diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/libc/gen/getvfsbyname.3 | 3 | ||||
| -rw-r--r-- | lib/libc/sys/write.2 | 20 |
2 files changed, 22 insertions, 1 deletions
diff --git a/lib/libc/gen/getvfsbyname.3 b/lib/libc/gen/getvfsbyname.3 index 9365d043a1fc..19fa12419353 100644 --- a/lib/libc/gen/getvfsbyname.3 +++ b/lib/libc/gen/getvfsbyname.3 @@ -27,7 +27,7 @@ .\" .\" @(#)kvm_getvfsbyname.3 8.3 (Berkeley) 5/4/95 .\" -.Dd August 16, 2018 +.Dd October 28, 2025 .Dt GETVFSBYNAME 3 .Os .Sh NAME @@ -104,6 +104,7 @@ argument specifies a file system that is unknown or not configured in the kernel. .El .Sh SEE ALSO +.Xr lsvfs 1 , .Xr jail 2 , .Xr mount 2 , .Xr sysctl 3 , diff --git a/lib/libc/sys/write.2 b/lib/libc/sys/write.2 index adf60aa91d7a..2f0a9d034038 100644 --- a/lib/libc/sys/write.2 +++ b/lib/libc/sys/write.2 @@ -134,6 +134,26 @@ and may write fewer bytes than requested; the return value must be noted, and the remainder of the operation should be retried when possible. +.Sh ATOMICITY OF WRITES +When operating on regular files on local file systems, the effects of +.Fn write +are atomic. +As required by the POSIX standard, +the +.Fn read , +.Fn write , +and +.Fn ftruncate +functions and their variations are atomic with respect to +each other on the file data and metadata for regular files. +See for instance +.St -p1003.1-2024 +Volume 2, Section 2.9.7 for more information. +.Pp +.Fx +implements the requirement by taking +a read/write range lock on the file byte range +affected by the corresponding function. .Sh RETURN VALUES Upon successful completion the number of bytes which were written is returned. |