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authorRitesh Harjani (IBM) <ritesh.list@gmail.com>2023-04-21 15:16:15 +0530
committerJan Kara <jack@suse.cz>2023-05-16 11:32:42 +0200
commitfb5de4358e1aa4753dce73c4dc1aca73ff39cedd (patch)
treed647a3da6edfb7b8c8ec0d9c9982a897c0eec6c4 /fs/ext2/file.c
parentd05307042500e3f2c06fc2f9e76e8db31d61c7c0 (diff)
ext2: Move direct-io to use iomap
This patch converts ext2 direct-io path to iomap interface. - This also takes care of DIO_SKIP_HOLES part in which we return -ENOTBLK from ext2_iomap_begin(), in case if the write is done on a hole. - This fallbacks to buffered-io in case of DIO_SKIP_HOLES or in case of a partial write or if any error is detected in ext2_iomap_end(). We try to return -ENOTBLK in such cases. - For any unaligned or extending DIO writes, we pass IOMAP_DIO_FORCE_WAIT flag to ensure synchronous writes. - For extending writes we set IOMAP_F_DIRTY in ext2_iomap_begin because otherwise with dsync writes on devices that support FUA, generic_write_sync won't be called and we might miss inode metadata updates. - Since ext2 already now uses _nolock vartiant of sync write. Hence there is no inode lock problem with iomap in this patch. - ext2_iomap_ops are now being shared by DIO, DAX & fiemap path Tested-by: Disha Goel <disgoel@linux.ibm.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz> Message-Id: <610b672a52f2a7ff6dc550fd14d0f995806232a5.1682069716.git.ritesh.list@gmail.com>
Diffstat (limited to 'fs/ext2/file.c')
-rw-r--r--fs/ext2/file.c115
1 files changed, 115 insertions, 0 deletions
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index 749163787139..98add36c1a59 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -162,12 +162,124 @@ int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync)
return ret;
}
+static ssize_t ext2_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+ struct file *file = iocb->ki_filp;
+ struct inode *inode = file->f_mapping->host;
+ ssize_t ret;
+
+ inode_lock_shared(inode);
+ ret = iomap_dio_rw(iocb, to, &ext2_iomap_ops, NULL, 0, NULL, 0);
+ inode_unlock_shared(inode);
+
+ return ret;
+}
+
+static int ext2_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)
+ goto out;
+
+ /*
+ * If we are extending the file, we have to update i_size here before
+ * page cache gets invalidated in iomap_dio_rw(). This prevents racing
+ * buffered reads from zeroing out too much from page cache pages.
+ * Note that all extending writes always happens synchronously with
+ * inode lock held by ext2_dio_write_iter(). So it is safe to update
+ * inode size here for extending file writes.
+ */
+ pos += size;
+ if (pos > i_size_read(inode)) {
+ i_size_write(inode, pos);
+ mark_inode_dirty(inode);
+ }
+out:
+ return error;
+}
+
+static const struct iomap_dio_ops ext2_dio_write_ops = {
+ .end_io = ext2_dio_write_end_io,
+};
+
+static ssize_t ext2_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct file *file = iocb->ki_filp;
+ struct inode *inode = file->f_mapping->host;
+ ssize_t ret;
+ unsigned int flags = 0;
+ unsigned long blocksize = inode->i_sb->s_blocksize;
+ loff_t offset = iocb->ki_pos;
+ loff_t count = iov_iter_count(from);
+
+ inode_lock(inode);
+ ret = generic_write_checks(iocb, from);
+ if (ret <= 0)
+ goto out_unlock;
+
+ ret = kiocb_modified(iocb);
+ if (ret)
+ goto out_unlock;
+
+ /* use IOMAP_DIO_FORCE_WAIT for unaligned or extending writes */
+ if (iocb->ki_pos + iov_iter_count(from) > i_size_read(inode) ||
+ (!IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(from), blocksize)))
+ flags |= IOMAP_DIO_FORCE_WAIT;
+
+ ret = iomap_dio_rw(iocb, from, &ext2_iomap_ops, &ext2_dio_write_ops,
+ flags, NULL, 0);
+
+ /* ENOTBLK is magic return value for fallback to buffered-io */
+ if (ret == -ENOTBLK)
+ ret = 0;
+
+ if (ret < 0 && ret != -EIOCBQUEUED)
+ ext2_write_failed(inode->i_mapping, offset + count);
+
+ /* handle case for partial write and for fallback to buffered write */
+ if (ret >= 0 && iov_iter_count(from)) {
+ loff_t pos, endbyte;
+ ssize_t status;
+ int ret2;
+
+ iocb->ki_flags &= ~IOCB_DIRECT;
+ pos = iocb->ki_pos;
+ status = generic_perform_write(iocb, from);
+ if (unlikely(status < 0)) {
+ ret = status;
+ goto out_unlock;
+ }
+
+ iocb->ki_pos += status;
+ ret += status;
+ endbyte = pos + status - 1;
+ ret2 = filemap_write_and_wait_range(inode->i_mapping, pos,
+ endbyte);
+ if (!ret2)
+ invalidate_mapping_pages(inode->i_mapping,
+ pos >> PAGE_SHIFT,
+ endbyte >> PAGE_SHIFT);
+ if (ret > 0)
+ generic_write_sync(iocb, ret);
+ }
+
+out_unlock:
+ inode_unlock(inode);
+ return ret;
+}
+
static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
#ifdef CONFIG_FS_DAX
if (IS_DAX(iocb->ki_filp->f_mapping->host))
return ext2_dax_read_iter(iocb, to);
#endif
+ if (iocb->ki_flags & IOCB_DIRECT)
+ return ext2_dio_read_iter(iocb, to);
+
return generic_file_read_iter(iocb, to);
}
@@ -177,6 +289,9 @@ static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (IS_DAX(iocb->ki_filp->f_mapping->host))
return ext2_dax_write_iter(iocb, from);
#endif
+ if (iocb->ki_flags & IOCB_DIRECT)
+ return ext2_dio_write_iter(iocb, from);
+
return generic_file_write_iter(iocb, from);
}