xfs: merge xfs_lrw.c into xfs_file.c

Currently the code to implement the file operations is split over
two small files.  Merge the content of xfs_lrw.c into xfs_file.c to
have it in one place.  Note that I haven't done various cleanups
that are possible after this yet, they will follow in the next
patch.  Also the function xfs_dev_is_read_only which was in
xfs_lrw.c before really doesn't fit in here at all and was moved to
xfs_mount.c.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <david@fromorbit.com>
Signed-off-by: NAlex Elder <aelder@sgi.com>

fs/xfs/Makefile

@@ -105,7 +105,6 @@ xfs-y				+= $(addprefix $(XFS_LINUX)/, \
 				   xfs_globals.o \
 				   xfs_ioctl.o \
 				   xfs_iops.o \
-				   xfs_lrw.o \
 				   xfs_super.o \
 				   xfs_sync.o \
 				   xfs_xattr.o)

fs/xfs/linux-2.6/xfs_file.c

@@ -16,6 +16,7 @@
  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 #include "xfs.h"
+#include "xfs_fs.h"
 #include "xfs_bit.h"
 #include "xfs_log.h"
 #include "xfs_inum.h"
@@ -34,16 +35,738 @@
 #include "xfs_dir2_sf.h"
 #include "xfs_dinode.h"
 #include "xfs_inode.h"
+#include "xfs_bmap.h"
 #include "xfs_error.h"
 #include "xfs_rw.h"
 #include "xfs_vnodeops.h"
 #include "xfs_da_btree.h"
 #include "xfs_ioctl.h"
+#include "xfs_trace.h"
 
 #include <linux/dcache.h>
 
 static const struct vm_operations_struct xfs_file_vm_ops;
 
+/*
+ *	xfs_iozero
+ *
+ *	xfs_iozero clears the specified range of buffer supplied,
+ *	and marks all the affected blocks as valid and modified.  If
+ *	an affected block is not allocated, it will be allocated.  If
+ *	an affected block is not completely overwritten, and is not
+ *	valid before the operation, it will be read from disk before
+ *	being partially zeroed.
+ */
+STATIC int
+xfs_iozero(
+	struct xfs_inode	*ip,	/* inode			*/
+	loff_t			pos,	/* offset in file		*/
+	size_t			count)	/* size of data to zero		*/
+{
+	struct page		*page;
+	struct address_space	*mapping;
+	int			status;
+
+	mapping = VFS_I(ip)->i_mapping;
+	do {
+		unsigned offset, bytes;
+		void *fsdata;
+
+		offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
+		bytes = PAGE_CACHE_SIZE - offset;
+		if (bytes > count)
+			bytes = count;
+
+		status = pagecache_write_begin(NULL, mapping, pos, bytes,
+					AOP_FLAG_UNINTERRUPTIBLE,
+					&page, &fsdata);
+		if (status)
+			break;
+
+		zero_user(page, offset, bytes);
+
+		status = pagecache_write_end(NULL, mapping, pos, bytes, bytes,
+					page, fsdata);
+		WARN_ON(status <= 0); /* can't return less than zero! */
+		pos += bytes;
+		count -= bytes;
+		status = 0;
+	} while (count);
+
+	return (-status);
+}
+
+ssize_t			/* bytes read, or (-)  error */
+xfs_read(
+	xfs_inode_t		*ip,
+	struct kiocb		*iocb,
+	const struct iovec	*iovp,
+	unsigned int		segs,
+	loff_t			*offset,
+	int			ioflags)
+{
+	struct file		*file = iocb->ki_filp;
+	struct inode		*inode = file->f_mapping->host;
+	xfs_mount_t		*mp = ip->i_mount;
+	size_t			size = 0;
+	ssize_t			ret = 0;
+	xfs_fsize_t		n;
+	unsigned long		seg;
+
+
+	XFS_STATS_INC(xs_read_calls);
+
+	/* START copy & waste from filemap.c */
+	for (seg = 0; seg < segs; seg++) {
+		const struct iovec *iv = &iovp[seg];
+
+		/*
+		 * If any segment has a negative length, or the cumulative
+		 * length ever wraps negative then return -EINVAL.
+		 */
+		size += iv->iov_len;
+		if (unlikely((ssize_t)(size|iv->iov_len) < 0))
+			return XFS_ERROR(-EINVAL);
+	}
+	/* END copy & waste from filemap.c */
+
+	if (unlikely(ioflags & IO_ISDIRECT)) {
+		xfs_buftarg_t	*target =
+			XFS_IS_REALTIME_INODE(ip) ?
+				mp->m_rtdev_targp : mp->m_ddev_targp;
+		if ((*offset & target->bt_smask) ||
+		    (size & target->bt_smask)) {
+			if (*offset == ip->i_size) {
+				return (0);
+			}
+			return -XFS_ERROR(EINVAL);
+		}
+	}
+
+	n = XFS_MAXIOFFSET(mp) - *offset;
+	if ((n <= 0) || (size == 0))
+		return 0;
+
+	if (n < size)
+		size = n;
+
+	if (XFS_FORCED_SHUTDOWN(mp))
+		return -EIO;
+
+	if (unlikely(ioflags & IO_ISDIRECT))
+		mutex_lock(&inode->i_mutex);
+	xfs_ilock(ip, XFS_IOLOCK_SHARED);
+
+	if (DM_EVENT_ENABLED(ip, DM_EVENT_READ) && !(ioflags & IO_INVIS)) {
+		int dmflags = FILP_DELAY_FLAG(file) | DM_SEM_FLAG_RD(ioflags);
+		int iolock = XFS_IOLOCK_SHARED;
+
+		ret = -XFS_SEND_DATA(mp, DM_EVENT_READ, ip, *offset, size,
+					dmflags, &iolock);
+		if (ret) {
+			xfs_iunlock(ip, XFS_IOLOCK_SHARED);
+			if (unlikely(ioflags & IO_ISDIRECT))
+				mutex_unlock(&inode->i_mutex);
+			return ret;
+		}
+	}
+
+	if (unlikely(ioflags & IO_ISDIRECT)) {
+		if (inode->i_mapping->nrpages)
+			ret = -xfs_flushinval_pages(ip, (*offset & PAGE_CACHE_MASK),
+						    -1, FI_REMAPF_LOCKED);
+		mutex_unlock(&inode->i_mutex);
+		if (ret) {
+			xfs_iunlock(ip, XFS_IOLOCK_SHARED);
+			return ret;
+		}
+	}
+
+	trace_xfs_file_read(ip, size, *offset, ioflags);
+
+	iocb->ki_pos = *offset;
+	ret = generic_file_aio_read(iocb, iovp, segs, *offset);
+	if (ret > 0)
+		XFS_STATS_ADD(xs_read_bytes, ret);
+
+	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
+	return ret;
+}
+
+ssize_t
+xfs_splice_read(
+	xfs_inode_t		*ip,
+	struct file		*infilp,
+	loff_t			*ppos,
+	struct pipe_inode_info	*pipe,
+	size_t			count,
+	int			flags,
+	int			ioflags)
+{
+	xfs_mount_t		*mp = ip->i_mount;
+	ssize_t			ret;
+
+	XFS_STATS_INC(xs_read_calls);
+	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
+		return -EIO;
+
+	xfs_ilock(ip, XFS_IOLOCK_SHARED);
+
+	if (DM_EVENT_ENABLED(ip, DM_EVENT_READ) && !(ioflags & IO_INVIS)) {
+		int iolock = XFS_IOLOCK_SHARED;
+		int error;
+
+		error = XFS_SEND_DATA(mp, DM_EVENT_READ, ip, *ppos, count,
+					FILP_DELAY_FLAG(infilp), &iolock);
+		if (error) {
+			xfs_iunlock(ip, XFS_IOLOCK_SHARED);
+			return -error;
+		}
+	}
+
+	trace_xfs_file_splice_read(ip, count, *ppos, ioflags);
+
+	ret = generic_file_splice_read(infilp, ppos, pipe, count, flags);
+	if (ret > 0)
+		XFS_STATS_ADD(xs_read_bytes, ret);
+
+	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
+	return ret;
+}
+
+ssize_t
+xfs_splice_write(
+	xfs_inode_t		*ip,
+	struct pipe_inode_info	*pipe,
+	struct file		*outfilp,
+	loff_t			*ppos,
+	size_t			count,
+	int			flags,
+	int			ioflags)
+{
+	xfs_mount_t		*mp = ip->i_mount;
+	ssize_t			ret;
+	struct inode		*inode = outfilp->f_mapping->host;
+	xfs_fsize_t		isize, new_size;
+
+	XFS_STATS_INC(xs_write_calls);
+	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
+		return -EIO;
+
+	xfs_ilock(ip, XFS_IOLOCK_EXCL);
+
+	if (DM_EVENT_ENABLED(ip, DM_EVENT_WRITE) && !(ioflags & IO_INVIS)) {
+		int iolock = XFS_IOLOCK_EXCL;
+		int error;
+
+		error = XFS_SEND_DATA(mp, DM_EVENT_WRITE, ip, *ppos, count,
+					FILP_DELAY_FLAG(outfilp), &iolock);
+		if (error) {
+			xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+			return -error;
+		}
+	}
+
+	new_size = *ppos + count;
+
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	if (new_size > ip->i_size)
+		ip->i_new_size = new_size;
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+	trace_xfs_file_splice_write(ip, count, *ppos, ioflags);
+
+	ret = generic_file_splice_write(pipe, outfilp, ppos, count, flags);
+	if (ret > 0)
+		XFS_STATS_ADD(xs_write_bytes, ret);
+
+	isize = i_size_read(inode);
+	if (unlikely(ret < 0 && ret != -EFAULT && *ppos > isize))
+		*ppos = isize;
+
+	if (*ppos > ip->i_size) {
+		xfs_ilock(ip, XFS_ILOCK_EXCL);
+		if (*ppos > ip->i_size)
+			ip->i_size = *ppos;
+		xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	}
+
+	if (ip->i_new_size) {
+		xfs_ilock(ip, XFS_ILOCK_EXCL);
+		ip->i_new_size = 0;
+		if (ip->i_d.di_size > ip->i_size)
+			ip->i_d.di_size = ip->i_size;
+		xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	}
+	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+	return ret;
+}
+
+/*
+ * This routine is called to handle zeroing any space in the last
+ * block of the file that is beyond the EOF.  We do this since the
+ * size is being increased without writing anything to that block
+ * and we don't want anyone to read the garbage on the disk.
+ */
+STATIC int				/* error (positive) */
+xfs_zero_last_block(
+	xfs_inode_t	*ip,
+	xfs_fsize_t	offset,
+	xfs_fsize_t	isize)
+{
+	xfs_fileoff_t	last_fsb;
+	xfs_mount_t	*mp = ip->i_mount;
+	int		nimaps;
+	int		zero_offset;
+	int		zero_len;
+	int		error = 0;
+	xfs_bmbt_irec_t	imap;
+
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+
+	zero_offset = XFS_B_FSB_OFFSET(mp, isize);
+	if (zero_offset == 0) {
+		/*
+		 * There are no extra bytes in the last block on disk to
+		 * zero, so return.
+		 */
+		return 0;
+	}
+
+	last_fsb = XFS_B_TO_FSBT(mp, isize);
+	nimaps = 1;
+	error = xfs_bmapi(NULL, ip, last_fsb, 1, 0, NULL, 0, &imap,
+			  &nimaps, NULL, NULL);
+	if (error) {
+		return error;
+	}
+	ASSERT(nimaps > 0);
+	/*
+	 * If the block underlying isize is just a hole, then there
+	 * is nothing to zero.
+	 */
+	if (imap.br_startblock == HOLESTARTBLOCK) {
+		return 0;
+	}
+	/*
+	 * Zero the part of the last block beyond the EOF, and write it
+	 * out sync.  We need to drop the ilock while we do this so we
+	 * don't deadlock when the buffer cache calls back to us.
+	 */
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+	zero_len = mp->m_sb.sb_blocksize - zero_offset;
+	if (isize + zero_len > offset)
+		zero_len = offset - isize;
+	error = xfs_iozero(ip, isize, zero_len);
+
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	ASSERT(error >= 0);
+	return error;
+}
+
+/*
+ * Zero any on disk space between the current EOF and the new,
+ * larger EOF.  This handles the normal case of zeroing the remainder
+ * of the last block in the file and the unusual case of zeroing blocks
+ * out beyond the size of the file.  This second case only happens
+ * with fixed size extents and when the system crashes before the inode
+ * size was updated but after blocks were allocated.  If fill is set,
+ * then any holes in the range are filled and zeroed.  If not, the holes
+ * are left alone as holes.
+ */
+
+int					/* error (positive) */
+xfs_zero_eof(
+	xfs_inode_t	*ip,
+	xfs_off_t	offset,		/* starting I/O offset */
+	xfs_fsize_t	isize)		/* current inode size */
+{
+	xfs_mount_t	*mp = ip->i_mount;
+	xfs_fileoff_t	start_zero_fsb;
+	xfs_fileoff_t	end_zero_fsb;
+	xfs_fileoff_t	zero_count_fsb;
+	xfs_fileoff_t	last_fsb;
+	xfs_fileoff_t	zero_off;
+	xfs_fsize_t	zero_len;
+	int		nimaps;
+	int		error = 0;
+	xfs_bmbt_irec_t	imap;
+
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_IOLOCK_EXCL));
+	ASSERT(offset > isize);
+
+	/*
+	 * First handle zeroing the block on which isize resides.
+	 * We only zero a part of that block so it is handled specially.
+	 */
+	error = xfs_zero_last_block(ip, offset, isize);
+	if (error) {
+		ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_IOLOCK_EXCL));
+		return error;
+	}
+
+	/*
+	 * Calculate the range between the new size and the old
+	 * where blocks needing to be zeroed may exist.  To get the
+	 * block where the last byte in the file currently resides,
+	 * we need to subtract one from the size and truncate back
+	 * to a block boundary.  We subtract 1 in case the size is
+	 * exactly on a block boundary.
+	 */
+	last_fsb = isize ? XFS_B_TO_FSBT(mp, isize - 1) : (xfs_fileoff_t)-1;
+	start_zero_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize);
+	end_zero_fsb = XFS_B_TO_FSBT(mp, offset - 1);
+	ASSERT((xfs_sfiloff_t)last_fsb < (xfs_sfiloff_t)start_zero_fsb);
+	if (last_fsb == end_zero_fsb) {
+		/*
+		 * The size was only incremented on its last block.
+		 * We took care of that above, so just return.
+		 */
+		return 0;
+	}
+
+	ASSERT(start_zero_fsb <= end_zero_fsb);
+	while (start_zero_fsb <= end_zero_fsb) {
+		nimaps = 1;
+		zero_count_fsb = end_zero_fsb - start_zero_fsb + 1;
+		error = xfs_bmapi(NULL, ip, start_zero_fsb, zero_count_fsb,
+				  0, NULL, 0, &imap, &nimaps, NULL, NULL);
+		if (error) {
+			ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_IOLOCK_EXCL));
+			return error;
+		}
+		ASSERT(nimaps > 0);
+
+		if (imap.br_state == XFS_EXT_UNWRITTEN ||
+		    imap.br_startblock == HOLESTARTBLOCK) {
+			/*
+			 * This loop handles initializing pages that were
+			 * partially initialized by the code below this
+			 * loop. It basically zeroes the part of the page
+			 * that sits on a hole and sets the page as P_HOLE
+			 * and calls remapf if it is a mapped file.
+			 */
+			start_zero_fsb = imap.br_startoff + imap.br_blockcount;
+			ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
+			continue;
+		}
+
+		/*
+		 * There are blocks we need to zero.
+		 * Drop the inode lock while we're doing the I/O.
+		 * We'll still have the iolock to protect us.
+		 */
+		xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+		zero_off = XFS_FSB_TO_B(mp, start_zero_fsb);
+		zero_len = XFS_FSB_TO_B(mp, imap.br_blockcount);
+
+		if ((zero_off + zero_len) > offset)
+			zero_len = offset - zero_off;
+
+		error = xfs_iozero(ip, zero_off, zero_len);
+		if (error) {
+			goto out_lock;
+		}
+
+		start_zero_fsb = imap.br_startoff + imap.br_blockcount;
+		ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
+
+		xfs_ilock(ip, XFS_ILOCK_EXCL);
+	}
+
+	return 0;
+
+out_lock:
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	ASSERT(error >= 0);
+	return error;
+}
+
+ssize_t				/* bytes written, or (-) error */
+xfs_write(
+	struct xfs_inode	*xip,
+	struct kiocb		*iocb,
+	const struct iovec	*iovp,
+	unsigned int		nsegs,
+	loff_t			*offset,
+	int			ioflags)
+{
+	struct file		*file = iocb->ki_filp;
+	struct address_space	*mapping = file->f_mapping;
+	struct inode		*inode = mapping->host;
+	unsigned long		segs = nsegs;
+	xfs_mount_t		*mp;
+	ssize_t			ret = 0, error = 0;
+	xfs_fsize_t		isize, new_size;
+	int			iolock;
+	int			eventsent = 0;
+	size_t			ocount = 0, count;
+	loff_t			pos;
+	int			need_i_mutex;
+
+	XFS_STATS_INC(xs_write_calls);
+
+	error = generic_segment_checks(iovp, &segs, &ocount, VERIFY_READ);
+	if (error)
+		return error;
+
+	count = ocount;
+	pos = *offset;
+
+	if (count == 0)
+		return 0;
+
+	mp = xip->i_mount;
+
+	xfs_wait_for_freeze(mp, SB_FREEZE_WRITE);
+
+	if (XFS_FORCED_SHUTDOWN(mp))
+		return -EIO;
+
+relock:
+	if (ioflags & IO_ISDIRECT) {
+		iolock = XFS_IOLOCK_SHARED;
+		need_i_mutex = 0;
+	} else {
+		iolock = XFS_IOLOCK_EXCL;
+		need_i_mutex = 1;
+		mutex_lock(&inode->i_mutex);
+	}
+
+	xfs_ilock(xip, XFS_ILOCK_EXCL|iolock);
+
+start:
+	error = -generic_write_checks(file, &pos, &count,
+					S_ISBLK(inode->i_mode));
+	if (error) {
+		xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
+		goto out_unlock_mutex;
+	}
+
+	if ((DM_EVENT_ENABLED(xip, DM_EVENT_WRITE) &&
+	    !(ioflags & IO_INVIS) && !eventsent)) {
+		int		dmflags = FILP_DELAY_FLAG(file);
+
+		if (need_i_mutex)
+			dmflags |= DM_FLAGS_IMUX;
+
+		xfs_iunlock(xip, XFS_ILOCK_EXCL);
+		error = XFS_SEND_DATA(xip->i_mount, DM_EVENT_WRITE, xip,
+				      pos, count, dmflags, &iolock);
+		if (error) {
+			goto out_unlock_internal;
+		}
+		xfs_ilock(xip, XFS_ILOCK_EXCL);
+		eventsent = 1;
+
+		/*
+		 * The iolock was dropped and reacquired in XFS_SEND_DATA
+		 * so we have to recheck the size when appending.
+		 * We will only "goto start;" once, since having sent the
+		 * event prevents another call to XFS_SEND_DATA, which is
+		 * what allows the size to change in the first place.
+		 */
+		if ((file->f_flags & O_APPEND) && pos != xip->i_size)
+			goto start;
+	}
+
+	if (ioflags & IO_ISDIRECT) {
+		xfs_buftarg_t	*target =
+			XFS_IS_REALTIME_INODE(xip) ?
+				mp->m_rtdev_targp : mp->m_ddev_targp;
+
+		if ((pos & target->bt_smask) || (count & target->bt_smask)) {
+			xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
+			return XFS_ERROR(-EINVAL);
+		}
+
+		if (!need_i_mutex && (mapping->nrpages || pos > xip->i_size)) {
+			xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
+			iolock = XFS_IOLOCK_EXCL;
+			need_i_mutex = 1;
+			mutex_lock(&inode->i_mutex);
+			xfs_ilock(xip, XFS_ILOCK_EXCL|iolock);
+			goto start;
+		}
+	}
+
+	new_size = pos + count;
+	if (new_size > xip->i_size)
+		xip->i_new_size = new_size;
+
+	if (likely(!(ioflags & IO_INVIS)))
+		file_update_time(file);
+
+	/*
+	 * If the offset is beyond the size of the file, we have a couple
+	 * of things to do. First, if there is already space allocated
+	 * we need to either create holes or zero the disk or ...
+	 *
+	 * If there is a page where the previous size lands, we need
+	 * to zero it out up to the new size.
+	 */
+
+	if (pos > xip->i_size) {
+		error = xfs_zero_eof(xip, pos, xip->i_size);
+		if (error) {
+			xfs_iunlock(xip, XFS_ILOCK_EXCL);
+			goto out_unlock_internal;
+		}
+	}
+	xfs_iunlock(xip, XFS_ILOCK_EXCL);
+
+	/*
+	 * If we're writing the file then make sure to clear the
+	 * setuid and setgid bits if the process is not being run
+	 * by root.  This keeps people from modifying setuid and
+	 * setgid binaries.
+	 */
+	error = -file_remove_suid(file);
+	if (unlikely(error))
+		goto out_unlock_internal;
+
+	/* We can write back this queue in page reclaim */
+	current->backing_dev_info = mapping->backing_dev_info;
+
+	if ((ioflags & IO_ISDIRECT)) {
+		if (mapping->nrpages) {
+			WARN_ON(need_i_mutex == 0);
+			error = xfs_flushinval_pages(xip,
+					(pos & PAGE_CACHE_MASK),
+					-1, FI_REMAPF_LOCKED);
+			if (error)
+				goto out_unlock_internal;
+		}
+
+		if (need_i_mutex) {
+			/* demote the lock now the cached pages are gone */
+			xfs_ilock_demote(xip, XFS_IOLOCK_EXCL);
+			mutex_unlock(&inode->i_mutex);
+
+			iolock = XFS_IOLOCK_SHARED;
+			need_i_mutex = 0;
+		}
+
+		trace_xfs_file_direct_write(xip, count, *offset, ioflags);
+		ret = generic_file_direct_write(iocb, iovp,
+				&segs, pos, offset, count, ocount);
+
+		/*
+		 * direct-io write to a hole: fall through to buffered I/O
+		 * for completing the rest of the request.
+		 */
+		if (ret >= 0 && ret != count) {
+			XFS_STATS_ADD(xs_write_bytes, ret);
+
+			pos += ret;
+			count -= ret;
+
+			ioflags &= ~IO_ISDIRECT;
+			xfs_iunlock(xip, iolock);
+			goto relock;
+		}
+	} else {
+		int enospc = 0;
+		ssize_t ret2 = 0;
+
+write_retry:
+		trace_xfs_file_buffered_write(xip, count, *offset, ioflags);
+		ret2 = generic_file_buffered_write(iocb, iovp, segs,
+				pos, offset, count, ret);
+		/*
+		 * if we just got an ENOSPC, flush the inode now we
+		 * aren't holding any page locks and retry *once*
+		 */
+		if (ret2 == -ENOSPC && !enospc) {
+			error = xfs_flush_pages(xip, 0, -1, 0, FI_NONE);
+			if (error)
+				goto out_unlock_internal;
+			enospc = 1;
+			goto write_retry;
+		}
+		ret = ret2;
+	}
+
+	current->backing_dev_info = NULL;
+
+	isize = i_size_read(inode);
+	if (unlikely(ret < 0 && ret != -EFAULT && *offset > isize))
+		*offset = isize;
+
+	if (*offset > xip->i_size) {
+		xfs_ilock(xip, XFS_ILOCK_EXCL);
+		if (*offset > xip->i_size)
+			xip->i_size = *offset;
+		xfs_iunlock(xip, XFS_ILOCK_EXCL);
+	}
+
+	if (ret == -ENOSPC &&
+	    DM_EVENT_ENABLED(xip, DM_EVENT_NOSPACE) && !(ioflags & IO_INVIS)) {
+		xfs_iunlock(xip, iolock);
+		if (need_i_mutex)
+			mutex_unlock(&inode->i_mutex);
+		error = XFS_SEND_NAMESP(xip->i_mount, DM_EVENT_NOSPACE, xip,
+				DM_RIGHT_NULL, xip, DM_RIGHT_NULL, NULL, NULL,
+				0, 0, 0); /* Delay flag intentionally  unused */
+		if (need_i_mutex)
+			mutex_lock(&inode->i_mutex);
+		xfs_ilock(xip, iolock);
+		if (error)
+			goto out_unlock_internal;
+		goto start;
+	}
+
+	error = -ret;
+	if (ret <= 0)
+		goto out_unlock_internal;
+
+	XFS_STATS_ADD(xs_write_bytes, ret);
+
+	/* Handle various SYNC-type writes */
+	if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) {
+		loff_t end = pos + ret - 1;
+		int error2;
+
+		xfs_iunlock(xip, iolock);
+		if (need_i_mutex)
+			mutex_unlock(&inode->i_mutex);
+
+		error2 = filemap_write_and_wait_range(mapping, pos, end);
+		if (!error)
+			error = error2;
+		if (need_i_mutex)
+			mutex_lock(&inode->i_mutex);
+		xfs_ilock(xip, iolock);
+
+		error2 = xfs_fsync(xip);
+		if (!error)
+			error = error2;
+	}
+
+ out_unlock_internal:
+	if (xip->i_new_size) {
+		xfs_ilock(xip, XFS_ILOCK_EXCL);
+		xip->i_new_size = 0;
+		/*
+		 * If this was a direct or synchronous I/O that failed (such
+		 * as ENOSPC) then part of the I/O may have been written to
+		 * disk before the error occured.  In this case the on-disk
+		 * file size may have been adjusted beyond the in-memory file
+		 * size and now needs to be truncated back.
+		 */
+		if (xip->i_d.di_size > xip->i_size)
+			xip->i_d.di_size = xip->i_size;
+		xfs_iunlock(xip, XFS_ILOCK_EXCL);
+	}
+	xfs_iunlock(xip, iolock);
+ out_unlock_mutex:
+	if (need_i_mutex)
+		mutex_unlock(&inode->i_mutex);
+	return -error;
+}
+
 STATIC ssize_t
 xfs_file_aio_read(
 	struct kiocb		*iocb,

fs/xfs/xfs_mount.c

@@ -2052,6 +2052,26 @@ xfs_mount_log_sb(
 	return error;
 }
 
+/*
+ * If the underlying (data/log/rt) device is readonly, there are some
+ * operations that cannot proceed.
+ */
+int
+xfs_dev_is_read_only(
+	struct xfs_mount	*mp,
+	char			*message)
+{
+	if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
+	    xfs_readonly_buftarg(mp->m_logdev_targp) ||
+	    (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
+		cmn_err(CE_NOTE,
+			"XFS: %s required on read-only device.", message);
+		cmn_err(CE_NOTE,
+			"XFS: write access unavailable, cannot proceed.");
+		return EROFS;
+	}
+	return 0;
+}
 
 #ifdef HAVE_PERCPU_SB
 /*

fs/xfs/xfs_vnodeops.h

@@ -50,18 +50,6 @@ int xfs_attr_set(struct xfs_inode *dp, const unsigned char *name,
 int xfs_attr_remove(struct xfs_inode *dp, const unsigned char *name, int flags);
 int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
 		int flags, struct attrlist_cursor_kern *cursor);
-ssize_t xfs_read(struct xfs_inode *ip, struct kiocb *iocb,
-		const struct iovec *iovp, unsigned int segs,
-		loff_t *offset, int ioflags);
-ssize_t xfs_splice_read(struct xfs_inode *ip, struct file *infilp,
-		loff_t *ppos, struct pipe_inode_info *pipe, size_t count,
-		int flags, int ioflags);
-ssize_t xfs_splice_write(struct xfs_inode *ip,
-		struct pipe_inode_info *pipe, struct file *outfilp,
-		loff_t *ppos, size_t count, int flags, int ioflags);
-ssize_t xfs_write(struct xfs_inode *xip, struct kiocb *iocb,
-		const struct iovec *iovp, unsigned int nsegs,
-		loff_t *offset, int ioflags);
 int xfs_bmap(struct xfs_inode *ip, xfs_off_t offset, ssize_t count,
 		int flags, struct xfs_iomap *iomapp, int *niomaps);
 void xfs_tosspages(struct xfs_inode *inode, xfs_off_t first,