[debbugs-tracker] bug#20595: closed (24.4; Data lost when modifying file on filesystem with no space left on device / disc full)

[GNU bug Tracking System]

Your message dated Fri, 29 May 2015 23:24:56 -0700
with message-id <address@hidden>
and subject line Re: 24.4; Data lost when modifying file on filesystem with no 
space left on device / disc full
has caused the debbugs.gnu.org bug report #20595,
regarding 24.4; Data lost when modifying file on filesystem with no space left 
on device / disc full
to be marked as done.

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-- 
20595: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=20595
GNU Bug Tracking System
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> --- Begin Message ---
>
>
>
> Subject: 
>
> 24.4; Data lost when modifying file on filesystem with no space left on device / disc full
>
>
>
>
> Date: 
>
> Sun, 17 May 2015 11:52:47 +0000
>
>
>
>
> I attempted to edit a file on the filesystem containing $HOME, with no
> space left (for non-root users).
>
> Filesystem           1B-blocks            Used Available Use% Mounted on
> /dev/sdb1      105,559,908,352 104,591,810,560         0 100% /home
>
> When I saved the file (C-x C-s) Emacs gave the error "Write error: no
> space left on device, /home", so I quit (C-x C-c), pressed "n" to not
> save the file, and "yes" to exit with a modified buffer.  I expected the
> original file to exist, but instead I have three zero-byte files:
>
> -rwx------ 1 matt users     0 2015-05-17 11:57 script~
> -rwxr-xr-x 1 matt users     0 2015-05-17 11:57 script
> -rwxr-xr-x 1 matt users     0 2015-05-17 11:58 #script#
>
> Example steps to reproduce:
>
> dd if=/dev/zero of=small bs=1M count=10
> mkfs.ext4 small
> sudo mount -o loop small /mnt
> sudo dd if=/dev/zero of=/mnt/85pc bs=1k count=8500
> man man | sudo tee /mnt/man > /dev/null
> sudo mkdir /mnt/.emacs.d
> sudo chown -R $USER /mnt
> HOME=/mnt emacs /mnt/man
>
> (Edit the file, attempt to save, then exit discarding changes.)
>
> ls -lAr /mnt
>
> /mnt:
> total 8,718,336
> -rw-r--r-- 1 matt root  8,704,000 2015-05-17 11:31 85pc
> drwxr-xr-x 2 matt root      1,024 2015-05-17 11:31 .emacs.d
> drwx------ 2 matt root     12,288 2015-05-17 11:31 lost+found
> -rw-r--r-- 1 matt root          0 2015-05-17 11:31 man
> -rw-r--r-- 1 matt users         0 2015-05-17 11:31 #man#
> -rw------- 1 matt users         0 2015-05-17 11:31 man~
>
> /mnt/.emacs.d:
> total 0
> -rw------- 1 matt users 0 2015-05-17 11:31 %backup%~
>
> I'd expect /mnt/man to be unchanged, or at minimum one of /mnt/man~ or
> ~/.emacs.d/%backup%~ to contain the original file's contents.
>
> Cheers,
>
> Matt
>
>
>
> In GNU Emacs 24.4.1 (arm-unknown-linux-gnueabihf)
>  of 2014-12-19 on henze, modified by Debian
> System Description:     Debian GNU/Linux 8.0 (jessie)
>
> Configured using:
>  `configure --build arm-linux-gnueabihf --prefix=/usr
>  --sharedstatedir=/var/lib --libexecdir=/usr/lib
>  --localstatedir=/var/lib --infodir=/usr/share/info
>  --mandir=/usr/share/man --with-pop=yes
>  
> --enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.4/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.4/site-lisp:/usr/share/emacs/site-lisp
>  --build arm-linux-gnueabihf --prefix=/usr --sharedstatedir=/var/lib
>  --libexecdir=/usr/lib --localstatedir=/var/lib
>  --infodir=/usr/share/info --mandir=/usr/share/man --with-pop=yes
>  
> --enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.4/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.4/site-lisp:/usr/share/emacs/site-lisp
>  --with-x=no --without-gconf --without-gsettings 'CFLAGS=-g -O2
>  -fstack-protector-strong -Wformat -Werror=format-security -Wall'
>  CPPFLAGS=-D_FORTIFY_SOURCE=2 LDFLAGS=-Wl,-z,relro'
>
> Important settings:
>   value of $LANG: en_GB.UTF-8
>   locale-coding-system: utf-8-unix
>
> Major mode: Fundamental
>
> Minor modes in effect:
>   tooltip-mode: t
>   electric-indent-mode: t
>   menu-bar-mode: t
>   file-name-shadow-mode: t
>   global-font-lock-mode: t
>   font-lock-mode: t
>   auto-composition-mode: t
>   auto-encryption-mode: t
>   auto-compression-mode: t
>   line-number-mode: t
>   transient-mark-mode: t
>
> Recent input:
> ESC [ > 0 ; 1 1 5 ; 0 c C-x C-f DEL DEL / t m p / x 
> DEL TAB TAB y RET C-x b RET RET C-x C-s C-x C-k RET 
> n C-x k RET y e s RET ESC x r e p - e - b TAB RET
>
> Recent messages:
> Loading 00debian-vars...done
> Loading /etc/emacs/site-start.d/50puppet-el.el (source)...done
> For information about GNU Emacs and the GNU system, type C-h C-a.
> Making completion list...
> Saving file /mnt/man...
> Cannot write backup file; backing up in ~/.emacs.d/%backup%~
> basic-save-buffer-2: Write error: no space left on device, /mnt/man
> No keyboard macro defined.  Create one? (y or n) n
> Quit
>
> Load-path shadows:
> /usr/share/emacs/24.4/site-lisp/debian-startup hides 
> /usr/share/emacs/site-lisp/debian-startup
> /usr/share/emacs/24.4/site-lisp/puppet-el/puppet-mode hides 
> /usr/share/emacs/site-lisp/puppet-mode
>
> Features:
> (shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
> mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
> gmm-utils mailheader sendmail regexp-opt rfc2047 rfc2045 ietf-drums
> mm-util help-fns mail-prsvr mail-utils edmacro cl-loaddefs cl-lib kmacro
> help-mode easymenu image xterm time-date tooltip electric uniquify
> ediff-hook vc-hooks lisp-float-type tabulated-list newcomment lisp-mode
> prog-mode register page menu-bar rfn-eshadow timer select mouse jit-lock
> font-lock syntax facemenu font-core frame cham georgian utf-8-lang
> misc-lang vietnamese tibetan thai tai-viet lao korean japanese hebrew
> greek romanian slovak czech european ethiopic indian cyrillic chinese
> case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer nadvice
> loaddefs button faces cus-face macroexp files text-properties overlay
> sha1 md5 base64 format env code-pages mule custom widget
> hashtable-print-readable backquote make-network-process dbusbind
> gfilenotify multi-tty emacs)
>
> Memory information:
> ((conses 8 76608 7488)
>  (symbols 24 17393 0)
>  (miscs 20 35 135)
>  (strings 16 10778 7177)
>  (string-bytes 1 311082)
>  (vectors 8 14096)
>  (vector-slots 4 1145426 57182)
>  (floats 8 65 408)
>  (intervals 28 226 29)
>  (buffers 512 13)
>  (heap 1024 7950 543))
>
>
>
> --- End Message ---

--- Begin Message --- Subject: Re: 24.4; Data lost when modifying file on filesystem with no space left on device / disc full Date: Fri, 29 May 2015 23:24:56 -0700 User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 Thank you for reporting this, and for the recipe for reproducing this important bug in Emacs. I installed the attached patches into the GNU Emacs master to fix the problem. The 1st patch doesn't actually fix the bug, but it fixes some related ones. The 2nd patch fixes the bug -- at least, it worked for me on your test case. I generated the 2nd patch with "diff -b" so its indenting won't match the source code; you can pick up the full gory details in savannah git master, around commit ab27722721afca4647a7eec0933ac9209e0eac30.

0001-copy-file-now-truncates-output-after-writing.patch
Description: Text Data

bugfix.patch
Description: Text Data

--- End Message ---