kernel/linux.git/fs/smb/client/link.c, branch linux-7.0.y

smb: client: use atomic_t for mnt_cifs_flags

2026-02-27T00:17:08+00:00

Use atomic_t for cifs_sb_info::mnt_cifs_flags as it's currently accessed locklessly and may be changed concurrently in mount/remount and reconnect paths. Signed-off-by: Paulo Alcantara (Red Hat) Reviewed-by: David Howells Cc: linux-cifs@vger.kernel.org Signed-off-by: Steve French

cifs: SMB1 split: Split SMB1 protocol defs into smb1pdu.h

2026-02-08T23:07:45+00:00

Split SMB1 protocol defs into smb1pdu.h. This should perhaps go in the common/ directory. Signed-off-by: David Howells cc: Steve French cc: Paulo Alcantara cc: Enzo Matsumiya cc: linux-cifs@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-kernel@vger.kernel.org Acked-by: Enzo Matsumiya Signed-off-by: Steve French

cifs: Add a tracepoint to log EIO errors

2025-12-05T23:11:43+00:00

Add a tracepoint to log EIO errors and give it the capacity to convey up to two integers of information. This is then wrapped with three functions: int smb_EIO(enum smb_eio_trace trace) int smb_EIO1(enum smb_eio_trace trace, unsigned long info) int smb_EIO2(enum smb_eio_trace trace, unsigned long info, unsigned long info2) depending on how many bits of info are desired to be logged with any particular trace. The functions all return -EIO and can be used in place of -EIO. The trace argument is an enum value that gets translated to a string when the trace is printed. This makes is easier to log EIO instances when the client is under high load than turning on a printk wrapper such as cifs_dbg(). Granted, EIO could have its own separate EIO printing since EIO shouldn't happen. Signed-off-by: David Howells Reviewed-by: Paulo Alcantara (Red Hat) cc: linux-cifs@vger.kernel.org cc: linux-fsdevel@vger.kernel.org Signed-off-by: Steve French

smb: client: Use MD5 library for M-F symlink hashing

2025-10-16T03:10:28+00:00

Convert parse_mf_symlink() and format_mf_symlink() to use the MD5 library instead of a "md5" crypto_shash. This is simpler and faster. With the library there's no need to allocate memory, no need to handle errors, and the MD5 code is accessed directly without inefficient indirect calls and other unnecessary API overhead. This also fixes an issue where these functions did not work on kernels booted in FIPS mode. The use of MD5 here is for data integrity rather than a security purpose, so it can use a non-FIPS-approved algorithm. Reviewed-by: Stefan Metzmacher Acked-by: Ard Biesheuvel Signed-off-by: Eric Biggers Signed-off-by: Steve French

smb: client: fix creating symlinks under POSIX mounts

2025-08-05T00:29:14+00:00

SMB3.1.1 POSIX mounts support native symlinks that are created with IO_REPARSE_TAG_SYMLINK reparse points, so skip the checking of FILE_SUPPORTS_REPARSE_POINTS as some servers might not have it set. Cc: linux-cifs@vger.kernel.org Cc: Ralph Boehme Cc: David Howells Cc: Reported-by: Matthew Richardson Closes: https://marc.info/?i=1124e7cd-6a46-40a6-9f44-b7664a66654b@ed.ac.uk Signed-off-by: Paulo Alcantara (Red Hat) Signed-off-by: Steve French

smb: client: set symlink type as native for POSIX mounts

2025-08-01T05:16:19+00:00

SMB3.1.1 POSIX mounts require symlinks to be created natively with IO_REPARSE_TAG_SYMLINK reparse point. Cc: linux-cifs@vger.kernel.org Cc: Ralph Boehme Cc: David Howells Cc: Reported-by: Matthew Richardson Closes: https://marc.info/?i=1124e7cd-6a46-40a6-9f44-b7664a66654b@ed.ac.uk Signed-off-by: Paulo Alcantara (Red Hat) Signed-off-by: Steve French

cifs: Add support for creating reparse points over SMB1

2025-07-27T22:43:08+00:00

SMB1 already supports querying reparse points and detecting types of symlink, fifo, socket, block and char. This change implements the missing part - ability to create a new reparse points over SMB1. This includes everything which SMB2+ already supports: - native SMB symlinks and sockets - NFS style of special files (symlinks, fifos, sockets, char/block devs) - WSL style of special files (symlinks, fifos, sockets, char/block devs) Attaching a reparse point to an existing file or directory is done via SMB1 SMB_COM_NT_TRANSACT/NT_TRANSACT_IOCTL/FSCTL_SET_REPARSE_POINT command and implemented in a new cifs_create_reparse_inode() function. This change introduce a new callback ->create_reparse_inode() which creates a new reperse point file or directory and returns inode. For SMB1 it is provided via that new cifs_create_reparse_inode() function. Existing reparse.c code was only slightly updated to call new protocol callback ->create_reparse_inode() instead of hardcoded SMB2+ function. This make the whole reparse.c code to work with every SMB dialect. The original callback ->create_reparse_symlink() is not needed anymore as the implementation of new create_reparse_symlink() function is dialect agnostic too. So the link.c code was updated to call that function directly (and not via callback). Signed-off-by: Pali Rohár Signed-off-by: Steve French

cifs: Fix querying and creating MF symlinks over SMB1

2025-04-01T06:54:17+00:00

Old SMB1 servers without CAP_NT_SMBS do not support CIFS_open() function and instead SMBLegacyOpen() needs to be used. This logic is already handled in cifs_open_file() function, which is server->ops->open callback function. So for querying and creating MF symlinks use open callback function instead of CIFS_open() function directly. This change fixes querying and creating new MF symlinks on Windows 98. Currently cifs_query_mf_symlink() is not able to detect MF symlink and cifs_create_mf_symlink() is failing with EIO error. Signed-off-by: Pali Rohár Signed-off-by: Steve French

cifs: Check if server supports reparse points before using them

2025-03-26T19:50:37+00:00

Do not attempt to query or create reparse point when server fs does not support it. This will prevent creating unusable empty object on the server. Signed-off-by: Pali Rohár Signed-off-by: Steve French

cifs: Add mount option -o symlink= for choosing symlink create type

2025-01-29T23:35:32+00:00

Currently Linux CIFS client creates a new symlink of the first flavor which is allowed by mount options, parsed in this order: -o (no)mfsymlinks, -o (no)sfu, -o (no)unix (+ its aliases) and -o reparse=[type]. Introduce a new mount option -o symlink= for explicitly choosing a symlink flavor. Possible options are: -o symlink=default - The default behavior, like before this change. -o symlink=none - Disallow creating a new symlinks -o symlink=native - Create as native SMB symlink reparse point -o symlink=unix - Create via SMB1 unix extension command -o symlink=mfsymlinks - Create as regular file of mfsymlinks format -o symlink=sfu - Create as regular system file of SFU format -o symlink=nfs - Create as NFS reparse point -o symlink=wsl - Create as WSL reparse point So for example specifying -o sfu,mfsymlinks,symlink=native will allow to parse symlinks also of SFU and mfsymlinks types (which are disabled by default unless mount option is explicitly specified), but new symlinks will be created under native SMB type (which parsing is always enabled). Signed-off-by: Pali Rohár Signed-off-by: Steve French