[GFS2] Tidy up meta_io code

Fix a bug in the directory reading code, where we might have dereferenced
a NULL pointer in case of OOM. Updated the directory code to use the new
& improved version of gfs2_meta_ra() which now returns the first block
that was being read. Previously it was releasing it requiring following
code to grab the block again at each point it was called.

Also turned off readahead on directory lookups since we are reading a
hash table, and therefore reading the entries in order is very
unlikely. Readahead is still used for all other calls to the
directory reading function (e.g. when growing the hash table).

Removed the DIO_START constant. Everywhere this was used, it was
used to unconditionally start i/o aside from a couple of places, so
I've removed it and made the couple of exceptions to this rule into
separate functions.

Also hunted through the other DIO flags and removed them as arguments
from functions which were always called with the same combination of
arguments.

Updated gfs2_meta_indirect_buffer to be a bit more efficient and
hopefully also be a bit easier to read.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 11 insertions, 12 deletions

diff --git a/fs/gfs2/eattr.c b/fs/gfs2/eattr.c
index 698942ec7c99..bd5ca602f9f0 100644
--- a/fs/gfs2/eattr.c
+++ b/fs/gfs2/eattr.c
@@ -115,7 +115,7 @@ static int ea_foreach(struct gfs2_inode *ip, ea_call_t ea_call, void *data)
 	u64 *eablk, *end;
 	int error;
 
-	error = gfs2_meta_read(ip->i_gl, ip->i_di.di_eattr, DIO_START | DIO_WAIT, &bh);
+	error = gfs2_meta_read(ip->i_gl, ip->i_di.di_eattr, DIO_WAIT, &bh);
 	if (error)
 		return error;
 
@@ -139,7 +139,7 @@ static int ea_foreach(struct gfs2_inode *ip, ea_call_t ea_call, void *data)
 			break;
 		bn = be64_to_cpu(*eablk);
 
-		error = gfs2_meta_read(ip->i_gl, bn, DIO_START | DIO_WAIT, &eabh);
+		error = gfs2_meta_read(ip->i_gl, bn, DIO_WAIT, &eabh);
 		if (error)
 			break;
 		error = ea_foreach_i(ip, eabh, ea_call, data);
@@ -453,8 +453,8 @@ static int ea_get_unstuffed(struct gfs2_inode *ip, struct gfs2_ea_header *ea,
 		return -ENOMEM;
 
 	for (x = 0; x < nptrs; x++) {
-		error = gfs2_meta_read(ip->i_gl, be64_to_cpu(*dataptrs),
-				       DIO_START, bh + x);
+		error = gfs2_meta_read(ip->i_gl, be64_to_cpu(*dataptrs), 0,
+				       bh + x);
 		if (error) {
 			while (x--)
 				brelse(bh[x]);
@@ -464,7 +464,7 @@ static int ea_get_unstuffed(struct gfs2_inode *ip, struct gfs2_ea_header *ea,
 	}
 
 	for (x = 0; x < nptrs; x++) {
-		error = gfs2_meta_reread(sdp, bh[x], DIO_WAIT);
+		error = gfs2_meta_wait(sdp, bh[x]);
 		if (error) {
 			for (; x < nptrs; x++)
 				brelse(bh[x]);
@@ -938,8 +938,8 @@ static int ea_set_block(struct gfs2_inode *ip, struct gfs2_ea_request *er,
 	if (ip->i_di.di_flags & GFS2_DIF_EA_INDIRECT) {
 		u64 *end;
 
-		error = gfs2_meta_read(ip->i_gl, ip->i_di.di_eattr,
-				       DIO_START | DIO_WAIT, &indbh);
+		error = gfs2_meta_read(ip->i_gl, ip->i_di.di_eattr, DIO_WAIT,
+				       &indbh);
 		if (error)
 			return error;
 
@@ -1215,8 +1215,8 @@ static int ea_acl_chmod_unstuffed(struct gfs2_inode *ip,
 		goto out;
 
 	for (x = 0; x < nptrs; x++) {
-		error = gfs2_meta_read(ip->i_gl, be64_to_cpu(*dataptrs),
-				       DIO_START, bh + x);
+		error = gfs2_meta_read(ip->i_gl, be64_to_cpu(*dataptrs), 0,
+				       bh + x);
 		if (error) {
 			while (x--)
 				brelse(bh[x]);
@@ -1226,7 +1226,7 @@ static int ea_acl_chmod_unstuffed(struct gfs2_inode *ip,
 	}
 
 	for (x = 0; x < nptrs; x++) {
-		error = gfs2_meta_reread(sdp, bh[x], DIO_WAIT);
+		error = gfs2_meta_wait(sdp, bh[x]);
 		if (error) {
 			for (; x < nptrs; x++)
 				brelse(bh[x]);
@@ -1310,8 +1310,7 @@ static int ea_dealloc_indirect(struct gfs2_inode *ip)
 
 	memset(&rlist, 0, sizeof(struct gfs2_rgrp_list));
 
-	error = gfs2_meta_read(ip->i_gl, ip->i_di.di_eattr,
-			       DIO_START | DIO_WAIT, &indbh);
+	error = gfs2_meta_read(ip->i_gl, ip->i_di.di_eattr, DIO_WAIT, &indbh);
 	if (error)
 		return error;