diff options
Diffstat (limited to 'man7/xattr.7')
| -rw-r--r-- | man7/xattr.7 | 30 |
1 files changed, 15 insertions, 15 deletions
diff --git a/man7/xattr.7 b/man7/xattr.7 index c2f12c9..c90aaf8 100644 --- a/man7/xattr.7 +++ b/man7/xattr.7 @@ -6,7 +6,7 @@ .\" .\" SPDX-License-Identifier: GPL-2.0-or-later .\" -.TH xattr 7 2023-02-05 "Linux man-pages 6.05.01" +.TH xattr 7 2023-10-31 "Linux man-pages 6.7" .SH NAME xattr \- Extended attributes .SH DESCRIPTION @@ -15,7 +15,7 @@ files and directories, similar to the environment strings associated with a process. An attribute may be defined or undefined. If it is defined, its value may be empty or non-empty. -.PP +.P Extended attributes are extensions to the normal attributes which are associated with all inodes in the system (i.e., the .BR stat (2) @@ -23,11 +23,11 @@ data). They are often used to provide additional functionality to a filesystem\[em]for example, additional security features such as Access Control Lists (ACLs) may be implemented using extended attributes. -.PP +.P Users with search access to a file or directory may use .BR listxattr (2) to retrieve a list of attribute names defined for that file or directory. -.PP +.P Extended attributes are accessed as atomic objects. Reading .RB ( getxattr (2)) @@ -35,7 +35,7 @@ retrieves the whole value of an attribute and stores it in a buffer. Writing .RB ( setxattr (2)) replaces any previous value with the new value. -.PP +.P Space consumed for extended attributes may be counted towards the disk quotas of the file owner and file group. .SS Extended attribute namespaces @@ -48,14 +48,14 @@ form, for example, .IR system.posix_acl_access , or .IR security.selinux . -.PP +.P The namespace mechanism is used to define different classes of extended attributes. These different classes exist for several reasons; for example, the permissions and capabilities required for manipulating extended attributes of one namespace may differ to another. -.PP +.P Currently, the .IR security , .IR system , @@ -97,7 +97,7 @@ The access permissions for user attributes are defined by the file permission bits: read permission is required to retrieve the attribute value, and writer permission is required to change it. -.PP +.P The file permission bits of regular files and directories are interpreted differently from the file permission bits of special files and symbolic links. @@ -108,7 +108,7 @@ The file permissions of symbolic links are not used in access checks. These differences would allow users to consume filesystem resources in a way not controllable by disk quotas for group or world writable special files and directories. -.PP +.P For this reason, user extended attributes are allowed only for regular files and directories, and access to user extended attributes is restricted to the @@ -125,26 +125,26 @@ The list of attribute names that can be returned is also limited to 64\ kB (see BUGS in .BR listxattr (2)). -.PP +.P Some filesystems, such as Reiserfs (and, historically, ext2 and ext3), require the filesystem to be mounted with the .B user_xattr mount option in order for user extended attributes to be used. -.PP +.P In the current ext2, ext3, and ext4 filesystem implementations, the total bytes used by the names and values of all of a file's extended attributes must fit in a single filesystem block (1024, 2048 or 4096 bytes, depending on the block size specified when the filesystem was created). -.PP +.P In the Btrfs, XFS, and Reiserfs filesystem implementations, there is no practical limit on the number of extended attributes associated with a file, and the algorithms used to store extended attribute information on disk are scalable. -.PP +.P In the JFS, XFS, and Reiserfs filesystem implementations, the limit on bytes used in an EA value is the ceiling imposed by the VFS. -.PP +.P In the Btrfs filesystem implementation, the total bytes used for the name, value, and implementation overhead bytes is limited to the filesystem @@ -158,7 +158,7 @@ Since the filesystems on which extended attributes are stored might also be used on architectures with a different byte order and machine word size, care should be taken to store attribute values in an architecture-independent format. -.PP +.P This page was formerly named .BR attr (5). .\" .SH AUTHORS |