| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * linux/fs/ext4/file.c |
| * |
| * Copyright (C) 1992, 1993, 1994, 1995 |
| * Remy Card (card@masi.ibp.fr) |
| * Laboratoire MASI - Institut Blaise Pascal |
| * Universite Pierre et Marie Curie (Paris VI) |
| * |
| * from |
| * |
| * linux/fs/minix/file.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * |
| * ext4 fs regular file handling primitives |
| * |
| * 64-bit file support on 64-bit platforms by Jakub Jelinek |
| * (jj@sunsite.ms.mff.cuni.cz) |
| */ |
| |
| #include <linux/time.h> |
| #include <linux/fs.h> |
| #include <linux/iomap.h> |
| #include <linux/mount.h> |
| #include <linux/path.h> |
| #include <linux/dax.h> |
| #include <linux/quotaops.h> |
| #include <linux/pagevec.h> |
| #include <linux/uio.h> |
| #include <linux/mman.h> |
| #include "ext4.h" |
| #include "ext4_jbd2.h" |
| #include "xattr.h" |
| #include "acl.h" |
| |
| #ifdef CONFIG_FS_DAX |
| static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to) |
| { |
| struct inode *inode = file_inode(iocb->ki_filp); |
| ssize_t ret; |
| |
| if (iocb->ki_flags & IOCB_NOWAIT) { |
| if (!inode_trylock_shared(inode)) |
| return -EAGAIN; |
| } else { |
| inode_lock_shared(inode); |
| } |
| /* |
| * Recheck under inode lock - at this point we are sure it cannot |
| * change anymore |
| */ |
| if (!IS_DAX(inode)) { |
| inode_unlock_shared(inode); |
| /* Fallback to buffered IO in case we cannot support DAX */ |
| return generic_file_read_iter(iocb, to); |
| } |
| ret = dax_iomap_rw(iocb, to, &ext4_iomap_ops); |
| inode_unlock_shared(inode); |
| |
| file_accessed(iocb->ki_filp); |
| return ret; |
| } |
| #endif |
| |
| static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to) |
| { |
| if (unlikely(ext4_forced_shutdown(EXT4_SB(file_inode(iocb->ki_filp)->i_sb)))) |
| return -EIO; |
| |
| if (!iov_iter_count(to)) |
| return 0; /* skip atime */ |
| |
| #ifdef CONFIG_FS_DAX |
| if (IS_DAX(file_inode(iocb->ki_filp))) |
| return ext4_dax_read_iter(iocb, to); |
| #endif |
| return generic_file_read_iter(iocb, to); |
| } |
| |
| /* |
| * Called when an inode is released. Note that this is different |
| * from ext4_file_open: open gets called at every open, but release |
| * gets called only when /all/ the files are closed. |
| */ |
| static int ext4_release_file(struct inode *inode, struct file *filp) |
| { |
| if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) { |
| ext4_alloc_da_blocks(inode); |
| ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE); |
| } |
| /* if we are the last writer on the inode, drop the block reservation */ |
| if ((filp->f_mode & FMODE_WRITE) && |
| (atomic_read(&inode->i_writecount) == 1) && |
| !EXT4_I(inode)->i_reserved_data_blocks) |
| { |
| down_write(&EXT4_I(inode)->i_data_sem); |
| ext4_discard_preallocations(inode); |
| up_write(&EXT4_I(inode)->i_data_sem); |
| } |
| if (is_dx(inode) && filp->private_data) |
| ext4_htree_free_dir_info(filp->private_data); |
| |
| return 0; |
| } |
| |
| static void ext4_unwritten_wait(struct inode *inode) |
| { |
| wait_queue_head_t *wq = ext4_ioend_wq(inode); |
| |
| wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_unwritten) == 0)); |
| } |
| |
| /* |
| * This tests whether the IO in question is block-aligned or not. |
| * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they |
| * are converted to written only after the IO is complete. Until they are |
| * mapped, these blocks appear as holes, so dio_zero_block() will assume that |
| * it needs to zero out portions of the start and/or end block. If 2 AIO |
| * threads are at work on the same unwritten block, they must be synchronized |
| * or one thread will zero the other's data, causing corruption. |
| */ |
| static int |
| ext4_unaligned_aio(struct inode *inode, struct iov_iter *from, loff_t pos) |
| { |
| struct super_block *sb = inode->i_sb; |
| int blockmask = sb->s_blocksize - 1; |
| |
| if (pos >= ALIGN(i_size_read(inode), sb->s_blocksize)) |
| return 0; |
| |
| if ((pos | iov_iter_alignment(from)) & blockmask) |
| return 1; |
| |
| return 0; |
| } |
| |
| /* Is IO overwriting allocated and initialized blocks? */ |
| static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len) |
| { |
| struct ext4_map_blocks map; |
| unsigned int blkbits = inode->i_blkbits; |
| int err, blklen; |
| |
| if (pos + len > i_size_read(inode)) |
| return false; |
| |
| map.m_lblk = pos >> blkbits; |
| map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits); |
| blklen = map.m_len; |
| |
| err = ext4_map_blocks(NULL, inode, &map, 0); |
| /* |
| * 'err==len' means that all of the blocks have been preallocated, |
| * regardless of whether they have been initialized or not. To exclude |
| * unwritten extents, we need to check m_flags. |
| */ |
| return err == blklen && (map.m_flags & EXT4_MAP_MAPPED); |
| } |
| |
| static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from) |
| { |
| struct inode *inode = file_inode(iocb->ki_filp); |
| ssize_t ret; |
| |
| ret = generic_write_checks(iocb, from); |
| if (ret <= 0) |
| return ret; |
| |
| if (unlikely(IS_IMMUTABLE(inode))) |
| return -EPERM; |
| |
| /* |
| * If we have encountered a bitmap-format file, the size limit |
| * is smaller than s_maxbytes, which is for extent-mapped files. |
| */ |
| if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) { |
| struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); |
| |
| if (iocb->ki_pos >= sbi->s_bitmap_maxbytes) |
| return -EFBIG; |
| iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos); |
| } |
| return iov_iter_count(from); |
| } |
| |
| #ifdef CONFIG_FS_DAX |
| static ssize_t |
| ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) |
| { |
| struct inode *inode = file_inode(iocb->ki_filp); |
| ssize_t ret; |
| |
| if (iocb->ki_flags & IOCB_NOWAIT) { |
| if (!inode_trylock(inode)) |
| return -EAGAIN; |
| } else { |
| inode_lock(inode); |
| } |
| ret = ext4_write_checks(iocb, from); |
| if (ret <= 0) |
| goto out; |
| ret = file_remove_privs(iocb->ki_filp); |
| if (ret) |
| goto out; |
| ret = file_update_time(iocb->ki_filp); |
| if (ret) |
| goto out; |
| |
| ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops); |
| out: |
| inode_unlock(inode); |
| if (ret > 0) |
| ret = generic_write_sync(iocb, ret); |
| return ret; |
| } |
| #endif |
| |
| static ssize_t |
| ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) |
| { |
| struct inode *inode = file_inode(iocb->ki_filp); |
| int o_direct = iocb->ki_flags & IOCB_DIRECT; |
| int unaligned_aio = 0; |
| int overwrite = 0; |
| ssize_t ret; |
| |
| if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) |
| return -EIO; |
| |
| #ifdef CONFIG_FS_DAX |
| if (IS_DAX(inode)) |
| return ext4_dax_write_iter(iocb, from); |
| #endif |
| |
| if (!inode_trylock(inode)) { |
| if (iocb->ki_flags & IOCB_NOWAIT) |
| return -EAGAIN; |
| inode_lock(inode); |
| } |
| |
| ret = ext4_write_checks(iocb, from); |
| if (ret <= 0) |
| goto out; |
| |
| /* |
| * Unaligned direct AIO must be serialized among each other as zeroing |
| * of partial blocks of two competing unaligned AIOs can result in data |
| * corruption. |
| */ |
| if (o_direct && ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) && |
| !is_sync_kiocb(iocb) && |
| ext4_unaligned_aio(inode, from, iocb->ki_pos)) { |
| unaligned_aio = 1; |
| ext4_unwritten_wait(inode); |
| } |
| |
| iocb->private = &overwrite; |
| /* Check whether we do a DIO overwrite or not */ |
| if (o_direct && !unaligned_aio) { |
| if (ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from))) { |
| if (ext4_should_dioread_nolock(inode)) |
| overwrite = 1; |
| } else if (iocb->ki_flags & IOCB_NOWAIT) { |
| ret = -EAGAIN; |
| goto out; |
| } |
| } |
| |
| ret = __generic_file_write_iter(iocb, from); |
| /* |
| * Unaligned direct AIO must be the only IO in flight. Otherwise |
| * overlapping aligned IO after unaligned might result in data |
| * corruption. |
| */ |
| if (ret == -EIOCBQUEUED && unaligned_aio) |
| ext4_unwritten_wait(inode); |
| inode_unlock(inode); |
| |
| if (ret > 0) |
| ret = generic_write_sync(iocb, ret); |
| |
| return ret; |
| |
| out: |
| inode_unlock(inode); |
| return ret; |
| } |
| |
| #ifdef CONFIG_FS_DAX |
| static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf, |
| enum page_entry_size pe_size) |
| { |
| int error = 0; |
| vm_fault_t result; |
| int retries = 0; |
| handle_t *handle = NULL; |
| struct inode *inode = file_inode(vmf->vma->vm_file); |
| struct super_block *sb = inode->i_sb; |
| |
| /* |
| * We have to distinguish real writes from writes which will result in a |
| * COW page; COW writes should *not* poke the journal (the file will not |
| * be changed). Doing so would cause unintended failures when mounted |
| * read-only. |
| * |
| * We check for VM_SHARED rather than vmf->cow_page since the latter is |
| * unset for pe_size != PE_SIZE_PTE (i.e. only in do_cow_fault); for |
| * other sizes, dax_iomap_fault will handle splitting / fallback so that |
| * we eventually come back with a COW page. |
| */ |
| bool write = (vmf->flags & FAULT_FLAG_WRITE) && |
| (vmf->vma->vm_flags & VM_SHARED); |
| pfn_t pfn; |
| |
| if (write) { |
| sb_start_pagefault(sb); |
| file_update_time(vmf->vma->vm_file); |
| down_read(&EXT4_I(inode)->i_mmap_sem); |
| retry: |
| handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE, |
| EXT4_DATA_TRANS_BLOCKS(sb)); |
| if (IS_ERR(handle)) { |
| up_read(&EXT4_I(inode)->i_mmap_sem); |
| sb_end_pagefault(sb); |
| return VM_FAULT_SIGBUS; |
| } |
| } else { |
| down_read(&EXT4_I(inode)->i_mmap_sem); |
| } |
| result = dax_iomap_fault(vmf, pe_size, &pfn, &error, &ext4_iomap_ops); |
| if (write) { |
| ext4_journal_stop(handle); |
| |
| if ((result & VM_FAULT_ERROR) && error == -ENOSPC && |
| ext4_should_retry_alloc(sb, &retries)) |
| goto retry; |
| /* Handling synchronous page fault? */ |
| if (result & VM_FAULT_NEEDDSYNC) |
| result = dax_finish_sync_fault(vmf, pe_size, pfn); |
| up_read(&EXT4_I(inode)->i_mmap_sem); |
| sb_end_pagefault(sb); |
| } else { |
| up_read(&EXT4_I(inode)->i_mmap_sem); |
| } |
| |
| return result; |
| } |
| |
| static vm_fault_t ext4_dax_fault(struct vm_fault *vmf) |
| { |
| return ext4_dax_huge_fault(vmf, PE_SIZE_PTE); |
| } |
| |
| static const struct vm_operations_struct ext4_dax_vm_ops = { |
| .fault = ext4_dax_fault, |
| .huge_fault = ext4_dax_huge_fault, |
| .page_mkwrite = ext4_dax_fault, |
| .pfn_mkwrite = ext4_dax_fault, |
| }; |
| #else |
| #define ext4_dax_vm_ops ext4_file_vm_ops |
| #endif |
| |
| static const struct vm_operations_struct ext4_file_vm_ops = { |
| .fault = ext4_filemap_fault, |
| .map_pages = filemap_map_pages, |
| .page_mkwrite = ext4_page_mkwrite, |
| }; |
| |
| static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma) |
| { |
| struct inode *inode = file->f_mapping->host; |
| struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); |
| struct dax_device *dax_dev = sbi->s_daxdev; |
| |
| if (unlikely(ext4_forced_shutdown(sbi))) |
| return -EIO; |
| |
| /* |
| * We don't support synchronous mappings for non-DAX files and |
| * for DAX files if underneath dax_device is not synchronous. |
| */ |
| if (!daxdev_mapping_supported(vma, dax_dev)) |
| return -EOPNOTSUPP; |
| |
| file_accessed(file); |
| if (IS_DAX(file_inode(file))) { |
| vma->vm_ops = &ext4_dax_vm_ops; |
| vma->vm_flags |= VM_HUGEPAGE; |
| } else { |
| vma->vm_ops = &ext4_file_vm_ops; |
| } |
| return 0; |
| } |
| |
| static int ext4_sample_last_mounted(struct super_block *sb, |
| struct vfsmount *mnt) |
| { |
| struct ext4_sb_info *sbi = EXT4_SB(sb); |
| struct path path; |
| char buf[64], *cp; |
| handle_t *handle; |
| int err; |
| |
| if (likely(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED)) |
| return 0; |
| |
| if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb)) |
| return 0; |
| |
| sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED; |
| /* |
| * Sample where the filesystem has been mounted and |
| * store it in the superblock for sysadmin convenience |
| * when trying to sort through large numbers of block |
| * devices or filesystem images. |
| */ |
| memset(buf, 0, sizeof(buf)); |
| path.mnt = mnt; |
| path.dentry = mnt->mnt_root; |
| cp = d_path(&path, buf, sizeof(buf)); |
| err = 0; |
| if (IS_ERR(cp)) |
| goto out; |
| |
| handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1); |
| err = PTR_ERR(handle); |
| if (IS_ERR(handle)) |
| goto out; |
| BUFFER_TRACE(sbi->s_sbh, "get_write_access"); |
| err = ext4_journal_get_write_access(handle, sbi->s_sbh); |
| if (err) |
| goto out_journal; |
| strncpy(sbi->s_es->s_last_mounted, cp, |
| sizeof(sbi->s_es->s_last_mounted)); |
| ext4_handle_dirty_super(handle, sb); |
| out_journal: |
| ext4_journal_stop(handle); |
| out: |
| sb_end_intwrite(sb); |
| return err; |
| } |
| |
| static int ext4_file_open(struct inode * inode, struct file * filp) |
| { |
| int ret; |
| |
| if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) |
| return -EIO; |
| |
| ret = ext4_sample_last_mounted(inode->i_sb, filp->f_path.mnt); |
| if (ret) |
| return ret; |
| |
| ret = fscrypt_file_open(inode, filp); |
| if (ret) |
| return ret; |
| |
| ret = fsverity_file_open(inode, filp); |
| if (ret) |
| return ret; |
| |
| /* |
| * Set up the jbd2_inode if we are opening the inode for |
| * writing and the journal is present |
| */ |
| if (filp->f_mode & FMODE_WRITE) { |
| ret = ext4_inode_attach_jinode(inode); |
| if (ret < 0) |
| return ret; |
| } |
| |
| filp->f_mode |= FMODE_NOWAIT; |
| return dquot_file_open(inode, filp); |
| } |
| |
| /* |
| * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values |
| * by calling generic_file_llseek_size() with the appropriate maxbytes |
| * value for each. |
| */ |
| loff_t ext4_llseek(struct file *file, loff_t offset, int whence) |
| { |
| struct inode *inode = file->f_mapping->host; |
| loff_t maxbytes; |
| |
| if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) |
| maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes; |
| else |
| maxbytes = inode->i_sb->s_maxbytes; |
| |
| switch (whence) { |
| default: |
| return generic_file_llseek_size(file, offset, whence, |
| maxbytes, i_size_read(inode)); |
| case SEEK_HOLE: |
| inode_lock_shared(inode); |
| offset = iomap_seek_hole(inode, offset, &ext4_iomap_ops); |
| inode_unlock_shared(inode); |
| break; |
| case SEEK_DATA: |
| inode_lock_shared(inode); |
| offset = iomap_seek_data(inode, offset, &ext4_iomap_ops); |
| inode_unlock_shared(inode); |
| break; |
| } |
| |
| if (offset < 0) |
| return offset; |
| return vfs_setpos(file, offset, maxbytes); |
| } |
| |
| const struct file_operations ext4_file_operations = { |
| .llseek = ext4_llseek, |
| .read_iter = ext4_file_read_iter, |
| .write_iter = ext4_file_write_iter, |
| .unlocked_ioctl = ext4_ioctl, |
| #ifdef CONFIG_COMPAT |
| .compat_ioctl = ext4_compat_ioctl, |
| #endif |
| .mmap = ext4_file_mmap, |
| .mmap_supported_flags = MAP_SYNC, |
| .open = ext4_file_open, |
| .release = ext4_release_file, |
| .fsync = ext4_sync_file, |
| .get_unmapped_area = thp_get_unmapped_area, |
| .splice_read = generic_file_splice_read, |
| .splice_write = iter_file_splice_write, |
| .fallocate = ext4_fallocate, |
| }; |
| |
| const struct inode_operations ext4_file_inode_operations = { |
| .setattr = ext4_setattr, |
| .getattr = ext4_file_getattr, |
| .listxattr = ext4_listxattr, |
| .get_acl = ext4_get_acl, |
| .set_acl = ext4_set_acl, |
| .fiemap = ext4_fiemap, |
| }; |
| |