From 6ef48ec391c8733c89fce33b5a6a2747aa1b8178 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 22 May 2023 14:50:12 +0100 Subject: [PATCH] zonefs: Provide a splice-read wrapper Provide a splice_read wrapper for zonefs. This does some checks before proceeding and locks the inode across the call to filemap_splice_read() and a size check in case of truncation. Splicing from direct I/O is handled by the caller. Signed-off-by: David Howells cc: Christoph Hellwig cc: Al Viro cc: Jens Axboe cc: Darrick J. Wong cc: linux-xfs@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-block@vger.kernel.org cc: linux-mm@kvack.org Acked-by: Damien Le Moal Link: https://lore.kernel.org/r/20230522135018.2742245-26-dhowells@redhat.com Signed-off-by: Jens Axboe --- fs/zonefs/file.c | 40 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 39 insertions(+), 1 deletion(-) diff --git a/fs/zonefs/file.c b/fs/zonefs/file.c index 132f01d3461f..65d4c4fe6364 100644 --- a/fs/zonefs/file.c +++ b/fs/zonefs/file.c @@ -752,6 +752,44 @@ inode_unlock: return ret; } +static ssize_t zonefs_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); + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct zonefs_zone *z = zonefs_inode_zone(inode); + loff_t isize; + ssize_t ret = 0; + + /* Offline zones cannot be read */ + if (unlikely(IS_IMMUTABLE(inode) && !(inode->i_mode & 0777))) + return -EPERM; + + if (*ppos >= z->z_capacity) + return 0; + + inode_lock_shared(inode); + + /* Limit read operations to written data */ + mutex_lock(&zi->i_truncate_mutex); + isize = i_size_read(inode); + if (*ppos >= isize) + len = 0; + else + len = min_t(loff_t, len, isize - *ppos); + mutex_unlock(&zi->i_truncate_mutex); + + if (len > 0) { + ret = filemap_splice_read(in, ppos, pipe, len, flags); + if (ret == -EIO) + zonefs_io_error(inode, false); + } + + inode_unlock_shared(inode); + return ret; +} + /* * Write open accounting is done only for sequential files. */ @@ -896,7 +934,7 @@ const struct file_operations zonefs_file_operations = { .llseek = zonefs_file_llseek, .read_iter = zonefs_file_read_iter, .write_iter = zonefs_file_write_iter, - .splice_read = generic_file_splice_read, + .splice_read = zonefs_file_splice_read, .splice_write = iter_file_splice_write, .iopoll = iocb_bio_iopoll, };