
+zpl_readpages(struct file *filp, struct address_space *mapping,
+ struct list_head *pages, unsigned nr_pages)
+{
+ return (read_cache_pages(mapping, pages,
+ (filler_t *)zpl_readpage, filp));
+}
+
+int
+zpl_putpage(struct page *pp, struct writeback_control *wbc, void *data)
+{
+ struct address_space *mapping = data;
+
+ ASSERT(PageLocked(pp));
+ ASSERT(!PageWriteback(pp));
+ ASSERT(!(current->flags & PF_NOFS));
+
+ /*
+ * Annotate this call path with a flag that indicates that it is
+ * unsafe to use KM_SLEEP during memory allocations due to the
+ * potential for a deadlock. KM_PUSHPAGE should be used instead.
+ */
+ current->flags |= PF_NOFS;
+ (void) zfs_putpage(mapping->host, pp, wbc);
+ current->flags &= ~PF_NOFS;
+
+ return (0);
+}
+
+static int
+zpl_writepages(struct address_space *mapping, struct writeback_control *wbc)
+{
+ return write_cache_pages(mapping, wbc, zpl_putpage, mapping);
+}
+
+/*
+ * Write out dirty pages to the ARC, this function is only required to
+ * support mmap(2). Mapped pages may be dirtied by memory operations
+ * which never call .write(). These dirty pages are kept in sync with
+ * the ARC buffers via this hook.
+ */
+static int
+zpl_writepage(struct page *pp, struct writeback_control *wbc)
+{
+ return zpl_putpage(pp, wbc, pp->mapping);
+}
+
+/*
+ * The only flag combination which matches the behavior of zfs_space()
+ * is FALLOC_FL_PUNCH_HOLE. This flag was introduced in the 2.6.38 kernel.
+ */
+long
+zpl_fallocate_common(struct inode *ip, int mode, loff_t offset, loff_t len)
+{
+ cred_t *cr = CRED();
+ int error = -EOPNOTSUPP;
+
+ if (mode & FALLOC_FL_KEEP_SIZE)
+ return (-EOPNOTSUPP);
+
+ crhold(cr);
+
+#ifdef FALLOC_FL_PUNCH_HOLE
+ if (mode & FALLOC_FL_PUNCH_HOLE) {
+ flock64_t bf;
+
+ bf.l_type = F_WRLCK;
+ bf.l_whence = 0;
+ bf.l_start = offset;
+ bf.l_len = len;
+ bf.l_pid = 0;
+
+ error = -zfs_space(ip, F_FREESP, &bf, FWRITE, offset, cr);
+ }
+#endif /* FALLOC_FL_PUNCH_HOLE */
+
+ crfree(cr);
+
+ ASSERT3S(error, <=, 0);
+ return (error);
+}
+
+#ifdef HAVE_FILE_FALLOCATE
+static long
+zpl_fallocate(struct file *filp, int mode, loff_t offset, loff_t len)
+{
+ return zpl_fallocate_common(filp->f_path.dentry->d_inode,
+ mode, offset, len);
+}
+#endif /* HAVE_FILE_FALLOCATE */
+
+static long
+zpl_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+ switch (cmd) {
+ case ZFS_IOC_GETFLAGS:
+ case ZFS_IOC_SETFLAGS:
+ return (-EOPNOTSUPP);
+ default:
+ return (-ENOTTY);
+ }
+}
+
+#ifdef CONFIG_COMPAT
+static long
+zpl_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+ return zpl_ioctl(filp, cmd, arg);
+}
+#endif /* CONFIG_COMPAT */
+
+
const struct address_space_operations zpl_address_space_operations = {
-#if 0
+ .readpages = zpl_readpages,
.readpage = zpl_readpage,
.writepage = zpl_writepage,
- .direct_IO = zpl_direct_IO,
-#endif
+ .writepages = zpl_writepages,
};
const struct file_operations zpl_file_operations = {
- .open = generic_file_open,
+ .open = zpl_open,
+ .release = zpl_release,
.llseek = generic_file_llseek,
- .read = zpl_read, /* do_sync_read */
- .write = zpl_write, /* do_sync_write */
- .readdir = zpl_readdir,
- .mmap = generic_file_mmap,
+ .read = zpl_read,
+ .write = zpl_write,
+ .mmap = zpl_mmap,
.fsync = zpl_fsync,
- .aio_read = NULL, /* generic_file_aio_read */
- .aio_write = NULL, /* generic_file_aio_write */
+#ifdef HAVE_FILE_FALLOCATE
+ .fallocate = zpl_fallocate,
+#endif /* HAVE_FILE_FALLOCATE */
+ .unlocked_ioctl = zpl_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = zpl_compat_ioctl,
+#endif
};
const struct file_operations zpl_dir_file_operations = {
.read = generic_read_dir,
.readdir = zpl_readdir,
.fsync = zpl_fsync,
+ .unlocked_ioctl = zpl_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = zpl_compat_ioctl,
+#endif
};
git://git.camperquake.de / zfs.git / blobdiff