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CIFS: refactor cifs_get_inode_info()

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Make logic of cifs_get_inode() much clearer by moving code to sub
functions and adding comments.

Document the steps this function does.

cifs_get_inode_info() gets and updates a file inode metadata from its
file path.

* If caller already has raw info data from server they can pass it.
* If inode already exists (just need to update) caller can pass it.

Step 1: get raw data from server if none was passed
Step 2: parse raw data into intermediate internal cifs_fattr struct
Step 3: set fattr uniqueid which is later used for inode number. This
        can sometime be done from raw data
Step 4: tweak fattr according to mount options (file_mode, acl to mode
        bits, uid, gid, etc)
Step 5: update or create inode from final fattr struct

* add is_smb1_server() helper
* add is_inode_cache_good() helper
* move SMB1-backupcreds-getinfo-retry to separate func
  cifs_backup_query_path_info().
* move set-uniqueid code to separate func cifs_set_fattr_ino()
* don't clobber uniqueid from backup cred retry
* fix some probable corner cases memleaks

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Aurelien Aptel 2019-11-18 21:04:08 +01:00 committed by Steve French
parent f6a6bf7c4d
commit b8f7442bc4
2 changed files with 213 additions and 145 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
fs/cifs/cifsglob.h
View File

@ -1967,4 +1967,10 @@ extern struct smb_version_values smb302_values;
#define ALT_SMB311_VERSION_STRING "3.11"
extern struct smb_version_operations smb311_operations;
extern struct smb_version_values smb311_values;
static inline bool is_smb1_server(struct TCP_Server_Info *server)
{
return strcmp(server->vals->version_string, SMB1_VERSION_STRING) == 0;
}
#endif /* _CIFS_GLOB_H */

352
fs/cifs/inode.c
View File

@ -727,22 +727,138 @@ static __u64 simple_hashstr(const char *str)
return hash;
}
/**
* cifs_backup_query_path_info - SMB1 fallback code to get ino
*
* Fallback code to get file metadata when we don't have access to
* @full_path (EACCESS) and have backup creds.
*
* @data will be set to search info result buffer
* @resp_buf will be set to cifs resp buf and needs to be freed with
* cifs_buf_release() when done with @data.
*/
static int
cifs_backup_query_path_info(int xid,
struct cifs_tcon *tcon,
struct super_block *sb,
const char *full_path,
void **resp_buf,
FILE_ALL_INFO **data)
{
struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
struct cifs_search_info info = {0};
u16 flags;
int rc;
*resp_buf = NULL;
info.endOfSearch = false;
if (tcon->unix_ext)
info.info_level = SMB_FIND_FILE_UNIX;
else if ((tcon->ses->capabilities &
tcon->ses->server->vals->cap_nt_find) == 0)
info.info_level = SMB_FIND_FILE_INFO_STANDARD;
else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)
info.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
else /* no srvino useful for fallback to some netapp */
info.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
flags = CIFS_SEARCH_CLOSE_ALWAYS |
CIFS_SEARCH_CLOSE_AT_END |
CIFS_SEARCH_BACKUP_SEARCH;
rc = CIFSFindFirst(xid, tcon, full_path,
cifs_sb, NULL, flags, &info, false);
if (rc)
return rc;
*resp_buf = (void *)info.ntwrk_buf_start;
*data = (FILE_ALL_INFO *)info.srch_entries_start;
return 0;
}
static void
cifs_set_fattr_ino(int xid,
struct cifs_tcon *tcon,
struct super_block *sb,
struct inode **inode,
const char *full_path,
FILE_ALL_INFO *data,
struct cifs_fattr *fattr)
{
struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
struct TCP_Server_Info *server = tcon->ses->server;
int rc;
if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
if (*inode)
fattr->cf_uniqueid = CIFS_I(*inode)->uniqueid;
else
fattr->cf_uniqueid = iunique(sb, ROOT_I);
return;
}
/*
* If we have an inode pass a NULL tcon to ensure we don't
* make a round trip to the server. This only works for SMB2+.
*/
rc = server->ops->get_srv_inum(xid,
*inode ? NULL : tcon,
cifs_sb, full_path,
&fattr->cf_uniqueid,
data);
if (rc) {
/*
* If that fails reuse existing ino or generate one
* and disable server ones
*/
if (*inode)
fattr->cf_uniqueid = CIFS_I(*inode)->uniqueid;
else {
fattr->cf_uniqueid = iunique(sb, ROOT_I);
cifs_autodisable_serverino(cifs_sb);
}
return;
}
/* If no errors, check for zero root inode (invalid) */
if (fattr->cf_uniqueid == 0 && strlen(full_path) == 0) {
cifs_dbg(FYI, "Invalid (0) inodenum\n");
if (*inode) {
/* reuse */
fattr->cf_uniqueid = CIFS_I(*inode)->uniqueid;
} else {
/* make an ino by hashing the UNC */
fattr->cf_flags |= CIFS_FATTR_FAKE_ROOT_INO;
fattr->cf_uniqueid = simple_hashstr(tcon->treeName);
}
}
}
static inline bool is_inode_cache_good(struct inode *ino)
{
return ino && CIFS_CACHE_READ(CIFS_I(ino)) && CIFS_I(ino)->time != 0;
}
int
cifs_get_inode_info(struct inode **inode, const char *full_path,
FILE_ALL_INFO *data, struct super_block *sb, int xid,
cifs_get_inode_info(struct inode **inode,
const char *full_path,
FILE_ALL_INFO *in_data,
struct super_block *sb, int xid,
const struct cifs_fid *fid)
{
__u16 srchflgs;
int rc = 0, tmprc = ENOSYS;
struct cifs_tcon *tcon;
struct TCP_Server_Info *server;
struct tcon_link *tlink;
struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
char *buf = NULL;
bool adjust_tz = false;
struct cifs_fattr fattr;
struct cifs_search_info *srchinf = NULL;
struct cifs_fattr fattr = {0};
bool symlink = false;
FILE_ALL_INFO *data = in_data;
FILE_ALL_INFO *tmp_data = NULL;
void *smb1_backup_rsp_buf = NULL;
int rc = 0;
int tmprc = 0;
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink))
@ -750,142 +866,88 @@ cifs_get_inode_info(struct inode **inode, const char *full_path,
tcon = tlink_tcon(tlink);
server = tcon->ses->server;
cifs_dbg(FYI, "Getting info on %s\n", full_path);
/*
* 1. Fetch file metadata if not provided (data)
*/
if ((data == NULL) && (*inode != NULL)) {
if (CIFS_CACHE_READ(CIFS_I(*inode)) &&
CIFS_I(*inode)->time != 0) {
if (!data) {
if (is_inode_cache_good(*inode)) {
cifs_dbg(FYI, "No need to revalidate cached inode sizes\n");
goto cgii_exit;
goto out;
}
}
/* if inode info is not passed, get it from server */
if (data == NULL) {
if (!server->ops->query_path_info) {
rc = -ENOSYS;
goto cgii_exit;
}
buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
if (buf == NULL) {
tmp_data = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
if (!tmp_data) {
rc = -ENOMEM;
goto cgii_exit;
goto out;
}
data = (FILE_ALL_INFO *)buf;
rc = server->ops->query_path_info(xid, tcon, cifs_sb, full_path,
data, &adjust_tz, &symlink);
rc = server->ops->query_path_info(xid, tcon, cifs_sb,
full_path, tmp_data,
&adjust_tz, &symlink);
data = tmp_data;
}
if (!rc) {
cifs_all_info_to_fattr(&fattr, data, sb, adjust_tz,
symlink);
} else if (rc == -EREMOTE) {
cifs_create_dfs_fattr(&fattr, sb);
rc = 0;
} else if ((rc == -EACCES) && backup_cred(cifs_sb) &&
(strcmp(server->vals->version_string, SMB1_VERSION_STRING)
== 0)) {
/*
* For SMB2 and later the backup intent flag is already
* sent if needed on open and there is no path based
* FindFirst operation to use to retry with
*/
srchinf = kzalloc(sizeof(struct cifs_search_info),
GFP_KERNEL);
if (srchinf == NULL) {
rc = -ENOMEM;
goto cgii_exit;
}
srchinf->endOfSearch = false;
if (tcon->unix_ext)
srchinf->info_level = SMB_FIND_FILE_UNIX;
else if ((tcon->ses->capabilities &
tcon->ses->server->vals->cap_nt_find) == 0)
srchinf->info_level = SMB_FIND_FILE_INFO_STANDARD;
else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)
srchinf->info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
else /* no srvino useful for fallback to some netapp */
srchinf->info_level = SMB_FIND_FILE_DIRECTORY_INFO;
srchflgs = CIFS_SEARCH_CLOSE_ALWAYS |
CIFS_SEARCH_CLOSE_AT_END |
CIFS_SEARCH_BACKUP_SEARCH;
rc = CIFSFindFirst(xid, tcon, full_path,
cifs_sb, NULL, srchflgs, srchinf, false);
if (!rc) {
data = (FILE_ALL_INFO *)srchinf->srch_entries_start;
cifs_dir_info_to_fattr(&fattr,
(FILE_DIRECTORY_INFO *)data, cifs_sb);
fattr.cf_uniqueid = le64_to_cpu(
((SEARCH_ID_FULL_DIR_INFO *)data)->UniqueId);
cifs_buf_release(srchinf->ntwrk_buf_start);
}
kfree(srchinf);
if (rc)
goto cgii_exit;
} else
goto cgii_exit;
/*
* If an inode wasn't passed in, then get the inode number
*
* Is an i_ino of zero legal? Can we use that to check if the server
* supports returning inode numbers? Are there other sanity checks we
* can use to ensure that the server is really filling in that field?
* 2. Convert it to internal cifs metadata (fattr)
*/
if (*inode == NULL) {
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
if (server->ops->get_srv_inum)
tmprc = server->ops->get_srv_inum(xid,
tcon, cifs_sb, full_path,
&fattr.cf_uniqueid, data);
if (tmprc) {
cifs_dbg(FYI, "GetSrvInodeNum rc %d\n",
tmprc);
fattr.cf_uniqueid = iunique(sb, ROOT_I);
cifs_autodisable_serverino(cifs_sb);
} else if ((fattr.cf_uniqueid == 0) &&
strlen(full_path) == 0) {
/* some servers ret bad root ino ie 0 */
cifs_dbg(FYI, "Invalid (0) inodenum\n");
fattr.cf_flags |=
CIFS_FATTR_FAKE_ROOT_INO;
fattr.cf_uniqueid =
simple_hashstr(tcon->treeName);
}
} else
fattr.cf_uniqueid = iunique(sb, ROOT_I);
} else {
if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)
&& server->ops->get_srv_inum) {
/*
* Pass a NULL tcon to ensure we don't make a round
* trip to the server. This only works for SMB2+.
*/
tmprc = server->ops->get_srv_inum(xid,
NULL, cifs_sb, full_path,
&fattr.cf_uniqueid, data);
if (tmprc)
fattr.cf_uniqueid = CIFS_I(*inode)->uniqueid;
else if ((fattr.cf_uniqueid == 0) &&
strlen(full_path) == 0) {
/*
* Reuse existing root inode num since
* inum zero for root causes ls of . and .. to
* not be returned
*/
cifs_dbg(FYI, "Srv ret 0 inode num for root\n");
fattr.cf_uniqueid = CIFS_I(*inode)->uniqueid;
}
} else
fattr.cf_uniqueid = CIFS_I(*inode)->uniqueid;
switch (rc) {
case 0:
cifs_all_info_to_fattr(&fattr, data, sb, adjust_tz, symlink);
break;
case -EREMOTE:
/* DFS link, no metadata available on this server */
cifs_create_dfs_fattr(&fattr, sb);
rc = 0;
break;
case -EACCES:
/*
* perm errors, try again with backup flags if possible
*
* For SMB2 and later the backup intent flag
* is already sent if needed on open and there
* is no path based FindFirst operation to use
* to retry with
*/
if (backup_cred(cifs_sb) && is_smb1_server(server)) {
/* for easier reading */
FILE_DIRECTORY_INFO *fdi;
SEARCH_ID_FULL_DIR_INFO *si;
rc = cifs_backup_query_path_info(xid, tcon, sb,
full_path,
&smb1_backup_rsp_buf,
&data);
if (rc)
goto out;
fdi = (FILE_DIRECTORY_INFO *)data;
si = (SEARCH_ID_FULL_DIR_INFO *)data;
cifs_dir_info_to_fattr(&fattr, fdi, cifs_sb);
fattr.cf_uniqueid = le64_to_cpu(si->UniqueId);
/* uniqueid set, skip get inum step */
goto handle_mnt_opt;
} else {
/* nothing we can do, bail out */
goto out;
}
break;
default:
cifs_dbg(FYI, "%s: unhandled err rc %d\n", __func__, rc);
goto out;
}
/*
* 3. Get or update inode number (fattr.cf_uniqueid)
*/
cifs_set_fattr_ino(xid, tcon, sb, inode, full_path, data, &fattr);
/*
* 4. Tweak fattr based on mount options
*/
handle_mnt_opt:
/* query for SFU type info if supported and needed */
if (fattr.cf_cifsattrs & ATTR_SYSTEM &&
cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
@ -900,16 +962,15 @@ cifs_get_inode_info(struct inode **inode, const char *full_path,
full_path, fid);
if (rc) {
cifs_dbg(FYI, "%s: Get mode from SID failed. rc=%d\n",
__func__, rc);
goto cgii_exit;
__func__, rc);
goto out;
}
} else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL) {
rc = cifs_acl_to_fattr(cifs_sb, &fattr, *inode, false,
full_path, fid);
if (rc) {
full_path, fid); if (rc) {
cifs_dbg(FYI, "%s: Getting ACL failed with error: %d\n",
__func__, rc);
goto cgii_exit;
goto out;
}
}
@ -925,6 +986,10 @@ cifs_get_inode_info(struct inode **inode, const char *full_path,
cifs_dbg(FYI, "check_mf_symlink: %d\n", tmprc);
}
/*
* 5. Update inode with final fattr data
*/
if (!*inode) {
*inode = cifs_iget(sb, &fattr);
if (!*inode)
@ -937,7 +1002,7 @@ cifs_get_inode_info(struct inode **inode, const char *full_path,
CIFS_I(*inode)->uniqueid != fattr.cf_uniqueid)) {
CIFS_I(*inode)->time = 0; /* force reval */
rc = -ESTALE;
goto cgii_exit;
goto out;
}
/* if filetype is different, return error */
@ -945,18 +1010,15 @@ cifs_get_inode_info(struct inode **inode, const char *full_path,
(fattr.cf_mode & S_IFMT))) {
CIFS_I(*inode)->time = 0; /* force reval */
rc = -ESTALE;
goto cgii_exit;
goto out;
}
cifs_fattr_to_inode(*inode, &fattr);
}
cgii_exit:
if ((*inode) && ((*inode)->i_ino == 0))
cifs_dbg(FYI, "inode number of zero returned\n");
kfree(buf);
out:
cifs_buf_release(smb1_backup_rsp_buf);
cifs_put_tlink(tlink);
kfree(tmp_data);
return rc;
}