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From: Ramsay Jones <ramsay@ramsay1•demon.co.uk>
To: Michael Haggerty <mhagger@alum•mit.edu>,
	Junio C Hamano <gitster@pobox•com>
Cc: git@vger•kernel.org
Subject: Re: [PATCH 4/5] safe_create_leading_directories(): fix a mkdir/rmdir race
Date: Sun, 22 Dec 2013 22:42:55 +0000	[thread overview]
Message-ID: <52B76AEF.70200@ramsay1.demon.co.uk> (raw)
In-Reply-To: <1387696451-32224-5-git-send-email-mhagger@alum.mit.edu>

On 22/12/13 07:14, Michael Haggerty wrote:
> It could be that some other process is trying to clean up empty
> directories at the same time that safe_create_leading_directories() is
> attempting to create them.  In this case, it could happen that
> directory "a/b" was present at the end of one iteration of the loop
> (either it was already present or we just created it ourselves), but
> by the time we try to create directory "a/b/c", directory "a/b" has
> been deleted.  In fact, directory "a" might also have been deleted.
> 
> So, if a call to mkdir() fails with ENOENT, then try checking/making
> all directories again from the beginning.  Attempt up to three times
> before giving up.
> 
> Signed-off-by: Michael Haggerty <mhagger@alum•mit.edu>
> ---
>  sha1_file.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/sha1_file.c b/sha1_file.c
> index dcfd35a..abcb56b 100644
> --- a/sha1_file.c
> +++ b/sha1_file.c
> @@ -108,6 +108,7 @@ int mkdir_in_gitdir(const char *path)
>  int safe_create_leading_directories(char *path)
>  {
>  	char *next_component = path + offset_1st_component(path);
> +	int attempts = 3;
>  	int retval = 0;
>  
>  	while (!retval && next_component) {
> @@ -132,6 +133,16 @@ int safe_create_leading_directories(char *path)
>  			if (errno == EEXIST &&
>  			    !stat(path, &st) && S_ISDIR(st.st_mode)) {
>  				; /* somebody created it since we checked */
> +			} else if (errno == ENOENT && --attempts) {
> +				/*
> +				 * Either mkdir() failed bacause

s/bacause/because/

> +				 * somebody just pruned the containing
> +				 * directory, or stat() failed because
> +				 * the file that was in our way was
> +				 * just removed.  Either way, try
> +				 * again from the beginning:
> +				 */
> +				next_component = path + offset_1st_component(path);
>  			} else {
>  				retval = -1;
>  			}
> 

ATB,
Ramsay Jones

  reply	other threads:[~2013-12-22 22:43 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-22  7:14 [PATCH 0/5] Fix two mkdir/rmdir races Michael Haggerty
2013-12-22  7:14 ` [PATCH 1/5] safe_create_leading_directories(): modernize format of "if" chaining Michael Haggerty
2013-12-26 21:52   ` Jonathan Nieder
2013-12-22  7:14 ` [PATCH 2/5] safe_create_leading_directories(): reduce scope of local variable Michael Haggerty
2013-12-26 21:55   ` Jonathan Nieder
2014-01-01 12:39     ` Michael Haggerty
2013-12-22  7:14 ` [PATCH 3/5] safe_create_leading_directories(): add "slash" pointer Michael Haggerty
2013-12-26 22:34   ` Jonathan Nieder
2014-01-01 21:10     ` Michael Haggerty
2013-12-22  7:14 ` [PATCH 4/5] safe_create_leading_directories(): fix a mkdir/rmdir race Michael Haggerty
2013-12-22 22:42   ` Ramsay Jones [this message]
2013-12-26 23:02   ` Jonathan Nieder
2014-01-02  0:53     ` Michael Haggerty
2013-12-22  7:14 ` [PATCH 5/5] rename_ref(): fix a mkdir()/rmdir() race Michael Haggerty
2013-12-26 23:20   ` Jonathan Nieder

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