[PATCH 4.16 196/272] gfs2: Fix fallocate chunk size

Greg Kroah-Hartman
2018-05-28T11:13:02Z

From: Andreas Gruenbacher <agruenba@redhat.com>

[ Upstream commit 174d1232ebc84fcde8f5889d1171c9c7e74a10a7 ]

The chunk size of allocations in __gfs2_fallocate is calculated
incorrectly. The size can collapse, causing __gfs2_fallocate to
allocate one block at a time, which is very inefficient. This needs
fixing in two places:

In gfs2_quota_lock_check, always set ap->allowed to UINT_MAX to indicate
that there is no quota limit. This fixes callers that rely on
ap->allowed to be set even when quotas are off.

In __gfs2_fallocate, reset max_blks to UINT_MAX in each iteration of the
loop to make sure that allocation limits from one resource group won't
spill over into another resource group.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/gfs2/file.c | 5 +++--
fs/gfs2/quota.h | 2 ++
2 files changed, 5 insertions(+), 2 deletions(-)

--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -809,7 +809,7 @@ static long __gfs2_fallocate(struct file
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, max_blks = UINT_MAX;
+ loff_t bytes, max_bytes, max_blks;
int error;
const loff_t pos = offset;
const loff_t count = len;
@@ -861,7 +861,8 @@ static long __gfs2_fallocate(struct file
return error;
/* 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 = UINT_MAX;
+ if (ap.allowed)
max_blks = ap.allowed;

error = gfs2_inplace_reserve(ip, &ap);
--- a/fs/gfs2/quota.h
+++ b/fs/gfs2/quota.h
@@ -45,6 +45,8 @@ static inline int gfs2_quota_lock_check(
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
int ret;
+
+ ap->allowed = UINT_MAX; /* Assume we are permitted a whole lot */
if (sdp->sd_args.ar_quota == GFS2_QUOTA_OFF)
return 0;
ret = gfs2_quota_lock(ip, NO_UID_QUOTA_CHANGE, NO_GID_QUOTA_CHANGE);