From a9e5f4d0780ec9cda7a70b08294d7718431b62a1 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Tue, 25 Jul 2006 17:24:12 -0400 Subject: [PATCH] [GFS2] Alter direct I/O path As per comments received, alter the GFS2 direct I/O path so that it uses the standard read functions "out of the box". Needs a small change to one of the VFS functions. This reduces the size of the code quite a lot and also removes the need for one new export. Some more work remains to be done, but this is the bones of the thing. Signed-off-by: Steven Whitehouse --- fs/gfs2/ops_address.c | 54 ++++---------- fs/gfs2/ops_file.c | 170 +----------------------------------------- mm/filemap.c | 4 +- 3 files changed, 21 insertions(+), 207 deletions(-) diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c index 031270ad55..d33f6aa797 100644 --- a/fs/gfs2/ops_address.c +++ b/fs/gfs2/ops_address.c @@ -589,8 +589,9 @@ static void gfs2_invalidatepage(struct page *page, unsigned long offset) return; } -static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov, - loff_t offset, unsigned long nr_segs) +static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb, + const struct iovec *iov, loff_t offset, + unsigned long nr_segs) { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; @@ -598,8 +599,10 @@ static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov, struct gfs2_holder gh; int rv; + if (rw == READ) + mutex_lock(&inode->i_mutex); /* - * Shared lock, even though its write, since we do no allocation + * Shared lock, even if its a write, since we do no allocation * on this path. All we need change is atime. */ gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh); @@ -607,6 +610,9 @@ static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov, if (rv) goto out; + if (offset > i_size_read(inode)) + goto out; + /* * Should we return an error here? I can't see that O_DIRECT for * a journaled file makes any sense. For now we'll silently fall @@ -619,47 +625,19 @@ static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov, if (gfs2_is_stuffed(ip)) goto out; - rv = __blockdev_direct_IO(WRITE, iocb, inode, inode->i_sb->s_bdev, - iov, offset, nr_segs, gfs2_get_block, - NULL, DIO_OWN_LOCKING); + rv = blockdev_direct_IO_own_locking(rw, iocb, inode, + inode->i_sb->s_bdev, + iov, offset, nr_segs, + gfs2_get_block, NULL); out: gfs2_glock_dq_m(1, &gh); gfs2_holder_uninit(&gh); + if (rw == READ) + mutex_unlock(&inode->i_mutex); return rv; } -/** - * gfs2_direct_IO - * - * This is called with a shared lock already held for the read path. - * Currently, no locks are held when the write path is called. - */ -static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb, - const struct iovec *iov, loff_t offset, - unsigned long nr_segs) -{ - struct file *file = iocb->ki_filp; - struct inode *inode = file->f_mapping->host; - struct gfs2_inode *ip = GFS2_I(inode); - struct gfs2_sbd *sdp = GFS2_SB(inode); - int ret; - - if (rw == WRITE) - return gfs2_direct_IO_write(iocb, iov, offset, nr_segs); - - if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)) || - gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip))) - return -EINVAL; - - mutex_lock(&inode->i_mutex); - ret = __blockdev_direct_IO(READ, iocb, inode, inode->i_sb->s_bdev, iov, - offset, nr_segs, gfs2_get_block, NULL, - DIO_OWN_LOCKING); - mutex_unlock(&inode->i_mutex); - return ret; -} - /** * stuck_releasepage - We're stuck in gfs2_releasepage(). Print stuff out. * @bh: the buffer we're stuck on @@ -765,7 +743,7 @@ int gfs2_releasepage(struct page *page, gfp_t gfp_mask) } while (bh != head); - out: +out: return try_to_free_buffers(page); } diff --git a/fs/gfs2/ops_file.c b/fs/gfs2/ops_file.c index 6764ca69bc..d13e04e8a9 100644 --- a/fs/gfs2/ops_file.c +++ b/fs/gfs2/ops_file.c @@ -148,170 +148,6 @@ static loff_t gfs2_llseek(struct file *file, loff_t offset, int origin) return error; } - -static ssize_t gfs2_direct_IO_read(struct kiocb *iocb, const struct iovec *iov, - loff_t offset, unsigned long nr_segs) -{ - struct file *file = iocb->ki_filp; - struct address_space *mapping = file->f_mapping; - ssize_t retval; - - retval = filemap_write_and_wait(mapping); - if (retval == 0) { - retval = mapping->a_ops->direct_IO(READ, iocb, iov, offset, - nr_segs); - } - return retval; -} - -/** - * __gfs2_file_aio_read - The main GFS2 read function - * - * N.B. This is almost, but not quite the same as __generic_file_aio_read() - * the important subtle different being that inode->i_size isn't valid - * unless we are holding a lock, and we do this _only_ on the O_DIRECT - * path since otherwise locking is done entirely at the page cache - * layer. - */ -static ssize_t __gfs2_file_aio_read(struct kiocb *iocb, - const struct iovec *iov, - unsigned long nr_segs, loff_t *ppos) -{ - struct file *filp = iocb->ki_filp; - struct gfs2_inode *ip = GFS2_I(filp->f_mapping->host); - struct gfs2_holder gh; - ssize_t retval; - unsigned long seg; - size_t count; - - count = 0; - for (seg = 0; seg < nr_segs; seg++) { - const struct iovec *iv = &iov[seg]; - - /* - * If any segment has a negative length, or the cumulative - * length ever wraps negative then return -EINVAL. - */ - count += iv->iov_len; - if (unlikely((ssize_t)(count|iv->iov_len) < 0)) - return -EINVAL; - if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len)) - continue; - if (seg == 0) - return -EFAULT; - nr_segs = seg; - count -= iv->iov_len; /* This segment is no good */ - break; - } - - /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ - if (filp->f_flags & O_DIRECT) { - loff_t pos = *ppos, size; - struct address_space *mapping; - struct inode *inode; - - mapping = filp->f_mapping; - inode = mapping->host; - retval = 0; - if (!count) - goto out; /* skip atime */ - - gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh); - retval = gfs2_glock_nq_m_atime(1, &gh); - if (retval) - goto out; - if (gfs2_is_stuffed(ip)) { - gfs2_glock_dq_m(1, &gh); - gfs2_holder_uninit(&gh); - goto fallback_to_normal; - } - size = i_size_read(inode); - if (pos < size) { - retval = gfs2_direct_IO_read(iocb, iov, pos, nr_segs); - if (retval > 0 && !is_sync_kiocb(iocb)) - retval = -EIOCBQUEUED; - if (retval > 0) - *ppos = pos + retval; - } - file_accessed(filp); - gfs2_glock_dq_m(1, &gh); - gfs2_holder_uninit(&gh); - goto out; - } - -fallback_to_normal: - retval = 0; - if (count) { - for (seg = 0; seg < nr_segs; seg++) { - read_descriptor_t desc; - - desc.written = 0; - desc.arg.buf = iov[seg].iov_base; - desc.count = iov[seg].iov_len; - if (desc.count == 0) - continue; - desc.error = 0; - do_generic_file_read(filp,ppos,&desc,file_read_actor); - retval += desc.written; - if (desc.error) { - retval = retval ?: desc.error; - break; - } - } - } -out: - return retval; -} - -/** - * gfs2_read - Read bytes from a file - * @file: The file to read from - * @buf: The buffer to copy into - * @size: The amount of data requested - * @offset: The current file offset - * - * Outputs: Offset - updated according to number of bytes read - * - * Returns: The number of bytes read, errno on failure - */ - -static ssize_t gfs2_read(struct file *filp, char __user *buf, size_t size, - loff_t *offset) -{ - struct iovec local_iov = { .iov_base = buf, .iov_len = size }; - struct kiocb kiocb; - ssize_t ret; - - init_sync_kiocb(&kiocb, filp); - ret = __gfs2_file_aio_read(&kiocb, &local_iov, 1, offset); - if (-EIOCBQUEUED == ret) - ret = wait_on_sync_kiocb(&kiocb); - return ret; -} - -static ssize_t gfs2_file_readv(struct file *filp, const struct iovec *iov, - unsigned long nr_segs, loff_t *ppos) -{ - struct kiocb kiocb; - ssize_t ret; - - init_sync_kiocb(&kiocb, filp); - ret = __gfs2_file_aio_read(&kiocb, iov, nr_segs, ppos); - if (-EIOCBQUEUED == ret) - ret = wait_on_sync_kiocb(&kiocb); - return ret; -} - -static ssize_t gfs2_file_aio_read(struct kiocb *iocb, char __user *buf, - size_t count, loff_t pos) -{ - struct iovec local_iov = { .iov_base = buf, .iov_len = count }; - - BUG_ON(iocb->ki_pos != pos); - return __gfs2_file_aio_read(iocb, &local_iov, 1, &iocb->ki_pos); -} - - /** * filldir_reg_func - Report a directory entry to the caller of gfs2_dir_read() * @opaque: opaque data used by the function @@ -949,9 +785,9 @@ static int gfs2_flock(struct file *file, int cmd, struct file_lock *fl) const struct file_operations gfs2_file_fops = { .llseek = gfs2_llseek, - .read = gfs2_read, - .readv = gfs2_file_readv, - .aio_read = gfs2_file_aio_read, + .read = generic_file_read, + .readv = generic_file_readv, + .aio_read = generic_file_aio_read, .write = generic_file_write, .writev = generic_file_writev, .aio_write = generic_file_aio_write, diff --git a/mm/filemap.c b/mm/filemap.c index b9c91ab7f0..a92d690b3a 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1122,7 +1122,6 @@ success: desc->arg.buf += size; return size; } -EXPORT_SYMBOL_GPL(file_read_actor); /** * __generic_file_aio_read - generic filesystem read routine @@ -1184,7 +1183,8 @@ __generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, *ppos = pos + retval; } file_accessed(filp); - goto out; + if (retval != 0) + goto out; } retval = 0; -- 2.39.2