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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/inode.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/inode.c')
-rw-r--r-- | fs/gfs2/inode.c | 125 |
1 files changed, 99 insertions, 26 deletions
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c index ede16ae7..bbb2715 100644 --- a/fs/gfs2/inode.c +++ b/fs/gfs2/inode.c @@ -535,6 +535,7 @@ static int gfs2_security_init(struct gfs2_inode *dip, struct gfs2_inode *ip, * gfs2_create_inode - Create a new inode * @dir: The parent directory * @dentry: The new dentry + * @file: If non-NULL, the file which is being opened * @mode: The permissions on the new inode * @dev: For device nodes, this is the device number * @symname: For symlinks, this is the link destination @@ -544,8 +545,9 @@ static int gfs2_security_init(struct gfs2_inode *dip, struct gfs2_inode *ip, */ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry, + struct file *file, umode_t mode, dev_t dev, const char *symname, - unsigned int size, int excl) + unsigned int size, int excl, int *opened) { const struct qstr *name = &dentry->d_name; struct gfs2_holder ghs[2]; @@ -553,6 +555,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry, struct gfs2_inode *dip = GFS2_I(dir), *ip; struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode); struct gfs2_glock *io_gl; + struct dentry *d; int error; u32 aflags = 0; int arq; @@ -579,9 +582,20 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry, inode = gfs2_dir_search(dir, &dentry->d_name, !S_ISREG(mode) || excl); error = PTR_ERR(inode); if (!IS_ERR(inode)) { + d = d_splice_alias(inode, dentry); + error = 0; + if (file && !IS_ERR(d)) { + if (d == NULL) + d = dentry; + if (S_ISREG(inode->i_mode)) + error = finish_open(file, d, gfs2_open_common, opened); + else + error = finish_no_open(file, d); + } gfs2_glock_dq_uninit(ghs); - d_instantiate(dentry, inode); - return 0; + if (IS_ERR(d)) + return PTR_RET(d); + return error; } else if (error != -ENOENT) { goto fail_gunlock; } @@ -679,10 +693,12 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry, goto fail_gunlock3; mark_inode_dirty(inode); + d_instantiate(dentry, inode); + if (file) + error = finish_open(file, dentry, gfs2_open_common, opened); gfs2_glock_dq_uninit(ghs); gfs2_glock_dq_uninit(ghs + 1); - d_instantiate(dentry, inode); - return 0; + return error; fail_gunlock3: gfs2_glock_dq_uninit(ghs + 1); @@ -722,36 +738,56 @@ fail: static int gfs2_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) { - return gfs2_create_inode(dir, dentry, S_IFREG | mode, 0, NULL, 0, excl); + return gfs2_create_inode(dir, dentry, NULL, S_IFREG | mode, 0, NULL, 0, excl, NULL); } /** - * gfs2_lookup - Look up a filename in a directory and return its inode + * __gfs2_lookup - Look up a filename in a directory and return its inode * @dir: The directory inode * @dentry: The dentry of the new inode - * @nd: passed from Linux VFS, ignored by us + * @file: File to be opened + * @opened: atomic_open flags * - * Called by the VFS layer. Lock dir and call gfs2_lookupi() * * Returns: errno */ -static struct dentry *gfs2_lookup(struct inode *dir, struct dentry *dentry, - unsigned int flags) +static struct dentry *__gfs2_lookup(struct inode *dir, struct dentry *dentry, + struct file *file, int *opened) { - struct inode *inode = gfs2_lookupi(dir, &dentry->d_name, 0); - if (inode && !IS_ERR(inode)) { - struct gfs2_glock *gl = GFS2_I(inode)->i_gl; - struct gfs2_holder gh; - int error; - error = gfs2_glock_nq_init(gl, LM_ST_SHARED, LM_FLAG_ANY, &gh); - if (error) { - iput(inode); - return ERR_PTR(error); - } - gfs2_glock_dq_uninit(&gh); + struct inode *inode; + struct dentry *d; + struct gfs2_holder gh; + struct gfs2_glock *gl; + int error; + + inode = gfs2_lookupi(dir, &dentry->d_name, 0); + if (!inode) + return NULL; + if (IS_ERR(inode)) + return ERR_CAST(inode); + + gl = GFS2_I(inode)->i_gl; + error = gfs2_glock_nq_init(gl, LM_ST_SHARED, LM_FLAG_ANY, &gh); + if (error) { + iput(inode); + return ERR_PTR(error); } - return d_splice_alias(inode, dentry); + + d = d_splice_alias(inode, dentry); + if (file && S_ISREG(inode->i_mode)) + error = finish_open(file, dentry, gfs2_open_common, opened); + + gfs2_glock_dq_uninit(&gh); + if (error) + return ERR_PTR(error); + return d; +} + +static struct dentry *gfs2_lookup(struct inode *dir, struct dentry *dentry, + unsigned flags) +{ + return __gfs2_lookup(dir, dentry, NULL, NULL); } /** @@ -1069,7 +1105,7 @@ static int gfs2_symlink(struct inode *dir, struct dentry *dentry, if (size > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode) - 1) return -ENAMETOOLONG; - return gfs2_create_inode(dir, dentry, S_IFLNK | S_IRWXUGO, 0, symname, size, 0); + return gfs2_create_inode(dir, dentry, NULL, S_IFLNK | S_IRWXUGO, 0, symname, size, 0, NULL); } /** @@ -1085,7 +1121,7 @@ static int gfs2_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) { struct gfs2_sbd *sdp = GFS2_SB(dir); unsigned dsize = sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode); - return gfs2_create_inode(dir, dentry, S_IFDIR | mode, 0, NULL, dsize, 0); + return gfs2_create_inode(dir, dentry, NULL, S_IFDIR | mode, 0, NULL, dsize, 0, NULL); } /** @@ -1100,7 +1136,43 @@ static int gfs2_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) static int gfs2_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) { - return gfs2_create_inode(dir, dentry, mode, dev, NULL, 0, 0); + return gfs2_create_inode(dir, dentry, NULL, mode, dev, NULL, 0, 0, NULL); +} + +/** + * gfs2_atomic_open - Atomically open a file + * @dir: The directory + * @dentry: The proposed new entry + * @file: The proposed new struct file + * @flags: open flags + * @mode: File mode + * @opened: Flag to say whether the file has been opened or not + * + * Returns: error code or 0 for success + */ + +static int gfs2_atomic_open(struct inode *dir, struct dentry *dentry, + struct file *file, unsigned flags, + umode_t mode, int *opened) +{ + struct dentry *d; + bool excl = !!(flags & O_EXCL); + + d = __gfs2_lookup(dir, dentry, file, opened); + if (IS_ERR(d)) + return PTR_ERR(d); + if (d == NULL) + d = dentry; + if (d->d_inode) { + if (!(*opened & FILE_OPENED)) + return finish_no_open(file, d); + return 0; + } + + if (!(flags & O_CREAT)) + return -ENOENT; + + return gfs2_create_inode(dir, dentry, file, S_IFREG | mode, 0, NULL, 0, excl, opened); } /* @@ -1780,6 +1852,7 @@ const struct inode_operations gfs2_dir_iops = { .removexattr = gfs2_removexattr, .fiemap = gfs2_fiemap, .get_acl = gfs2_get_acl, + .atomic_open = gfs2_atomic_open, }; const struct inode_operations gfs2_symlink_iops = { |