Merge tag 'gfs2-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2

Pull GFS2 updates from Bob Peterson:
 "Here is a list of patches we've accumulated for GFS2 for the current
  upstream merge window.

  Most of the patches fix GFS2 quotas, which were not properly enforced.
  There's another that adds me as a GFS2 co-maintainer, and a couple
  patches that fix a kernel panic doing splice_write on GFS2 as well as
  a few correctness patches"

* tag 'gfs2-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: fix quota refresh race in do_glock()
  gfs2: incorrect check for debugfs returns
  gfs2: allow fallocate to max out quotas/fs efficiently
  gfs2: allow quota_check and inplace_reserve to return available blocks
  gfs2: perform quota checks against allocation parameters
  GFS2: Move gfs2_file_splice_write outside of #ifdef
  GFS2: Allocate reservation during splice_write
  GFS2: gfs2_set_acl(): Cache "no acl" as well
  Add myself (Bob Peterson) as a maintainer of GFS2

1 files changed, 71 insertions, 30 deletions

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index f6fc412b1100..8ec43ab5babf 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -428,11 +428,11 @@ static int gfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 	if (ret)
 		goto out_unlock;
 
-	ret = gfs2_quota_lock_check(ip);
-	if (ret)
-		goto out_unlock;
 	gfs2_write_calc_reserv(ip, PAGE_CACHE_SIZE, &data_blocks, &ind_blocks);
 	ap.target = data_blocks + ind_blocks;
+	ret = gfs2_quota_lock_check(ip, &ap);
+	if (ret)
+		goto out_unlock;
 	ret = gfs2_inplace_reserve(ip, &ap);
 	if (ret)
 		goto out_quota_unlock;
@@ -764,22 +764,30 @@ out:
 	brelse(dibh);
 	return error;
 }
-
-static void calc_max_reserv(struct gfs2_inode *ip, loff_t max, loff_t *len,
-			    unsigned int *data_blocks, unsigned int *ind_blocks)
+/**
+ * calc_max_reserv() - Reverse of write_calc_reserv. Given a number of
+ *                     blocks, determine how many bytes can be written.
+ * @ip:          The inode in question.
+ * @len:         Max cap of bytes. What we return in *len must be <= this.
+ * @data_blocks: Compute and return the number of data blocks needed
+ * @ind_blocks:  Compute and return the number of indirect blocks needed
+ * @max_blocks:  The total blocks available to work with.
+ *
+ * Returns: void, but @len, @data_blocks and @ind_blocks are filled in.
+ */
+static void calc_max_reserv(struct gfs2_inode *ip, loff_t *len,
+			    unsigned int *data_blocks, unsigned int *ind_blocks,
+			    unsigned int max_blocks)
 {
+	loff_t max = *len;
 	const struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
-	unsigned int max_blocks = ip->i_rgd->rd_free_clone;
 	unsigned int tmp, max_data = max_blocks - 3 * (sdp->sd_max_height - 1);
 
 	for (tmp = max_data; tmp > sdp->sd_diptrs;) {
 		tmp = DIV_ROUND_UP(tmp, sdp->sd_inptrs);
 		max_data -= tmp;
 	}
-	/* This calculation isn't the exact reverse of gfs2_write_calc_reserve,
-	   so it might end up with fewer data blocks */
-	if (max_data <= *data_blocks)
-		return;
+
 	*data_blocks = max_data;
 	*ind_blocks = max_blocks - max_data;
 	*len = ((loff_t)max_data - 3) << sdp->sd_sb.sb_bsize_shift;
@@ -796,7 +804,7 @@ static long __gfs2_fallocate(struct file *file, int mode, loff_t offset, loff_t
 	struct gfs2_inode *ip = GFS2_I(inode);
 	struct gfs2_alloc_parms ap = { .aflags = 0, };
 	unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
-	loff_t bytes, max_bytes;
+	loff_t bytes, max_bytes, max_blks = UINT_MAX;
 	int error;
 	const loff_t pos = offset;
 	const loff_t count = len;
@@ -818,6 +826,9 @@ static long __gfs2_fallocate(struct file *file, int mode, loff_t offset, loff_t
 
 	gfs2_size_hint(file, offset, len);
 
+	gfs2_write_calc_reserv(ip, PAGE_SIZE, &data_blocks, &ind_blocks);
+	ap.min_target = data_blocks + ind_blocks;
+
 	while (len > 0) {
 		if (len < bytes)
 			bytes = len;
@@ -826,27 +837,41 @@ static long __gfs2_fallocate(struct file *file, int mode, loff_t offset, loff_t
 			offset += bytes;
 			continue;
 		}
-		error = gfs2_quota_lock_check(ip);
+
+		/* We need to determine how many bytes we can actually
+		 * fallocate without exceeding quota or going over the
+		 * end of the fs. We start off optimistically by assuming
+		 * we can write max_bytes */
+		max_bytes = (len > max_chunk_size) ? max_chunk_size : len;
+
+		/* Since max_bytes is most likely a theoretical max, we
+		 * calculate a more realistic 'bytes' to serve as a good
+		 * starting point for the number of bytes we may be able
+		 * to write */
+		gfs2_write_calc_reserv(ip, bytes, &data_blocks, &ind_blocks);
+		ap.target = data_blocks + ind_blocks;
+
+		error = gfs2_quota_lock_check(ip, &ap);
 		if (error)
 			return error;
-retry:
-		gfs2_write_calc_reserv(ip, bytes, &data_blocks, &ind_blocks);
+		/* ap.allowed tells us how many blocks quota will allow
+		 * us to write. Check if this reduces max_blks */
+		if (ap.allowed && ap.allowed < max_blks)
+			max_blks = ap.allowed;
 
-		ap.target = data_blocks + ind_blocks;
 		error = gfs2_inplace_reserve(ip, &ap);
-		if (error) {
-			if (error == -ENOSPC && bytes > sdp->sd_sb.sb_bsize) {
-				bytes >>= 1;
-				bytes &= bsize_mask;
-				if (bytes == 0)
-					bytes = sdp->sd_sb.sb_bsize;
-				goto retry;
-			}
+		if (error)
 			goto out_qunlock;
-		}
-		max_bytes = bytes;
-		calc_max_reserv(ip, (len > max_chunk_size)? max_chunk_size: len,
-				&max_bytes, &data_blocks, &ind_blocks);
+
+		/* check if the selected rgrp limits our max_blks further */
+		if (ap.allowed && ap.allowed < max_blks)
+			max_blks = ap.allowed;
+
+		/* Almost done. Calculate bytes that can be written using
+		 * max_blks. We also recompute max_bytes, data_blocks and
+		 * ind_blocks */
+		calc_max_reserv(ip, &max_bytes, &data_blocks,
+				&ind_blocks, max_blks);
 
 		rblocks = RES_DINODE + ind_blocks + RES_STATFS + RES_QUOTA +
 			  RES_RG_HDR + gfs2_rg_blocks(ip, data_blocks + ind_blocks);
@@ -930,6 +955,22 @@ out_uninit:
 	return ret;
 }
 
+static ssize_t gfs2_file_splice_write(struct pipe_inode_info *pipe,
+				      struct file *out, loff_t *ppos,
+				      size_t len, unsigned int flags)
+{
+	int error;
+	struct gfs2_inode *ip = GFS2_I(out->f_mapping->host);
+
+	error = gfs2_rs_alloc(ip);
+	if (error)
+		return (ssize_t)error;
+
+	gfs2_size_hint(out, *ppos, len);
+
+	return iter_file_splice_write(pipe, out, ppos, len, flags);
+}
+
 #ifdef CONFIG_GFS2_FS_LOCKING_DLM
 
 /**
@@ -1076,7 +1117,7 @@ const struct file_operations gfs2_file_fops = {
 	.lock		= gfs2_lock,
 	.flock		= gfs2_flock,
 	.splice_read	= generic_file_splice_read,
-	.splice_write	= iter_file_splice_write,
+	.splice_write	= gfs2_file_splice_write,
 	.setlease	= simple_nosetlease,
 	.fallocate	= gfs2_fallocate,
 };
@@ -1106,7 +1147,7 @@ const struct file_operations gfs2_file_fops_nolock = {
 	.release	= gfs2_release,
 	.fsync		= gfs2_fsync,
 	.splice_read	= generic_file_splice_read,
-	.splice_write	= iter_file_splice_write,
+	.splice_write	= gfs2_file_splice_write,
 	.setlease	= generic_setlease,
 	.fallocate	= gfs2_fallocate,
 };