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author | Steven Whitehouse <swhiteho@redhat.com> | 2006-11-27 09:55:28 -0500 |
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committer | Steven Whitehouse <swhiteho@redhat.com> | 2006-11-30 10:36:53 -0500 |
commit | 300c7d75f3a5e8edd3e390ccd56b808f3fb14e33 (patch) | |
tree | 1cc627b0e6ef37c3e72691cc75c5be5db14cac72 | |
parent | cb4c03131836a55bf95e1c165409244ac6b4f39f (diff) | |
download | kernel_samsung_smdk4412-300c7d75f3a5e8edd3e390ccd56b808f3fb14e33.zip kernel_samsung_smdk4412-300c7d75f3a5e8edd3e390ccd56b808f3fb14e33.tar.gz kernel_samsung_smdk4412-300c7d75f3a5e8edd3e390ccd56b808f3fb14e33.tar.bz2 |
[GFS2] Fix recursive locking in gfs2_permission
Since gfs2_permission may be called either from the VFS (in which case
we need to obtain a shared glock) or from GFS2 (in which case we already
have a glock) we need to test to see whether or not a lock is required.
The original test was buggy due to a potential race. This one should
be safe.
This fixes Red Hat bugzilla #217129
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
-rw-r--r-- | fs/gfs2/ops_inode.c | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/fs/gfs2/ops_inode.c b/fs/gfs2/ops_inode.c index b247f25..fd9fee2 100644 --- a/fs/gfs2/ops_inode.c +++ b/fs/gfs2/ops_inode.c @@ -835,6 +835,10 @@ static void *gfs2_follow_link(struct dentry *dentry, struct nameidata *nd) * @mask: * @nd: passed from Linux VFS, ignored by us * + * This may be called from the VFS directly, or from within GFS2 with the + * inode locked, so we look to see if the glock is already locked and only + * lock the glock if its not already been done. + * * Returns: errno */ @@ -843,15 +847,18 @@ static int gfs2_permission(struct inode *inode, int mask, struct nameidata *nd) struct gfs2_inode *ip = GFS2_I(inode); struct gfs2_holder i_gh; int error; + int unlock = 0; - if (!test_bit(GIF_INVALID, &ip->i_flags)) - return generic_permission(inode, mask, gfs2_check_acl); + if (gfs2_glock_is_locked_by_me(ip->i_gl) == 0) { + error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh); + if (error) + return error; + unlock = 1; + } - error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh); - if (!error) { - error = generic_permission(inode, mask, gfs2_check_acl_locked); + error = generic_permission(inode, mask, gfs2_check_acl_locked); + if (unlock) gfs2_glock_dq_uninit(&i_gh); - } return error; } |