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-rw-r--r--fs/ext4/file.c961
1 files changed, 961 insertions, 0 deletions
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
new file mode 100644
index 0000000000..6aa15dafc6
--- /dev/null
+++ b/fs/ext4/file.c
@@ -0,0 +1,961 @@
+// 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 <linux/backing-dev.h>
+#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_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, 0);
+ 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;
+}
+
+/* Is IO overwriting allocated or initialized blocks? */
+static bool ext4_overwrite_io(struct inode *inode,
+ loff_t pos, loff_t len, bool *unwritten)
+{
+ 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);
+ if (err != blklen)
+ return false;
+ /*
+ * 'err==len' means that all of the blocks have been preallocated,
+ * regardless of whether they have been initialized or not. We need to
+ * check m_flags to distinguish the unwritten extents.
+ */
+ *unwritten = !(map.m_flags & EXT4_MAP_MAPPED);
+ return true;
+}
+
+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)
+{
+ ssize_t ret, count;
+
+ count = ext4_generic_write_checks(iocb, from);
+ if (count <= 0)
+ return count;
+
+ ret = file_modified(iocb->ki_filp);
+ 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);
+ 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 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 + count)) {
+ int ret = ext4_mark_inode_dirty(handle, inode);
+ if (unlikely(ret)) {
+ ext4_journal_stop(handle);
+ return ret;
+ }
+ }
+
+ if (inode->i_nlink)
+ ext4_orphan_del(handle, inode);
+ ext4_journal_stop(handle);
+
+ return count;
+}
+
+/*
+ * 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, ssize_t count)
+{
+ lockdep_assert_held_write(&inode->i_rwsem);
+ if (count < 0) {
+ 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 (!list_empty(&EXT4_I(inode)->i_orphan) && 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)
+ error = ext4_convert_unwritten_extents(NULL, inode, pos, size);
+ 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 size;
+ return ext4_handle_inode_extension(inode, pos, size);
+}
+
+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.
+ *
+ * - For unaligned_io we never take shared lock as it may cause data corruption
+ * when two unaligned IO tries to modify the same block e.g. while zeroing.
+ *
+ * - For extending writes case we don't take the shared lock, since it requires
+ * updating inode i_disksize and/or orphan handling with exclusive lock.
+ *
+ * - shared locking will only be true mostly with overwrites, including
+ * initialized blocks and unwritten blocks. For overwrite unwritten blocks
+ * we protect splitting extents by i_data_sem in ext4_inode_info, so we can
+ * also release exclusive i_rwsem lock.
+ *
+ * - Otherwise we will switch to exclusive i_rwsem lock.
+ */
+static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
+ bool *ilock_shared, bool *extend,
+ bool *unwritten, 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 overwrite, unaligned_io;
+
+restart:
+ ret = ext4_generic_write_checks(iocb, from);
+ if (ret <= 0)
+ goto out;
+
+ offset = iocb->ki_pos;
+ count = ret;
+
+ unaligned_io = ext4_unaligned_io(inode, from, offset);
+ *extend = ext4_extending_io(inode, offset, count);
+ overwrite = ext4_overwrite_io(inode, offset, count, unwritten);
+
+ /*
+ * Determine whether we need to upgrade to an exclusive lock. This is
+ * required to change security info in file_modified(), for extending
+ * I/O, any form of non-overwrite I/O, and unaligned I/O to unwritten
+ * extents (as partial block zeroing may be required).
+ *
+ * Note that unaligned writes are allowed under shared lock so long as
+ * they are pure overwrites. Otherwise, concurrent unaligned writes risk
+ * data corruption due to partial block zeroing in the dio layer, and so
+ * the I/O must occur exclusively.
+ */
+ if (*ilock_shared &&
+ ((!IS_NOSEC(inode) || *extend || !overwrite ||
+ (unaligned_io && *unwritten)))) {
+ 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. The inode lock is already held exclusive if the
+ * write is non-overwrite or extending, so drain all outstanding dio and
+ * set the force wait dio flag.
+ */
+ if (!*ilock_shared && (unaligned_io || *extend)) {
+ if (iocb->ki_flags & IOCB_NOWAIT) {
+ ret = -EAGAIN;
+ goto out;
+ }
+ if (unaligned_io && (!overwrite || *unwritten))
+ inode_dio_wait(inode);
+ *dio_flags = IOMAP_DIO_FORCE_WAIT;
+ }
+
+ ret = file_modified(file);
+ 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);
+ const struct iomap_ops *iomap_ops = &ext4_iomap_ops;
+ bool extend = false, unwritten = 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,
+ &unwritten, &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);
+ if (ret) {
+ ext4_journal_stop(handle);
+ goto out;
+ }
+
+ ext4_journal_stop(handle);
+ }
+
+ if (ilock_shared && !unwritten)
+ iomap_ops = &ext4_iomap_overwrite_ops;
+ ret = iomap_dio_rw(iocb, from, 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);
+ }
+
+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;
+
+ 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) {
+ 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);
+ ext4_inode_extension_cleanup(inode, ret);
+ }
+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);
+
+ if (unlikely(ext4_forced_shutdown(inode->i_sb)))
+ return -EIO;
+
+#ifdef CONFIG_FS_DAX
+ if (IS_DAX(inode))
+ return ext4_dax_write_iter(iocb, from);
+#endif
+ 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;
+ pfn_t 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(struct file *file, struct vm_area_struct *vma)
+{
+ struct inode *inode = file->f_mapping->host;
+ struct dax_device *dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
+
+ if (unlikely(ext4_forced_shutdown(inode->i_sb)))
+ 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;
+ vm_flags_set(vma, 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(ext4_test_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED)))
+ return 0;
+
+ if (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.
+ */
+ 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, sb, sbi->s_sbh,
+ EXT4_JTR_NONE);
+ if (err)
+ goto out_journal;
+ lock_buffer(sbi->s_sbh);
+ strncpy(sbi->s_es->s_last_mounted, cp,
+ sizeof(sbi->s_es->s_last_mounted));
+ 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 (unlikely(ext4_forced_shutdown(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 | FMODE_BUF_RASYNC |
+ FMODE_DIO_PARALLEL_WRITE;
+ 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_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 = 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 = ext4_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_inode_acl = ext4_get_acl,
+ .set_acl = ext4_set_acl,
+ .fiemap = ext4_fiemap,
+ .fileattr_get = ext4_fileattr_get,
+ .fileattr_set = ext4_fileattr_set,
+};
+
generated by cgit v1.2.3 (git 2.39.1) at 2024-08-22 18:02:11 +0000