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author | Steven Whitehouse <swhiteho@redhat.com> | 2013-06-14 11:17:15 +0100 |
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committer | Steven Whitehouse <swhiteho@redhat.com> | 2013-06-14 11:17:15 +0100 |
commit | 6d4ade986f9c8df31e68fd30643997f79cc5a5f8 (patch) | |
tree | f0758a7a9b008d0bd3665234a5074e3cf6f4d455 /fs/gfs2/file.c | |
parent | 5a00f3cc978be45b9d2597851bedaa40630bc597 (diff) | |
download | op-kernel-dev-6d4ade986f9c8df31e68fd30643997f79cc5a5f8.zip op-kernel-dev-6d4ade986f9c8df31e68fd30643997f79cc5a5f8.tar.gz |
GFS2: Add atomic_open support
I've restricted atomic_open to only operate on regular files, although
I still don't understand why atomic_open should not be possible also for
directories on GFS2. That can always be added in later though, if it
makes sense.
The ->atomic_open function can be passed negative dentries, which
in most cases means either ENOENT (->lookup) or a call to d_instantiate
(->create). In the GFS2 case though, we need to actually perform the
look up, since we do not know whether there has been a new inode created
on another node. The look up calls d_splice_alias which then tries to
rehash the dentry - so the solution here is to simply check for that
in d_splice_alias. The same issue is likely to affect any other cluster
filesystem implementing ->atomic_open
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "J. Bruce Fields" <bfields fieldses org>
Cc: Jeff Layton <jlayton@redhat.com>
Diffstat (limited to 'fs/gfs2/file.c')
-rw-r--r-- | fs/gfs2/file.c | 69 |
1 files changed, 46 insertions, 23 deletions
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index ad0dc38..4ed6a03 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -538,21 +538,30 @@ static int gfs2_mmap(struct file *file, struct vm_area_struct *vma) } /** - * gfs2_open - open a file - * @inode: the inode to open - * @file: the struct file for this opening + * gfs2_open_common - This is common to open and atomic_open + * @inode: The inode being opened + * @file: The file being opened * - * Returns: errno + * This maybe called under a glock or not depending upon how it has + * been called. We must always be called under a glock for regular + * files, however. For other file types, it does not matter whether + * we hold the glock or not. + * + * Returns: Error code or 0 for success */ -static int gfs2_open(struct inode *inode, struct file *file) +int gfs2_open_common(struct inode *inode, struct file *file) { - struct gfs2_inode *ip = GFS2_I(inode); - struct gfs2_holder i_gh; struct gfs2_file *fp; - int error; + int ret; - fp = kzalloc(sizeof(struct gfs2_file), GFP_KERNEL); + if (S_ISREG(inode->i_mode)) { + ret = generic_file_open(inode, file); + if (ret) + return ret; + } + + fp = kzalloc(sizeof(struct gfs2_file), GFP_NOFS); if (!fp) return -ENOMEM; @@ -560,29 +569,43 @@ static int gfs2_open(struct inode *inode, struct file *file) gfs2_assert_warn(GFS2_SB(inode), !file->private_data); file->private_data = fp; + return 0; +} + +/** + * gfs2_open - open a file + * @inode: the inode to open + * @file: the struct file for this opening + * + * After atomic_open, this function is only used for opening files + * which are already cached. We must still get the glock for regular + * files to ensure that we have the file size uptodate for the large + * file check which is in the common code. That is only an issue for + * regular files though. + * + * Returns: errno + */ + +static int gfs2_open(struct inode *inode, struct file *file) +{ + struct gfs2_inode *ip = GFS2_I(inode); + struct gfs2_holder i_gh; + int error; + bool need_unlock = false; if (S_ISREG(ip->i_inode.i_mode)) { error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh); if (error) - goto fail; + return error; + need_unlock = true; + } - if (!(file->f_flags & O_LARGEFILE) && - i_size_read(inode) > MAX_NON_LFS) { - error = -EOVERFLOW; - goto fail_gunlock; - } + error = gfs2_open_common(inode, file); + if (need_unlock) gfs2_glock_dq_uninit(&i_gh); - } - - return 0; -fail_gunlock: - gfs2_glock_dq_uninit(&i_gh); -fail: - file->private_data = NULL; - kfree(fp); return error; } |