Fix macOS fsync error when saving SMB shared file #4016
Closed
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Correctly handle fcntl() failure when calling on unsupported storage systems (e.g. SMB network shared file). The current code only checks for ENOTTY but the OS actually returns ENOTSUP (45) when trying to save to a network shared file. Currently this incorrect handling leads to files not being properly fsync'ed and display a scary error to the user.
justinmk
added a commit
to justinmk/neovim
that referenced
this pull request
Feb 20, 2019
macOS: Try direct fsync() if F_FULLFSYNC fails. closes neovim#6725 ref vim/vim#4016 vim-patch:8.1.0957 > on macOS F_FULLFSYNC fails with ENOTSUP for unsupported storage systems > (e.g. SMB), though this is not documented in the Apple fcntl man page. libuv fixed this in v1.25.0: libuv/libuv@6fc797c
justinmk
added a commit
to justinmk/neovim
that referenced
this pull request
Feb 21, 2019
macOS: Try direct fsync() if F_FULLFSYNC fails. closes neovim#6725 ref vim/vim#4016 vim-patch:8.1.0957 > on macOS F_FULLFSYNC fails with ENOTSUP for unsupported storage systems > (e.g. SMB), though this is not documented in the Apple fcntl man page. libuv fixed this in v1.25.0: libuv/libuv@6fc797c
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Correctly handle fcntl() failure when calling on unsupported storage systems (e.g. SMB network shared file). The current code only checks for ENOTTY but the OS actually returns ENOTSUP (45) when trying to save to a network shared file. Currently this incorrect handling leads to files not being properly fsync'ed and display a scary error to the user.
Reproduce
To reproduce this case, on a Mac, just mount a shared SMB drive (from Windows). Then try to open a shared network file and save to it. You see see an error saying "E667: Fsync failed".
Notes
Annoyingly, both
ENOTTYandENOTSUPerror codes are not documented in the Applefcntlman page.Descriptions for
ENOTSUPcan be found here:This makes sense to me because the docs says
fcntlis only implemented for some filesystems so returningENOTSUPjust means you should usefsyncas a backup.An alternative is to simply not check error code and always try
fsyncas a backup.Related