* [PATCHv1 0/2] xen/xenfs: fix /proc/xen/xenbus
@ 2016-05-16 17:44 David Vrabel
2016-05-16 17:44 ` [PATCHv1 1/2] libfs: allow simple_fill_super() to add symlinks David Vrabel
` (3 more replies)
0 siblings, 4 replies; 7+ messages in thread
From: David Vrabel @ 2016-05-16 17:44 UTC (permalink / raw)
To: xen-devel; +Cc: Juergen Gross, Boris Ostrovsky, David Vrabel
"Fix" /proc/xen/xenbus by making it a symlink to the working
/dev/xen/xenbus. Do the same for /proc/xen/privcmd so it matches.
If there's agreement on this approach I'll resend to Cc the fs
maintainers.
David
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^ permalink raw reply [flat|nested] 7+ messages in thread* [PATCHv1 1/2] libfs: allow simple_fill_super() to add symlinks 2016-05-16 17:44 [PATCHv1 0/2] xen/xenfs: fix /proc/xen/xenbus David Vrabel @ 2016-05-16 17:44 ` David Vrabel 2016-05-16 17:44 ` [PATCHv1 2/2] xen/xenfs: replace xenbus and privcmd with symlinks David Vrabel ` (2 subsequent siblings) 3 siblings, 0 replies; 7+ messages in thread From: David Vrabel @ 2016-05-16 17:44 UTC (permalink / raw) To: xen-devel; +Cc: Juergen Gross, Boris Ostrovsky, David Vrabel simple_fill_super() will add symlinks if an entry has mode & S_IFLNK. The target is provided in the new "link" field. Signed-off-by: David Vrabel <david.vrabel@citrix.com> --- fs/libfs.c | 23 ++++++++++++++++++++--- include/linux/fs.h | 2 +- 2 files changed, 21 insertions(+), 4 deletions(-) diff --git a/fs/libfs.c b/fs/libfs.c index f3fa82c..894e182 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -500,6 +500,8 @@ int simple_fill_super(struct super_block *s, unsigned long magic, if (!root) return -ENOMEM; for (i = 0; !files->name || files->name[0]; i++, files++) { + char *link = NULL; + if (!files->name) continue; @@ -509,17 +511,32 @@ int simple_fill_super(struct super_block *s, unsigned long magic, "with an index of 1!\n", __func__, s->s_type->name); + if (files->mode & S_IFLNK) { + link = kstrdup(files->link, GFP_KERNEL); + if (!link) + goto out; + } + dentry = d_alloc_name(root, files->name); - if (!dentry) + if (!dentry) { + kfree(link); goto out; + } inode = new_inode(s); if (!inode) { dput(dentry); + kfree(link); goto out; } - inode->i_mode = S_IFREG | files->mode; + inode->i_mode = files->mode; + if (files->mode & S_IFLNK) { + inode->i_op = &simple_symlink_inode_operations; + inode->i_link = link; + } else { + inode->i_fop = files->ops; + inode->i_mode |= S_IFREG; + } inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; - inode->i_fop = files->ops; inode->i_ino = i; d_add(dentry, inode); } diff --git a/include/linux/fs.h b/include/linux/fs.h index 70e61b5..8a09998 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2897,7 +2897,7 @@ extern const struct file_operations simple_dir_operations; extern const struct inode_operations simple_dir_inode_operations; extern void make_empty_dir_inode(struct inode *inode); extern bool is_empty_dir_inode(struct inode *inode); -struct tree_descr { char *name; const struct file_operations *ops; int mode; }; +struct tree_descr { char *name; const struct file_operations *ops; int mode; char *link; }; struct dentry *d_alloc_name(struct dentry *, const char *); extern int simple_fill_super(struct super_block *, unsigned long, struct tree_descr *); extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count); -- 2.1.4 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel ^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCHv1 2/2] xen/xenfs: replace xenbus and privcmd with symlinks 2016-05-16 17:44 [PATCHv1 0/2] xen/xenfs: fix /proc/xen/xenbus David Vrabel 2016-05-16 17:44 ` [PATCHv1 1/2] libfs: allow simple_fill_super() to add symlinks David Vrabel @ 2016-05-16 17:44 ` David Vrabel 2016-05-16 18:36 ` [PATCHv1 0/2] xen/xenfs: fix /proc/xen/xenbus Boris Ostrovsky 2016-05-16 22:23 ` Doug Goldstein 3 siblings, 0 replies; 7+ messages in thread From: David Vrabel @ 2016-05-16 17:44 UTC (permalink / raw) To: xen-devel; +Cc: Juergen Gross, Boris Ostrovsky, David Vrabel /proc/xen/xenbus does not work correctly. A read blocked waiting for a xenbus message will deadlock a write to the same file handle due to the requirement for atomic file position updates on regular files. /proc/xen/xenbus and /proc/xen/privcmd are supposed to be identical to the character devices /dev/xen/xenbus and /dev/xen/privcmd so replace the files with symlinks. Signed-off-by: David Vrabel <david.vrabel@citrix.com> --- drivers/xen/xenfs/super.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c index 8559a71..09c239e 100644 --- a/drivers/xen/xenfs/super.c +++ b/drivers/xen/xenfs/super.c @@ -45,16 +45,16 @@ static const struct file_operations capabilities_file_ops = { static int xenfs_fill_super(struct super_block *sb, void *data, int silent) { static struct tree_descr xenfs_files[] = { - [2] = { "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR }, + [2] = { "xenbus", NULL, S_IFLNK | S_IRWXUGO, "/dev/xen/xenbus" }, { "capabilities", &capabilities_file_ops, S_IRUGO }, - { "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR }, + { "privcmd", NULL, S_IFLNK | S_IRWXUGO, "/dev/xen/privcmd" }, {""}, }; static struct tree_descr xenfs_init_files[] = { - [2] = { "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR }, + [2] = { "xenbus", NULL, S_IFLNK | S_IRWXUGO, "/dev/xen/xenbus" }, { "capabilities", &capabilities_file_ops, S_IRUGO }, - { "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR }, + { "privcmd", NULL, S_IFLNK | S_IRWXUGO, "/dev/xen/privcmd" }, { "xsd_kva", &xsd_kva_file_ops, S_IRUSR|S_IWUSR}, { "xsd_port", &xsd_port_file_ops, S_IRUSR|S_IWUSR}, #ifdef CONFIG_XEN_SYMS -- 2.1.4 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCHv1 0/2] xen/xenfs: fix /proc/xen/xenbus 2016-05-16 17:44 [PATCHv1 0/2] xen/xenfs: fix /proc/xen/xenbus David Vrabel 2016-05-16 17:44 ` [PATCHv1 1/2] libfs: allow simple_fill_super() to add symlinks David Vrabel 2016-05-16 17:44 ` [PATCHv1 2/2] xen/xenfs: replace xenbus and privcmd with symlinks David Vrabel @ 2016-05-16 18:36 ` Boris Ostrovsky 2016-05-16 22:23 ` Doug Goldstein 3 siblings, 0 replies; 7+ messages in thread From: Boris Ostrovsky @ 2016-05-16 18:36 UTC (permalink / raw) To: David Vrabel, xen-devel; +Cc: Juergen Gross On 05/16/2016 01:44 PM, David Vrabel wrote: > "Fix" /proc/xen/xenbus by making it a symlink to the working > /dev/xen/xenbus. Do the same for /proc/xen/privcmd so it matches. > > If there's agreement on this approach I'll resend to Cc the fs > maintainers. Looks good to me. -boris _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCHv1 0/2] xen/xenfs: fix /proc/xen/xenbus 2016-05-16 17:44 [PATCHv1 0/2] xen/xenfs: fix /proc/xen/xenbus David Vrabel ` (2 preceding siblings ...) 2016-05-16 18:36 ` [PATCHv1 0/2] xen/xenfs: fix /proc/xen/xenbus Boris Ostrovsky @ 2016-05-16 22:23 ` Doug Goldstein 3 siblings, 0 replies; 7+ messages in thread From: Doug Goldstein @ 2016-05-16 22:23 UTC (permalink / raw) To: David Vrabel, xen-devel; +Cc: Juergen Gross, Boris Ostrovsky [-- Attachment #1.1.1: Type: text/plain, Size: 451 bytes --] On 5/16/16 12:44 PM, David Vrabel wrote: > "Fix" /proc/xen/xenbus by making it a symlink to the working > /dev/xen/xenbus. Do the same for /proc/xen/privcmd so it matches. > > If there's agreement on this approach I'll resend to Cc the fs > maintainers. > > David > Looks good to me. Looks like the bits you're using were introduced in 4.2 which explains why I believed some more infra needed to be wired up. -- Doug Goldstein [-- Attachment #1.2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 959 bytes --] [-- Attachment #2: Type: text/plain, Size: 126 bytes --] _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel ^ permalink raw reply [flat|nested] 7+ messages in thread
[parent not found: <1463480843-3860-1-git-send-email-david.vrabel@citrix.com>]
* [PATCHv1 1/2] libfs: allow simple_fill_super() to add symlinks [not found] <1463480843-3860-1-git-send-email-david.vrabel@citrix.com> @ 2016-05-17 10:27 ` David Vrabel [not found] ` <1463480843-3860-2-git-send-email-david.vrabel@citrix.com> 1 sibling, 0 replies; 7+ messages in thread From: David Vrabel @ 2016-05-17 10:27 UTC (permalink / raw) To: Alexander Viro Cc: Juergen Gross, linux-kernel, David Vrabel, linux-fsdevel, xen-devel, Boris Ostrovsky simple_fill_super() will add symlinks if an entry has mode & S_IFLNK. The target is provided in the new "link" field. Signed-off-by: David Vrabel <david.vrabel@citrix.com> --- v2: - simplified. --- fs/libfs.c | 15 +++++++++++++-- include/linux/fs.h | 2 +- 2 files changed, 14 insertions(+), 3 deletions(-) diff --git a/fs/libfs.c b/fs/libfs.c index f3fa82c..5b3a391 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -517,9 +517,20 @@ int simple_fill_super(struct super_block *s, unsigned long magic, dput(dentry); goto out; } - inode->i_mode = S_IFREG | files->mode; + if (files->mode & S_IFLNK) { + inode->i_mode = files->mode; + inode->i_op = &simple_symlink_inode_operations; + inode->i_link = kstrdup(files->link, GFP_KERNEL); + if (!inode->i_link) { + iput(inode); + dput(dentry); + goto out; + } + } else { + inode->i_mode = S_IFREG | files->mode; + inode->i_fop = files->ops; + } inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; - inode->i_fop = files->ops; inode->i_ino = i; d_add(dentry, inode); } diff --git a/include/linux/fs.h b/include/linux/fs.h index 70e61b5..8a09998 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2897,7 +2897,7 @@ extern const struct file_operations simple_dir_operations; extern const struct inode_operations simple_dir_inode_operations; extern void make_empty_dir_inode(struct inode *inode); extern bool is_empty_dir_inode(struct inode *inode); -struct tree_descr { char *name; const struct file_operations *ops; int mode; }; +struct tree_descr { char *name; const struct file_operations *ops; int mode; char *link; }; struct dentry *d_alloc_name(struct dentry *, const char *); extern int simple_fill_super(struct super_block *, unsigned long, struct tree_descr *); extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count); -- 2.1.4 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel ^ permalink raw reply related [flat|nested] 7+ messages in thread
[parent not found: <1463480843-3860-2-git-send-email-david.vrabel@citrix.com>]
* Re: [PATCHv1 1/2] libfs: allow simple_fill_super() to add symlinks [not found] ` <1463480843-3860-2-git-send-email-david.vrabel@citrix.com> @ 2016-06-10 13:13 ` David Vrabel 0 siblings, 0 replies; 7+ messages in thread From: David Vrabel @ 2016-06-10 13:13 UTC (permalink / raw) To: David Vrabel, Alexander Viro Cc: Juergen Gross, linux-fsdevel, Boris Ostrovsky, linux-kernel, xen-devel On 17/05/16 11:27, David Vrabel wrote: > simple_fill_super() will add symlinks if an entry has mode & S_IFLNK. > The target is provided in the new "link" field. Ping? > Signed-off-by: David Vrabel <david.vrabel@citrix.com> > --- > v2: > - simplified. > --- > fs/libfs.c | 15 +++++++++++++-- > include/linux/fs.h | 2 +- > 2 files changed, 14 insertions(+), 3 deletions(-) > > diff --git a/fs/libfs.c b/fs/libfs.c > index f3fa82c..5b3a391 100644 > --- a/fs/libfs.c > +++ b/fs/libfs.c > @@ -517,9 +517,20 @@ int simple_fill_super(struct super_block *s, unsigned long magic, > dput(dentry); > goto out; > } > - inode->i_mode = S_IFREG | files->mode; > + if (files->mode & S_IFLNK) { > + inode->i_mode = files->mode; > + inode->i_op = &simple_symlink_inode_operations; > + inode->i_link = kstrdup(files->link, GFP_KERNEL); > + if (!inode->i_link) { > + iput(inode); > + dput(dentry); > + goto out; > + } > + } else { > + inode->i_mode = S_IFREG | files->mode; > + inode->i_fop = files->ops; > + } > inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; > - inode->i_fop = files->ops; > inode->i_ino = i; > d_add(dentry, inode); > } > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 70e61b5..8a09998 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -2897,7 +2897,7 @@ extern const struct file_operations simple_dir_operations; > extern const struct inode_operations simple_dir_inode_operations; > extern void make_empty_dir_inode(struct inode *inode); > extern bool is_empty_dir_inode(struct inode *inode); > -struct tree_descr { char *name; const struct file_operations *ops; int mode; }; > +struct tree_descr { char *name; const struct file_operations *ops; int mode; char *link; }; > struct dentry *d_alloc_name(struct dentry *, const char *); > extern int simple_fill_super(struct super_block *, unsigned long, struct tree_descr *); > extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count); > _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel ^ permalink raw reply [flat|nested] 7+ messages in thread
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2016-05-16 17:44 [PATCHv1 0/2] xen/xenfs: fix /proc/xen/xenbus David Vrabel
2016-05-16 17:44 ` [PATCHv1 1/2] libfs: allow simple_fill_super() to add symlinks David Vrabel
2016-05-16 17:44 ` [PATCHv1 2/2] xen/xenfs: replace xenbus and privcmd with symlinks David Vrabel
2016-05-16 18:36 ` [PATCHv1 0/2] xen/xenfs: fix /proc/xen/xenbus Boris Ostrovsky
2016-05-16 22:23 ` Doug Goldstein
[not found] <1463480843-3860-1-git-send-email-david.vrabel@citrix.com>
2016-05-17 10:27 ` [PATCHv1 1/2] libfs: allow simple_fill_super() to add symlinks David Vrabel
[not found] ` <1463480843-3860-2-git-send-email-david.vrabel@citrix.com>
2016-06-10 13:13 ` David Vrabel
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