Wiki code for Heads Up: File system framework changes (supplement to CIFS' "head's up")

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1: == Heads Up: File system framework changes (supplement to CIFS’ "head’s up")
2: 
3: {{{
4: 
5: Date: Fri, 26 Oct 2007 16:08:58 -0500
6: From: Rich Brown <Rich.Brown at Sun dot COM>
7: To: onnv-gate at onnv dot eng dot sun dot com, on-all at eng dot sun dot com
8: Subject: Heads Up: File system framework changes (supplement to CIFS’ "head’s up")
9: 
10: If you don’t know what a VOP is and will never, ever make a change
11: to a kernel file that uses the vfs/vnode interface, then feel free
12: to delete this.
13: 
14: Yesterday’s CIFS putback
15: 
16:          6617183 CIFS Service - PSARC 2006/715
17: 
18: introduced several changes to the file system framework in Solaris.  The
19: following outlines the changes and the corresponding PSARC cases.
20: 
21: For further details, please see the mail and spec files in the PSARC case
22: directories:
23: 
24:    http://http://opensolaris.org/os/community/arc/caselog/2007/{insert-case-number}
25: 
26: If you have additional questions, please send them to cifs-vfs-team at sun dot com
27: 
28: PSARC 2007/218 caller_context_t in all VOPs
29: 
30:          *All* vnode operations now pass a pointer to caller_context_t.
31:          These are primarily used by File Event Monitors (FEM) however
32:          the file system is responsible for passing any caller_context_t
33:          parameters to subsequent VOP calls.
34: 
35: PSARC 2007/227 VFS Feature Registration and ACL on Create
36: 
37:          There are three significant parts to this:
38: 
39:          - VFS structures are now allocated using vfs_alloc() and vfs_free().
40:            Note that the last VFS_RELE()/vfs_rele() calls vfs_free() when
41:            the last reference is removed.
42: 
43:          - VOP_CREATE() and VOP_MKDIR() now take an optional pointer to a
44:            vsecattr_t.  This allows the caller to set an ACL on create.
45: 
46:          - We now have a "feature registration" facility for the various
47:            behaviors that a file system can support.  These are typically
48:            set by a file system at mount time and is checked in the fop
49:            layer to verify that the file system supports the requested
50:            feature (e.g., case-insensitive behavior).  It has a very
51:            simple interface:
52: 
53:                  /* Register a feature in the vfs */
54:                  void vfs_set_feature(vfs_t *vfsp, vfs_feature_t feature)
55: 
56:                  /*
57:                   * Query a vfs for a feature.
58:                   * Returns 1 if feature is present, 0 if not
59:                   */
60:                  int vfs_has_feature(vfs_t *vfsp, vfs_feature_t feature)
61: 
62:            The current list of features (see following PSARC cases) are:
63: 
64:                  VFSFT_XVATTR            /* Supports xvattr for attrs */
65:                  VFSFT_CASEINSENSITIVE   /* Supports case-insensitive */
66:                  VFSFT_NOCASESENSITIVE   /* NOT case-sensitive */
67:                  VFSFT_DIRENTFLAGS       /* Supports dirent flags */
68:                  VFSFT_ACLONCREATE       /* Supports ACL on create */
69:                  VFSFT_ACEMASKONACCESS   /* Can use ACEMASK for access */
70: 
71: PSARC 2007/244 ZFS case-insensitive support
72: 
73:          This case covers the changes at vnode/vfs interface level as
74:          well as the ZFS level to support case-insensitive behavior:
75: 
76:          - The following vnode operations take a new flag, FIGNORECASE
77:            (in file.h) to request case-insensitive behavior: VOP_CREATE,
78:            VOP_REMOVE, VOP_LINK, VOP_RENAME, VOP_MKDIR, VOP_RMDIR,
79:            VOP_SYMLINK.
80: 
81:            If the file system does not support the requested behavior
82:            then EINVAL is returned by the appropriate fop-level routine.
83: 
84:          - VOP_READDIR takes a new flag, V_RDDIR_ENTFLAGS to request
85:            that the directory information be retrieved in edirent_t
86:            format.  The edirent_t structure adds directory entry flags
87:            which may contain ED_CASE_CONFLICT.  This means that case-
88:            insensitive conflict exists.  See sys/extdirent.h.
89: 
90:            If the file system does not support the requested behavior
91:            then EINVAL is returned by the fop_readdir().
92: 
93:          - pathconf(2) has new a variable which describes case behavior:
94:            _PC_CASE_BEHAVIOR.  It can take the following values:
95:            _CASE_SENSITIVE and _CASE_INSENSITIVE.
96: 
97: PSARC 2007/268 Support for CIFS share reservations
98: 
99:          New flags for share reservations (see sys/fcntl.h):
100:                  F_RMACC (for f_access) specifies "delete share access"
101:                  F_RMDNY (for f_deny) specifies "deny delete share access"
102: 
103: PSARC 2007/315 Extensible Attribute Interfaces
104: 
105:          This case adds optional, extensible system attributes.  The
106:          VOP_GETATTR/VOP_SETATTR interface can support an xvattr_t
107:          structure which is a superset of the vattr_t structure.  If
108:          AT_XVATTR is set in the va_mask field, then the structure is
109:          really an xvattr_t structure.
110: 
111:          The following new attributes have been added to ZFS:
112: 
113:          CREATETIME      /* Create time of file */
114:          ARCHIVE         /* Archive */
115:          SYSTEM          /* System */
116:          READONLY        /* Readonly */
117:          HIDDEN          /* Hidden */
118:          NOUNLINK        /* Nounlink */
119:          IMMUTABLE       /* immutable */
120:          APPENDONLY      /* appendonly */
121:          NODUMP          /* nodump */
122:          AV_QUARANTINED  /* anti-virus quarantine */
123:          AV_MODIFIED     /* anti-virus modified */
124: 
125:          For more details, see "spec.final.txt" in the case directory.
126: 
127: PSARC 2007/403 Modified Access Checks for CIFS
128: 
129:          - VOP_ACCESS() can now take V_APPEND in its ’flags’ field
130:            to check for ACE-enforced append-only access to a vnode.
131: 
132:          - VOP_ACCESS() can now take V_ACE_MASK in its ’flags’ field
133:            which informs the implementation to treat the ’mode’
134:            parameter as a 32 bit ACE-style access mask.
135: 
136:          - ATTR_NOACLCHECK can be passed in the flags field of vnode
137:            operations that retrieve/modify attributes and ACLs.  This
138:            prevents ACL checks from being performed when the caller has
139:            already been granted the permission to perform the operation
140:            on the vnode.
141: 
142: PSARC 2007/440 nbmand changes for CIFS Service
143: 
144:          - Change nbmand file rename/remove share violation checks.
145:          - Adds F_MDACC to support for meta data access with nbmand
146:          - Do not allow nbmand mount option state to change on remount.
147: 
148: }}}
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