file.c 5.2 KB

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  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * linux/fs/ext2/file.c
  4. *
  5. * Copyright (C) 1992, 1993, 1994, 1995
  6. * Remy Card (card@masi.ibp.fr)
  7. * Laboratoire MASI - Institut Blaise Pascal
  8. * Universite Pierre et Marie Curie (Paris VI)
  9. *
  10. * from
  11. *
  12. * linux/fs/minix/file.c
  13. *
  14. * Copyright (C) 1991, 1992 Linus Torvalds
  15. *
  16. * ext2 fs regular file handling primitives
  17. *
  18. * 64-bit file support on 64-bit platforms by Jakub Jelinek
  19. * (jj@sunsite.ms.mff.cuni.cz)
  20. */
  21. #include <linux/time.h>
  22. #include <linux/pagemap.h>
  23. #include <linux/dax.h>
  24. #include <linux/quotaops.h>
  25. #include <linux/iomap.h>
  26. #include <linux/uio.h>
  27. #include "ext2.h"
  28. #include "xattr.h"
  29. #include "acl.h"
  30. #ifdef CONFIG_FS_DAX
  31. static ssize_t ext2_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
  32. {
  33. struct inode *inode = iocb->ki_filp->f_mapping->host;
  34. ssize_t ret;
  35. if (!iov_iter_count(to))
  36. return 0; /* skip atime */
  37. inode_lock_shared(inode);
  38. ret = dax_iomap_rw(iocb, to, &ext2_iomap_ops);
  39. inode_unlock_shared(inode);
  40. file_accessed(iocb->ki_filp);
  41. return ret;
  42. }
  43. static ssize_t ext2_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
  44. {
  45. struct file *file = iocb->ki_filp;
  46. struct inode *inode = file->f_mapping->host;
  47. ssize_t ret;
  48. inode_lock(inode);
  49. ret = generic_write_checks(iocb, from);
  50. if (ret <= 0)
  51. goto out_unlock;
  52. ret = file_remove_privs(file);
  53. if (ret)
  54. goto out_unlock;
  55. ret = file_update_time(file);
  56. if (ret)
  57. goto out_unlock;
  58. ret = dax_iomap_rw(iocb, from, &ext2_iomap_ops);
  59. if (ret > 0 && iocb->ki_pos > i_size_read(inode)) {
  60. i_size_write(inode, iocb->ki_pos);
  61. mark_inode_dirty(inode);
  62. }
  63. out_unlock:
  64. inode_unlock(inode);
  65. if (ret > 0)
  66. ret = generic_write_sync(iocb, ret);
  67. return ret;
  68. }
  69. /*
  70. * The lock ordering for ext2 DAX fault paths is:
  71. *
  72. * mmap_lock (MM)
  73. * sb_start_pagefault (vfs, freeze)
  74. * ext2_inode_info->dax_sem
  75. * address_space->i_mmap_rwsem or page_lock (mutually exclusive in DAX)
  76. * ext2_inode_info->truncate_mutex
  77. *
  78. * The default page_lock and i_size verification done by non-DAX fault paths
  79. * is sufficient because ext2 doesn't support hole punching.
  80. */
  81. static vm_fault_t ext2_dax_fault(struct vm_fault *vmf)
  82. {
  83. struct inode *inode = file_inode(vmf->vma->vm_file);
  84. struct ext2_inode_info *ei = EXT2_I(inode);
  85. vm_fault_t ret;
  86. bool write = (vmf->flags & FAULT_FLAG_WRITE) &&
  87. (vmf->vma->vm_flags & VM_SHARED);
  88. if (write) {
  89. sb_start_pagefault(inode->i_sb);
  90. file_update_time(vmf->vma->vm_file);
  91. }
  92. down_read(&ei->dax_sem);
  93. ret = dax_iomap_fault(vmf, PE_SIZE_PTE, NULL, NULL, &ext2_iomap_ops);
  94. up_read(&ei->dax_sem);
  95. if (write)
  96. sb_end_pagefault(inode->i_sb);
  97. return ret;
  98. }
  99. static const struct vm_operations_struct ext2_dax_vm_ops = {
  100. .fault = ext2_dax_fault,
  101. /*
  102. * .huge_fault is not supported for DAX because allocation in ext2
  103. * cannot be reliably aligned to huge page sizes and so pmd faults
  104. * will always fail and fail back to regular faults.
  105. */
  106. .page_mkwrite = ext2_dax_fault,
  107. .pfn_mkwrite = ext2_dax_fault,
  108. };
  109. static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma)
  110. {
  111. if (!IS_DAX(file_inode(file)))
  112. return generic_file_mmap(file, vma);
  113. file_accessed(file);
  114. vma->vm_ops = &ext2_dax_vm_ops;
  115. return 0;
  116. }
  117. #else
  118. #define ext2_file_mmap generic_file_mmap
  119. #endif
  120. /*
  121. * Called when filp is released. This happens when all file descriptors
  122. * for a single struct file are closed. Note that different open() calls
  123. * for the same file yield different struct file structures.
  124. */
  125. static int ext2_release_file (struct inode * inode, struct file * filp)
  126. {
  127. if (filp->f_mode & FMODE_WRITE) {
  128. mutex_lock(&EXT2_I(inode)->truncate_mutex);
  129. ext2_discard_reservation(inode);
  130. mutex_unlock(&EXT2_I(inode)->truncate_mutex);
  131. }
  132. return 0;
  133. }
  134. int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync)
  135. {
  136. int ret;
  137. struct super_block *sb = file->f_mapping->host->i_sb;
  138. ret = generic_file_fsync(file, start, end, datasync);
  139. if (ret == -EIO)
  140. /* We don't really know where the IO error happened... */
  141. ext2_error(sb, __func__,
  142. "detected IO error when writing metadata buffers");
  143. return ret;
  144. }
  145. static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
  146. {
  147. #ifdef CONFIG_FS_DAX
  148. if (IS_DAX(iocb->ki_filp->f_mapping->host))
  149. return ext2_dax_read_iter(iocb, to);
  150. #endif
  151. return generic_file_read_iter(iocb, to);
  152. }
  153. static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
  154. {
  155. #ifdef CONFIG_FS_DAX
  156. if (IS_DAX(iocb->ki_filp->f_mapping->host))
  157. return ext2_dax_write_iter(iocb, from);
  158. #endif
  159. return generic_file_write_iter(iocb, from);
  160. }
  161. const struct file_operations ext2_file_operations = {
  162. .llseek = generic_file_llseek,
  163. .read_iter = ext2_file_read_iter,
  164. .write_iter = ext2_file_write_iter,
  165. .unlocked_ioctl = ext2_ioctl,
  166. #ifdef CONFIG_COMPAT
  167. .compat_ioctl = ext2_compat_ioctl,
  168. #endif
  169. .mmap = ext2_file_mmap,
  170. .open = dquot_file_open,
  171. .release = ext2_release_file,
  172. .fsync = ext2_fsync,
  173. .get_unmapped_area = thp_get_unmapped_area,
  174. .splice_read = generic_file_splice_read,
  175. .splice_write = iter_file_splice_write,
  176. };
  177. const struct inode_operations ext2_file_inode_operations = {
  178. .listxattr = ext2_listxattr,
  179. .getattr = ext2_getattr,
  180. .setattr = ext2_setattr,
  181. .get_acl = ext2_get_acl,
  182. .set_acl = ext2_set_acl,
  183. .fiemap = ext2_fiemap,
  184. };