--- title: Provenance Time Proposed As A New Timestamp For Linux description: A new Linux kernel timestamp called provenance time, or 'ptime', has been proposed to track a file's original creation date across file-system boundaries.... canonical: https://daily.dev/posts/provenance-time-proposed-as-a-new-timestamp-for-linux-aim79esjp twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Provenance Time Proposed As A New Timestamp For Linux | daily.dev og:description: A new Linux kernel timestamp called provenance time, or 'ptime', has been proposed to track a file's original creation date across file-system boundaries.... og:url: https://daily.dev/posts/provenance-time-proposed-as-a-new-timestamp-for-linux-aim79esjp og:image: https://api.daily.dev/og/posts/aiM79ESJP.png og:image:alt: Provenance Time Proposed As A New Timestamp For Linux og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Provenance Time Proposed As A New Timestamp For Linux **[Phoronix](https://daily.dev/sources/phoronix)** · 2 min read · 0 upvotes · 0 comments ## Summary A new Linux kernel timestamp called provenance time, or 'ptime', has been proposed to track a file's original creation date across file-system boundaries. Unlike birth time, ptime is user-settable so it can be preserved for backups, filesystem conversions, and archives. It matches btime on a newly created file and is preserved whenever mtime is preserved. Request-for-comments patches add ptime to the kernel VFS layer with an initial Btrfs implementation, plus proof-of-concept Coreutils patches for 'stat' and 'cp'. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is the proposed 'ptime' timestamp in the Linux kernel and how is it different from birth time? Provenance time ('ptime') is a proposed Linux kernel timestamp that tracks when a file's contents were originally created, even after the file is copied across filesystems. Unlike birth time, which resets to the copy date, ptime is user-settable and preserved whenever mtime is preserved, matching btime only on a newly created file. For example, a '.zsh_history' file created in 2019 keeps a 2019 ptime even after being copied to a new filesystem, while its btime reflects the copy date. _Developers tracking Linux VFS changes like this follow kernel RFCs on daily.dev before they land._ ### Which filesystem has an initial implementation of the Linux ptime proposal? Btrfs has an initial implementation in the request-for-comments patches submitted for the provenance time proposal. The patches also add ptime support to the Linux kernel VFS layer, plus proof-of-concept Coreutils patches enabling ptime usage with the 'stat' and 'cp' commands. _Keep up with early filesystem RFCs like this on daily.dev before they reach mainline kernels._ ## Similar posts on daily.dev - [Linux 2026 "Spring Cleaning" To Address Some Code Remnants As Far Back As Linux v0.1](https://daily.dev/posts/linux-2026-spring-cleaning-to-address-some-code-remnants-as-far-back-as-linux-v0-1-qwelpqswb) · Phoronix · 0 upvotes · 0 comments - [The fastest Linux timestamps · hmpc](https://daily.dev/posts/the-fastest-linux-timestamps-hmpc-evqoy4ob7) · Lobsters · 0 upvotes · 0 comments - [How a 40-Line Fix Eliminated a 400x Performance Gap](https://daily.dev/posts/how-a-40-line-fix-eliminated-a-400x-performance-gap-knjx43zh3) · Hacker News · 1 upvotes · 0 comments - [One Giant Leap: 95% Less Sampling Cost](https://daily.dev/posts/one-giant-leap-95-less-sampling-cost-knpvkaex9) · Inside Java · 0 upvotes · 0 comments --- Tags: [#open-source](https://daily.dev/tags/open-source), [#linux](https://daily.dev/tags/linux), [#filesystems](https://daily.dev/tags/filesystems) [View this post on daily.dev](https://daily.dev/posts/provenance-time-proposed-as-a-new-timestamp-for-linux-aim79esjp) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Provenance Time Proposed As A New Timestamp For Linux","url":"https://daily.dev/posts/provenance-time-proposed-as-a-new-timestamp-for-linux-aim79esjp","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/provenance-time-proposed-as-a-new-timestamp-for-linux-aim79esjp"},"datePublished":"2026-10-28T12:33:31.612Z","dateModified":"2026-10-28T14:58:44.015Z","description":"A new Linux kernel timestamp called provenance time, or 'ptime', has been proposed to track a file's original creation date across file-system boundaries....","image":"https://media.daily.dev/image/upload/s--0_ODbtD2--/f_auto/v1722860399/public/Placeholder%2008","thumbnailUrl":"https://media.daily.dev/image/upload/s--0_ODbtD2--/f_auto/v1722860399/public/Placeholder%2008","isAccessibleForFree":true,"articleSection":"Phoronix","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Phoronix","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/6a26ba379dd64932830aa0c9803dd7ee","url":"https://daily.dev/sources/phoronix"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/provenance-time-proposed-as-a-new-timestamp-for-linux-aim79esjp","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"open-source,linux,filesystems","timeRequired":"PT2M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Phoronix","item":"https://daily.dev/sources/phoronix"},{"@type":"ListItem","position":3,"name":"Provenance Time Proposed As A New Timestamp For Linux"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/provenance-time-proposed-as-a-new-timestamp-for-linux-aim79esjp#faq","mainEntity":[{"@type":"Question","name":"What is the proposed 'ptime' timestamp in the Linux kernel and how is it different from birth time?","acceptedAnswer":{"@type":"Answer","text":"Provenance time ('ptime') is a proposed Linux kernel timestamp that tracks when a file's contents were originally created, even after the file is copied across filesystems. Unlike birth time, which resets to the copy date, ptime is user-settable and preserved whenever mtime is preserved, matching btime only on a newly created file. For example, a '.zsh_history' file created in 2019 keeps a 2019 ptime even after being copied to a new filesystem, while its btime reflects the copy date. Developers tracking Linux VFS changes like this follow kernel RFCs on daily.dev before they land."}},{"@type":"Question","name":"Which filesystem has an initial implementation of the Linux ptime proposal?","acceptedAnswer":{"@type":"Answer","text":"Btrfs has an initial implementation in the request-for-comments patches submitted for the provenance time proposal. The patches also add ptime support to the Linux kernel VFS layer, plus proof-of-concept Coreutils patches enabling ptime usage with the 'stat' and 'cp' commands. Keep up with early filesystem RFCs like this on daily.dev before they reach mainline kernels."}}]} ```