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gfs2: Change inode qa_data to allow multiple users

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Before this patch, multiple users called gfs2_qa_alloc which allocated
a qadata structure to the inode, if quotas are turned on. Later, in
file close or evict, the structure was deleted with gfs2_qa_delete.
But there can be several competing processes who need access to the
structure. There were races between file close (release) and the others.
Thus, a release could delete the structure out from under a process
that relied upon its existence. For example, chown.

This patch changes the management of the qadata structures to be
a get/put scheme. Function gfs2_qa_alloc has been changed to gfs2_qa_get
and if the structure is allocated, the count essentially starts out at
1. Function gfs2_qa_delete has been renamed to gfs2_qa_put, and the
last guy to decrement the count to 0 frees the memory.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
This commit is contained in:
Bob Peterson
2020-02-27 12:47:53 -06:00
parent d580712a37
commit 2fba46a04c
10 changed files with 101 additions and 58 deletions
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6
fs/gfs2/acl.c
View File

@@ -117,14 +117,14 @@ int gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
if (acl && acl->a_count > GFS2_ACL_MAX_ENTRIES(GFS2_SB(inode)))
return -E2BIG;
ret = gfs2_qa_alloc(ip);
ret = gfs2_qa_get(ip);
if (ret)
return ret;
if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
if (ret)
return ret;
goto out;
need_unlock = true;
}
@@ -144,5 +144,7 @@ int gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
unlock:
if (need_unlock)
gfs2_glock_dq_uninit(&gh);
out:
gfs2_qa_put(ip);
return ret;
}