[PATCH 12/21] cifs: implement i_op->atomic_open()
From: Miklos Szeredi
Date: Tue Jun 05 2012 - 09:11:11 EST
From: Miklos Szeredi <mszeredi@xxxxxxx>
Add an ->atomic_open implementation which replaces the atomic lookup+open+create
operation implemented via ->lookup and ->create operations.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
CC: Steve French <sfrench@xxxxxxxxx>
---
fs/cifs/cifsfs.c | 1 +
fs/cifs/cifsfs.h | 3 +
fs/cifs/dir.c | 437 ++++++++++++++++++++++++++++++------------------------
3 files changed, 245 insertions(+), 196 deletions(-)
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 8b6e344..dd29c7c 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -778,6 +778,7 @@ struct file_system_type cifs_fs_type = {
};
const struct inode_operations cifs_dir_inode_ops = {
.create = cifs_create,
+ .atomic_open = cifs_atomic_open,
.lookup = cifs_lookup,
.getattr = cifs_getattr,
.unlink = cifs_unlink,
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 6536535..3a572bf 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -46,6 +46,9 @@ extern const struct inode_operations cifs_dir_inode_ops;
extern struct inode *cifs_root_iget(struct super_block *);
extern int cifs_create(struct inode *, struct dentry *, umode_t,
struct nameidata *);
+extern struct file *cifs_atomic_open(struct inode *, struct dentry *,
+ struct opendata *, unsigned, umode_t,
+ bool *);
extern struct dentry *cifs_lookup(struct inode *, struct dentry *,
struct nameidata *);
extern int cifs_unlink(struct inode *dir, struct dentry *dentry);
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index ec4e9a2..7a3dcd1 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -133,108 +133,141 @@ cifs_bp_rename_retry:
return full_path;
}
+/*
+ * Don't allow the separator character in a path component.
+ * The VFS will not allow "/", but "\" is allowed by posix.
+ */
+static int
+check_name(struct dentry *direntry)
+{
+ struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
+ int i;
+
+ if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)) {
+ for (i = 0; i < direntry->d_name.len; i++) {
+ if (direntry->d_name.name[i] == '\\') {
+ cFYI(1, "Invalid file name");
+ return -EINVAL;
+ }
+ }
+ }
+ return 0;
+}
+
+
/* Inode operations in similar order to how they appear in Linux file fs.h */
-int
-cifs_create(struct inode *inode, struct dentry *direntry, umode_t mode,
- struct nameidata *nd)
+static int cifs_do_create(struct inode *inode, struct dentry *direntry,
+ int xid, struct tcon_link *tlink, unsigned oflags,
+ umode_t mode, __u32 *oplock, __u16 *fileHandle,
+ bool *created)
{
int rc = -ENOENT;
- int xid;
int create_options = CREATE_NOT_DIR;
- __u32 oplock = 0;
- int oflags;
- /*
- * BB below access is probably too much for mknod to request
- * but we have to do query and setpathinfo so requesting
- * less could fail (unless we want to request getatr and setatr
- * permissions (only). At least for POSIX we do not have to
- * request so much.
- */
- int desiredAccess = GENERIC_READ | GENERIC_WRITE;
- __u16 fileHandle;
- struct cifs_sb_info *cifs_sb;
- struct tcon_link *tlink;
- struct cifs_tcon *tcon;
+ int desiredAccess;
+ struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+ struct cifs_tcon *tcon = tlink_tcon(tlink);
char *full_path = NULL;
FILE_ALL_INFO *buf = NULL;
struct inode *newinode = NULL;
- int disposition = FILE_OVERWRITE_IF;
-
- xid = GetXid();
-
- cifs_sb = CIFS_SB(inode->i_sb);
- tlink = cifs_sb_tlink(cifs_sb);
- if (IS_ERR(tlink)) {
- FreeXid(xid);
- return PTR_ERR(tlink);
- }
- tcon = tlink_tcon(tlink);
+ int disposition;
+ *oplock = 0;
if (tcon->ses->server->oplocks)
- oplock = REQ_OPLOCK;
-
- if (nd)
- oflags = nd->intent.open.file->f_flags;
- else
- oflags = O_RDONLY | O_CREAT;
+ *oplock = REQ_OPLOCK;
full_path = build_path_from_dentry(direntry);
if (full_path == NULL) {
rc = -ENOMEM;
- goto cifs_create_out;
+ goto out;
}
if (tcon->unix_ext && (tcon->ses->capabilities & CAP_UNIX) &&
+ !tcon->broken_posix_open &&
(CIFS_UNIX_POSIX_PATH_OPS_CAP &
le64_to_cpu(tcon->fsUnixInfo.Capability))) {
rc = cifs_posix_open(full_path, &newinode,
- inode->i_sb, mode, oflags, &oplock, &fileHandle, xid);
- /* EIO could indicate that (posix open) operation is not
- supported, despite what server claimed in capability
- negotiation. EREMOTE indicates DFS junction, which is not
- handled in posix open */
+ inode->i_sb, mode, oflags, oplock, fileHandle, xid);
+ switch (rc) {
+ case 0:
+ if (newinode == NULL) {
+ /* query inode info */
+ goto cifs_create_get_file_info;
+ }
- if (rc == 0) {
- if (newinode == NULL) /* query inode info */
+ if (!S_ISREG(newinode->i_mode)) {
+ /*
+ * The server may allow us to open things like
+ * FIFOs, but the client isn't set up to deal
+ * with that. If it's not a regular file, just
+ * close it and proceed as if it were a normal
+ * lookup.
+ */
+ CIFSSMBClose(xid, tcon, *fileHandle);
goto cifs_create_get_file_info;
- else /* success, no need to query */
- goto cifs_create_set_dentry;
- } else if ((rc != -EIO) && (rc != -EREMOTE) &&
- (rc != -EOPNOTSUPP) && (rc != -EINVAL))
- goto cifs_create_out;
- /* else fallthrough to retry, using older open call, this is
- case where server does not support this SMB level, and
- falsely claims capability (also get here for DFS case
- which should be rare for path not covered on files) */
- }
+ }
+ /* success, no need to query */
+ goto cifs_create_set_dentry;
+
+ case -ENOENT:
+ goto cifs_create_get_file_info;
+
+ case -EIO:
+ case -EINVAL:
+ /*
+ * EIO could indicate that (posix open) operation is not
+ * supported, despite what server claimed in capability
+ * negotiation.
+ *
+ * POSIX open in samba versions 3.3.1 and earlier could
+ * incorrectly fail with invalid parameter.
+ */
+ tcon->broken_posix_open = true;
+ break;
- if (nd) {
- /* if the file is going to stay open, then we
- need to set the desired access properly */
- desiredAccess = 0;
- if (OPEN_FMODE(oflags) & FMODE_READ)
- desiredAccess |= GENERIC_READ; /* is this too little? */
- if (OPEN_FMODE(oflags) & FMODE_WRITE)
- desiredAccess |= GENERIC_WRITE;
+ case -EREMOTE:
+ case -EOPNOTSUPP:
+ /*
+ * EREMOTE indicates DFS junction, which is not handled
+ * in posix open. If either that or op not supported
+ * returned, follow the normal lookup.
+ */
+ break;
- if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
- disposition = FILE_CREATE;
- else if ((oflags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
- disposition = FILE_OVERWRITE_IF;
- else if ((oflags & O_CREAT) == O_CREAT)
- disposition = FILE_OPEN_IF;
- else
- cFYI(1, "Create flag not set in create function");
+ default:
+ goto out;
+ }
+ /*
+ * fallthrough to retry, using older open call, this is case
+ * where server does not support this SMB level, and falsely
+ * claims capability (also get here for DFS case which should be
+ * rare for path not covered on files)
+ */
}
+ desiredAccess = 0;
+ if (OPEN_FMODE(oflags) & FMODE_READ)
+ desiredAccess |= GENERIC_READ; /* is this too little? */
+ if (OPEN_FMODE(oflags) & FMODE_WRITE)
+ desiredAccess |= GENERIC_WRITE;
+
+ disposition = FILE_OVERWRITE_IF;
+ if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
+ disposition = FILE_CREATE;
+ else if ((oflags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
+ disposition = FILE_OVERWRITE_IF;
+ else if ((oflags & O_CREAT) == O_CREAT)
+ disposition = FILE_OPEN_IF;
+ else
+ cFYI(1, "Create flag not set in create function");
+
/* BB add processing to set equivalent of mode - e.g. via CreateX with
ACLs */
buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
if (buf == NULL) {
rc = -ENOMEM;
- goto cifs_create_out;
+ goto out;
}
/*
@@ -250,7 +283,7 @@ cifs_create(struct inode *inode, struct dentry *direntry, umode_t mode,
if (tcon->ses->capabilities & CAP_NT_SMBS)
rc = CIFSSMBOpen(xid, tcon, full_path, disposition,
desiredAccess, create_options,
- &fileHandle, &oplock, buf, cifs_sb->local_nls,
+ fileHandle, oplock, buf, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
else
rc = -EIO; /* no NT SMB support fall into legacy open below */
@@ -259,17 +292,17 @@ cifs_create(struct inode *inode, struct dentry *direntry, umode_t mode,
/* old server, retry the open legacy style */
rc = SMBLegacyOpen(xid, tcon, full_path, disposition,
desiredAccess, create_options,
- &fileHandle, &oplock, buf, cifs_sb->local_nls,
+ fileHandle, oplock, buf, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
}
if (rc) {
cFYI(1, "cifs_create returned 0x%x", rc);
- goto cifs_create_out;
+ goto out;
}
/* If Open reported that we actually created a file
then we now have to set the mode if possible */
- if ((tcon->unix_ext) && (oplock & CIFS_CREATE_ACTION)) {
+ if ((tcon->unix_ext) && (*oplock & CIFS_CREATE_ACTION)) {
struct cifs_unix_set_info_args args = {
.mode = mode,
.ctime = NO_CHANGE_64,
@@ -278,6 +311,7 @@ cifs_create(struct inode *inode, struct dentry *direntry, umode_t mode,
.device = 0,
};
+ *created = true;
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
args.uid = (__u64) current_fsuid();
if (inode->i_mode & S_ISGID)
@@ -288,7 +322,7 @@ cifs_create(struct inode *inode, struct dentry *direntry, umode_t mode,
args.uid = NO_CHANGE_64;
args.gid = NO_CHANGE_64;
}
- CIFSSMBUnixSetFileInfo(xid, tcon, &args, fileHandle,
+ CIFSSMBUnixSetFileInfo(xid, tcon, &args, *fileHandle,
current->tgid);
} else {
/* BB implement mode setting via Windows security
@@ -305,11 +339,11 @@ cifs_create_get_file_info:
inode->i_sb, xid);
else {
rc = cifs_get_inode_info(&newinode, full_path, buf,
- inode->i_sb, xid, &fileHandle);
+ inode->i_sb, xid, fileHandle);
if (newinode) {
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DYNPERM)
newinode->i_mode = mode;
- if ((oplock & CIFS_CREATE_ACTION) &&
+ if ((*oplock & CIFS_CREATE_ACTION) &&
(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID)) {
newinode->i_uid = current_fsuid();
if (inode->i_mode & S_ISGID)
@@ -321,37 +355,139 @@ cifs_create_get_file_info:
}
cifs_create_set_dentry:
- if (rc == 0)
- d_instantiate(direntry, newinode);
- else
+ if (rc != 0) {
cFYI(1, "Create worked, get_inode_info failed rc = %d", rc);
+ goto out;
+ }
+ d_drop(direntry);
+ d_add(direntry, newinode);
- if (newinode && nd) {
- struct cifsFileInfo *pfile_info;
- struct file *filp;
+ /* ENOENT for create? How weird... */
+ rc = -ENOENT;
+ if (!newinode) {
+ CIFSSMBClose(xid, tcon, *fileHandle);
+ goto out;
+ }
+ rc = 0;
- filp = lookup_instantiate_filp(nd, direntry, generic_file_open);
- if (IS_ERR(filp)) {
- rc = PTR_ERR(filp);
- CIFSSMBClose(xid, tcon, fileHandle);
- goto cifs_create_out;
- }
+out:
+ kfree(buf);
+ kfree(full_path);
+ return rc;
+}
- pfile_info = cifs_new_fileinfo(fileHandle, filp, tlink, oplock);
- if (pfile_info == NULL) {
- fput(filp);
- CIFSSMBClose(xid, tcon, fileHandle);
- rc = -ENOMEM;
- }
- } else {
+struct file *
+cifs_atomic_open(struct inode *inode, struct dentry *direntry,
+ struct opendata *od, unsigned oflags, umode_t mode,
+ bool *created)
+{
+ int rc;
+ int xid;
+ struct tcon_link *tlink;
+ struct cifs_tcon *tcon;
+ __u16 fileHandle;
+ __u32 oplock;
+ struct file *filp;
+ struct cifsFileInfo *pfile_info;
+
+ /* Posix open is only called (at lookup time) for file create now. For
+ * opens (rather than creates), because we do not know if it is a file
+ * or directory yet, and current Samba no longer allows us to do posix
+ * open on dirs, we could end up wasting an open call on what turns out
+ * to be a dir. For file opens, we wait to call posix open till
+ * cifs_open. It could be added to atomic_open in the future but the
+ * performance tradeoff of the extra network request when EISDIR or
+ * EACCES is returned would have to be weighed against the 50% reduction
+ * in network traffic in the other paths.
+ */
+ if (!(oflags & O_CREAT)) {
+ struct dentry *res = cifs_lookup(inode, direntry, NULL);
+ if (IS_ERR(res))
+ return ERR_CAST(res);
+
+ finish_no_open(od, res);
+ return NULL;
+ }
+
+ rc = check_name(direntry);
+ if (rc)
+ return ERR_PTR(rc);
+
+ xid = GetXid();
+
+ cFYI(1, "parent inode = 0x%p name is: %s and dentry = 0x%p",
+ inode, direntry->d_name.name, direntry);
+
+ tlink = cifs_sb_tlink(CIFS_SB(inode->i_sb));
+ filp = ERR_CAST(tlink);
+ if (IS_ERR(tlink))
+ goto free_xid;
+
+ tcon = tlink_tcon(tlink);
+
+ rc = cifs_do_create(inode, direntry, xid, tlink, oflags, mode,
+ &oplock, &fileHandle, created);
+
+ if (rc) {
+ filp = ERR_PTR(rc);
+ goto out;
+ }
+
+ filp = finish_open(od, direntry, generic_file_open);
+ if (IS_ERR(filp)) {
CIFSSMBClose(xid, tcon, fileHandle);
+ goto out;
}
-cifs_create_out:
- kfree(buf);
- kfree(full_path);
+ pfile_info = cifs_new_fileinfo(fileHandle, filp, tlink, oplock);
+ if (pfile_info == NULL) {
+ CIFSSMBClose(xid, tcon, fileHandle);
+ fput(filp);
+ filp = ERR_PTR(-ENOMEM);
+ }
+
+out:
+ cifs_put_tlink(tlink);
+free_xid:
+ FreeXid(xid);
+ return filp;
+}
+
+int cifs_create(struct inode *inode, struct dentry *direntry, umode_t mode,
+ struct nameidata *nd)
+{
+ int rc;
+ int xid = GetXid();
+ /*
+ * BB below access is probably too much for mknod to request
+ * but we have to do query and setpathinfo so requesting
+ * less could fail (unless we want to request getatr and setatr
+ * permissions (only). At least for POSIX we do not have to
+ * request so much.
+ */
+ unsigned oflags = O_EXCL | O_CREAT | O_RDWR;
+ struct tcon_link *tlink;
+ __u16 fileHandle;
+ __u32 oplock;
+ bool created = true;
+
+ cFYI(1, "cifs_create parent inode = 0x%p name is: %s and dentry = 0x%p",
+ inode, direntry->d_name.name, direntry);
+
+ tlink = cifs_sb_tlink(CIFS_SB(inode->i_sb));
+ rc = PTR_ERR(tlink);
+ if (IS_ERR(tlink))
+ goto free_xid;
+
+ rc = cifs_do_create(inode, direntry, xid, tlink, oflags, mode,
+ &oplock, &fileHandle, &created);
+ if (!rc)
+ CIFSSMBClose(xid, tlink_tcon(tlink), fileHandle);
+
cifs_put_tlink(tlink);
+free_xid:
FreeXid(xid);
+
return rc;
}
@@ -492,16 +628,11 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
{
int xid;
int rc = 0; /* to get around spurious gcc warning, set to zero here */
- __u32 oplock;
- __u16 fileHandle = 0;
- bool posix_open = false;
struct cifs_sb_info *cifs_sb;
struct tcon_link *tlink;
struct cifs_tcon *pTcon;
- struct cifsFileInfo *cfile;
struct inode *newInode = NULL;
char *full_path = NULL;
- struct file *filp;
xid = GetXid();
@@ -518,31 +649,9 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
}
pTcon = tlink_tcon(tlink);
- oplock = pTcon->ses->server->oplocks ? REQ_OPLOCK : 0;
-
- /*
- * Don't allow the separator character in a path component.
- * The VFS will not allow "/", but "\" is allowed by posix.
- */
- if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)) {
- int i;
- for (i = 0; i < direntry->d_name.len; i++)
- if (direntry->d_name.name[i] == '\\') {
- cFYI(1, "Invalid file name");
- rc = -EINVAL;
- goto lookup_out;
- }
- }
-
- /*
- * O_EXCL: optimize away the lookup, but don't hash the dentry. Let
- * the VFS handle the create.
- */
- if (nd && (nd->flags & LOOKUP_EXCL)) {
- d_instantiate(direntry, NULL);
- rc = 0;
+ rc = check_name(direntry);
+ if (rc)
goto lookup_out;
- }
/* can not grab the rename sem here since it would
deadlock in the cases (beginning of sys_rename itself)
@@ -560,80 +669,16 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
}
cFYI(1, "Full path: %s inode = 0x%p", full_path, direntry->d_inode);
- /* Posix open is only called (at lookup time) for file create now.
- * For opens (rather than creates), because we do not know if it
- * is a file or directory yet, and current Samba no longer allows
- * us to do posix open on dirs, we could end up wasting an open call
- * on what turns out to be a dir. For file opens, we wait to call posix
- * open till cifs_open. It could be added here (lookup) in the future
- * but the performance tradeoff of the extra network request when EISDIR
- * or EACCES is returned would have to be weighed against the 50%
- * reduction in network traffic in the other paths.
- */
if (pTcon->unix_ext) {
- if (nd && !(nd->flags & LOOKUP_DIRECTORY) &&
- (nd->flags & LOOKUP_OPEN) && !pTcon->broken_posix_open &&
- (nd->intent.open.file->f_flags & O_CREAT)) {
- rc = cifs_posix_open(full_path, &newInode,
- parent_dir_inode->i_sb,
- nd->intent.open.create_mode,
- nd->intent.open.file->f_flags, &oplock,
- &fileHandle, xid);
- /*
- * The check below works around a bug in POSIX
- * open in samba versions 3.3.1 and earlier where
- * open could incorrectly fail with invalid parameter.
- * If either that or op not supported returned, follow
- * the normal lookup.
- */
- switch (rc) {
- case 0:
- /*
- * The server may allow us to open things like
- * FIFOs, but the client isn't set up to deal
- * with that. If it's not a regular file, just
- * close it and proceed as if it were a normal
- * lookup.
- */
- if (newInode && !S_ISREG(newInode->i_mode)) {
- CIFSSMBClose(xid, pTcon, fileHandle);
- break;
- }
- case -ENOENT:
- posix_open = true;
- case -EOPNOTSUPP:
- break;
- default:
- pTcon->broken_posix_open = true;
- }
- }
- if (!posix_open)
- rc = cifs_get_inode_info_unix(&newInode, full_path,
- parent_dir_inode->i_sb, xid);
- } else
+ rc = cifs_get_inode_info_unix(&newInode, full_path,
+ parent_dir_inode->i_sb, xid);
+ } else {
rc = cifs_get_inode_info(&newInode, full_path, NULL,
parent_dir_inode->i_sb, xid, NULL);
+ }
if ((rc == 0) && (newInode != NULL)) {
d_add(direntry, newInode);
- if (posix_open) {
- filp = lookup_instantiate_filp(nd, direntry,
- generic_file_open);
- if (IS_ERR(filp)) {
- rc = PTR_ERR(filp);
- CIFSSMBClose(xid, pTcon, fileHandle);
- goto lookup_out;
- }
-
- cfile = cifs_new_fileinfo(fileHandle, filp, tlink,
- oplock);
- if (cfile == NULL) {
- fput(filp);
- CIFSSMBClose(xid, pTcon, fileHandle);
- rc = -ENOMEM;
- goto lookup_out;
- }
- }
/* since paths are not looked up by component - the parent
directories are presumed to be good here */
renew_parental_timestamps(direntry);
--
1.7.7
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