Link back open deleted files - a working solution
Hi (and happy new year). I've had this idea ever since someone asked about this situation on this forum a few months ago: Considering that you have a long running process writing stuff into a large file, and you accidentally delete that file. You can still access the file's content through /proc/pid/fd/fd and that's basically the suggestion he was given (cp /proc... new file), but the limitations of this solution are: 1. It will loose any changes made to the deleted file after the copy. 2. It creates another copy of the data (could be a problem if there isn't enough space on any partition). My solution (available in http://sourceforge.net/projects/fdlink) is to enable the user to link back the deleted file to a new name on the same filesystem as the deleted file. The solution involves as small kernel module and a simple program which calls ioctl(2) on the special device created by that module. The idea is that if someone finds themselves in that situation they should be able to install that module and use it without having to reboot the system (and thus loosing the whole point of it). I have a couple of enhancement that I'm waiting to find time to implement: 1. Update the symlink content under fd/fd to point to the new file name. 2. Implement this as a system call and offer this to be included in 2.6 The module was tested under Debian 2.6.18 and later on x86_64. Any comments/suggestions/contributions are welcome. Cheers, --Amos
Re: Link back open deleted files - a working solution
Can it link back a loopmounted filesystem? On 9/13/07, Amos Shapira [EMAIL PROTECTED] wrote: Hi (and happy new year). I've had this idea ever since someone asked about this situation on this forum a few months ago: Considering that you have a long running process writing stuff into a large file, and you accidentally delete that file. You can still access the file's content through /proc/pid/fd/fd and that's basically the suggestion he was given (cp /proc... new file), but the limitations of this solution are: 1. It will loose any changes made to the deleted file after the copy. 2. It creates another copy of the data (could be a problem if there isn't enough space on any partition). My solution (available in http://sourceforge.net/projects/fdlink) is to enable the user to link back the deleted file to a new name on the same filesystem as the deleted file. The solution involves as small kernel module and a simple program which calls ioctl(2) on the special device created by that module. The idea is that if someone finds themselves in that situation they should be able to install that module and use it without having to reboot the system (and thus loosing the whole point of it). I have a couple of enhancement that I'm waiting to find time to implement: 1. Update the symlink content under fd/fd to point to the new file name. 2. Implement this as a system call and offer this to be included in 2.6 The module was tested under Debian 2.6.18 and later on x86_64. Any comments/suggestions/contributions are welcome. Cheers, --Amos = To unsubscribe, send mail to [EMAIL PROTECTED] with the word unsubscribe in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
Re: Link back open deleted files - a working solution
On 13/09/2007, Alon Altman [EMAIL PROTECTED] wrote: Can it link back a loopmounted filesystem? I started testing then realized why you ask :), I now have a mounted image which I can't get rid off, ah well. a) If you can find a way to get a file descriptor to the mounted image then it'll work as-is. b) If you can find a way to point to the mounted image's dentry then I can possibly tweak it to add a link to that dentry. So far I couldn't find a way to achieve (a), I'm trying to look at (b) for a few minutes now. --Amos
Re: Link back open deleted files - a working solution
Here is similar solution: http://sourceforge.net/projects/vfs-undelete/ -- Constantine = To unsubscribe, send mail to [EMAIL PROTECTED] with the word unsubscribe in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
Re: Link back open deleted files - a working solution
Constantine Shulyupin wrote: Here is similar solution: http://sourceforge.net/projects/vfs-undelete/ this looks like a dead link there's nothing to download yet, and when browsing via CVS, i only see empty directories, no files. am i missing something? it looks as if there were files there in CVS in the past - but someone deleted all of them --guy -- Constantine = To unsubscribe, send mail to [EMAIL PROTECTED] with the word unsubscribe in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED] = To unsubscribe, send mail to [EMAIL PROTECTED] with the word unsubscribe in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
Re: Link back open deleted files - a working solution
On 13/09/2007, guy keren [EMAIL PROTECTED] wrote: Constantine Shulyupin wrote: Here is similar solution: http://sourceforge.net/projects/vfs-undelete/ Yes indeed, it looks like its purpose is identical to fdlink's, though they have much more code around the plain ioctl I provide, maybe because they started with 2.4 and moved to 2.6 (according to the comit logs on the kernel mode file). In case it's not clear - my code works and ready for used by anyone, just do a make; insmod flink_dev.ko and you area ready to use the provided flinkapp, I don't know about theirs. this looks like a dead link there's nothing to download yet, and when browsing via CVS, i only see empty directories, no files. am i missing something? it looks as if there were files there in CVS in the past - but someone deleted all of them You can click on the dead files link to see the deleted files. --Amos
Re: Link back open deleted files - a working solution
I'll talk with author of the utility On 9/14/07, guy keren [EMAIL PROTECTED] wrote: Amos Shapira wrote: On 13/09/2007, *guy keren* [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: Constantine Shulyupin wrote: Here is similar solution: http://sourceforge.net/projects/vfs-undelete/ Yes indeed, it looks like its purpose is identical to fdlink's, though they have much more code around the plain ioctl I provide, maybe because they started with 2.4 and moved to 2.6 (according to the comit logs on the kernel mode file). In case it's not clear - my code works and ready for used by anyone, just do a make; insmod flink_dev.ko and you area ready to use the provided flinkapp, I don't know about theirs. this looks like a dead link there's nothing to download yet, and when browsing via CVS, i only see empty directories, no files. am i missing something? it looks as if there were files there in CVS in the past - but someone deleted all of them You can click on the dead files link to see the deleted files. i did, at least on one of the kernel source files. it came out empty... --guy = To unsubscribe, send mail to [EMAIL PROTECTED] with the word unsubscribe in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED] -- Constantine Shulyupin Freelance Embedded Linux Engineer 054-4234440 http://www.linuxdriver.co.il/ = To unsubscribe, send mail to [EMAIL PROTECTED] with the word unsubscribe in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
Re: Link back open deleted files - a working solution
Amos Shapira wrote: On 13/09/2007, *guy keren* [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: Constantine Shulyupin wrote: Here is similar solution: http://sourceforge.net/projects/vfs-undelete/ Yes indeed, it looks like its purpose is identical to fdlink's, though they have much more code around the plain ioctl I provide, maybe because they started with 2.4 and moved to 2.6 (according to the comit logs on the kernel mode file). In case it's not clear - my code works and ready for used by anyone, just do a make; insmod flink_dev.ko and you area ready to use the provided flinkapp, I don't know about theirs. this looks like a dead link there's nothing to download yet, and when browsing via CVS, i only see empty directories, no files. am i missing something? it looks as if there were files there in CVS in the past - but someone deleted all of them You can click on the dead files link to see the deleted files. i did, at least on one of the kernel source files. it came out empty... --guy = To unsubscribe, send mail to [EMAIL PROTECTED] with the word unsubscribe in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
