Orangefs: kernel client part 2

Signed-off-by: Mike Marshall <hubcap@omnibond.com>

1 files changed, 1019 insertions, 0 deletions

diff --git a/fs/orangefs/file.c b/fs/orangefs/file.c
new file mode 100644
index 000000000000..8e26f9fac289
--- /dev/null
+++ b/fs/orangefs/file.c
@@ -0,0 +1,1019 @@
+/*
+ * (C) 2001 Clemson University and The University of Chicago
+ *
+ * See COPYING in top-level directory.
+ */
+
+/*
+ *  Linux VFS file operations.
+ */
+
+#include "protocol.h"
+#include "pvfs2-kernel.h"
+#include "pvfs2-bufmap.h"
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+
+#define wake_up_daemon_for_return(op)			\
+do {							\
+	spin_lock(&op->lock);                           \
+	op->io_completed = 1;                           \
+	spin_unlock(&op->lock);                         \
+	wake_up_interruptible(&op->io_completion_waitq);\
+} while (0)
+
+/*
+ * Copy to client-core's address space from the buffers specified
+ * by the iovec upto total_size bytes.
+ * NOTE: the iovector can either contain addresses which
+ *       can futher be kernel-space or user-space addresses.
+ *       or it can pointers to struct page's
+ */
+static int precopy_buffers(struct pvfs2_bufmap *bufmap,
+			   int buffer_index,
+			   const struct iovec *vec,
+			   unsigned long nr_segs,
+			   size_t total_size,
+			   int from_user)
+{
+	int ret = 0;
+
+	/*
+	 * copy data from application/kernel by pulling it out
+	 * of the iovec.
+	 */
+	/* Are we copying from User Virtual Addresses? */
+	if (from_user)
+		ret = pvfs_bufmap_copy_iovec_from_user(
+			bufmap,
+			buffer_index,
+			vec,
+			nr_segs,
+			total_size);
+	/* Are we copying from Kernel Virtual Addresses? */
+	else
+		ret = pvfs_bufmap_copy_iovec_from_kernel(
+			bufmap,
+			buffer_index,
+			vec,
+			nr_segs,
+			total_size);
+	if (ret < 0)
+		gossip_err("%s: Failed to copy-in buffers. Please make sure that the pvfs2-client is running. %ld\n",
+			__func__,
+			(long)ret);
+	return ret;
+}
+
+/*
+ * Copy from client-core's address space to the buffers specified
+ * by the iovec upto total_size bytes.
+ * NOTE: the iovector can either contain addresses which
+ *       can futher be kernel-space or user-space addresses.
+ *       or it can pointers to struct page's
+ */
+static int postcopy_buffers(struct pvfs2_bufmap *bufmap,
+			    int buffer_index,
+			    const struct iovec *vec,
+			    int nr_segs,
+			    size_t total_size,
+			    int to_user)
+{
+	int ret = 0;
+
+	/*
+	 * copy data to application/kernel by pushing it out to
+	 * the iovec. NOTE; target buffers can be addresses or
+	 * struct page pointers.
+	 */
+	if (total_size) {
+		/* Are we copying to User Virtual Addresses? */
+		if (to_user)
+			ret = pvfs_bufmap_copy_to_user_iovec(
+				bufmap,
+				buffer_index,
+				vec,
+				nr_segs,
+				total_size);
+		/* Are we copying to Kern Virtual Addresses? */
+		else
+			ret = pvfs_bufmap_copy_to_kernel_iovec(
+				bufmap,
+				buffer_index,
+				vec,
+				nr_segs,
+				total_size);
+		if (ret < 0)
+			gossip_err("%s: Failed to copy-out buffers.  Please make sure that the pvfs2-client is running (%ld)\n",
+				__func__,
+				(long)ret);
+	}
+	return ret;
+}
+
+/*
+ * Post and wait for the I/O upcall to finish
+ */
+static ssize_t wait_for_direct_io(enum PVFS_io_type type, struct inode *inode,
+		loff_t *offset, struct iovec *vec, unsigned long nr_segs,
+		size_t total_size, loff_t readahead_size, int to_user)
+{
+	struct pvfs2_inode_s *pvfs2_inode = PVFS2_I(inode);
+	struct pvfs2_khandle *handle = &pvfs2_inode->refn.khandle;
+	struct pvfs2_bufmap *bufmap = NULL;
+	struct pvfs2_kernel_op_s *new_op = NULL;
+	int buffer_index = -1;
+	ssize_t ret;
+
+	new_op = op_alloc(PVFS2_VFS_OP_FILE_IO);
+	if (!new_op) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	/* synchronous I/O */
+	new_op->upcall.req.io.async_vfs_io = PVFS_VFS_SYNC_IO;
+	new_op->upcall.req.io.readahead_size = readahead_size;
+	new_op->upcall.req.io.io_type = type;
+	new_op->upcall.req.io.refn = pvfs2_inode->refn;
+
+populate_shared_memory:
+	/* get a shared buffer index */
+	ret = pvfs_bufmap_get(&bufmap, &buffer_index);
+	if (ret < 0) {
+		gossip_debug(GOSSIP_FILE_DEBUG,
+			     "%s: pvfs_bufmap_get failure (%ld)\n",
+			     __func__, (long)ret);
+		goto out;
+	}
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		     "%s(%pU): GET op %p -> buffer_index %d\n",
+		     __func__,
+		     handle,
+		     new_op,
+		     buffer_index);
+
+	new_op->uses_shared_memory = 1;
+	new_op->upcall.req.io.buf_index = buffer_index;
+	new_op->upcall.req.io.count = total_size;
+	new_op->upcall.req.io.offset = *offset;
+
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		     "%s(%pU): copy_to_user %d nr_segs %lu, offset: %llu total_size: %zd\n",
+		     __func__,
+		     handle,
+		     to_user,
+		     nr_segs,
+		     llu(*offset),
+		     total_size);
+	/*
+	 * Stage 1: copy the buffers into client-core's address space
+	 * precopy_buffers only pertains to writes.
+	 */
+	if (type == PVFS_IO_WRITE) {
+		ret = precopy_buffers(bufmap,
+				      buffer_index,
+				      vec,
+				      nr_segs,
+				      total_size,
+				      to_user);
+		if (ret < 0)
+			goto out;
+	}
+
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		     "%s(%pU): Calling post_io_request with tag (%llu)\n",
+		     __func__,
+		     handle,
+		     llu(new_op->tag));
+
+	/* Stage 2: Service the I/O operation */
+	ret = service_operation(new_op,
+				type == PVFS_IO_WRITE ?
+					"file_write" :
+					"file_read",
+				get_interruptible_flag(inode));
+
+	/*
+	 * If service_operation() returns -EAGAIN #and# the operation was
+	 * purged from pvfs2_request_list or htable_ops_in_progress, then
+	 * we know that the client was restarted, causing the shared memory
+	 * area to be wiped clean.  To restart a  write operation in this
+	 * case, we must re-copy the data from the user's iovec to a NEW
+	 * shared memory location. To restart a read operation, we must get
+	 * a new shared memory location.
+	 */
+	if (ret == -EAGAIN && op_state_purged(new_op)) {
+		pvfs_bufmap_put(bufmap, buffer_index);
+		gossip_debug(GOSSIP_FILE_DEBUG,
+			     "%s:going to repopulate_shared_memory.\n",
+			     __func__);
+		goto populate_shared_memory;
+	}
+
+	if (ret < 0) {
+		handle_io_error(); /* defined in pvfs2-kernel.h */
+		/*
+		   don't write an error to syslog on signaled operation
+		   termination unless we've got debugging turned on, as
+		   this can happen regularly (i.e. ctrl-c)
+		 */
+		if (ret == -EINTR)
+			gossip_debug(GOSSIP_FILE_DEBUG,
+				     "%s: returning error %ld\n", __func__,
+				     (long)ret);
+		else
+			gossip_err("%s: error in %s handle %pU, returning %zd\n",
+				__func__,
+				type == PVFS_IO_READ ?
+					"read from" : "write to",
+				handle, ret);
+		goto out;
+	}
+
+	/*
+	 * Stage 3: Post copy buffers from client-core's address space
+	 * postcopy_buffers only pertains to reads.
+	 */
+	if (type == PVFS_IO_READ) {
+		ret = postcopy_buffers(bufmap,
+				       buffer_index,
+				       vec,
+				       nr_segs,
+				       new_op->downcall.resp.io.amt_complete,
+				       to_user);
+		if (ret < 0) {
+			/*
+			 * put error codes in downcall so that handle_io_error()
+			 * preserves it properly
+			 */
+			new_op->downcall.status = ret;
+			handle_io_error();
+			goto out;
+		}
+	}
+	gossip_debug(GOSSIP_FILE_DEBUG,
+	    "%s(%pU): Amount written as returned by the sys-io call:%d\n",
+	    __func__,
+	    handle,
+	    (int)new_op->downcall.resp.io.amt_complete);
+
+	ret = new_op->downcall.resp.io.amt_complete;
+
+	/*
+	   tell the device file owner waiting on I/O that this read has
+	   completed and it can return now.  in this exact case, on
+	   wakeup the daemon will free the op, so we *cannot* touch it
+	   after this.
+	 */
+	wake_up_daemon_for_return(new_op);
+	new_op = NULL;
+
+out:
+	if (buffer_index >= 0) {
+		pvfs_bufmap_put(bufmap, buffer_index);
+		gossip_debug(GOSSIP_FILE_DEBUG,
+			     "%s(%pU): PUT buffer_index %d\n",
+			     __func__, handle, buffer_index);
+		buffer_index = -1;
+	}
+	if (new_op) {
+		op_release(new_op);
+		new_op = NULL;
+	}
+	return ret;
+}
+
+/*
+ * The reason we need to do this is to be able to support readv and writev
+ * that are larger than (pvfs_bufmap_size_query()) Default is
+ * PVFS2_BUFMAP_DEFAULT_DESC_SIZE MB. What that means is that we will
+ * create a new io vec descriptor for those memory addresses that
+ * go beyond the limit. Return value for this routine is negative in case
+ * of errors and 0 in case of success.
+ *
+ * Further, the new_nr_segs pointer is updated to hold the new value
+ * of number of iovecs, the new_vec pointer is updated to hold the pointer
+ * to the new split iovec, and the size array is an array of integers holding
+ * the number of iovecs that straddle pvfs_bufmap_size_query().
+ * The max_new_nr_segs value is computed by the caller and returned.
+ * (It will be (count of all iov_len/ block_size) + 1).
+ */
+static int split_iovecs(unsigned long max_new_nr_segs,		/* IN */
+			unsigned long nr_segs,			/* IN */
+			const struct iovec *original_iovec,	/* IN */
+			unsigned long *new_nr_segs,		/* OUT */
+			struct iovec **new_vec,			/* OUT */
+			unsigned long *seg_count,		/* OUT */
+			unsigned long **seg_array)		/* OUT */
+{
+	unsigned long seg;
+	unsigned long count = 0;
+	unsigned long begin_seg;
+	unsigned long tmpnew_nr_segs = 0;
+	struct iovec *new_iovec = NULL;
+	struct iovec *orig_iovec;
+	unsigned long *sizes = NULL;
+	unsigned long sizes_count = 0;
+
+	if (nr_segs <= 0 ||
+	    original_iovec == NULL ||
+	    new_nr_segs == NULL ||
+	    new_vec == NULL ||
+	    seg_count == NULL ||
+	    seg_array == NULL ||
+	    max_new_nr_segs <= 0) {
+		gossip_err("Invalid parameters to split_iovecs\n");
+		return -EINVAL;
+	}
+	*new_nr_segs = 0;
+	*new_vec = NULL;
+	*seg_count = 0;
+	*seg_array = NULL;
+	/* copy the passed in iovec descriptor to a temp structure */
+	orig_iovec = kmalloc_array(nr_segs,
+				   sizeof(*orig_iovec),
+				   PVFS2_BUFMAP_GFP_FLAGS);
+	if (orig_iovec == NULL) {
+		gossip_err(
+		    "split_iovecs: Could not allocate memory for %lu bytes!\n",
+		    (unsigned long)(nr_segs * sizeof(*orig_iovec)));
+		return -ENOMEM;
+	}
+	new_iovec = kcalloc(max_new_nr_segs,
+			    sizeof(*new_iovec),
+			    PVFS2_BUFMAP_GFP_FLAGS);
+	if (new_iovec == NULL) {
+		kfree(orig_iovec);
+		gossip_err(
+		    "split_iovecs: Could not allocate memory for %lu bytes!\n",
+		    (unsigned long)(max_new_nr_segs * sizeof(*new_iovec)));
+		return -ENOMEM;
+	}
+	sizes = kcalloc(max_new_nr_segs,
+			sizeof(*sizes),
+			PVFS2_BUFMAP_GFP_FLAGS);
+	if (sizes == NULL) {
+		kfree(new_iovec);
+		kfree(orig_iovec);
+		gossip_err(
+		    "split_iovecs: Could not allocate memory for %lu bytes!\n",
+		    (unsigned long)(max_new_nr_segs * sizeof(*sizes)));
+		return -ENOMEM;
+	}
+	/* copy the passed in iovec to a temp structure */
+	memcpy(orig_iovec, original_iovec, nr_segs * sizeof(*orig_iovec));
+	begin_seg = 0;
+repeat:
+	for (seg = begin_seg; seg < nr_segs; seg++) {
+		if (tmpnew_nr_segs >= max_new_nr_segs ||
+		    sizes_count >= max_new_nr_segs) {
+			kfree(sizes);
+			kfree(orig_iovec);
+			kfree(new_iovec);
+			gossip_err
+			    ("split_iovecs: exceeded the index limit (%lu)\n",
+			    tmpnew_nr_segs);
+			return -EINVAL;
+		}
+		if (count + orig_iovec[seg].iov_len <
+		    pvfs_bufmap_size_query()) {
+			count += orig_iovec[seg].iov_len;
+			memcpy(&new_iovec[tmpnew_nr_segs],
+			       &orig_iovec[seg],
+			       sizeof(*new_iovec));
+			tmpnew_nr_segs++;
+			sizes[sizes_count]++;
+		} else {
+			new_iovec[tmpnew_nr_segs].iov_base =
+			    orig_iovec[seg].iov_base;
+			new_iovec[tmpnew_nr_segs].iov_len =
+			    (pvfs_bufmap_size_query() - count);
+			tmpnew_nr_segs++;
+			sizes[sizes_count]++;
+			sizes_count++;
+			begin_seg = seg;
+			orig_iovec[seg].iov_base +=
+			    (pvfs_bufmap_size_query() - count);
+			orig_iovec[seg].iov_len -=
+			    (pvfs_bufmap_size_query() - count);
+			count = 0;
+			break;
+		}
+	}
+	if (seg != nr_segs)
+		goto repeat;
+	else
+		sizes_count++;
+
+	*new_nr_segs = tmpnew_nr_segs;
+	/* new_iovec is freed by the caller */
+	*new_vec = new_iovec;
+	*seg_count = sizes_count;
+	/* seg_array is also freed by the caller */
+	*seg_array = sizes;
+	kfree(orig_iovec);
+	return 0;
+}
+
+static long bound_max_iovecs(const struct iovec *curr, unsigned long nr_segs,
+			     ssize_t *total_count)
+{
+	unsigned long i;
+	long max_nr_iovecs;
+	ssize_t total;
+	ssize_t count;
+
+	total = 0;
+	count = 0;
+	max_nr_iovecs = 0;
+	for (i = 0; i < nr_segs; i++) {
+		const struct iovec *iv = &curr[i];
+
+		count += iv->iov_len;
+		if (unlikely((ssize_t) (count | iv->iov_len) < 0))
+			return -EINVAL;
+		if (total + iv->iov_len < pvfs_bufmap_size_query()) {
+			total += iv->iov_len;
+			max_nr_iovecs++;
+		} else {
+			total =
+			    (total + iv->iov_len - pvfs_bufmap_size_query());
+			max_nr_iovecs += (total / pvfs_bufmap_size_query() + 2);
+		}
+	}
+	*total_count = count;
+	return max_nr_iovecs;
+}
+
+/*
+ * Common entry point for read/write/readv/writev
+ * This function will dispatch it to either the direct I/O
+ * or buffered I/O path depending on the mount options and/or
+ * augmented/extended metadata attached to the file.
+ * Note: File extended attributes override any mount options.
+ */
+static ssize_t do_readv_writev(enum PVFS_io_type type, struct file *file,
+		loff_t *offset, const struct iovec *iov, unsigned long nr_segs)
+{
+	struct inode *inode = file->f_mapping->host;
+	struct pvfs2_inode_s *pvfs2_inode = PVFS2_I(inode);
+	struct pvfs2_khandle *handle = &pvfs2_inode->refn.khandle;
+	ssize_t ret;
+	ssize_t total_count;
+	unsigned int to_free;
+	size_t count;
+	unsigned long seg;
+	unsigned long new_nr_segs = 0;
+	unsigned long max_new_nr_segs = 0;
+	unsigned long seg_count = 0;
+	unsigned long *seg_array = NULL;
+	struct iovec *iovecptr = NULL;
+	struct iovec *ptr = NULL;
+
+	total_count = 0;
+	ret = -EINVAL;
+	count = 0;
+	to_free = 0;
+
+	/* Compute total and max number of segments after split */
+	max_new_nr_segs = bound_max_iovecs(iov, nr_segs, &count);
+	if (max_new_nr_segs < 0) {
+		gossip_lerr("%s: could not bound iovec %lu\n",
+			    __func__,
+			    max_new_nr_segs);
+		goto out;
+	}
+
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		"%s-BEGIN(%pU): count(%d) after estimate_max_iovecs.\n",
+		__func__,
+		handle,
+		(int)count);
+
+	if (type == PVFS_IO_WRITE) {
+		gossip_debug(GOSSIP_FILE_DEBUG,
+			     "%s(%pU): proceeding with offset : %llu, "
+			     "size %d\n",
+			     __func__,
+			     handle,
+			     llu(*offset),
+			     (int)count);
+	}
+
+	if (count == 0) {
+		ret = 0;
+		goto out;
+	}
+
+	/*
+	 * if the total size of data transfer requested is greater than
+	 * the kernel-set blocksize of PVFS2, then we split the iovecs
+	 * such that no iovec description straddles a block size limit
+	 */
+
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		     "%s: pvfs_bufmap_size:%d\n",
+		     __func__,
+		     pvfs_bufmap_size_query());
+
+	if (count > pvfs_bufmap_size_query()) {
+		/*
+		 * Split up the given iovec description such that
+		 * no iovec descriptor straddles over the block-size limitation.
+		 * This makes us our job easier to stage the I/O.
+		 * In addition, this function will also compute an array
+		 * with seg_count entries that will store the number of
+		 * segments that straddle the block-size boundaries.
+		 */
+		ret = split_iovecs(max_new_nr_segs,	/* IN */
+				   nr_segs,		/* IN */
+				   iov,			/* IN */
+				   &new_nr_segs,	/* OUT */
+				   &iovecptr,		/* OUT */
+				   &seg_count,		/* OUT */
+				   &seg_array);		/* OUT */
+		if (ret < 0) {
+			gossip_err("%s: Failed to split iovecs to satisfy larger than blocksize readv/writev request %zd\n",
+				__func__,
+				ret);
+			goto out;
+		}
+		gossip_debug(GOSSIP_FILE_DEBUG,
+			     "%s: Splitting iovecs from %lu to %lu"
+			     " [max_new %lu]\n",
+			     __func__,
+			     nr_segs,
+			     new_nr_segs,
+			     max_new_nr_segs);
+		/* We must free seg_array and iovecptr */
+		to_free = 1;
+	} else {
+		new_nr_segs = nr_segs;
+		/* use the given iovec description */
+		iovecptr = (struct iovec *)iov;
+		/* There is only 1 element in the seg_array */
+		seg_count = 1;
+		/* and its value is the number of segments passed in */
+		seg_array = &nr_segs;
+		/* We dont have to free up anything */
+		to_free = 0;
+	}
+	ptr = iovecptr;
+
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		     "%s(%pU) %zd@%llu\n",
+		     __func__,
+		     handle,
+		     count,
+		     llu(*offset));
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		     "%s(%pU): new_nr_segs: %lu, seg_count: %lu\n",
+		     __func__,
+		     handle,
+		     new_nr_segs, seg_count);
+
+/* PVFS2_KERNEL_DEBUG is a CFLAGS define. */
+#ifdef PVFS2_KERNEL_DEBUG
+	for (seg = 0; seg < new_nr_segs; seg++)
+		gossip_debug(GOSSIP_FILE_DEBUG,
+			     "%s: %d) %p to %p [%d bytes]\n",
+			     __func__,
+			     (int)seg + 1,
+			     iovecptr[seg].iov_base,
+			     iovecptr[seg].iov_base + iovecptr[seg].iov_len,
+			     (int)iovecptr[seg].iov_len);
+	for (seg = 0; seg < seg_count; seg++)
+		gossip_debug(GOSSIP_FILE_DEBUG,
+			     "%s: %zd) %lu\n",
+			     __func__,
+			     seg + 1,
+			     seg_array[seg]);
+#endif
+	seg = 0;
+	while (total_count < count) {
+		size_t each_count;
+		size_t amt_complete;
+
+		/* how much to transfer in this loop iteration */
+		each_count =
+		   (((count - total_count) > pvfs_bufmap_size_query()) ?
+			pvfs_bufmap_size_query() :
+			(count - total_count));
+
+		gossip_debug(GOSSIP_FILE_DEBUG,
+			     "%s(%pU): size of each_count(%d)\n",
+			     __func__,
+			     handle,
+			     (int)each_count);
+		gossip_debug(GOSSIP_FILE_DEBUG,
+			     "%s(%pU): BEFORE wait_for_io: offset is %d\n",
+			     __func__,
+			     handle,
+			     (int)*offset);
+
+		ret = wait_for_direct_io(type, inode, offset, ptr,
+				seg_array[seg], each_count, 0, 1);
+		gossip_debug(GOSSIP_FILE_DEBUG,
+			     "%s(%pU): return from wait_for_io:%d\n",
+			     __func__,
+			     handle,
+			     (int)ret);
+
+		if (ret < 0)
+			goto out;
+
+		/* advance the iovec pointer */
+		ptr += seg_array[seg];
+		seg++;
+		*offset += ret;
+		total_count += ret;
+		amt_complete = ret;
+
+		gossip_debug(GOSSIP_FILE_DEBUG,
+			     "%s(%pU): AFTER wait_for_io: offset is %d\n",
+			     __func__,
+			     handle,
+			     (int)*offset);
+
+		/*
+		 * if we got a short I/O operations,
+		 * fall out and return what we got so far
+		 */
+		if (amt_complete < each_count)
+			break;
+	} /*end while */
+
+	if (total_count > 0)
+		ret = total_count;
+out:
+	if (to_free) {
+		kfree(iovecptr);
+		kfree(seg_array);
+	}
+	if (ret > 0) {
+		if (type == PVFS_IO_READ) {
+			file_accessed(file);
+		} else {
+			SetMtimeFlag(pvfs2_inode);
+			inode->i_mtime = CURRENT_TIME;
+			mark_inode_dirty_sync(inode);
+		}
+	}
+
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		     "%s(%pU): Value(%d) returned.\n",
+		     __func__,
+		     handle,
+		     (int)ret);
+
+	return ret;
+}
+
+/*
+ * Read data from a specified offset in a file (referenced by inode).
+ * Data may be placed either in a user or kernel buffer.
+ */
+ssize_t pvfs2_inode_read(struct inode *inode,
+			 char __user *buf,
+			 size_t count,
+			 loff_t *offset,
+			 loff_t readahead_size)
+{
+	struct pvfs2_inode_s *pvfs2_inode = PVFS2_I(inode);
+	size_t bufmap_size;
+	struct iovec vec;
+	ssize_t ret = -EINVAL;
+
+	g_pvfs2_stats.reads++;
+
+	vec.iov_base = buf;
+	vec.iov_len = count;
+
+	bufmap_size = pvfs_bufmap_size_query();
+	if (count > bufmap_size) {
+		gossip_debug(GOSSIP_FILE_DEBUG,
+			     "%s: count is too large (%zd/%zd)!\n",
+			     __func__, count, bufmap_size);
+		return -EINVAL;
+	}
+
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		     "%s(%pU) %zd@%llu\n",
+		     __func__,
+		     &pvfs2_inode->refn.khandle,
+		     count,
+		     llu(*offset));
+
+	ret = wait_for_direct_io(PVFS_IO_READ, inode, offset, &vec, 1,
+			count, readahead_size, 0);
+	if (ret > 0)
+		*offset += ret;
+
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		     "%s(%pU): Value(%zd) returned.\n",
+		     __func__,
+		     &pvfs2_inode->refn.khandle,
+		     ret);
+
+	return ret;
+}
+
+static ssize_t pvfs2_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct file *file = iocb->ki_filp;
+	loff_t pos = *(&iocb->ki_pos);
+	ssize_t rc = 0;
+	unsigned long nr_segs = iter->nr_segs;
+
+	BUG_ON(iocb->private);
+
+	gossip_debug(GOSSIP_FILE_DEBUG, "pvfs2_file_read_iter\n");
+
+	g_pvfs2_stats.reads++;
+
+	rc = do_readv_writev(PVFS_IO_READ,
+			     file,
+			     &pos,
+			     iter->iov,
+			     nr_segs);
+	iocb->ki_pos = pos;
+
+	return rc;
+}
+
+static ssize_t pvfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct file *file = iocb->ki_filp;
+	loff_t pos = *(&iocb->ki_pos);
+	unsigned long nr_segs = iter->nr_segs;
+	ssize_t rc;
+
+	BUG_ON(iocb->private);
+
+	gossip_debug(GOSSIP_FILE_DEBUG, "pvfs2_file_write_iter\n");
+
+	mutex_lock(&file->f_mapping->host->i_mutex);
+
+	/* Make sure generic_write_checks sees an up to date inode size. */
+	if (file->f_flags & O_APPEND) {
+		rc = pvfs2_inode_getattr(file->f_mapping->host,
+					 PVFS_ATTR_SYS_SIZE);
+		if (rc) {
+			gossip_err("%s: pvfs2_inode_getattr failed, rc:%zd:.\n",
+				   __func__, rc);
+			goto out;
+		}
+	}
+
+	if (file->f_pos > i_size_read(file->f_mapping->host))
+		pvfs2_i_size_write(file->f_mapping->host, file->f_pos);
+
+	rc = generic_write_checks(iocb, iter);
+
+	if (rc <= 0) {
+		gossip_err("%s: generic_write_checks failed, rc:%zd:.\n",
+			   __func__, rc);
+		goto out;
+	}
+
+	rc = do_readv_writev(PVFS_IO_WRITE,
+			     file,
+			     &pos,
+			     iter->iov,
+			     nr_segs);
+	if (rc < 0) {
+		gossip_err("%s: do_readv_writev failed, rc:%zd:.\n",
+			   __func__, rc);
+		goto out;
+	}
+
+	iocb->ki_pos = pos;
+	g_pvfs2_stats.writes++;
+
+out:
+
+	mutex_unlock(&file->f_mapping->host->i_mutex);
+	return rc;
+}
+
+/*
+ * Perform a miscellaneous operation on a file.
+ */
+long pvfs2_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	int ret = -ENOTTY;
+	__u64 val = 0;
+	unsigned long uval;
+
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		     "pvfs2_ioctl: called with cmd %d\n",
+		     cmd);
+
+	/*
+	 * we understand some general ioctls on files, such as the immutable
+	 * and append flags
+	 */
+	if (cmd == FS_IOC_GETFLAGS) {
+		val = 0;
+		ret = pvfs2_xattr_get_default(file->f_path.dentry,
+					      "user.pvfs2.meta_hint",
+					      &val,
+					      sizeof(val),
+					      0);
+		if (ret < 0 && ret != -ENODATA)
+			return ret;
+		else if (ret == -ENODATA)
+			val = 0;
+		uval = val;
+		gossip_debug(GOSSIP_FILE_DEBUG,
+			     "pvfs2_ioctl: FS_IOC_GETFLAGS: %llu\n",
+			     (unsigned long long)uval);
+		return put_user(uval, (int __user *)arg);
+	} else if (cmd == FS_IOC_SETFLAGS) {
+		ret = 0;
+		if (get_user(uval, (int __user *)arg))
+			return -EFAULT;
+		/*
+		 * PVFS_MIRROR_FL is set internally when the mirroring mode
+		 * is turned on for a file. The user is not allowed to turn
+		 * on this bit, but the bit is present if the user first gets
+		 * the flags and then updates the flags with some new
+		 * settings. So, we ignore it in the following edit. bligon.
+		 */
+		if ((uval & ~PVFS_MIRROR_FL) &
+		    (~(FS_IMMUTABLE_FL | FS_APPEND_FL | FS_NOATIME_FL))) {
+			gossip_err("pvfs2_ioctl: the FS_IOC_SETFLAGS only supports setting one of FS_IMMUTABLE_FL|FS_APPEND_FL|FS_NOATIME_FL\n");
+			return -EINVAL;
+		}
+		val = uval;
+		gossip_debug(GOSSIP_FILE_DEBUG,
+			     "pvfs2_ioctl: FS_IOC_SETFLAGS: %llu\n",
+			     (unsigned long long)val);
+		ret = pvfs2_xattr_set_default(file->f_path.dentry,
+					      "user.pvfs2.meta_hint",
+					      &val,
+					      sizeof(val),
+					      0,
+					      0);
+	}
+
+	return ret;
+}
+
+/*
+ * Memory map a region of a file.
+ */
+static int pvfs2_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		     "pvfs2_file_mmap: called on %s\n",
+		     (file ?
+			(char *)file->f_path.dentry->d_name.name :
+			(char *)"Unknown"));
+
+	/* set the sequential readahead hint */
+	vma->vm_flags |= VM_SEQ_READ;
+	vma->vm_flags &= ~VM_RAND_READ;
+	return generic_file_mmap(file, vma);
+}
+
+#define mapping_nrpages(idata) ((idata)->nrpages)
+
+/*
+ * Called to notify the module that there are no more references to
+ * this file (i.e. no processes have it open).
+ *
+ * \note Not called when each file is closed.
+ */
+int pvfs2_file_release(struct inode *inode, struct file *file)
+{
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		     "pvfs2_file_release: called on %s\n",
+		     file->f_path.dentry->d_name.name);
+
+	pvfs2_flush_inode(inode);
+
+	/*
+	   remove all associated inode pages from the page cache and mmap
+	   readahead cache (if any); this forces an expensive refresh of
+	   data for the next caller of mmap (or 'get_block' accesses)
+	 */
+	if (file->f_path.dentry->d_inode &&
+	    file->f_path.dentry->d_inode->i_mapping &&
+	    mapping_nrpages(&file->f_path.dentry->d_inode->i_data))
+		truncate_inode_pages(file->f_path.dentry->d_inode->i_mapping,
+				     0);
+	return 0;
+}
+
+/*
+ * Push all data for a specific file onto permanent storage.
+ */
+int pvfs2_fsync(struct file *file, loff_t start, loff_t end, int datasync)
+{
+	int ret = -EINVAL;
+	struct pvfs2_inode_s *pvfs2_inode =
+		PVFS2_I(file->f_path.dentry->d_inode);
+	struct pvfs2_kernel_op_s *new_op = NULL;
+
+	/* required call */
+	filemap_write_and_wait_range(file->f_mapping, start, end);
+
+	new_op = op_alloc(PVFS2_VFS_OP_FSYNC);
+	if (!new_op)
+		return -ENOMEM;
+	new_op->upcall.req.fsync.refn = pvfs2_inode->refn;
+
+	ret = service_operation(new_op,
+			"pvfs2_fsync",
+			get_interruptible_flag(file->f_path.dentry->d_inode));
+
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		     "pvfs2_fsync got return value of %d\n",
+		     ret);
+
+	op_release(new_op);
+
+	pvfs2_flush_inode(file->f_path.dentry->d_inode);
+	return ret;
+}
+
+/*
+ * Change the file pointer position for an instance of an open file.
+ *
+ * \note If .llseek is overriden, we must acquire lock as described in
+ *       Documentation/filesystems/Locking.
+ *
+ * Future upgrade could support SEEK_DATA and SEEK_HOLE but would
+ * require much changes to the FS
+ */
+loff_t pvfs2_file_llseek(struct file *file, loff_t offset, int origin)
+{
+	int ret = -EINVAL;
+	struct inode *inode = file->f_path.dentry->d_inode;
+
+	if (!inode) {
+		gossip_err("pvfs2_file_llseek: invalid inode (NULL)\n");
+		return ret;
+	}
+
+	if (origin == PVFS2_SEEK_END) {
+		/*
+		 * revalidate the inode's file size.
+		 * NOTE: We are only interested in file size here,
+		 * so we set mask accordingly.
+		 */
+		ret = pvfs2_inode_getattr(inode, PVFS_ATTR_SYS_SIZE);
+		if (ret) {
+			gossip_debug(GOSSIP_FILE_DEBUG,
+				     "%s:%s:%d calling make bad inode\n",
+				     __FILE__,
+				     __func__,
+				     __LINE__);
+			pvfs2_make_bad_inode(inode);
+			return ret;
+		}
+	}
+
+	gossip_debug(GOSSIP_FILE_DEBUG,
+		     "pvfs2_file_llseek: offset is %ld | origin is %d | "
+		     "inode size is %lu\n",
+		     (long)offset,
+		     origin,
+		     (unsigned long)file->f_path.dentry->d_inode->i_size);
+
+	return generic_file_llseek(file, offset, origin);
+}
+
+/*
+ * Support local locks (locks that only this kernel knows about)
+ * if Orangefs was mounted -o local_lock.
+ */
+int pvfs2_lock(struct file *filp, int cmd, struct file_lock *fl)
+{
+	int rc = -ENOLCK;
+
+	if (PVFS2_SB(filp->f_inode->i_sb)->flags & PVFS2_OPT_LOCAL_LOCK) {
+		if (cmd == F_GETLK) {
+			rc = 0;
+			posix_test_lock(filp, fl);
+		} else {
+			rc = posix_lock_file(filp, fl, NULL);
+		}
+	}
+
+	return rc;
+}
+
+/** PVFS2 implementation of VFS file operations */
+const struct file_operations pvfs2_file_operations = {
+	.llseek		= pvfs2_file_llseek,
+	.read_iter	= pvfs2_file_read_iter,
+	.write_iter	= pvfs2_file_write_iter,
+	.lock		= pvfs2_lock,
+	.unlocked_ioctl	= pvfs2_ioctl,
+	.mmap		= pvfs2_file_mmap,
+	.open		= generic_file_open,
+	.release	= pvfs2_file_release,
+	.fsync		= pvfs2_fsync,
+};