diff options
| author | Rajasi Mandal <rajasimandal@microsoft.com> | 2025-11-18 02:26:55 +0000 |
|---|---|---|
| committer | Steve French <stfrench@microsoft.com> | 2025-12-03 23:32:44 -0600 |
| commit | 1ef15fbe6771119dc1d3bd4ed201100cfacb842e (patch) | |
| tree | 3bd045af59431bad738f14c6022e66f2be3a08ca /fs | |
| parent | 869737543b39a145809c41a7253c6ee777e22729 (diff) | |
| download | tip-1ef15fbe6771119dc1d3bd4ed201100cfacb842e.tar.gz | |
cifs: client: enforce consistent handling of multichannel and max_channels
Previously, the behavior of the multichannel and max_channels mount
options was inconsistent and order-dependent. For example, specifying
"multichannel,max_channels=1" would result in 2 channels, while
"max_channels=1,multichannel" would result in 1 channel. Additionally,
conflicting combinations such as "nomultichannel,max_channels=3" or
"multichannel,max_channels=1" did not produce errors and could lead to
unexpected channel counts.
This commit introduces two new fields in smb3_fs_context to explicitly
track whether multichannel and max_channels were specified during
mount. The option parsing and validation logic is updated to ensure:
- The outcome is no longer dependent on the order of options.
- Conflicting combinations (e.g., "nomultichannel,max_channels=3" or
"multichannel,max_channels=1") are detected and result in an error.
- The number of channels created is consistent with the specified
options.
This improves the reliability and predictability of mount option
handling for SMB3 multichannel support.
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Rajasi Mandal <rajasimandal@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/smb/client/cifsfs.c | 1 | ||||
| -rw-r--r-- | fs/smb/client/fs_context.c | 65 | ||||
| -rw-r--r-- | fs/smb/client/fs_context.h | 2 |
3 files changed, 50 insertions, 18 deletions
diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c index 6eccb9ed9daa38..71801d6bd4656b 100644 --- a/fs/smb/client/cifsfs.c +++ b/fs/smb/client/cifsfs.c @@ -1016,7 +1016,6 @@ cifs_smb3_do_mount(struct file_system_type *fs_type, } else { cifs_info("Attempting to mount %s\n", old_ctx->source); } - cifs_sb = kzalloc(sizeof(*cifs_sb), GFP_KERNEL); if (!cifs_sb) return ERR_PTR(-ENOMEM); diff --git a/fs/smb/client/fs_context.c b/fs/smb/client/fs_context.c index 2a0d8b87bd8ea8..a966c6a8b1f5bf 100644 --- a/fs/smb/client/fs_context.c +++ b/fs/smb/client/fs_context.c @@ -711,6 +711,47 @@ smb3_parse_devname(const char *devname, struct smb3_fs_context *ctx) return 0; } +static int smb3_handle_conflicting_options(struct fs_context *fc) +{ + struct smb3_fs_context *ctx = smb3_fc2context(fc); + + if (ctx->multichannel_specified) { + if (ctx->multichannel) { + if (!ctx->max_channels_specified) { + ctx->max_channels = 2; + } else if (ctx->max_channels == 1) { + cifs_errorf(fc, + "max_channels must be greater than 1 when multichannel is enabled\n"); + return -EINVAL; + } + } else { + if (!ctx->max_channels_specified) { + ctx->max_channels = 1; + } else if (ctx->max_channels > 1) { + cifs_errorf(fc, + "max_channels must be equal to 1 when multichannel is disabled\n"); + return -EINVAL; + } + } + } else { + if (ctx->max_channels_specified) { + if (ctx->max_channels > 1) + ctx->multichannel = true; + else + ctx->multichannel = false; + } else { + ctx->multichannel = false; + ctx->max_channels = 1; + } + } + + //resetting default values as remount doesn't initialize fs_context again + ctx->multichannel_specified = false; + ctx->max_channels_specified = false; + + return 0; +} + static void smb3_fs_context_free(struct fs_context *fc); static int smb3_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *param); @@ -784,6 +825,7 @@ static int smb3_fs_context_parse_monolithic(struct fs_context *fc, if (ret < 0) break; } + ret = smb3_handle_conflicting_options(fc); return ret; } @@ -1250,15 +1292,11 @@ static int smb3_fs_context_parse_param(struct fs_context *fc, ctx->nodelete = 1; break; case Opt_multichannel: - if (result.negated) { + ctx->multichannel_specified = true; + if (result.negated) ctx->multichannel = false; - ctx->max_channels = 1; - } else { + else ctx->multichannel = true; - /* if number of channels not specified, default to 2 */ - if (ctx->max_channels < 2) - ctx->max_channels = 2; - } break; case Opt_uid: ctx->linux_uid = result.uid; @@ -1394,15 +1432,13 @@ static int smb3_fs_context_parse_param(struct fs_context *fc, ctx->max_credits = result.uint_32; break; case Opt_max_channels: + ctx->max_channels_specified = true; if (result.uint_32 < 1 || result.uint_32 > CIFS_MAX_CHANNELS) { cifs_errorf(fc, "%s: Invalid max_channels value, needs to be 1-%d\n", __func__, CIFS_MAX_CHANNELS); goto cifs_parse_mount_err; } ctx->max_channels = result.uint_32; - /* If more than one channel requested ... they want multichan */ - if (result.uint_32 > 1) - ctx->multichannel = true; break; case Opt_max_cached_dirs: if (result.uint_32 < 1) { @@ -1820,13 +1856,6 @@ static int smb3_fs_context_parse_param(struct fs_context *fc, goto cifs_parse_mount_err; } - /* - * Multichannel is not meaningful if max_channels is 1. - * Force multichannel to false to ensure consistent configuration. - */ - if (ctx->multichannel && ctx->max_channels == 1) - ctx->multichannel = false; - return 0; cifs_parse_mount_err: @@ -1913,6 +1942,8 @@ int smb3_init_fs_context(struct fs_context *fc) /* default to no multichannel (single server connection) */ ctx->multichannel = false; + ctx->multichannel_specified = false; + ctx->max_channels_specified = false; ctx->max_channels = 1; ctx->backupuid_specified = false; /* no backup intent for a user */ diff --git a/fs/smb/client/fs_context.h b/fs/smb/client/fs_context.h index b0fec6b9a23b4f..7af7cbbe420884 100644 --- a/fs/smb/client/fs_context.h +++ b/fs/smb/client/fs_context.h @@ -294,6 +294,8 @@ struct smb3_fs_context { bool domainauto:1; bool rdma:1; bool multichannel:1; + bool multichannel_specified:1; /* true if user specified multichannel or nomultichannel */ + bool max_channels_specified:1; /* true if user specified max_channels */ bool use_client_guid:1; /* reuse existing guid for multichannel */ u8 client_guid[SMB2_CLIENT_GUID_SIZE]; |