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