module/os/linux/zfs/zpl_file_range.c

   1 /*
   2  * CDDL HEADER START
   3  *
   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.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or https://opensource.org/licenses/CDDL-1.0.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  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]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2023, Klara Inc.
  23  */
  24
  25 #ifdef CONFIG_COMPAT
  26 #include <linux/compat.h>
  27 #endif
  28 #include <linux/fs.h>
  29 #ifdef HAVE_VFS_SPLICE_COPY_FILE_RANGE
  30 #include <linux/splice.h>
  31 #endif
  32 #include <sys/file.h>
  33 #include <sys/zfs_znode.h>
  34 #include <sys/zfs_vnops.h>
  35 #include <sys/zfeature.h>
  36
  37 /*
  38  * Clone part of a file via block cloning.
  39  *
  40  * Note that we are not required to update file offsets; the kernel will take
  41  * care of that depending on how it was called.
  42  */
  43 static ssize_t
  44 zpl_clone_file_range_impl(struct file *src_file, loff_t src_off,
  45     struct file *dst_file, loff_t dst_off, size_t len)
  46 {
  47         struct inode *src_i = file_inode(src_file);
  48         struct inode *dst_i = file_inode(dst_file);
  49         uint64_t src_off_o = (uint64_t)src_off;
  50         uint64_t dst_off_o = (uint64_t)dst_off;
  51         uint64_t len_o = (uint64_t)len;
  52         cred_t *cr = CRED();
  53         fstrans_cookie_t cookie;
  54         int err;
  55
  56         if (!zfs_bclone_enabled)
  57                 return (-EOPNOTSUPP);
  58
  59         if (!spa_feature_is_enabled(
  60             dmu_objset_spa(ITOZSB(dst_i)->z_os), SPA_FEATURE_BLOCK_CLONING))
  61                 return (-EOPNOTSUPP);
  62
  63         if (src_i != dst_i)
  64                 spl_inode_lock_shared(src_i);
  65         spl_inode_lock(dst_i);
  66
  67         crhold(cr);
  68         cookie = spl_fstrans_mark();
  69
  70         err = -zfs_clone_range(ITOZ(src_i), &src_off_o, ITOZ(dst_i),
  71             &dst_off_o, &len_o, cr);
  72
  73         spl_fstrans_unmark(cookie);
  74         crfree(cr);
  75
  76         spl_inode_unlock(dst_i);
  77         if (src_i != dst_i)
  78                 spl_inode_unlock_shared(src_i);
  79
  80         if (err < 0)
  81                 return (err);
  82
  83         return ((ssize_t)len_o);
  84 }
  85
  86 #if defined(HAVE_VFS_COPY_FILE_RANGE) || \
  87     defined(HAVE_VFS_FILE_OPERATIONS_EXTEND)
  88 /*
  89  * Entry point for copy_file_range(). Copy len bytes from src_off in src_file
  90  * to dst_off in dst_file. We are permitted to do this however we like, so we
  91  * try to just clone the blocks, and if we can't support it, fall back to the
  92  * kernel's generic byte copy function.
  93  */
  94 ssize_t
  95 zpl_copy_file_range(struct file *src_file, loff_t src_off,
  96     struct file *dst_file, loff_t dst_off, size_t len, unsigned int flags)
  97 {
  98         ssize_t ret;
  99
 100         /* Flags is reserved for future extensions and must be zero. */
 101         if (flags != 0)
 102                 return (-EINVAL);
 103
 104         /* Try to do it via zfs_clone_range() and allow shortening. */
 105         ret = zpl_clone_file_range_impl(src_file, src_off,
 106             dst_file, dst_off, len);
 107
 108 #if defined(HAVE_VFS_GENERIC_COPY_FILE_RANGE)
 109         /*
 110          * Since Linux 5.3 the filesystem driver is responsible for executing
 111          * an appropriate fallback, and a generic fallback function is provided.
 112          */
 113         if (ret == -EOPNOTSUPP || ret == -EINVAL || ret == -EXDEV ||
 114             ret == -EAGAIN)
 115                 ret = generic_copy_file_range(src_file, src_off, dst_file,
 116                     dst_off, len, flags);
 117 #elif defined(HAVE_VFS_SPLICE_COPY_FILE_RANGE)
 118         /*
 119          * Since 6.8 the fallback function is called splice_copy_file_range
 120          * and has a slightly different signature.
 121          */
 122         if (ret == -EOPNOTSUPP || ret == -EINVAL || ret == -EXDEV ||
 123             ret == -EAGAIN)
 124                 ret = splice_copy_file_range(src_file, src_off, dst_file,
 125                     dst_off, len);
 126 #else
 127         /*
 128          * Before Linux 5.3 the filesystem has to return -EOPNOTSUPP to signal
 129          * to the kernel that it should fallback to a content copy.
 130          */
 131         if (ret == -EINVAL || ret == -EXDEV || ret == -EAGAIN)
 132                 ret = -EOPNOTSUPP;
 133 #endif /* HAVE_VFS_GENERIC_COPY_FILE_RANGE || HAVE_VFS_SPLICE_COPY_FILE_RANGE */
 134
 135         return (ret);
 136 }
 137 #endif /* HAVE_VFS_COPY_FILE_RANGE || HAVE_VFS_FILE_OPERATIONS_EXTEND */
 138
 139 #ifdef HAVE_VFS_REMAP_FILE_RANGE
 140 /*
 141  * Entry point for FICLONE/FICLONERANGE/FIDEDUPERANGE.
 142  *
 143  * FICLONE and FICLONERANGE are basically the same as copy_file_range(), except
 144  * that they must clone - they cannot fall back to copying. FICLONE is exactly
 145  * FICLONERANGE, for the entire file. We don't need to try to tell them apart;
 146  * the kernel will sort that out for us.
 147  *
 148  * FIDEDUPERANGE is for turning a non-clone into a clone, that is, compare the
 149  * range in both files and if they're the same, arrange for them to be backed
 150  * by the same storage.
 151  *
 152  * REMAP_FILE_CAN_SHORTEN lets us know we can clone less than the given range
 153  * if we want. It's designed for filesystems that may need to shorten the
 154  * length for alignment, EOF, or any other requirement. ZFS may shorten the
 155  * request when there is outstanding dirty data which hasn't been written.
 156  */
 157 loff_t
 158 zpl_remap_file_range(struct file *src_file, loff_t src_off,
 159     struct file *dst_file, loff_t dst_off, loff_t len, unsigned int flags)
 160 {
 161         if (flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_CAN_SHORTEN))
 162                 return (-EINVAL);
 163
 164         /* No support for dedup yet */
 165         if (flags & REMAP_FILE_DEDUP)
 166                 return (-EOPNOTSUPP);
 167
 168         /* Zero length means to clone everything to the end of the file */
 169         if (len == 0)
 170                 len = i_size_read(file_inode(src_file)) - src_off;
 171
 172         ssize_t ret = zpl_clone_file_range_impl(src_file, src_off,
 173             dst_file, dst_off, len);
 174
 175         if (!(flags & REMAP_FILE_CAN_SHORTEN) && ret >= 0 && ret != len)
 176                 ret = -EINVAL;
 177
 178         return (ret);
 179 }
 180 #endif /* HAVE_VFS_REMAP_FILE_RANGE */
 181
 182 #if defined(HAVE_VFS_CLONE_FILE_RANGE) || \
 183     defined(HAVE_VFS_FILE_OPERATIONS_EXTEND)
 184 /*
 185  * Entry point for FICLONE and FICLONERANGE, before Linux 4.20.
 186  */
 187 int
 188 zpl_clone_file_range(struct file *src_file, loff_t src_off,
 189     struct file *dst_file, loff_t dst_off, uint64_t len)
 190 {
 191         /* Zero length means to clone everything to the end of the file */
 192         if (len == 0)
 193                 len = i_size_read(file_inode(src_file)) - src_off;
 194
 195         /* The entire length must be cloned or this is an error. */
 196         ssize_t ret = zpl_clone_file_range_impl(src_file, src_off,
 197             dst_file, dst_off, len);
 198
 199         if (ret >= 0 && ret != len)
 200                 ret = -EINVAL;
 201
 202         return (ret);
 203 }
 204 #endif /* HAVE_VFS_CLONE_FILE_RANGE || HAVE_VFS_FILE_OPERATIONS_EXTEND */
 205
 206 #ifdef HAVE_VFS_DEDUPE_FILE_RANGE
 207 /*
 208  * Entry point for FIDEDUPERANGE, before Linux 4.20.
 209  */
 210 int
 211 zpl_dedupe_file_range(struct file *src_file, loff_t src_off,
 212     struct file *dst_file, loff_t dst_off, uint64_t len)
 213 {
 214         /* No support for dedup yet */
 215         return (-EOPNOTSUPP);
 216 }
 217 #endif /* HAVE_VFS_DEDUPE_FILE_RANGE */
 218
 219 /* Entry point for FICLONE, before Linux 4.5. */
 220 long
 221 zpl_ioctl_ficlone(struct file *dst_file, void *arg)
 222 {
 223         unsigned long sfd = (unsigned long)arg;
 224
 225         struct file *src_file = fget(sfd);
 226         if (src_file == NULL)
 227                 return (-EBADF);
 228
 229         if (dst_file->f_op != src_file->f_op) {
 230                 fput(src_file);
 231                 return (-EXDEV);
 232         }
 233
 234         size_t len = i_size_read(file_inode(src_file));
 235
 236         ssize_t ret = zpl_clone_file_range_impl(src_file, 0, dst_file, 0, len);
 237
 238         fput(src_file);
 239
 240         if (ret < 0) {
 241                 if (ret == -EOPNOTSUPP)
 242                         return (-ENOTTY);
 243                 return (ret);
 244         }
 245
 246         if (ret != len)
 247                 return (-EINVAL);
 248
 249         return (0);
 250 }
 251
 252 /* Entry point for FICLONERANGE, before Linux 4.5. */
 253 long
 254 zpl_ioctl_ficlonerange(struct file *dst_file, void __user *arg)
 255 {
 256         zfs_ioc_compat_file_clone_range_t fcr;
 257
 258         if (copy_from_user(&fcr, arg, sizeof (fcr)))
 259                 return (-EFAULT);
 260
 261         struct file *src_file = fget(fcr.fcr_src_fd);
 262         if (src_file == NULL)
 263                 return (-EBADF);
 264
 265         if (dst_file->f_op != src_file->f_op) {
 266                 fput(src_file);
 267                 return (-EXDEV);
 268         }
 269
 270         size_t len = fcr.fcr_src_length;
 271         if (len == 0)
 272                 len = i_size_read(file_inode(src_file)) - fcr.fcr_src_offset;
 273
 274         ssize_t ret = zpl_clone_file_range_impl(src_file, fcr.fcr_src_offset,
 275             dst_file, fcr.fcr_dest_offset, len);
 276
 277         fput(src_file);
 278
 279         if (ret < 0) {
 280                 if (ret == -EOPNOTSUPP)
 281                         return (-ENOTTY);
 282                 return (ret);
 283         }
 284
 285         if (ret != len)
 286                 return (-EINVAL);
 287
 288         return (0);
 289 }
 290
 291 /* Entry point for FIDEDUPERANGE, before Linux 4.5. */
 292 long
 293 zpl_ioctl_fideduperange(struct file *filp, void *arg)
 294 {
 295         (void) arg;
 296
 297         /* No support for dedup yet */
 298         return (-ENOTTY);
 299 }