[PATCH v6 11/15] cifs: When caching, try to open O_WRONLY file rdwr on server

From: David Howells
Date: Thu Mar 28 2024 - 13:04:22 EST

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When we're engaged in local caching of a cifs filesystem, we cannot perform
caching of a partially written cache granule unless we can read the rest of
the granule. To deal with this, if a file is opened O_WRONLY locally, but
the mount was given the "-o fsc" flag, try first opening the remote file
with GENERIC_READ|GENERIC_WRITE and if that returns -EACCES, try dropping
the GENERIC_READ and doing the open again. If that last succeeds,
invalidate the cache for that file as for O_DIRECT.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Steve French <sfrench@xxxxxxxxx>
cc: Shyam Prasad N <nspmangalore@xxxxxxxxx>
cc: Rohith Surabattula <rohiths.msft@xxxxxxxxx>
cc: Jeff Layton <jlayton@xxxxxxxxxx>
cc: linux-cifs@xxxxxxxxxxxxxxx
cc: netfs@xxxxxxxxxxxxxxx
cc: linux-fsdevel@xxxxxxxxxxxxxxx
cc: linux-mm@xxxxxxxxx
---
fs/smb/client/dir.c | 15 ++++++++++++
fs/smb/client/file.c | 51 +++++++++++++++++++++++++++++++++--------
fs/smb/client/fscache.h | 6 +++++
3 files changed, 62 insertions(+), 10 deletions(-)

diff --git a/fs/smb/client/dir.c b/fs/smb/client/dir.c
index 89333d9bce36..37897b919dd5 100644
--- a/fs/smb/client/dir.c
+++ b/fs/smb/client/dir.c
@@ -189,6 +189,7 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned
int disposition;
struct TCP_Server_Info *server = tcon->ses->server;
struct cifs_open_parms oparms;
+ int rdwr_for_fscache = 0;

*oplock = 0;
if (tcon->ses->server->oplocks)
@@ -200,6 +201,10 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned
return PTR_ERR(full_path);
}

+ /* If we're caching, we need to be able to fill in around partial writes. */
+ if (cifs_fscache_enabled(inode) && (oflags & O_ACCMODE) == O_WRONLY)
+ rdwr_for_fscache = 1;
+
#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
if (tcon->unix_ext && cap_unix(tcon->ses) && !tcon->broken_posix_open &&
(CIFS_UNIX_POSIX_PATH_OPS_CAP &
@@ -276,6 +281,8 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned
desired_access |= GENERIC_READ; /* is this too little? */
if (OPEN_FMODE(oflags) & FMODE_WRITE)
desired_access |= GENERIC_WRITE;
+ if (rdwr_for_fscache == 1)
+ desired_access |= GENERIC_READ;

disposition = FILE_OVERWRITE_IF;
if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
@@ -304,6 +311,7 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned
if (!tcon->unix_ext && (mode & S_IWUGO) == 0)
create_options |= CREATE_OPTION_READONLY;

+retry_open:
oparms = (struct cifs_open_parms) {
.tcon = tcon,
.cifs_sb = cifs_sb,
@@ -317,8 +325,15 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned
rc = server->ops->open(xid, &oparms, oplock, buf);
if (rc) {
cifs_dbg(FYI, "cifs_create returned 0x%x\n", rc);
+ if (rc == -EACCES && rdwr_for_fscache == 1) {
+ desired_access &= ~GENERIC_READ;
+ rdwr_for_fscache = 2;
+ goto retry_open;
+ }
goto out;
}
+ if (rdwr_for_fscache == 2)
+ cifs_invalidate_cache(inode, FSCACHE_INVAL_DIO_WRITE);

#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
/*
diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index 73573dadf90e..761a80963f76 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -521,12 +521,12 @@ cifs_mark_open_files_invalid(struct cifs_tcon *tcon)
*/
}

-static inline int cifs_convert_flags(unsigned int flags)
+static inline int cifs_convert_flags(unsigned int flags, int rdwr_for_fscache)
{
if ((flags & O_ACCMODE) == O_RDONLY)
return GENERIC_READ;
else if ((flags & O_ACCMODE) == O_WRONLY)
- return GENERIC_WRITE;
+ return rdwr_for_fscache == 1 ? (GENERIC_READ | GENERIC_WRITE) : GENERIC_WRITE;
else if ((flags & O_ACCMODE) == O_RDWR) {
/* GENERIC_ALL is too much permission to request
can cause unnecessary access denied on create */
@@ -663,11 +663,16 @@ static int cifs_nt_open(const char *full_path, struct inode *inode, struct cifs_
int create_options = CREATE_NOT_DIR;
struct TCP_Server_Info *server = tcon->ses->server;
struct cifs_open_parms oparms;
+ int rdwr_for_fscache = 0;

if (!server->ops->open)
return -ENOSYS;

- desired_access = cifs_convert_flags(f_flags);
+ /* If we're caching, we need to be able to fill in around partial writes. */
+ if (cifs_fscache_enabled(inode) && (f_flags & O_ACCMODE) == O_WRONLY)
+ rdwr_for_fscache = 1;
+
+ desired_access = cifs_convert_flags(f_flags, rdwr_for_fscache);

/*********************************************************************
* open flag mapping table:
@@ -704,6 +709,7 @@ static int cifs_nt_open(const char *full_path, struct inode *inode, struct cifs_
if (f_flags & O_DIRECT)
create_options |= CREATE_NO_BUFFER;

+retry_open:
oparms = (struct cifs_open_parms) {
.tcon = tcon,
.cifs_sb = cifs_sb,
@@ -715,8 +721,16 @@ static int cifs_nt_open(const char *full_path, struct inode *inode, struct cifs_
};

rc = server->ops->open(xid, &oparms, oplock, buf);
- if (rc)
+ if (rc) {
+ if (rc == -EACCES && rdwr_for_fscache == 1) {
+ desired_access = cifs_convert_flags(f_flags, 0);
+ rdwr_for_fscache = 2;
+ goto retry_open;
+ }
return rc;
+ }
+ if (rdwr_for_fscache == 2)
+ cifs_invalidate_cache(inode, FSCACHE_INVAL_DIO_WRITE);

/* TODO: Add support for calling posix query info but with passing in fid */
if (tcon->unix_ext)
@@ -1149,11 +1163,14 @@ int cifs_open(struct inode *inode, struct file *file)
use_cache:
fscache_use_cookie(cifs_inode_cookie(file_inode(file)),
file->f_mode & FMODE_WRITE);
- if (file->f_flags & O_DIRECT &&
- (!((file->f_flags & O_ACCMODE) != O_RDONLY) ||
- file->f_flags & O_APPEND))
- cifs_invalidate_cache(file_inode(file),
- FSCACHE_INVAL_DIO_WRITE);
+ //if ((file->f_flags & O_ACCMODE) == O_WRONLY)
+ // goto inval;
+ if (!(file->f_flags & O_DIRECT))
+ goto out;
+ if ((file->f_flags & (O_ACCMODE | O_APPEND)) == O_RDONLY)
+ goto out;
+//inval:
+ cifs_invalidate_cache(file_inode(file), FSCACHE_INVAL_DIO_WRITE);

out:
free_dentry_path(page);
@@ -1218,6 +1235,7 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
int disposition = FILE_OPEN;
int create_options = CREATE_NOT_DIR;
struct cifs_open_parms oparms;
+ int rdwr_for_fscache = 0;

xid = get_xid();
mutex_lock(&cfile->fh_mutex);
@@ -1281,7 +1299,11 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
}
#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */

- desired_access = cifs_convert_flags(cfile->f_flags);
+ /* If we're caching, we need to be able to fill in around partial writes. */
+ if (cifs_fscache_enabled(inode) && (cfile->f_flags & O_ACCMODE) == O_WRONLY)
+ rdwr_for_fscache = 1;
+
+ desired_access = cifs_convert_flags(cfile->f_flags, rdwr_for_fscache);

/* O_SYNC also has bit for O_DSYNC so following check picks up either */
if (cfile->f_flags & O_SYNC)
@@ -1293,6 +1315,7 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
if (server->ops->get_lease_key)
server->ops->get_lease_key(inode, &cfile->fid);

+retry_open:
oparms = (struct cifs_open_parms) {
.tcon = tcon,
.cifs_sb = cifs_sb,
@@ -1318,6 +1341,11 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
/* indicate that we need to relock the file */
oparms.reconnect = true;
}
+ if (rc == -EACCES && rdwr_for_fscache == 1) {
+ desired_access = cifs_convert_flags(cfile->f_flags, 0);
+ rdwr_for_fscache = 2;
+ goto retry_open;
+ }

if (rc) {
mutex_unlock(&cfile->fh_mutex);
@@ -1326,6 +1354,9 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
goto reopen_error_exit;
}

+ if (rdwr_for_fscache == 2)
+ cifs_invalidate_cache(inode, FSCACHE_INVAL_DIO_WRITE);
+
#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
reopen_success:
#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
diff --git a/fs/smb/client/fscache.h b/fs/smb/client/fscache.h
index a3d73720914f..1f2ea9f5cc9a 100644
--- a/fs/smb/client/fscache.h
+++ b/fs/smb/client/fscache.h
@@ -109,6 +109,11 @@ static inline void cifs_readahead_to_fscache(struct inode *inode,
__cifs_readahead_to_fscache(inode, pos, len);
}

+static inline bool cifs_fscache_enabled(struct inode *inode)
+{
+ return fscache_cookie_enabled(cifs_inode_cookie(inode));
+}
+
#else /* CONFIG_CIFS_FSCACHE */
static inline
void cifs_fscache_fill_coherency(struct inode *inode,
@@ -124,6 +129,7 @@ static inline void cifs_fscache_release_inode_cookie(struct inode *inode) {}
static inline void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update) {}
static inline struct fscache_cookie *cifs_inode_cookie(struct inode *inode) { return NULL; }
static inline void cifs_invalidate_cache(struct inode *inode, unsigned int flags) {}
+static inline bool cifs_fscache_enabled(struct inode *inode) { return false; }

static inline int cifs_fscache_query_occupancy(struct inode *inode,
pgoff_t first, unsigned int nr_pages,

Next message: David Howells: "[PATCH v6 12/15] cifs: Cut over to using netfslib"
Previous message: Alban Browaeys: "Re: [PATCH 1/3] phy: rockchip: emmc: Enable pulldown for strobe line"
In reply to: David Howells: "[PATCH v6 10/15] cifs: Implement netfslib hooks"
Next in thread: Naveen Mamindlapalli: "RE: [PATCH v6 11/15] cifs: When caching, try to open O_WRONLY file rdwr on server"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]