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 /*
  87  * Entry point for copy_file_range(). Copy len bytes from src_off in src_file
  88  * to dst_off in dst_file. We are permitted to do this however we like, so we
  89  * try to just clone the blocks, and if we can't support it, fall back to the
  90  * kernel's generic byte copy function.
  91  */
  92 ssize_t
  93 zpl_copy_file_range(struct file *src_file, loff_t src_off,
  94     struct file *dst_file, loff_t dst_off, size_t len, unsigned int flags)
  95 {
  96         ssize_t ret;
  97
  98         /* Flags is reserved for future extensions and must be zero. */
  99         if (flags != 0)
 100                 return (-EINVAL);
 101
 102         /* Try to do it via zfs_clone_range() and allow shortening. */
 103         ret = zpl_clone_file_range_impl(src_file, src_off,
 104             dst_file, dst_off, len);
 105
 106 #if defined(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 #elif defined(HAVE_VFS_SPLICE_COPY_FILE_RANGE)
 116         /*
 117          * Since 6.8 the fallback function is called splice_copy_file_range
 118          * and has a slightly different signature.
 119          */
 120         if (ret == -EOPNOTSUPP || ret == -EINVAL || ret == -EXDEV ||
 121             ret == -EAGAIN)
 122                 ret = splice_copy_file_range(src_file, src_off, dst_file,
 123                     dst_off, len);
 124 #else
 125         /*
 126          * Before Linux 5.3 the filesystem has to return -EOPNOTSUPP to signal
 127          * to the kernel that it should fallback to a content copy.
 128          */
 129         if (ret == -EINVAL || ret == -EXDEV || ret == -EAGAIN)
 130                 ret = -EOPNOTSUPP;
 131 #endif /* HAVE_VFS_GENERIC_COPY_FILE_RANGE || HAVE_VFS_SPLICE_COPY_FILE_RANGE */
 132
 133         return (ret);
 134 }
 135
 136 #ifdef HAVE_VFS_REMAP_FILE_RANGE
 137 /*
 138  * Entry point for FICLONE/FICLONERANGE/FIDEDUPERANGE.
 139  *
 140  * FICLONE and FICLONERANGE are basically the same as copy_file_range(), except
 141  * that they must clone - they cannot fall back to copying. FICLONE is exactly
 142  * FICLONERANGE, for the entire file. We don't need to try to tell them apart;
 143  * the kernel will sort that out for us.
 144  *
 145  * FIDEDUPERANGE is for turning a non-clone into a clone, that is, compare the
 146  * range in both files and if they're the same, arrange for them to be backed
 147  * by the same storage.
 148  *
 149  * REMAP_FILE_CAN_SHORTEN lets us know we can clone less than the given range
 150  * if we want. It's designed for filesystems that may need to shorten the
 151  * length for alignment, EOF, or any other requirement. ZFS may shorten the
 152  * request when there is outstanding dirty data which hasn't been written.
 153  */
 154 loff_t
 155 zpl_remap_file_range(struct file *src_file, loff_t src_off,
 156     struct file *dst_file, loff_t dst_off, loff_t len, unsigned int flags)
 157 {
 158         if (flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_CAN_SHORTEN))
 159                 return (-EINVAL);
 160
 161         /* No support for dedup yet */
 162         if (flags & REMAP_FILE_DEDUP)
 163                 return (-EOPNOTSUPP);
 164
 165         /* Zero length means to clone everything to the end of the file */
 166         if (len == 0)
 167                 len = i_size_read(file_inode(src_file)) - src_off;
 168
 169         ssize_t ret = zpl_clone_file_range_impl(src_file, src_off,
 170             dst_file, dst_off, len);
 171
 172         if (!(flags & REMAP_FILE_CAN_SHORTEN) && ret >= 0 && ret != len)
 173                 ret = -EINVAL;
 174
 175         return (ret);
 176 }
 177 #endif /* HAVE_VFS_REMAP_FILE_RANGE */
 178
 179 #if defined(HAVE_VFS_CLONE_FILE_RANGE)
 180 /*
 181  * Entry point for FICLONE and FICLONERANGE, before Linux 4.20.
 182  */
 183 int
 184 zpl_clone_file_range(struct file *src_file, loff_t src_off,
 185     struct file *dst_file, loff_t dst_off, uint64_t len)
 186 {
 187         /* Zero length means to clone everything to the end of the file */
 188         if (len == 0)
 189                 len = i_size_read(file_inode(src_file)) - src_off;
 190
 191         /* The entire length must be cloned or this is an error. */
 192         ssize_t ret = zpl_clone_file_range_impl(src_file, src_off,
 193             dst_file, dst_off, len);
 194
 195         if (ret >= 0 && ret != len)
 196                 ret = -EINVAL;
 197
 198         return (ret);
 199 }
 200 #endif /* HAVE_VFS_CLONE_FILE_RANGE */
 201
 202 #ifdef HAVE_VFS_DEDUPE_FILE_RANGE
 203 /*
 204  * Entry point for FIDEDUPERANGE, before Linux 4.20.
 205  */
 206 int
 207 zpl_dedupe_file_range(struct file *src_file, loff_t src_off,
 208     struct file *dst_file, loff_t dst_off, uint64_t len)
 209 {
 210         /* No support for dedup yet */
 211         return (-EOPNOTSUPP);
 212 }
 213 #endif /* HAVE_VFS_DEDUPE_FILE_RANGE */
 214
 215 /* Entry point for FICLONE, before Linux 4.5. */
 216 long
 217 zpl_ioctl_ficlone(struct file *dst_file, void *arg)
 218 {
 219         unsigned long sfd = (unsigned long)arg;
 220
 221         struct file *src_file = fget(sfd);
 222         if (src_file == NULL)
 223                 return (-EBADF);
 224
 225         if (dst_file->f_op != src_file->f_op) {
 226                 fput(src_file);
 227                 return (-EXDEV);
 228         }
 229
 230         size_t len = i_size_read(file_inode(src_file));
 231
 232         ssize_t ret = zpl_clone_file_range_impl(src_file, 0, dst_file, 0, len);
 233
 234         fput(src_file);
 235
 236         if (ret < 0) {
 237                 if (ret == -EOPNOTSUPP)
 238                         return (-ENOTTY);
 239                 return (ret);
 240         }
 241
 242         if (ret != len)
 243                 return (-EINVAL);
 244
 245         return (0);
 246 }
 247
 248 /* Entry point for FICLONERANGE, before Linux 4.5. */
 249 long
 250 zpl_ioctl_ficlonerange(struct file *dst_file, void __user *arg)
 251 {
 252         zfs_ioc_compat_file_clone_range_t fcr;
 253
 254         if (copy_from_user(&fcr, arg, sizeof (fcr)))
 255                 return (-EFAULT);
 256
 257         struct file *src_file = fget(fcr.fcr_src_fd);
 258         if (src_file == NULL)
 259                 return (-EBADF);
 260
 261         if (dst_file->f_op != src_file->f_op) {
 262                 fput(src_file);
 263                 return (-EXDEV);
 264         }
 265
 266         size_t len = fcr.fcr_src_length;
 267         if (len == 0)
 268                 len = i_size_read(file_inode(src_file)) - fcr.fcr_src_offset;
 269
 270         ssize_t ret = zpl_clone_file_range_impl(src_file, fcr.fcr_src_offset,
 271             dst_file, fcr.fcr_dest_offset, len);
 272
 273         fput(src_file);
 274
 275         if (ret < 0) {
 276                 if (ret == -EOPNOTSUPP)
 277                         return (-ENOTTY);
 278                 return (ret);
 279         }
 280
 281         if (ret != len)
 282                 return (-EINVAL);
 283
 284         return (0);
 285 }
 286
 287 /* Entry point for FIDEDUPERANGE, before Linux 4.5. */
 288 long
 289 zpl_ioctl_fideduperange(struct file *filp, void *arg)
 290 {
 291         (void) arg;
 292
 293         /* No support for dedup yet */
 294         return (-ENOTTY);
 295 }