// 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 #include #include #include #include #include #include #include #include #include #include #include "ext4.h" #include "ext4_jbd2.h" #include "xattr.h" #include "acl.h" #include "truncate.h" /* * Returns %true if the given DIO request should be attempted with DIO, or * %false if it should fall back to buffered I/O. * * DIO isn't well specified; when it's unsupported (either due to the request * being misaligned, or due to the file not supporting DIO at all), filesystems * either fall back to buffered I/O or return EINVAL. For files that don't use * any special features like encryption or verity, ext4 has traditionally * returned EINVAL for misaligned DIO. iomap_dio_rw() uses this convention too. * In this case, we should attempt the DIO, *not* fall back to buffered I/O. * * In contrast, in cases where DIO is unsupported due to ext4 features, ext4 * traditionally falls back to buffered I/O. * * This function implements the traditional ext4 behavior in all these cases. */ static bool ext4_should_use_dio(struct kiocb *iocb, struct iov_iter *iter) { struct inode *inode = file_inode(iocb->ki_filp); u32 dio_align = ext4_dio_alignment(inode); if (dio_align == 0) return false; if (dio_align == 1) return true; return IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(iter), dio_align); } static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to) { ssize_t ret; struct inode *inode = file_inode(iocb->ki_filp); if (iocb->ki_flags & IOCB_NOWAIT) { if (!inode_trylock_shared(inode)) return -EAGAIN; } else { inode_lock_shared(inode); } if (!ext4_should_use_dio(iocb, to)) { inode_unlock_shared(inode); /* * Fallback to buffered I/O if the operation being performed on * the inode is not supported by direct I/O. The IOCB_DIRECT * flag needs to be cleared here in order to ensure that the * direct I/O path within generic_file_read_iter() is not * taken. */ iocb->ki_flags &= ~IOCB_DIRECT; return generic_file_read_iter(iocb, to); } ret = iomap_dio_read_simple(iocb, to, ext4_iomap_begin); if (ret == -ENOTBLK) ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, 0, NULL, 0); inode_unlock_shared(inode); file_accessed(iocb->ki_filp); return ret; } #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) { struct inode *inode = file_inode(iocb->ki_filp); if (unlikely(ext4_forced_shutdown(inode->i_sb))) return -EIO; if (!iov_iter_count(to)) return 0; /* skip atime */ #ifdef CONFIG_FS_DAX if (IS_DAX(inode)) return ext4_dax_read_iter(iocb, to); #endif if (iocb->ki_flags & IOCB_DIRECT) return ext4_dio_read_iter(iocb, to); return generic_file_read_iter(iocb, to); } static ssize_t ext4_file_splice_read(struct file *in, loff_t *ppos, struct pipe_inode_info *pipe, size_t len, unsigned int flags) { struct inode *inode = file_inode(in); if (unlikely(ext4_forced_shutdown(inode->i_sb))) return -EIO; return filemap_splice_read(in, ppos, pipe, len, flags); } /* * 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; } /* * 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 bool ext4_unaligned_io(struct inode *inode, struct iov_iter *from, loff_t pos) { struct super_block *sb = inode->i_sb; unsigned long blockmask = sb->s_blocksize - 1; if ((pos | iov_iter_alignment(from)) & blockmask) return true; return false; } static bool ext4_extending_io(struct inode *inode, loff_t offset, size_t len) { if (offset + len > i_size_read(inode) || offset + len > EXT4_I(inode)->i_disksize) return true; return false; } /* * Does an unaligned DIO write require partial block zeroing? * * Partial block zeroing is performed only for the head and tail blocks * when they are partially covered by the write and the underlying extent * is a hole or unwritten. Middle blocks (fully covered by the write) * are written as whole blocks without zeroing. * * When zeroing is required, two concurrent unaligned DIO writes to the * same partial block can race and corrupt each other's data, so the * caller must take the exclusive i_rwsem and drain in-flight DIO. When * zeroing is not required, shared lock is safe -- block allocation and * unwritten conversion for middle blocks are protected by i_data_sem * and inode_dio_begin(). */ static bool ext4_dio_needs_zeroing(struct inode *inode, loff_t pos, loff_t len) { struct ext4_map_blocks map; unsigned int blkbits = inode->i_blkbits; unsigned long blockmask = inode->i_sb->s_blocksize - 1; bool head_partial, tail_partial; ext4_lblk_t head_lblk, tail_lblk; int err; if (pos + len > i_size_read(inode)) return true; head_partial = (pos & blockmask) != 0; tail_partial = ((pos + len) & blockmask) != 0; head_lblk = pos >> blkbits; tail_lblk = (pos + len - 1) >> blkbits; /* Check the head partial block. */ if (head_partial) { map.m_lblk = head_lblk; map.m_len = tail_lblk - head_lblk + 1; err = ext4_map_blocks(NULL, inode, &map, 0); if (err <= 0 || !(map.m_flags & EXT4_MAP_MAPPED)) return true; /* If this mapping already covers the tail block, we're done. */ if (!tail_partial || map.m_lblk + err > tail_lblk) return false; } /* Check the tail partial block. */ if (tail_partial) { map.m_lblk = tail_lblk; map.m_len = 1; err = ext4_map_blocks(NULL, inode, &map, 0); if (err <= 0 || !(map.m_flags & EXT4_MAP_MAPPED)) return true; } return false; } static ssize_t ext4_generic_write_checks(struct kiocb *iocb, struct iov_iter *from) { struct inode *inode = file_inode(iocb->ki_filp); ssize_t ret; if (unlikely(IS_IMMUTABLE(inode))) return -EPERM; ret = generic_write_checks(iocb, from); if (ret <= 0) return ret; /* * 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); } static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from) { struct inode *inode = file_inode(iocb->ki_filp); loff_t old_size = i_size_read(inode); ssize_t ret, count; count = ext4_generic_write_checks(iocb, from); if (count <= 0) return count; ret = kiocb_modified(iocb); if (ret) return ret; /* * If the position is beyond the EOF, it is necessary to zero out the * partial block that beyond the existing EOF, as it may contains * stale data written through mmap. */ if (iocb->ki_pos > old_size && !ext4_verity_in_progress(inode)) { if (iocb->ki_flags & IOCB_NOWAIT) return -EAGAIN; ret = ext4_block_zero_eof(inode, old_size, iocb->ki_pos); if (ret) return ret; } return count; } static ssize_t ext4_buffered_write_iter(struct kiocb *iocb, struct iov_iter *from) { ssize_t ret; struct inode *inode = file_inode(iocb->ki_filp); if (iocb->ki_flags & IOCB_NOWAIT) return -EOPNOTSUPP; inode_lock(inode); /* * Prevent concurrent direct I/O and buffered I/O to the same file * range. Wait for in-flight DIO to finish before dirtying pages. */ inode_dio_wait(inode); ret = ext4_write_checks(iocb, from); if (ret <= 0) goto out; ret = generic_perform_write(iocb, from); out: inode_unlock(inode); if (unlikely(ret <= 0)) return ret; return generic_write_sync(iocb, ret); } static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset, ssize_t written, ssize_t count) { handle_t *handle; lockdep_assert_held_write(&inode->i_rwsem); handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); if (IS_ERR(handle)) return PTR_ERR(handle); if (ext4_update_inode_size(inode, offset + written)) { int ret = ext4_mark_inode_dirty(handle, inode); if (unlikely(ret)) { ext4_journal_stop(handle); return ret; } } if ((written == count) && inode->i_nlink) ext4_orphan_del(handle, inode); ext4_journal_stop(handle); return written; } /* * Clean up the inode after DIO or DAX extending write has completed and the * inode size has been updated using ext4_handle_inode_extension(). */ static void ext4_inode_extension_cleanup(struct inode *inode, bool need_trunc) { lockdep_assert_held_write(&inode->i_rwsem); if (need_trunc) { ext4_truncate_failed_write(inode); /* * If the truncate operation failed early, then the inode may * still be on the orphan list. In that case, we need to try * remove the inode from the in-memory linked list. */ if (inode->i_nlink) ext4_orphan_del(NULL, inode); return; } /* * If i_disksize got extended either due to writeback of delalloc * blocks or extending truncate while the DIO was running we could fail * to cleanup the orphan list in ext4_handle_inode_extension(). Do it * now. */ if (ext4_inode_orphan_tracked(inode) && inode->i_nlink) { handle_t *handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); if (IS_ERR(handle)) { /* * The write has successfully completed. Not much to * do with the error here so just cleanup the orphan * list and hope for the best. */ ext4_orphan_del(NULL, inode); return; } ext4_orphan_del(handle, inode); ext4_journal_stop(handle); } } static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size, int error, unsigned int flags) { loff_t pos = iocb->ki_pos; struct inode *inode = file_inode(iocb->ki_filp); if (!error && size && (flags & IOMAP_DIO_UNWRITTEN) && (iocb->ki_flags & IOCB_ATOMIC)) error = ext4_convert_unwritten_extents_atomic(NULL, inode, pos, size); else if (!error && size && flags & IOMAP_DIO_UNWRITTEN) error = ext4_convert_unwritten_extents(NULL, inode, pos, size, NULL); if (error) return error; /* * Note that EXT4_I(inode)->i_disksize can get extended up to * inode->i_size while the I/O was running due to writeback of delalloc * blocks. But the code in ext4_iomap_alloc() is careful to use * zeroed/unwritten extents if this is possible; thus we won't leave * uninitialized blocks in a file even if we didn't succeed in writing * as much as we intended. Also we can race with truncate or write * expanding the file so we have to be a bit careful here. */ if (pos + size <= READ_ONCE(EXT4_I(inode)->i_disksize) && pos + size <= i_size_read(inode)) return 0; error = ext4_handle_inode_extension(inode, pos, size, size); return error < 0 ? error : 0; } static const struct iomap_dio_ops ext4_dio_write_ops = { .end_io = ext4_dio_write_end_io, }; /* * The intention here is to start with shared lock acquired then see if any * condition requires an exclusive inode lock. If yes, then we restart the * whole operation by releasing the shared lock and acquiring exclusive lock. * * The decision is layered, evaluated in this order: * * 1. If kiocb_modified() needs to update security info (!IS_NOSEC), upgrade * to the exclusive lock -- the security update itself requires it, * regardless of whether the write extends the file or is aligned. * * 2. If the write extends i_size or i_disksize, upgrade to the exclusive * lock to safely update i_disksize and the orphan list, regardless of * alignment. * * 3. Otherwise, for aligned non-extending writes, shared lock is always * sufficient regardless of extent state (written, unwritten, or hole). * truncate/punch_hole cannot run while we hold the shared i_rwsem * (they need it exclusively); after we release it, inode_dio_begin() * keeps their inode_dio_wait() blocked until in-flight bios complete. * i_data_sem serializes concurrent extent tree modifications. * * 4. Otherwise, the write is unaligned and non-extending. Shared lock is * safe unless the DIO layer needs to perform partial block zeroing -- * i.e. the head or tail partial block sits on a hole or unwritten * extent. In that case upgrade to the exclusive lock and drain * in-flight DIO to avoid races with concurrent partial block zeroing. */ static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from, bool *ilock_shared, bool *extend, int *dio_flags) { struct file *file = iocb->ki_filp; struct inode *inode = file_inode(file); loff_t offset; size_t count; ssize_t ret; bool needs_zeroing = false; restart: ret = ext4_generic_write_checks(iocb, from); if (ret <= 0) goto out; offset = iocb->ki_pos; count = ret; *extend = ext4_extending_io(inode, offset, count); /* * For unaligned writes, check whether partial block zeroing will be * needed. If so, exclusive lock is required to serialize against * concurrent DIO that could race with the zeroing. * * For aligned writes we skip this check entirely since allocation * under shared lock is safe. */ if (ext4_unaligned_io(inode, from, offset)) needs_zeroing = ext4_dio_needs_zeroing(inode, offset, count); /* Determine whether we need to upgrade to an exclusive lock. */ if (*ilock_shared && (!IS_NOSEC(inode) || *extend || needs_zeroing)) { if (iocb->ki_flags & IOCB_NOWAIT) { ret = -EAGAIN; goto out; } inode_unlock_shared(inode); *ilock_shared = false; inode_lock(inode); goto restart; } /* * Now that locking is settled, determine dio flags and exclusivity * requirements. We don't use DIO_OVERWRITE_ONLY because we enforce * behavior already. When holding the exclusive lock for a write that * needs partial block zeroing or is extending the file, we must wait * for the I/O to complete synchronously: * * - needs_zeroing: drain in-flight DIO whose end_io could race with * our partial block zeroing, and force synchronous completion so we * don't leave in-flight zeroing bios for the next writer to drain. * * - extend: the caller must update i_disksize after I/O completion, * which requires the data to be on disk first. */ if (!*ilock_shared && (needs_zeroing || *extend)) { if (iocb->ki_flags & IOCB_NOWAIT) { ret = -EAGAIN; goto out; } if (needs_zeroing) inode_dio_wait(inode); *dio_flags = IOMAP_DIO_FORCE_WAIT; } ret = kiocb_modified(iocb); if (ret < 0) goto out; return count; out: if (*ilock_shared) inode_unlock_shared(inode); else inode_unlock(inode); return ret; } static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from) { ssize_t ret; handle_t *handle; struct inode *inode = file_inode(iocb->ki_filp); loff_t offset = iocb->ki_pos; size_t count = iov_iter_count(from); bool extend = false; bool ilock_shared = true; int dio_flags = 0; /* * Quick check here without any i_rwsem lock to see if it is extending * IO. A more reliable check is done in ext4_dio_write_checks() with * proper locking in place. */ if (offset + count > i_size_read(inode)) ilock_shared = false; if (iocb->ki_flags & IOCB_NOWAIT) { if (ilock_shared) { if (!inode_trylock_shared(inode)) return -EAGAIN; } else { if (!inode_trylock(inode)) return -EAGAIN; } } else { if (ilock_shared) inode_lock_shared(inode); else inode_lock(inode); } /* Fallback to buffered I/O if the inode does not support direct I/O. */ if (!ext4_should_use_dio(iocb, from)) { if (ilock_shared) inode_unlock_shared(inode); else inode_unlock(inode); return ext4_buffered_write_iter(iocb, from); } /* * Prevent inline data from being created since we are going to allocate * blocks for DIO. We know the inode does not currently have inline data * because ext4_should_use_dio() checked for it, but we have to clear * the state flag before the write checks because a lock cycle could * introduce races with other writers. */ ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA); ret = ext4_dio_write_checks(iocb, from, &ilock_shared, &extend, &dio_flags); if (ret <= 0) return ret; offset = iocb->ki_pos; count = ret; if (extend) { handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out; } ret = ext4_orphan_add(handle, inode); ext4_journal_stop(handle); if (ret) goto out; } ret = iomap_dio_rw(iocb, from, &ext4_iomap_ops, &ext4_dio_write_ops, dio_flags, NULL, 0); if (ret == -ENOTBLK) ret = 0; if (extend) { /* * We always perform extending DIO write synchronously so by * now the IO is completed and ext4_handle_inode_extension() * was called. Cleanup the inode in case of error or race with * writeback of delalloc blocks. */ WARN_ON_ONCE(ret == -EIOCBQUEUED); ext4_inode_extension_cleanup(inode, ret < 0); } out: if (ilock_shared) inode_unlock_shared(inode); else inode_unlock(inode); if (ret >= 0 && iov_iter_count(from)) { ssize_t err; loff_t endbyte; /* * There is no support for atomic writes on buffered-io yet, * we should never fallback to buffered-io for DIO atomic * writes. */ WARN_ON_ONCE(iocb->ki_flags & IOCB_ATOMIC); offset = iocb->ki_pos; err = ext4_buffered_write_iter(iocb, from); if (err < 0) return err; /* * We need to ensure that the pages within the page cache for * the range covered by this I/O are written to disk and * invalidated. This is in attempt to preserve the expected * direct I/O semantics in the case we fallback to buffered I/O * to complete off the I/O request. */ ret += err; endbyte = offset + err - 1; err = filemap_write_and_wait_range(iocb->ki_filp->f_mapping, offset, endbyte); if (!err) invalidate_mapping_pages(iocb->ki_filp->f_mapping, offset >> PAGE_SHIFT, endbyte >> PAGE_SHIFT); } return ret; } #ifdef CONFIG_FS_DAX static ssize_t ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) { ssize_t ret; size_t count; loff_t offset; handle_t *handle; bool extend = false; struct inode *inode = file_inode(iocb->ki_filp); 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; offset = iocb->ki_pos; count = iov_iter_count(from); if (offset + count > EXT4_I(inode)->i_disksize) { if (iocb->ki_flags & IOCB_NOWAIT) { ret = -EAGAIN; goto out; } handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out; } ret = ext4_orphan_add(handle, inode); if (ret) { ext4_journal_stop(handle); goto out; } extend = true; ext4_journal_stop(handle); } ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops); if (extend) { ret = ext4_handle_inode_extension(inode, offset, ret, count); ext4_inode_extension_cleanup(inode, ret < (ssize_t)count); } 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) { int ret; struct inode *inode = file_inode(iocb->ki_filp); ret = ext4_emergency_state(inode->i_sb); if (unlikely(ret)) return ret; #ifdef CONFIG_FS_DAX if (IS_DAX(inode)) return ext4_dax_write_iter(iocb, from); #endif if (iocb->ki_flags & IOCB_ATOMIC) { size_t len = iov_iter_count(from); if (len < EXT4_SB(inode->i_sb)->s_awu_min || len > EXT4_SB(inode->i_sb)->s_awu_max) return -EINVAL; ret = generic_atomic_write_valid(iocb, from); if (ret) return ret; } if (iocb->ki_flags & IOCB_DIRECT) return ext4_dio_write_iter(iocb, from); else return ext4_buffered_write_iter(iocb, from); } #ifdef CONFIG_FS_DAX static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf, unsigned int order) { 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 order != 0 (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); struct address_space *mapping = vmf->vma->vm_file->f_mapping; unsigned long pfn; if (write) { sb_start_pagefault(sb); file_update_time(vmf->vma->vm_file); filemap_invalidate_lock_shared(mapping); retry: handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE, EXT4_DATA_TRANS_BLOCKS(sb)); if (IS_ERR(handle)) { filemap_invalidate_unlock_shared(mapping); sb_end_pagefault(sb); return VM_FAULT_SIGBUS; } } else { filemap_invalidate_lock_shared(mapping); } result = dax_iomap_fault(vmf, order, &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, order, pfn); filemap_invalidate_unlock_shared(mapping); sb_end_pagefault(sb); } else { filemap_invalidate_unlock_shared(mapping); } return result; } static vm_fault_t ext4_dax_fault(struct vm_fault *vmf) { return ext4_dax_huge_fault(vmf, 0); } 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 = filemap_fault, .map_pages = filemap_map_pages, .page_mkwrite = ext4_page_mkwrite, }; static int ext4_file_mmap_prepare(struct vm_area_desc *desc) { int ret; struct file *file = desc->file; struct inode *inode = file->f_mapping->host; struct dax_device *dax_dev = EXT4_SB(inode->i_sb)->s_daxdev; if (file->f_mode & FMODE_WRITE) ret = ext4_emergency_state(inode->i_sb); else ret = ext4_forced_shutdown(inode->i_sb) ? -EIO : 0; if (unlikely(ret)) return ret; /* * 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(desc, file_inode(file), dax_dev)) return -EOPNOTSUPP; file_accessed(file); if (IS_DAX(file_inode(file))) { desc->vm_ops = &ext4_dax_vm_ops; vma_desc_set_flags(desc, VMA_HUGEPAGE_BIT); } else { desc->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(ext4_test_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED))) return 0; if (ext4_emergency_state(sb) || sb_rdonly(sb) || !sb_start_intwrite_trylock(sb)) return 0; ext4_set_mount_flag(sb, 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. */ 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, sb, sbi->s_sbh, EXT4_JTR_NONE); if (err) goto out_journal; lock_buffer(sbi->s_sbh); strtomem_pad(sbi->s_es->s_last_mounted, cp, 0); ext4_superblock_csum_set(sb); unlock_buffer(sbi->s_sbh); ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh); 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 (filp->f_mode & FMODE_WRITE) ret = ext4_emergency_state(inode->i_sb); else ret = ext4_forced_shutdown(inode->i_sb) ? -EIO : 0; if (unlikely(ret)) return ret; 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; } if (ext4_inode_can_atomic_write(inode)) filp->f_mode |= FMODE_CAN_ATOMIC_WRITE; filp->f_mode |= FMODE_NOWAIT | FMODE_CAN_ODIRECT; 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 = ext4_get_maxbytes(inode); 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_report_ops); inode_unlock_shared(inode); break; case SEEK_DATA: inode_lock_shared(inode); offset = iomap_seek_data(inode, offset, &ext4_iomap_report_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, .iopoll = iocb_bio_iopoll, .unlocked_ioctl = ext4_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = ext4_compat_ioctl, #endif .mmap_prepare = ext4_file_mmap_prepare, .open = ext4_file_open, .release = ext4_release_file, .fsync = ext4_sync_file, .get_unmapped_area = thp_get_unmapped_area, .splice_read = ext4_file_splice_read, .splice_write = iter_file_splice_write, .fallocate = ext4_fallocate, .fop_flags = FOP_MMAP_SYNC | FOP_BUFFER_RASYNC | FOP_DIO_PARALLEL_WRITE | FOP_DONTCACHE, .setlease = generic_setlease, }; const struct inode_operations ext4_file_inode_operations = { .setattr = ext4_setattr, .getattr = ext4_file_getattr, .listxattr = ext4_listxattr, .get_inode_acl = ext4_get_acl, .set_acl = ext4_set_acl, .fiemap = ext4_fiemap, .fileattr_get = ext4_fileattr_get, .fileattr_set = ext4_fileattr_set, };