From 6d4ade986f9c8df31e68fd30643997f79cc5a5f8 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Fri, 14 Jun 2013 11:17:15 +0100 Subject: 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 Cc: Al Viro Cc: "J. Bruce Fields" Cc: Jeff Layton --- fs/gfs2/file.c | 69 ++++++++++++++++++++++++++++++++++++++-------------------- 1 file changed, 46 insertions(+), 23 deletions(-) (limited to 'fs/gfs2/file.c') diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index ad0dc38d87ab..4ed6a03e565b 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; } -- cgit v1.2.3 From d81a8ef59802d2d8908466d631573a3644c313d5 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 16 May 2013 14:14:48 -0400 Subject: [readdir] convert gfs2 Signed-off-by: Al Viro --- fs/gfs2/file.c | 23 ++++++++--------------- 1 file changed, 8 insertions(+), 15 deletions(-) (limited to 'fs/gfs2/file.c') diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index ad0dc38d87ab..b3333371aebb 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -82,35 +82,28 @@ static loff_t gfs2_llseek(struct file *file, loff_t offset, int whence) } /** - * gfs2_readdir - Read directory entries from a directory + * gfs2_readdir - Iterator for a directory * @file: The directory to read from - * @dirent: Buffer for dirents - * @filldir: Function used to do the copying + * @ctx: What to feed directory entries to * * Returns: errno */ -static int gfs2_readdir(struct file *file, void *dirent, filldir_t filldir) +static int gfs2_readdir(struct file *file, struct dir_context *ctx) { struct inode *dir = file->f_mapping->host; struct gfs2_inode *dip = GFS2_I(dir); struct gfs2_holder d_gh; - u64 offset = file->f_pos; int error; - gfs2_holder_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh); - error = gfs2_glock_nq(&d_gh); - if (error) { - gfs2_holder_uninit(&d_gh); + error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh); + if (error) return error; - } - error = gfs2_dir_read(dir, &offset, dirent, filldir, &file->f_ra); + error = gfs2_dir_read(dir, ctx, &file->f_ra); gfs2_glock_dq_uninit(&d_gh); - file->f_pos = offset; - return error; } @@ -1048,7 +1041,7 @@ const struct file_operations gfs2_file_fops = { }; const struct file_operations gfs2_dir_fops = { - .readdir = gfs2_readdir, + .iterate = gfs2_readdir, .unlocked_ioctl = gfs2_ioctl, .open = gfs2_open, .release = gfs2_release, @@ -1078,7 +1071,7 @@ const struct file_operations gfs2_file_fops_nolock = { }; const struct file_operations gfs2_dir_fops_nolock = { - .readdir = gfs2_readdir, + .iterate = gfs2_readdir, .unlocked_ioctl = gfs2_ioctl, .open = gfs2_open, .release = gfs2_release, -- cgit v1.2.3 From 1c8c601a8c0dc59fe64907dcd9d512a3d181ddc7 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Fri, 21 Jun 2013 08:58:15 -0400 Subject: locks: protect most of the file_lock handling with i_lock Having a global lock that protects all of this code is a clear scalability problem. Instead of doing that, move most of the code to be protected by the i_lock instead. The exceptions are the global lists that the ->fl_link sits on, and the ->fl_block list. ->fl_link is what connects these structures to the global lists, so we must ensure that we hold those locks when iterating over or updating these lists. Furthermore, sound deadlock detection requires that we hold the blocked_list state steady while checking for loops. We also must ensure that the search and update to the list are atomic. For the checking and insertion side of the blocked_list, push the acquisition of the global lock into __posix_lock_file and ensure that checking and update of the blocked_list is done without dropping the lock in between. On the removal side, when waking up blocked lock waiters, take the global lock before walking the blocked list and dequeue the waiters from the global list prior to removal from the fl_block list. With this, deadlock detection should be race free while we minimize excessive file_lock_lock thrashing. Finally, in order to avoid a lock inversion problem when handling /proc/locks output we must ensure that manipulations of the fl_block list are also protected by the file_lock_lock. Signed-off-by: Jeff Layton Signed-off-by: Al Viro --- fs/gfs2/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/gfs2/file.c') diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index b3333371aebb..cebfd404c1d9 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -889,7 +889,7 @@ out_uninit: * cluster; until we do, disable leases (by just returning -EINVAL), * unless the administrator has requested purely local locking. * - * Locking: called under lock_flocks + * Locking: called under i_lock * * Returns: errno */ -- cgit v1.2.3