GFS2: Use inode_newsize_ok and get_write_access in fallocate

gfs2_fallocate wasn't checking inode_newsize_ok nor get_write_access.
Split out the context setup and inode locking pieces into a separate
function to make it more clear and add these missing calls.

inode_newsize_ok is called conditional on FALLOC_FL_KEEP_SIZE as there
is no need to enforce a file size limit if it isn't going to change.

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

1 files changed, 44 insertions, 22 deletions

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 5ebe56831794..3786579dd348 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -797,8 +797,7 @@ static void calc_max_reserv(struct gfs2_inode *ip, loff_t max, loff_t *len,
         }
 }
 
-static long gfs2_fallocate(struct file *file, int mode, loff_t offset,
-                           loff_t len)
+static long __gfs2_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 {
         struct inode *inode = file_inode(file);
         struct gfs2_sbd *sdp = GFS2_SB(inode);
@@ -812,14 +811,9 @@ static long gfs2_fallocate(struct file *file, int mode, loff_t offset,
         loff_t bsize_mask = ~((loff_t)sdp->sd_sb.sb_bsize - 1);
         loff_t next = (offset + len - 1) >> sdp->sd_sb.sb_bsize_shift;
         loff_t max_chunk_size = UINT_MAX & bsize_mask;
-        struct gfs2_holder gh;
 
         next = (next + 1) << sdp->sd_sb.sb_bsize_shift;
 
-        /* We only support the FALLOC_FL_KEEP_SIZE mode */
-        if (mode & ~FALLOC_FL_KEEP_SIZE)
-                return -EOPNOTSUPP;
-
         offset &= bsize_mask;
 
         len = next - offset;
@@ -830,17 +824,6 @@ static long gfs2_fallocate(struct file *file, int mode, loff_t offset,
         if (bytes == 0)
                 bytes = sdp->sd_sb.sb_bsize;
 
-        error = gfs2_rs_alloc(ip);
-        if (error)
-                return error;
-
-        mutex_lock(&inode->i_mutex);
-
-        gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
-        error = gfs2_glock_nq(&gh);
-        if (unlikely(error))
-                goto out_uninit;
-
         gfs2_size_hint(file, offset, len);
 
         while (len > 0) {
@@ -853,8 +836,7 @@ static long gfs2_fallocate(struct file *file, int mode, loff_t offset,
                 }
                 error = gfs2_quota_lock_check(ip);
                 if (error)
-                        goto out_unlock;
-
+                        return error;
 retry:
                 gfs2_write_calc_reserv(ip, bytes, &data_blocks, &ind_blocks);
 
@@ -898,18 +880,58 @@ retry:
 
         if (error == 0)
                 error = generic_write_sync(file, pos, count);
-        goto out_unlock;
+        return error;
 
 out_trans_fail:
         gfs2_inplace_release(ip);
 out_qunlock:
         gfs2_quota_unlock(ip);
+        return error;
+}
+
+static long gfs2_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
+{
+        struct inode *inode = file_inode(file);
+        struct gfs2_inode *ip = GFS2_I(inode);
+        struct gfs2_holder gh;
+        int ret;
+
+        if (mode & ~FALLOC_FL_KEEP_SIZE)
+                return -EOPNOTSUPP;
+
+        mutex_lock(&inode->i_mutex);
+
+        gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
+        ret = gfs2_glock_nq(&gh);
+        if (ret)
+                goto out_uninit;
+
+        if (!(mode & FALLOC_FL_KEEP_SIZE) &&
+            (offset + len) > inode->i_size) {
+                ret = inode_newsize_ok(inode, offset + len);
+                if (ret)
+                        goto out_unlock;
+        }
+
+        ret = get_write_access(inode);
+        if (ret)
+                goto out_unlock;
+
+        ret = gfs2_rs_alloc(ip);
+        if (ret)
+                goto out_putw;
+
+        ret = __gfs2_fallocate(file, mode, offset, len);
+        if (ret)
+                gfs2_rs_deltree(ip->i_res);
+out_putw:
+        put_write_access(inode);
 out_unlock:
         gfs2_glock_dq(&gh);
 out_uninit:
         gfs2_holder_uninit(&gh);
         mutex_unlock(&inode->i_mutex);
-        return error;
+        return ret;
 }
 
 #ifdef CONFIG_GFS2_FS_LOCKING_DLM