From: Al Viro <viro@ZenIV.linux.org.uk>
To: linux-fsdevel@vger.kernel.org
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Subject: [PATCH 2/5] proc_lookupfd_common(): don't bother with instantiate unless the file is open
Date: Sat, 26 May 2018 01:04:07 +0100 [thread overview]
Message-ID: <20180526000410.10804-2-viro@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20180526000410.10804-1-viro@ZenIV.linux.org.uk>
From: Al Viro <viro@zeniv.linux.org.uk>
... and take the "check if file is open, pick ->f_mode" into a helper;
tid_fd_revalidate() can use it.
The next patch will get rid of tid_fd_revalidate() calls in instantiate
callbacks.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/proc/fd.c | 63 ++++++++++++++++++++++++++++++++----------------------------
1 file changed, 34 insertions(+), 29 deletions(-)
diff --git a/fs/proc/fd.c b/fs/proc/fd.c
index 6b80cd1e419a..d38845ecc408 100644
--- a/fs/proc/fd.c
+++ b/fs/proc/fd.c
@@ -81,12 +81,29 @@ static const struct file_operations proc_fdinfo_file_operations = {
.release = single_release,
};
+static bool tid_fd_mode(struct task_struct *task, unsigned fd, fmode_t *mode)
+{
+ struct files_struct *files = get_files_struct(task);
+ struct file *file;
+
+ if (!files)
+ return false;
+
+ rcu_read_lock();
+ file = fcheck_files(files, fd);
+ if (file)
+ *mode = file->f_mode;
+ rcu_read_unlock();
+ put_files_struct(files);
+ return !!file;
+}
+
static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
{
- struct files_struct *files;
struct task_struct *task;
struct inode *inode;
unsigned int fd;
+ fmode_t f_mode;
if (flags & LOOKUP_RCU)
return -ECHILD;
@@ -96,35 +113,20 @@ static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
fd = proc_fd(inode);
if (task) {
- files = get_files_struct(task);
- if (files) {
- struct file *file;
-
- rcu_read_lock();
- file = fcheck_files(files, fd);
- if (file) {
- unsigned f_mode = file->f_mode;
-
- rcu_read_unlock();
- put_files_struct(files);
-
- task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
-
- if (S_ISLNK(inode->i_mode)) {
- unsigned i_mode = S_IFLNK;
- if (f_mode & FMODE_READ)
- i_mode |= S_IRUSR | S_IXUSR;
- if (f_mode & FMODE_WRITE)
- i_mode |= S_IWUSR | S_IXUSR;
- inode->i_mode = i_mode;
- }
-
- security_task_to_inode(task, inode);
- put_task_struct(task);
- return 1;
+ if (tid_fd_mode(task, fd, &f_mode)) {
+ task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
+
+ if (S_ISLNK(inode->i_mode)) {
+ unsigned i_mode = S_IFLNK;
+ if (f_mode & FMODE_READ)
+ i_mode |= S_IRUSR | S_IXUSR;
+ if (f_mode & FMODE_WRITE)
+ i_mode |= S_IWUSR | S_IXUSR;
+ inode->i_mode = i_mode;
}
- rcu_read_unlock();
- put_files_struct(files);
+ security_task_to_inode(task, inode);
+ put_task_struct(task);
+ return 1;
}
put_task_struct(task);
}
@@ -203,11 +205,14 @@ static struct dentry *proc_lookupfd_common(struct inode *dir,
struct task_struct *task = get_proc_task(dir);
int result = -ENOENT;
unsigned fd = name_to_int(&dentry->d_name);
+ fmode_t f_mode;
if (!task)
goto out_no_task;
if (fd == ~0U)
goto out;
+ if (!tid_fd_mode(task, fd, &f_mode))
+ goto out;
result = instantiate(dir, dentry, task, (void *)(unsigned long)fd);
out:
--
2.11.0
next prev parent reply other threads:[~2018-05-26 0:04 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-13 21:26 [RFC][PATCHES] reducing d_add() use, part 1 Al Viro
2018-05-13 21:30 ` [PATCH 01/15] bfs_lookup(): use d_splice_alias() Al Viro
2018-05-13 21:30 ` [PATCH 02/15] bfs_find_entry: pass name/len as qstr pointer Al Viro
2018-05-13 21:30 ` [PATCH 03/15] bfs_add_entry: " Al Viro
2018-05-13 21:30 ` [PATCH 04/15] cramfs_lookup(): use d_splice_alias() Al Viro
2018-05-13 21:30 ` [PATCH 05/15] freevxfs_lookup(): " Al Viro
2018-05-14 8:41 ` Christoph Hellwig
2018-05-14 15:26 ` Al Viro
2018-05-13 21:30 ` [PATCH 06/15] minix_lookup: " Al Viro
2018-05-13 21:30 ` [PATCH 07/15] qnx4_lookup: " Al Viro
2018-05-14 10:48 ` Anders Larsen
2018-05-13 21:30 ` [PATCH 08/15] sysv_lookup: " Al Viro
2018-05-14 8:41 ` Christoph Hellwig
2018-05-13 21:30 ` [PATCH 09/15] ubifs_lookup: " Al Viro
2018-05-14 6:48 ` Richard Weinberger
2018-05-13 21:30 ` [PATCH 10/15] qnx6_lookup: switch to d_splice_alias() Al Viro
2018-05-13 21:30 ` [PATCH 11/15] romfs_lookup: hash negative lookups, use d_splice_alias() Al Viro
2018-05-13 21:30 ` [PATCH 12/15] adfs_lookup_byname: .. *is* taken care of in fs/namei.c Al Viro
2018-05-13 21:30 ` [PATCH 13/15] adfs_lookup: do not fail with ENOENT on negatives, use d_splice_alias() Al Viro
2018-05-13 21:30 ` [PATCH 14/15] xfs_vn_lookup: simplify a bit Al Viro
2018-05-14 8:41 ` Christoph Hellwig
2018-05-13 21:30 ` [PATCH 15/15] openpromfs: switch to d_splice_alias() Al Viro
2018-05-16 9:45 ` [PATCH 01/15] bfs_lookup(): use d_splice_alias() Tigran Aivazian
2018-05-25 23:53 ` [RFC][PATCHES] reducing d_add() use, part 2 Al Viro
2018-05-25 23:54 ` [PATCH 01/10] openpromfs: switch to d_splice_alias() Al Viro
2018-05-25 23:54 ` [PATCH 02/10] orangefs_lookup: simplify Al Viro
2018-05-31 18:23 ` Mike Marshall
2018-05-25 23:54 ` [PATCH 03/10] omfs_lookup(): report IO errors, use d_splice_alias() Al Viro
2018-05-25 23:54 ` [PATCH 04/10] hfs: " Al Viro
2018-05-25 23:54 ` [PATCH 05/10] hfs: don't allow mounting over .../rsrc Al Viro
2018-05-25 23:54 ` [PATCH 06/10] hfsplus: switch to d_splice_alias() Al Viro
2018-05-25 23:54 ` [PATCH 07/10] ncp_lookup(): use d_splice_alias() Al Viro
2018-05-25 23:54 ` [PATCH 08/10] 9p: unify paths in v9fs_vfs_lookup() Al Viro
2018-05-25 23:54 ` [PATCH 09/10] cifs_lookup(): cifs_get_inode_...() never returns 0 with *inode left NULL Al Viro
2018-05-25 23:54 ` [PATCH 10/10] cifs_lookup(): switch to d_splice_alias() Al Viro
2018-05-26 0:03 ` [RFC][PATCHES] reducing d_add() use, part 3 (procfs) Al Viro
2018-05-26 0:04 ` [PATCH 1/5] procfs: get rid of ancient BS in pid_revalidate() uses Al Viro
2018-05-26 0:04 ` Al Viro [this message]
2018-05-26 0:04 ` [PATCH 3/5] don't bother with tid_fd_revalidate() in lookups Al Viro
2018-05-26 0:04 ` [PATCH 4/5] procfs: switch instantiate_t to d_splice_alias() Al Viro
2018-05-26 0:04 ` [PATCH 5/5] switch the rest of procfs lookups " Al Viro
2018-05-31 8:28 ` [PATCH 1/5] procfs: get rid of ancient BS in pid_revalidate() uses Alexey Dobriyan
2018-05-26 13:07 ` [RFC][PATCHES] reducing d_add() use, part 3 (procfs) Alexey Dobriyan
2018-05-26 13:56 ` Alexey Dobriyan
2018-05-26 18:20 ` Al Viro
2018-05-26 18:38 ` Matthew Wilcox
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